Production cycle: duration of the production cycle, components, calculation. Production cycle How to find the production cycle
Under The duration of the production cycle of a batch of products is understood as the period of time during which blanks (basic materials) are transformed into finished parts .
The duration of the production cycle is one of the main indicators, which allows us to evaluate the organizational and technical level of production and determine the timing of the launch and release of products in conditions of single and serial production.
The amount of work in progress, which occupies a significant share in the composition, largely depends on the duration of the production cycle. working capital enterprises. Reducing work in progress leads to an acceleration of the turnover of working capital, which is of great importance economic importance for enterprise economics.
Let us introduce a number of more concepts.
An operating cycle is the time it takes to process a batch of parts in a specific operation.
The technological cycle is the time associated directly with the processing of a batch of parts at all operations of the technological process.
Considering that the duration of technological operations is standardized in most cases, the duration of the technological cycle can be calculated quite accurately. The time for performing auxiliary operations (control and transport) and laying down parts during the production process, as a rule, is not standardized, so their value is determined approximately taking into account the conditions of execution in the workshops of a machine-building enterprise.
Breaks associated with the accepted operating mode in the workshop are taken into account when the duration of the production cycle is determined in days (calendar or working).
The duration of the technological cycle for processing one batch of parts depends on the type of movement in production. There are three main (typical) types of movement of a batch of parts: sequential, parallel and parallel-sequential.
Sequential type of movement batches of parts for operations is characterized by the fact that a batch of parts is transferred to a subsequent operation after it has been completely processed in the previous operation. (TC AFTER)
TC PAST = p x , (1.1)
Where n – number of parts in the batch;
T- number of operations in the technological process;
ti- piece time i-th operations;
Ci– the number of parallel working machines (workstations) per operation.
In all cases ti should be determined taking into account the percentage of time standards fulfilled by workers.
Magnitude Shopping center does not include the time of breaks, preparatory and final time and the time of auxiliary operations, therefore it is always less than the actual duration of the production cycle of a batch of parts. The batch size of processed parts is assumed to be the same for all operations, although this condition is sometimes not met in practice.
Parallel-sequential type of movement of a batch of parts operations are characterized by the following characteristics:
1. The transfer of a batch of parts from operation to operation is carried out individually or in parts (transfer batches);
2. The start of processing a batch of parts at each operation is planned in such a way as to ensure continuity of processing of the entire batch at the operation;
3. Parallel processing of a batch of parts in separate operations is ensured.
The duration of the technological cycle for processing a batch of parts with this type of movement in operations (TC PP) will be determined by the formula
Tc PP = n x – (n-p) x , (1.2)
Where R – number of parts in the transfer batch.
Parallel view of the movement of a batch of parts operations are characterized by two characteristics:
1. The transfer of a batch of parts from operation to operation is carried out piece by piece or in transfer batches;
2. Each transfer batch enters processing at the subsequent operation immediately after its processing at the previous operation, i.e. Each transfer batch is processed for all operations continuously and independently of the other transfer batches.
The duration of the technological cycle for processing a batch of parts with this type of movement in operations (TC PAR) determined by the formula
TC PAR = p x + (n-p) x m ax (1.3)
From the formula it follows that the greatest influence on the value TC PAR with parallel processing, the “leading” operation has the effect, i.e. operation with the longest operating cycle. In all operations (with the exception of the “leading”), breaks occur between the end of processing of the previous one and the beginning of processing of the next transfer batch, if the durations of the operations are not equal or multiples.
Problems with solutions
Task 1.1. Determine the duration of the technological cycle for processing a batch of 100 parts with sequential, parallel and parallel-sequential types of movement of workpieces during the production process. Parts for complex types of movement are transferred from operation to operation in transfer batches of 20 pieces.
The technological process of processing a part includes 5 operations with a duration of t 1 = 2 min. , t 2 = 6 min. , t 3 = 5 min. , t 4 = 12 min. , t 5 = 5 min. In the second operation two machines are used, the fourth operation is performed in three machines, in the remaining operations one machine is operated.
Construct movement schedules for a batch of parts for each type of movement.
Solution
The duration of the technological cycle for processing a batch of parts will be:
TC AFTER = p x = 100 x 
= 1900 min;
TC PP = p x - (n-p) x = 1900 – (100-20) x
X 
= 860 min;
TC PAR = p x + (n-p) x m ax = 20 x +
+ (100-20) x = 780 min.
The movement schedules for a batch of parts for each type of movement will look like:
| m | |||||||||||||
0 200 400 600 800 1000 1200 1400 1600 Hz (min)
Rice. 1.1. Schedule of sequential movement of a batch of parts by operation
The construction of a schedule for the parallel-sequential type of movement of a batch of parts through operations depends on the ratio of the duration of the operating cycles of related operations. If the duration of the operating cycle at the subsequent operation is longer than at the previous one, then processing of the batch of parts at the subsequent operation begins after receiving the first transfer batch from the previous operation.
If the duration of the operating cycle at a subsequent operation is less than at the previous one, then the processing of a batch of parts at the subsequent operation is based on the moment of receipt of the last transfer batch from the previous operation. In this case, relative to this moment in the subsequent operation, the processing time of one transfer batch (the last one) is shown to the right, and the processing time of the remaining transfer batches is shown to the left.
| m | |||||||||||||||||||||||||||
0 200 400 600 800 Hz (min)
Rice. 1.2. Parallel-sequential movement schedule of a batch of parts
The procedure for constructing a graph with a parallel type of movement of a batch of parts by operation is as follows: first, a graph is constructed for one transfer batch, as with a sequential type of movement, and then, relative to the operation with the maximum operating cycle, a graph for the remaining transfer batches is similarly constructed.
| m | ||||||||||||||||||
0 200 400 600 800 Hz (min)
Rice. 1.3. Parallel movement schedule of a batch of parts
Problem 1.2. Determine the duration of the production cycle for sequential, parallel-sequential and parallel types of movement. Indicate the possible timing of launching the entire batch into production for these types of movement.
The size of the processed batch is 500 pcs., the transfer batch is 50 pcs., the release date of the entire batch of parts is September 1st. Production operates in two 8-hour shifts with two days off. The time limits for operations are as follows:
Time associated with transportation and inter-operational care, take 10 % on the duration of the technological cycle.
Solution
1. The duration of the technological cycle for processing a batch of parts will be:
a) with a sequential type of movement
TC AFTER = 500 x 
= 1100 hours;
b) with a parallel-sequential type of movement
TC PP = 1100 – (500-50) x 
= 560 hours;
c) with a parallel type of movement
TC PAR = 50 x + (500-50) x = 470 hours.
2. Duration of the production cycle for processing a batch of parts (tpc) in hours will be:
a) with a sequential type of movement
Tpts LAST = 1100 x 1.1 = 1210 hours;
b) with a parallel-sequential type of movement
Tpts PP = 560 x 1.1 = 616 hours;
c) with a parallel type of movement
Tpts PAR = 470 x 1.1 = 517 hours.
3. The duration of the production cycle for processing a batch of parts in working days will be:
a) with a sequential type of movement
Tpts AFTER = 1210: 16 = 75.6 days, we accept 76 working days;
b) with a parallel-sequential type of movement
TPC PP = 616: 16 = 38.5 days, we accept 39 working days;
c) with a parallel type of movement
Tpts PAR = 517: 16 = 32.3 days, accept 33 working days
4. The launch period, taking into account the operating mode of the enterprise according to the 2003 calendar, will be:
Problem 1.3. Determine the duration of the production cycle for a sequential type of movement with the following initial data:
· total time of operational cycles in operations – 840 minutes;
· preparatory and final time for a batch of parts in all operations – 60 minutes;
· time associated with moving and storing a batch of parts – 420 minutes;
· the coefficient of compliance with standards on the site is 1.2.
Solution
Tpts LAST = + 60 + 420 = 1180 min.
Problem 1.4. A mechanism consisting of two units and three parts is assembled. The mechanism assembly diagram is shown in Fig. 1.4.
| M | |||||||||||||||||||||||
| SB-1 | SB-2 | ||||||||||||||||||||||
| D-11 | D-12 | D-21 | D-22 | D-23 | D-1 | D 2 | D-3 | ||||||||||||||||
Rice. 1.4. Mechanism assembly diagram
The duration of the cycles is as follows:
The duration of production cycles for assembling units is as follows:
Determine the total duration of production of assembly units and the mechanism M as a whole.
Solution
If the production of parts and assembly of components will be carried out in parallel, the production time will be assembly unit 1 will be 7 days, assembly unit 2 - 7 days, mechanism M as a whole - 12 days.
Individual assignment on topic I:
“Determination of the duration of the production cycle of processing
batch of parts."
Exercise. Batch needs to be processed "n" details. Workpieces are transferred from operation to operation in transfer batches equal to "p" details. The technological process of processing a part consists of 6 operations with a duration t 1, t 2, …, t 6. In the second and fifth operations, two machines are used, the fourth operation is performed on three machines, in the remaining operations one machine is used. Lot size of parts "n", transfer batch "p" , duration of each operation of the technological process "t" are taken from the tables given in Appendix 1 in accordance with the individual code.
Define:
a/ the duration of the technological cycle for processing a batch of parts with sequential, parallel-sequential and parallel types of movement;
b/ build processing schedules for a batch of parts by type of movement;
Production cycle- one of the most important indicators, which is the basis for calculating many other indicators of the production and economic activity of an enterprise. For example, on the basis of the production cycle, the timing of launching products into production is established, the capacity of production units is calculated, the volume of unfinished construction and some other indicators are determined.
A production cycle is a calendar period of time during which a product or batch of products being processed undergoes all operations. production process or a certain part of it and turn into a completed product.
The calendar time interval from the beginning of the first production operation to the end of the last is called the duration of the production cycle in time, which is measured in days, hours, minutes depending on the type of product and the stage of processing.
The production cycle includes:
When performing technological operations- the main component of the production cycle, which is necessary to carry out specific work operations to transform the subject of labor into finished products. Preparatory and final time is allocated to the worker to familiarize himself with the delivery and to hand over the finished product. The duration of the operating cycle consists of the time it takes to complete a technological operation and the preparatory and final time, that is, the duration of the operating cycle is the processing time of one batch of parts for a specific operation of the technological cycle.
The duration of natural processes is determined by the characteristics of the technology (this is the time of concrete hardening, metal cooling, etc.), that is, natural processes are characterized only by the cost of time.
The duration of service processes consists of the time for performing control operations, warehouse and transport (including loading and unloading) operations. The totality of all components of the production process forms its working period.
Part of the production cycle is a break, consisting of inter-operational and inter-shift breaks.
Interoperative breaks form:
Breaks between batches occur when processing a batch of parts, because not all parts are processed at the same time. These interruptions can be reduced by reducing the volume of transport batches of parts, but this requires a certain increase in the costs of transporting parts between workplaces;
Waiting breaks - occur when the progress of a technological process is disrupted, when the previous technological operation has already ended, and workplace at the next operation has not yet been freed from performing certain work;
Picking interruptions occur during assembly operations when not all parts are received at the assembly site.
Inter-shift break (for lunch, weekends and holidays, between changes) is integral integral part production process.
The duration of production niklu (TV) is determined by the formula
where TOC is the duration of the operating cycle;
Tpr - duration of natural processes;
Tobsl - duration of servicing processes;
Tper is the time of mid-operational and inter-shift breaks.
The duration of the production cycle covers three stages:
Process equipment time;
Time Maintenance production;
Duration of the break.
The duration of the production cycle depends on:
The duration of working hours required for production of products;
Batch size;
duration of breaks in the production process;
The duration of operations not directly related to the production process.
The time for performing the main operations of processing a product is a technological cycle, which means the time during which the object of labor is processed. The length of the working period is influenced by a number of factors, the main of which are:
Quality of design and construction work;
level of product standardization;
Organizational factors.
Technological maintenance time includes quality control of product processing, control of the operating mode of machines and equipment, cleaning of the workplace, time of delivery of parts to the workplace.
Break time is the time during which the quality characteristics of the product change, but the product is not yet ready and the production process is not completed. There are regulated and unregulated breaks.
The company distinguishes the following types of breaks:
Intershift, which depend on the operating mode of the enterprise, the number of changes, as well as the number of holidays and weekends
Waiting breaks associated with equipment loading;
Interruptions of partitioning that occur when processing parts in batches;
Interruptions caused by imperfect organization of production and unforeseen circumstances (power outages, equipment failures, etc.).
The structure of the production cycle is presented in Fig. 19.3. The main component of the production cycle is the duration of technological operations, which constitutes the technological cycle.
As already noted, during the transformation of objects of labor into a specific product, they pass through many basic, auxiliary, etc. servicing processes occurring in parallel, parallel-sequentially or sequentially in time, depending on the prevailing situation at the enterprise production structure, type of production, level of specialization of production units, forms of organization of production processes and other factors. The set of these processes that ensure the manufacture of a product is usually called the production cycle, the main characteristics of which are its duration and structure.
The duration of the production cycle for manufacturing products is the calendar period of time during which raw materials, basic materials, semi-finished products and finished components are transformed into finished products. In other words, this is the period of time from the start of the production process to the moment of release finished product or a batch of parts, assembly units. Production cycle times are usually expressed in calendar days or hours.
Knowing the duration of the production cycle for the manufacture of all types of products is necessary for:
Drawing up a production program for the enterprise and its divisions;
Determining the timing of the start of the production process based on the timing of its completion;
Calculation of the normal value of work in progress.
The structure and duration of the production cycle depend on the type of production, the level of organization of the production process and other factors. Mechanical engineering products are characterized by a high proportion of technological operations in the total duration of the production cycle. Reducing the latter is of great economic importance. As a rule, the duration of the production cycle is determined for one part, a batch of parts, one assembly unit or batch of units, one product. It should be borne in mind that a product is any item or set of items that is to be manufactured at an enterprise or in its divisions.
When calculating the duration of the production cycle for manufacturing a product, only those time costs for transport and control operations, natural processes and breaks are taken into account, which do not overlap with the operating cycle.
Reducing production cycle times is of great economic importance. The shorter the duration of the production cycle, the more products per unit of time, other things being equal, can be produced at this enterprise, in the workshop or on the site; the higher the use of fixed assets of the enterprise; the lower the enterprise’s need for working capital invested in work in progress, the higher the capital productivity, etc.
Rice. 19.3. Production cycle structure
The technological cycle for processing a batch of items in one operation is equal to
where Tm is the technological cycle in time units, minutes
n - number of items in the batch;
t - duration of processing of one item;
M is the number of workstations at which the operation is performed.
When calculating the duration of a technological cycle, it is necessary to take into account the peculiarities of the movement of objects of labor across operations. The enterprise uses one of the following types of movement:
Consistent;
Parallel;
Parallel-serial (mixed, combined).
In practice industrial enterprises The production cycle is reduced simultaneously in three directions:
Time decreases labor processes;
The time of natural processes is reduced;
Interruptions of all types are completely eliminated or minimized.
Practical measures to reduce the production cycle follow from the principles of constructing the production process and, above all, from the principles of proportionality, parallelism, continuity, straight-precision, rhythm, etc.
Proportionality is a principle, the implementation of which ensures equal throughput of different workplaces of the same process, proportional provision of workplaces with information, material resources, personnel, etc. Proportionality is determined by the formula
Reducing the time of labor processes in terms of operating cycles is achieved by improving technological processes, as well as increasing the manufacturability of the product design.
The improvement of technological processes means their comprehensive mechanization and automation, the introduction of high-speed modes (for example, high-speed and power cutting, high-speed heating for forging and stamping), stamping instead of free forging, chill casting and injection molding instead of sand casting, as well as concentration of operations. The latter may consist in multi-tool and multi-item processing or in the submission of several different technological operations in one working cycle (for example, combining high-speed induction heating with stamping of a workpiece in one working cycle of a forging machine).
Increasing the manufacturability of product designs lies in bringing the latter as close as possible to the requirements of the technological process. In particular, the rational division of the product design into components and small assembly units is an important condition for their parallel compilation, and, consequently, for reducing the duration of the production cycle of assembly work.
The duration of transport operations can be significantly reduced as a result of redesigning equipment based on the principle of direct flow, mechanization and automation of lifting and moving products using various lifting and transport vehicles.
Reducing the time of control operations is achieved through their mechanization and automation, the introduction of advanced control methods, and a combination of time for performing technological and control operations. The time for preparatory and final work and setup time are also included in the cycle structure and are also subject to reduction. Equipment adjustment is usually carried out during non-working shifts, during lunch and other breaks. In factory practice, measures are successfully used to reduce the period of completion of this work, for example, the introduction of group processing of parts, standard and universal settings. The duration of natural processes is reduced by replacing them with appropriate technological operations. For example, natural drying of some painted parts can be replaced by induction drying in a high-frequency current field with a significant (5-7 times) acceleration of the process. Instead of natural aging of castings of critical parts, it lasts 10-15 days or more; in many cases, artificial aging can be used in thermal furnaces for several hours.
The time of interoperational breaks can be significantly reduced as a result of the transition from sequential to serial-parallel and then to parallel type of movement of objects of labor. It can also be reduced by organizing workshops and areas based on subject specialization. By ensuring the territorial proximity of the various stages of production, the subject form of constructing workshops and sections makes it possible to significantly simplify intra-factory and intra-shop traffic routes and thereby reduce the time spent on inter-shop and intra-shop transfers. Finally, the amount of breaks between shifts can be reduced even within the accepted operating mode of an enterprise, workshop, or site. For example, the organization of round-the-clock (three-shift *) work on the production of leading parts and products that have a long processing cycle determines the duration of the product cycle. To reveal reserves for shortening the production cycle (both labor processes and breaks), in practice the production cycle is photographed. By analyzing photographs, it is possible to identify reserves for reducing the duration of the production cycle for each of its elements.
The production cycle of a complex (assembly) process is the total duration of a complex of simple processes coordinated in time that are part of the complex process of manufacturing a product or its batches.
In conditions engineering production most typical examples complex processes are the processes of creating a machine, a metal-cutting machine or units, blocks, small units of which they consist.
The production cycle of a complex process includes production cycles for the manufacture of all parts, assembly of all assembly units, general assembly of the product, control, regulation and adjustment. In a complex production process, all considered types of movement of objects of labor through operations can be used: sequential, series-parallel and parallel. For the conditions for including unit production in a single cycle, as a rule, not only the manufacturing and assembly processes are necessary, but also the processes of product design and preparation for its production.
A complex production process usually consists of a large number of assembly, installation, adjustment and adjustment operations, operations of simple processes, therefore, determining and optimizing the production cycle requires not only a lot of time, but also often the use of a computer to perform calculations. The construction of a complex production process over time is carried out in order to determine the duration of the production cycle, coordinate the implementation of individual simple processes, obtain the necessary information for operational scheduling and calculation of the operation of launching and releasing items of labor. The purpose of coordinating production processes that make up a complex process is to ensure the completeness and uninterrupted flow of production when equipment, workplaces and workers are fully loaded.
The structure of the production cycle of a complex process is determined by the composition of operations and the connections between them. The composition of operations depends on the range of parts, assembly units and technological processes for their manufacture. The interrelation of operations and processes is determined by the fan-shaped assembly pattern of the product and its manufacturing technology. The fan-shaped diagram of product assembly shows which nodes, subassemblies or small assembly units can be manufactured in parallel, independently of each other, and which can only be manufactured sequentially.
Calculation of the production cycle duration of a complex process must be carried out in the following sequence:
determine the batch size of products;
It is planned to calculate the convenience of the rhythm;
Determine the operating cycle time of a batch of products;
Determine the number of jobs required for the manufacture of products;
Construct a cycle schedule for the assembly of products without taking into account the workload;
Consolidate operations at work stations;
Draw up a standard product assembly plan;
Construct an updated cycle schedule taking into account the workload;
Determine the duration of the production cycle and the advance of launch-release of assembly units and parts.
When deciding on the size of a batch, it is necessary to proceed from the economically optimal size. Working in large batches allows you to implement the principles of batching, which ensures:
a) the possibility of using a more productive process, which reduces the cost of manufacturing products;
b) reduction of preparatory and final time per unit of production;
c) reducing the time lost by assembly workers to master work techniques (adaptation to work)
d) simplification of production scheduling.
These factors contribute to increasing worker productivity and reducing production costs.
However, in single and serial production, where each workplace is assigned to perform several operations and where the sequential type of movement of objects of labor predominates, as the batch size increases, the degree of violation of the principle of continuity increases, since the holding time of each assembly unit increases, that is, the duration of the production cycle increases batches of products, the number of assembly units in production and storage (work in progress). In addition, there is an increasing need for storage space for products and material assets that are simultaneously necessary for production.
These and opposing factors associated with the implementation of one principle (party system) and the violation of another (continuity) require determining the size of the party at which the savings from the implementation of the first principle and losses from the violation of the other would be the most rational from an economic point of view. This batch size is usually called economically optimal.
Determining the optimal size of a batch of products is one of the most important schedule standards for organizing mass production, since all other schedule standards are established for a batch of items of labor.
Many formulas for calculating the optimal size of product batches, based on a comparison of savings and losses, have been proposed by various authors. However, due to the high complexity of calculations, these formulas are not widely used. Industrial enterprises usually use a simplified calculation method based on the acceptable coefficient of loss of working time for changeover and Maintenance jobs (αppr). As a rule, the size of this coefficient is taken in the range from 0.02 for large-scale and up to 0.1 for small-scale and single production (or from 2 to 10%). Asking for certain production conditions size given coefficientαper you can determine the number of products in a batch using the formula
where tpi is the preparatory and final time for technological process operations.
The result obtained is considered as the minimum size of the batch of products. Based on the maximum value, a monthly program for the production of products (assembly units) can be adopted. Thus, as a result of the calculations, we establish the limits of the normal size of a batch of products:
Limit sizes for product batches are adjusted based on minimum size. The adjustment begins with the establishment of a rhythm convenient for planning (Rr) - the period for alternating batches of products. If there are 20 working days in a month, then convenient rhythms for planning will be 20,10, 5,4, 2 and 1; if there are 21 days in a month, then such rhythms will be 21, 7, 3 and 1; if 22 days, then 22 11,2 and 1.
The period of alternation of batches of products is calculated by the formula
where Dr is the number of working days in a month.
If the calculation results in a fractional number, then the nearest whole number is selected from a number of rhythms convenient for planning, that is, the accepted value of the duty period.
The normal batch size of products should be a multiple of the monthly product release (launch) program.
The number of batches per month is determined by the formula
The duration of the operating cycle of a batch of products for each operation is calculated using the formula
The duration of the operating cycle of a batch of products by assembly units is determined by the formula
where K is the number of operations included in the assembly unit.
The required number of jobs for assembling products is calculated using the formula
If the calculated value of the number of workplaces is a fractional value, then it is necessary to adjust it upward or downward, taking into account the fact that each workplace can be overloaded by no more than 5%.
The required number of workers is determined by the formula
where Ksn is a coefficient taking into account the accounting number (usually taken equal to 1.1).
The construction of a cyclic schedule for assembling a product without taking into account workloads is carried out on the basis of a fan assembly scheme and the duration of assembly cycles for each i-th operation and each assembly unit. As a rule, such a schedule is constructed in reverse order of the technological process, starting with the last operation, taking into account the operation for which assembly units are supplied. The cycle time of this schedule will be minimal. However, production conditions and limited resources require fulfillment certain works sequentially, at the same workplace, stand. All this leads to changes in the cycle schedule and, as a rule, to a shift in launch to earlier dates, and as a result - to an increase in the cycle duration.
To achieve uniform loading of workplaces and assembly workers, it is necessary to consolidate operations at workplaces. For this purpose, a volume of work is collected for each workplace, the duration of the operating cycle of which should not exceed the throughput of the workplaces during a reasonable period of duty.
Construction of a standard product assembly plan (cyclic schedule taking into account workload). The schedule is constructed without taking into account the workload of workplaces and data on the assignment of operations to workplaces. In this case, the periods of execution of cycles of individual operations of the schedule must be projected onto the corresponding workplaces on the product assembly cycle schedule without taking into account the workload of workplaces. In this case, the duration of the production cycle is maintained on the graph constructed without taking into account the workload. However, this is not always possible. Shifting work to an earlier period of time will lead to an increase in the duration of the production cycle and the appearance of delayed assembly units. On the same schedule it is necessary to show the production of the second, third and subsequent batches of products until one duty period of batches of products is completely filled. The completed rotation period represents a standard plan, since it is here that the standard, repeating timing of individual addition operations by each assembly worker is shown.
Next, a refined cycle schedule for assembling the product is constructed and the actual duration of the production cycle is determined, usually slightly more than the minimum, since the implementation of some operations is shifted to earlier dates.
The updated product assembly schedule is built on the basis of already constructed standard product assembly plans without taking into account and taking into account the workload, the shift time of the launch of the corresponding assembly units, and from this schedule the actual duration of the production cycle for assembling a batch of products is determined.
Non-state educational institution of higher professional education
"Russian-British Institute of Management"
Faculty of Correspondence Studies
Course work
in the discipline "Production Management"
topic "Production cycle"
Direction 080500.62 Management
The work was carried out by student F.F. Yakhin
The work was checked by R.Sh. Zakirov
Chelyabinsk-2012
INTRODUCTION
PRODUCTION CYCLE OF PRODUCTS (WORKS, SERVICES)
1 The concept of the production cycle, its duration and structure
2 Methods for calculating the production cycle
3 Economic function of the production cycle, ways to improve its efficiency
2. Calculation of the production cycle using the example of the production of self-adhesive tape (adhesive tape)
1 Characteristics of Polymir LLC
2 Calculation of the production cycle for the production of self-adhesive tape (adhesive tape)
3 Ways to improve production organization
CONCLUSION
BIBLIOGRAPHY
Applications
INTRODUCTION
For the success of economic reforms carried out in Russia, changes in various areas of management are extremely important. There is a change in the socio-economic system; New requirements for enterprise management arise, put forward by market relations. Russian enterprises began to pay more attention to the organization of production, the formation of structures that ensure a clear division of work, control of implementation and stimulation of performers for the result of their work.
The production process is a set of individual labor processes aimed at transforming raw materials into finished products. The content of the production process has a decisive impact on the construction of the enterprise and its production units. The production process is the basis of any enterprise.
The production cycle is one of the constituent elements of the technological process and is used as a standard for operational planning production, financial management and other production planning calculations. The duration of the production cycle is also influenced by the forms of technological specialization of production units, the system of organization of the production processes themselves, the progressiveness of the technology used and the level of unification of manufactured products.
The duration of the production cycle is established and regulated both as a whole for all products (including their constituent elements), and separately for each element. Without a thorough analysis of the production cycle, it is impossible to say about the effectiveness of this production.
This topic is of particular relevance for enterprises engaged in the production of products (works, services), since at the stage of free market economy, production, like the product, must be competitive.
The purpose of the work is to consider the production cycle, its structure and ways to improve efficiency.
To address the topic, the following tasks were set and solved:
· study the production cycle;
· analyze existing methods for calculating the production cycle;
· consider one of the methods for calculating the production cycle using the example of Polymir LLC;
· formulate ways to improve the organization of production.
The object of this study is Polymir LLC, the subject of the study is the production cycle of adhesive tape.
1. PRODUCTION CYCLE OF PRODUCTS (WORKS, SERVICES)
1.1 The concept of the production cycle, its duration and structure
production cycle of self-adhesive tape
To measure the process of manufacturing a product over time, the indicator is used - production cycle. The production cycle is one of the most important technical economic indicators, which is the starting point for calculating many indicators of the production and economic activity of an enterprise. On its basis, for example, the timing of launching a product into production is established, taking into account the timing of its release, the capacity of production units is calculated, the volume of work in progress is determined, and other production planning calculations are carried out.
The production cycle of a product (batch) is the calendar period during which it is in production from launch starting materials and semi-finished products into main production until the finished product (batch) is received.
In the production conditions of a product consisting of many parts, a distinction is made between the cycle of manufacturing a product or product and the cycle of manufacturing parts or performing a group of operations. Shortening the cycle makes it possible for each production unit (shop, site) to complete a given program with a smaller volume of work in progress. This means that the company gets the opportunity to accelerate the turnover of working capital, fulfill established plan with less expenditure of these funds, free up part of the working capital.
The production cycle consists of two parts: the working period, that is, the period during which the object of labor is directly in the manufacturing process, and the time of breaks in this process.
The working period consists of the time for performing technological and non-technological operations; the latter include all control and transport operations from the moment the first production operation is performed until the delivery of the finished product.
The production cycle T c can be expressed by the formula:
T c = T vrp + T vrp, (1)
where T vrp is the time of the work process;
T vpr - time of breaks.
During the working period, technological operations are performed:
T vrp = T shk + T k + T tr + T e, (2)
where T shk - piece-calculation time;
Tk - time of control operations;
T tr - time of transportation of objects of labor;
T e - time of natural processes (aging, relaxation, natural drying, sedimentation of suspensions in liquids, etc.).
The sum of the times for piece work, control operations, and transportation is called operational time (T def):
T def = T shk + T k + T tr.(3)
In the operating cycle, the time of control operations T k and the time of transportation of objects of labor T tr are included conditionally, since organizationally they do not differ from technological operations.
T shk = T op + T pz + T en + T oto, (4)
where T op - operational time;
T pz - preparatory and final time when processing a new batch of parts;
T en - time for rest and natural needs of workers;
T oto - time for organizational and maintenance (receipt and delivery of tools, cleaning the workplace, lubrication of equipment, etc.).
Operating time T op in turn consists of the main T os and auxiliary time T in:
T op = T os + T v. (5)
Prime time is the actual time it takes to process or complete a job.
Auxiliary time expressed by the formula:
T in = T y + T z + T ok, (6)
where T y is the time for installing and removing a part (assembly unit) from the equipment;
T s - time of fastening and unfastening the part in the device;
Tok is the time of operational control of the worker (with equipment stopping) during the operation.
T vpr = T mo + T rt + T r + T org.(7)
The interoperational holding time T mo is determined by the time of batching breaks T pairs, waiting breaks T oz and acquisition breaks T kp, that is:
T mo = T steam + T cool + T cp.(8)
Interruptions in batching T pairs occur when products are manufactured in batches and are caused by the storage of processed parts until all parts in the batch are ready for the technological operation.
Waiting breaks are also caused by inconsistent durations of adjacent technological process operations.
Breaks in TKP acquisition occur during the transition from one phase of the production process to another.
Thus, in general view The production cycle is expressed by the formula:
T c = T def + T e + T mo + T rt + T r + T org.(9)
When calculating the production cycle, it is necessary to take into account the overlap of some time elements either with technological time or with interoperational holding time. The transportation time of labor items T tr and the time of selective quality control T k are overlapping elements.
Based on the above, the production cycle can be expressed by the formula:
T c = (T shk + T mo) k per kor + T e, (10)
where k per is the coefficient of conversion of working days to calendar days (the ratio of the number of calendar days (D k) to the number of working days in a year (D r), k per p = D k / D r);
k or - a coefficient that takes into account breaks for equipment maintenance between repairs and organizational problems (usually 1.15-1.2).
Based on the above, the following conclusions can be drawn. The duration of the production cycle is expressed in calendar days or hours. The duration of the production cycle depends on the labor intensity of the products, the level of equipment and technology, mechanization and automation of production processes, operating mode, organization of planning and logistics.
When calculating the duration of the production cycle, only those time costs are taken into account that are not covered by the time of technological operations (for example, time spent on control, transporting products). Breaks caused by organizational and technical problems (untimely provision of the workplace with materials, tools, violation labor discipline etc.) are not taken into account when calculating the planned production cycle duration.
.2 Methods for calculating the production cycle
There are simple (product manufacturing cycle) and complex (product manufacturing cycle) production cycles. The methods for determining the duration of the production cycle for these two cases are different.
At simple process, the duration of the production cycle consists of the operating cycle and the total time of interoperational breaks:
T c = T oc + T mo. (11)
The operating cycle is expressed in technological time per batch of items:
where: n - number of items in the batch; 0 - number of processing operations according to the technical process; j - piece-calculation (operational) time for the jth operation.
The total time of interoperational breaks is determined by the formula:
(13)
where t moj is the standard for non-overlapping interoperational time.
Thus, for a batch of items, the duration of the production cycle will be expressed by the formula:
(14)
Difficult process- the process of manufacturing a product or assembly unit - includes simple processes for manufacturing blanks and parts, processes for assembling individual assembly units (unit assembly), units (aggregate assembly), the device as a whole (general assembly), as well as finishing, adjustment, and configuration operations , tests.
For the manufacture of the specified parts of the product, corresponding sets of parallel partial production processes with their cycles are formed, which together constitute cycles of production stages (procurement, machining, assembly, etc.).
The total duration of the complex of these time-coordinated partial processes represents the production cycle of the complex process. The purpose of coordinating the processes that make up a complex process is to ensure the completeness and uninterrupted flow of production when equipment and workers are fully loaded.
As a result of coordination, a certain combination of a number of simple processes in a complex one is achieved, characterized by a parallelism coefficient:
(15)
where T c sl is the duration of the production cycle of a complex process;
T c prj - the duration of the production cycle of the j-th partial process included in the complex production cycle; - the number of partial processes.
Scheduling the production cycle of a complex process with a large number of partial processes is a complex task. The complexity of solving this problem increases many times over when planning the production of several products in the same period. In this case, it is necessary to decide: in what order, in which workshops and areas, at which workplaces, and within what time frames parts of the product should be launched, processed and assembled.
The duration of the production cycle largely depends on the size of interoperational breaks. In turn, the duration of interoperational breaks is greatly influenced by the method of transferring processed parts between operations, which determines the degree of combination of adjacent operations in time when processing batches of parts. The method of combining related operations in time is called the type of movement of objects of labor in the production process.
When calculating the duration of the production cycle, it is necessary to take into account the peculiarities of the movement of the subject of labor through the operations existing in the enterprise. Typically one of three types is used: serial, parallel, parallel-serial.
With a sequential type of movement a batch of n parts is completely transferred to the subsequent operation after finishing its processing at the previous operation. A graph of the sequential type of movement is presented in Appendix B.
The graph shows that for a production process consisting of K 0 operations, the duration of the production cycle is determined by the sum of single-operation cycles:
(16)
Since a number of operations can be performed not at one, but at several workplaces, the duration of the production cycle with sequential movement in the general case has the form:
(17)
where Ci is the number of jobs.
From an organizational point of view, this type of movement has some advantages: there are no interoperational breaks, batches of products are not split, therefore the number of planning and accounting units is small, and the pace of transportation is low. However, with large batches, the resulting long cycles lead to a deterioration in the economic performance of production. Difficulties arise in meeting strict deadlines for the completion and start of related operations.
A sequential type of movement is used in single and small-scale production, and to a limited extent in mass production.
With parallel movement the transfer of items from the previous operation to the next is carried out individually or in partial transport batches p, multiples of the whole batch n. A schedule for this type of movement is presented in Appendix B.
The graph highlights the most labor-intensive operation, called the “main” one:
(18)
The duration of the production cycle consists of three processing duration zones: p items in operations preceding the “main” one; the entire batch of items on the "main"; p items in operations following the “main”:
Where T c steam is the cycle time for parallel movement, hours;
P - the number of items in operations preceding the “main”, the entire batch of items in the “main”, items in operations following the “main”, pcs.;
t - time of operations preceding the “main”, time of the “main”, time of the operations following the “main”, hours;
Isolating the total complexity of processing a partial batch into an independent term, we obtain:
(20)
With parallel movement, the transfer of objects of labor to the subsequent operation is carried out individually or in a transport batch immediately after processing in the previous operation:
(21)
where p is the size of the transport lot, pcs; hl - time to perform the longest operation, min; C max - number of jobs in the longest operation.
The production cycle duration can be defined as the difference between the cycle duration for a sequential type of movement and the total time savings compared to a sequential type of movement, due to the partial overlap of the execution time of each pair of adjacent operations:
T C (PARAL-SEQUAL) = T C (SEQUIRE) -- STK OP (22)
With the parallel type of movement, the shortest production cycle takes place, and the parts do not lie waiting for processing. At the same time, in all operations, except the first and main ones, there is downtime of equipment and workers (micro-pauses) due to the disproportionality of the process. The number of planning and accounting units increases compared to the sequential type of movement. Elimination or reduction of downtime can be achieved by complete or partial synchronization of process operations.
A parallel type of movement is used in mass continuous flow production.
The need to equalize (synchronize) the duration of individual operations significantly limits the possibility of widespread use of parallel type of movement, which promotes the use of the third - parallel-sequential type of movement of objects of labor.
With a parallel-sequential type of movement transfer of items between operations is also carried out in partial batches or individually. In this case, the start of processing items in the subsequent operation is shifted in such a way as to eliminate equipment downtime. A schedule for this type of movement is presented in Appendix B.
The offsets of the beginnings of subsequent operations depend on the ratio of the operating time of adjacent operations. The magnitude of this displacement can be determined by the following rule:
t q j, j+1 = (n - p) t j .(23)
if t j< t j + 1 , то начало (j + 1)-й операции сдвигается вправо относительно начала jth operation for the partial cycle of the jth operation pt j . In this case, the amount of parallel combination of related operations (i.e., reducing the duration of the production cycle) will be equal to
if t j t j + 1, then the end of the (j + 1)th operation is shifted to the right relative to the end of the jth operation by a partial cycle of the (j + 1)th operation pt j + 1. In this case, the amount of combining or reducing the cycle duration will be:
t q j, j+1 = (n - p) t j+1 .(24)
In both cases, in the formulas for t c the values t j and t j + 1 are the complexity of the shortest pair of adjacent operations. Denoting them by t cor, we obtain a general formula for reducing the cycle duration for each pair of operations:
Then the cycle duration for a parallel-sequential type of movement will be determined by the formula:
The advantage of this type of movement is that the cycle duration is significantly reduced compared to the sequential type with continuous occupancy of jobs. However, at the same time, parts lie awaiting processing, the number of planning and accounting units increases, and the pace of operation of vehicles is higher.
This type of movement is used in mass discontinuous-flow and large-scale production, as well as partially in lower types of production to reduce the duration of the production cycle.
In the latter case, the parallel-sequential type of movement applies only to such a number of pairs of adjacent operations that will provide the required reduction in the duration of the production cycle.
1.3 Economic function of the production cycle, ways to improve its efficiency
Without a scientifically based calculation of the duration of the production cycle, it is impossible to correctly draw up the production program of the enterprise and workshops, and determine the technical and economic indicators of activity. To calculate the cycle of an entire product, it is necessary to have data on the production cycles of its elements. Using the duration of the production cycle, operational scheduling of the enterprise’s work is carried out, including the distribution of production tasks to workshops, sections and workers; control of timely execution of tasks in accordance with customer orders.
The duration of the production cycle affects the preparation time for the production of new products, the turnover of working capital, and is an important value in organizing operational production planning, logistics, etc.
The duration of the production cycle is influenced by many factors: technological, organizational and economic. Technological processes, their complexity and diversity, technical equipment determine the processing time of parts and the duration of assembly processes.
Organizational factors of the movement of objects of labor during processing are associated with the organization of jobs, the work itself and its payment. Organizational conditions have an even greater influence on the duration of auxiliary operations, service processes and breaks.
Economic factors determine the level of mechanization and equipment of processes (and, consequently, their duration), standards for work in progress. The production cycle (Tc) is directly related to the working capital standard:
T c = OS n.p / Q dn, (27)
where OS n.p is the volume of working capital in work in progress (rubles); Q day is one-day production output (rubles).
The duration of the production cycle determines the volume of work in progress, which is the most significant part of working capital in terms of specific weight, and also has a significant impact on the production and financial condition of the enterprise. The shorter the production cycle, the faster the raw materials are transformed into finished products, which, in turn, will enter the circulation sphere for sale and turn into the enterprise’s funds.
Consequently, reducing the duration of the production cycle leads to an acceleration of the turnover of these funds. The faster the production process takes place (the shorter the duration of the production cycle), which is one of the elements of the circulation of working capital, the greater will be the speed of their turnover, the greater the number of revolutions they make during the year.
As a result, monetary resources are released that can be used to expand production at a given enterprise. For the same reason, there is a reduction (absolute or relative) in the volume of work in progress. And this means the release of working capital in their material form, i.e. in the form of specific material resources. And all this ultimately leads to an increase in the profit of the enterprise.
The production capacity of an enterprise or workshop directly depends on the duration of the production cycle. Production capacity refers to the maximum possible output of products in the planning period. And therefore it is clear that the less time is spent on the production of one product, the greater their number can be produced in the same period of time.
Labor productivity, with a reduction in the duration of the production cycle, increases as a result of an increase in the volume of output due to an increase in production capacity, which leads to a decrease in the share of labor of auxiliary workers in a unit of production, as well as the share of labor of specialists and employees.
The cost of production when the production cycle is shortened is reduced due to the reduction in the cost of a unit of production of the share of general plant and workshop expenses with an increase in production capacity.
Thus, reducing the production cycle time is one of the the most important sources intensification and improvement of production efficiency at industrial enterprises.
The reserve for reducing the duration of the production cycle is the improvement of equipment and technology, the use of continuous and combined technological processes, deepening specialization and cooperation, and introducing methods scientific organization labor and workplace maintenance, introduction of robotics.
Organizational measures are aimed at improving the maintenance of workplaces with tools, workpieces, improving the operation of the control apparatus, intra-shop transport, warehousing etc.
Restructuring the production structure of a plant or workshop, for example, organizing subject-closed production areas, which helps reduce the time of interruptions in the production process by reducing the time of interoperational storage and transportation, leads to a reduction in the duration of the production cycle; especially significant economic effect provides the introduction of flow forms of organization of the production process.
Reducing the duration of the production cycle is one of the most important tasks in organizing production at an enterprise, on the proper solution of which its effective, cost-effective operation largely depends.
2. Calculation of the production cycle using the example of the production of self-adhesive tape (adhesive tape)
2.1 Characteristics of Polymir LLC
The production of adhesive tape occupies a leading position in the range of packaging products. Scotch tape has long taken its rightful place in our lives as a necessary packaging material and adhesive agent. It is necessary in the office, at work and at home. Scotch tape is a polypropylene film with a layer of acrylic glue applied to it.
Today, the types of adhesive tape and the technology for its production depend entirely on the area in which it will be used and the tasks for which it is intended. Consumers of these products are all sectors of the national economy where packaging of products in cardboard containers is necessary:
· food industry;
· production of building finishing materials;
· paint and varnish production;
· perfumery and cosmetics production;
· stationery;
· alcohol industry;
· production of synthetic detergents;
The thickness of the tape is measured in units of Micron, abbreviated as Micron. As a rule, the thickness of the polypropylene base is 25 microns (excluding adhesive tape with a thickness of 50 microns and above), and everything else is glue. The amount of glue on the tape can be different, and it is the thickness of the adhesive layer that determines the adhesive ability of the packaging tape.
Depending on the thickness, packaging (household, office) tape is used as follows:
· Adhesive tape 38 microns - an economical option - has a low adhesive ability, does not work well in the cold, is mainly sold in markets and stationery stores.
· Adhesive tape with a thickness of 45 microns is the most common among manufacturers. It is suitable for sealing medium-heavy boxes and provides a reliable and durable seal for both coated and regular corrugated boxes.
· Adhesive tape with a thickness of 50 microns - has maximum adhesive properties and increased tensile strength. It is used for sealing heavy boxes, as well as in cases where work is carried out at low temperatures. Also, adhesive tape of this thickness is used if the products are in transit for a long time to ensure reliable safety of the cargo.
Industrial tape 50mm x 990m and 75mm x 990m is designed for automatic packaging lines and is also equipped with a standard sleeve with a diameter of 76 mm.
The acrylic adhesive composition of the tape has sufficient frost resistance and allows packaging and storing sealed containers at high humidity with full preservation of the adhesive properties of the tape.
The thickness of the proposed adhesive tape is 40, 45 and 50 microns, which determines its adhesive properties (stickiness). Since the thickness of the polypropylene base is the same - 25 microns, the remaining difference of 15, 20 and 25 microns, respectively, is the thickness of the adhesive layer.
Products from leading manufacturers from Taiwan, China and Italy are used as raw materials, which in turn provides the opportunity for production to offer products High Quality in an acceptable price range.
Since in Russia, literally until recently, there was virtually no production of adhesive tapes, and there are still no producers of raw materials for the production of such tapes, therefore a product such as adhesive tape is not subject to mandatory certification.
However, the production, adhering to the principles of the ISO-9000 quality system, undergoes a voluntary certification procedure for each of its products. Maintain product quality at high level The internal control system also helps a lot.
The packaging tape market is growing at a rapid pace. An increasing number of manufacturers are starting to use it when packaging their products. In the world, the growth in the volume of launches of new PET tape production capacities alone is about 10% annually, and this does not count the increase in the capacity of already used equipment. But at the same time, there are a number of factors hindering the rapid growth of the PET packaging tape market in Russia:
Information ignorance of enterprise managers about the benefits of PET tape.
The need to purchase special equipment for packaging with PET tape.
Lack of experience working with PET tape.
Rules for the transportation of goods by rail, according to which only steel tape can be used as packing tape.
Climatic factor: high-quality connection of PET tape with hand tools is carried out using the friction welding method, and this requires that the temperature environment was not lower than +5° C, which in Russian conditions is not possible everywhere.
In general, assessing the packaging tape market, we can say that the market is young, but rapidly growing, which, provided that costs are reduced through the use of recycled materials, will allow the manufacturing company to take a strong position in the market.
The production process of adhesive tape consists of 2 basic technological processes:
Applying an adhesive coating to various substrates and winding the produced material with an adhesive layer into a large (JUMBO) role. This process is carried out using coating machines. A jumbo roll is a polypropylene reel 1.28 m wide and 4000 m long or more. Water-based acrylic adhesive is applied to polypropylene. The adhesive bonds with polypropylene at the molecular level.
Rewinding and slitting JUMBO rolls into custom or standard formats. This process is implemented according to a one-stage scheme using a rewinding machine, or according to a two-stage scheme using a set of two machines - a rewinder used for rewinding JUMBO rolls as custom diameters (LOG-rolls) and a cutting machine for longitudinal cutting of LOG rolls into adhesive tapes custom formats.
Polimir LLC has been operating on the Russian packaging materials market in the Siberian region since 2003 and has managed to establish itself as a young, professional, rapidly developing team.
Polymir LLC is legal entity, owns separate property accounted for on the balance sheet, acquires and carries out property and personal property in its own name moral rights, bears rights and obligations in accordance with the Charter of the Company and the legislation of the Russian Federation. LLC "Polimir" was created in order to saturate consumer market goods and services, as well as making profits in the interests of participants.
The authorized capital of Polymir LLC is 700 thousand rubles. The profit of Polymir LLC is determined at the end of each financial year. It is formed from revenue from economic, commercial activities after reimbursement of material and equivalent costs and labor costs. Taxes and other payments to the budget provided for by law, as well as interest on bank loans and bonds are paid from the balance sheet profit. The profit generated after these calculations remains at the full disposal of the Company, part of which is allocated for the development of the Company and general needs, and the other part (dividends) can be distributed based on the results of work for the year among the participants in proportion to their contribution to the Authorized Capital.
The goal of the Company is to effectively interact with partners, clients of the Company and provide high-quality packaging materials to organizations in all areas of Russian business. The company is a reliable supplier of a wide range of packaging materials at reasonable prices.
The production of Polymir LLC as of December 2011 consists of 2 lines for rewinding adhesive tape. The equipment allows us to produce tape rollers of various widths and lengths. Production capacity today is about 10,000 conventional boxes of various adhesive tapes,
The company acquired modern equipment and implemented unique technology production. For example, it takes into account which layer of glue to apply to polypropylene film for a specific type of packaging. The new high-performance tape rewinding line allows the production of rollers of various widths and lengths, which is also important for various packaging operations.
Polymir LLC provides not only the declared properties of adhesion (stickiness), tensile strength and other specific properties of the manufactured product, which the average consumer has never even heard of, but also guarantees the winding length.
In the future, Polymir LLC intends to present a wide range of packaging products: industrial adhesive tapes (packaging tape), printed adhesive tapes (logo tape), colored adhesive tapes (colored tape), packaging films (stretch film), films and bags air bubbles, polypropylene, polyester, metal tapes (strapping tapes), necessary consumables and equipment, hand protection (gloves) and much more.
Polimir LLC strives for long-term cooperation with each client and therefore provides high quality packaging materials produced, as well as quality service.
Due to the fact that the company is in the development stage, it is important for it to calculate the duration of the production cycle for the production of adhesive tape for further planning of production volumes and, accordingly, the development of the company.
2.2 Calculation of the production cycle for the production of self-adhesive tape (adhesive tape)
To calculate the duration of the production cycle, we will time the working time, that is, photograph the working time. Photography of working time is one of the most convenient methods for solving problems of assessing and analyzing the structure of costs and losses of working time, developing measures to improve the organization of work and increase its productivity by eliminating losses and waste of working time.
When taking photographs of working hours, the following must be provided:
· serviceability of machines, machines and equipment;
· the required quality of materials and tools necessary to complete the work and their timely supply;
· timely supply of electricity, gas and other energy sources;
· timely provision of technical documentation;
· healthy and safe conditions labor (compliance with labor safety standards and regulations, necessary lighting, heating and ventilation, minimizing the harmful effects of noise, radiation, vibration, etc.).
Working time photography (WPT) continues to be one of the most convenient and rational methods for studying the costs and losses of working time, as well as developing individual species labor standards.
We will take photographs of working hours not only to determine the duration of the production cycle, but also for the purpose of:
· increasing labor productivity;
· determining the required number, professional and qualification composition of employees;
· organizing operational planning;
· organization of remuneration;
· improving labor organization.
Working time is used by enterprise personnel not only for work; the structure of working time is much more complex. It includes (Appendix D):
· Working time - the period of time during which a worker performs this or that work, both provided and not provided for by the production task.
· Completion of tasks - the time for completing a task consists of preparatory and final time, operational time and time for servicing the workplace.
· Preparatory-final time is spent by the worker preparing himself and the means of production to complete a new production task, producing a new batch of products, and performing all the work associated with its completion (obtaining materials, tools, devices, work orders and technical documentation, undergoing training, installing and removing tools and devices, setting up equipment, handing over finished products, handing over devices, tools, work orders, technical documentation and remaining materials). It is calculated once for the entire batch of products. Depending on the serial production and equipment, it can range from 1 to 15% of working time.
· Operational time - the period during which a worker performs a given operation - changes the shape, properties and quality of the object of labor or its position in space.
· Core time - part of the operational time spent on achieving the goal this process by qualitative or quantitative change in the means of labor.
· Auxiliary time is part of the operational time spent on performing actions that make it possible to perform the main work (loading a machine with raw materials, unloading and removing finished products, installing and reinstalling parts, tools and devices, worker movements associated with the operation).
· Workplace maintenance - time spent on activities associated with maintaining the workplace and maintaining equipment, tools and devices in working order during the shift.
· Depending on the nature of the worker’s participation in production operations, work time can be the time of manual, machine-manual work and the time of observing the operation of equipment.
· Preparatory and final time, as a rule, is manual; basic - manual, machine-manual, machine, automated; auxiliary - manual, machine-manual or mechanized. Workplace maintenance time can be manual or machine-manual.
· Work not according to instructions - time spent on performing random operations that are not typical for a given worker, which can be eliminated (going for a tool, correcting defects, etc.).
· Random work - time spent performing random operations that are not typical for a given worker.
· Unproductive work - time spent on walking and searching (for materials, workpieces, tools, foreman, adjuster, etc.), as well as on manufacturing products that were rejected through no fault of the worker.
· Rest and personal breaks are used by workers to rest in order to prevent fatigue and maintain normal performance (rest), as well as for personal hygiene (personal needs).
· Interruptions of an organizational and technical nature are caused by the established technology and organization of production, as well as disruptions in the normal flow of the production process.
· Breaks for technological and organizational reasons - time to remove workers from the explosion zone, breaks between unloading and loading of the thermal furnace required by technology, etc. These breaks are regulated and included in the work norm.
· Interruptions due to disruption of the normal flow of the production process can be caused by delays in the supply of raw materials and semi-finished products, lack of energy, blanks, waiting for a foreman, auxiliary worker, transport, unscheduled repairs and other reasons that disrupt the normal course of the production process. These breaks are essentially downtime for various organizational and technical reasons depending on production.
· Breaks due to violation of labor discipline (lateness, unauthorized absences from the workplace, premature departure from work, etc.) are downtime due to the fault of the worker.
The production process of Polymir LLC is a set of individual labor processes aimed at transforming raw materials into finished products. The content of the production process has a decisive impact on the construction of the enterprise and its production units. The production process is the basis of any enterprise.
The main factors of the production process that determine the nature of production are means of labor (machines, equipment, buildings, structures, etc.), objects of labor (raw materials, materials, semi-finished products) and labor as the purposeful activity of people. The direct interaction of these three main factors forms the content of the production process.
The production process for the production of adhesive tape is based on the following design principles:
The principle of parallelism, which provides for the simultaneous implementation of individual parts of the production process associated with the manufacture of a specific product;
The principle of direct flow, providing the shortest path for the movement of objects of labor from the launch of raw materials or semi-finished products to the receipt of finished products;
The principle of continuity, which provides for the maximum reduction of breaks between operations;
The principle of rhythm, which means that the entire production process and its constituent partial processes for the production of a given quantity of products must be strictly repeated at equal intervals of time;
The principle of technical equipment, focused on mechanization and automation of the production process, the elimination of manual, monotonous, heavy labor harmful to human health.
We will formalize the results of the timekeeping carried out in the table “Observation sheet of working time” (Appendix D).
The production of adhesive tape can be classified as small-scale production, the arrangement of equipment is group, chain, the degree of implementation of the basic principles of production organization is an average degree of flow. The production of adhesive tape employs three workers who replace each other if necessary ( lunch break, natural needs, etc.), thus, it turns out that the time of breaks is reduced to a minimum, only in case of stopping the equipment for reconfiguration or lubrication. The tape is available in widths of 48 mm and 70 mm. One jumbo roll contains 4000 m of tape, its width is 1.28 m. From one cardboard tube 1.3 m long, a bobbin cutter produces tape spools of 26 and 18 pcs., respectively. These bobbins are put on the shaft of a 1.28 m long slitting machine, of which there are two on the machine. On the slitting machine, the film from the jumbo roll, passing through a system of shafts and knives, is cut and wound onto cardboard bobbins pre-attached to the shafts. The result is finished rollers of adhesive tape of a certain length. The length of winding depends on the client’s needs, but today the footage is 60 m, 120 m, 990 m. From one jumbo roll it turns out:
with a bobbin width of 48 mm:
60-meter tape - 1716 pcs;
120-meter tape - 858 pcs;
990-meter tape - 104 pcs.
with a bobbin width of 70 mm:
60-meter tape - 1188 pcs;
120-meter tape - 594 pcs;
990-meter tape - 72 pcs.
After the machine shafts are stopped, the finished rollers of adhesive tape are removed from the shafts and packed into corrugated containers. Depending on the size of the corrugated container, it can accommodate from 36 to 78 pieces. rollers of tape. The boxes of tape are then stored. This completes the production cycle.
Based on the results obtained, we will calculate the duration of the production cycle for the production of adhesive tape. The total amount of time spent on making tape 48 mm wide and 60 m long is 147 minutes, but due to the fact that some operations are carried out in parallel with others - 37 minutes. The type of movement is parallel-sequential. Thus, the duration of the production cycle for the production of adhesive tape 48 mm wide and 60 m long is 37 minutes. The production cycle for the production of adhesive tape with a width of 48 mm and a length of 120 m will be 38 minutes, and 990 m long - 61 minutes. The process of rewinding tape depends on the speed of the cutting machine shaft and the quality of the film on the jumbo roll.
2.3 Ways to improve production organization
One of the current tasks of the enterprise is the development of measures related to reducing the duration of the production cycle. The reduction must be carried out simultaneously in two directions: reducing the working period of the cycle and completely eliminating or minimizing various breaks. All practical measures to reduce the duration of the production cycle follow from the principles of constructing the production process, first of all, from the principles of proportionality, parallelism and continuity. There are two main directions for reducing the production cycle time.
Technological progress causes a reduction in the duration of the production process as a result of the introduction of more modern technological processes; completely eliminating some operations or replacing some with others that are more productive; intensification of the duration of the production process.
The duration of natural processes is significantly reduced as a result of replacing them with appropriate technological operations.
Reducing labor intensity can be achieved by changing the starting materials. Reducing preparatory and final time is achieved by introducing the flow method of organizing production, standard and universal devices. Reducing the duration of quality control of performed operations is achieved by their mechanization and automation, combining the time for performing technological and control operations.
Technical progress is expressed in increasing the manufacturability of the design, which is manifested in the maximum approximation of the design to the requirements of the technological process. Improving the organization of production often has a decisive influence on the duration of the production cycle.
The main ways to improve the organization of labor and production include:
1. rational layout of workplaces, in accordance with the sequence of technological operations and improving the organization of the transfer of parts from operation to operation within a site or workshop;
2. reducing the time of interruptions caused by equipment breakdowns, which requires a clear organization of scheduled preventive maintenance of equipment;
3. acceleration of auxiliary processes through their extensive mechanization and automation, due to which they are not only completed faster, but also increase the reliability of servicing the main processes;
4. organizing a preparatory shift, during which equipment is set up, preparation for the production of materials, tools, devices,
5. introduction of daily shift planning and organization of work according to an hourly schedule;
The discovery of reserves for reducing the duration of the work cycle is facilitated by photographs of the working day of those employed in various stages of the work cycle, which will make it possible to determine the actual duration of the working time of the cycle and the time of breaks, both dependent and independent of the workers. To identify reserves for reducing the production rate, data from special observations or data from planning and accounting documentation can be used.
Measures to reduce the duration of the PC provide a comprehensive economic effect. They create the preconditions for improved use production capacity, reducing the share of overhead costs in the unit cost of production. Thus, reducing the duration of all elements of the PC is an important condition for improving many technical and economic indicators of the enterprise.
CONCLUSION
A necessary condition for the effective operation of an enterprise is the rational construction of an organizational, production and management structure. To successfully conduct production, it is necessary to rationally build the production process in space, i.e. determine, based on the characteristics of production, the most effective structure of the enterprise.
The production cycle is one of the most important indicators of technical and economic development, which determines the capabilities of the enterprise in terms of production volume and the costs of its production.
The duration of the production cycle refers to the standards for organizing the production process. Both rational spatial placement and optimal production cycle duration are important.
Reducing the duration of the production cycle is one of the most important sources of intensification and increase in production efficiency at industrial enterprises. The reserve for reducing the duration of the production cycle is the improvement of equipment and technology, the use of continuous and combined technological processes, deepening specialization and cooperation, the introduction of methods of scientific organization of labor and maintenance of workplaces, and the introduction of robotics.
BIBLIOGRAPHY
1. Arkhipov V., Vetoshnova Yu. Strategies for the survival of industrial enterprises // Questions of Economics. - 2008.
Arkhipova L. Analysis of elements production management in conditions of simultaneous functioning of traditional and foundry production [Text] // Components and technologies. - 2007.
Asaul A.N. Organization entrepreneurial activity[Text] - St. Petersburg: Peter, 2009.
Basic system of microelement time standards (BSM). Methodological and regulatory materials. [Text] - M.: Economics, 2008.
Vasilyeva E.S. The concept of production structure and its components [Electronic resource] // Economist’s Handbook. - 2008 www.profiz.ru/se/1_2004/870/
Gribov V.D., Gruzinov V.P., Kuzmenko V. Economics of an organization (enterprise). [Text] - M.: KnoRus, 2008.
7. Dzhurabaev K.T.<#"584227.files/image014.gif">
Appendix B
Graph of sequential type of movement
The production cycle of manufacturing a particular machine or its separate node(details) is the calendar period of time during which this object of labor goes through all stages of the production process from the first production operation to delivery (acceptance) finished product inclusive. Shortening the cycle makes it possible for each production unit (shop, site) to complete a given program with a smaller volume of work in progress. This means that the company gets the opportunity to speed up the turnover of working capital, fulfill the established plan with less expenditure of these funds, and free up part of the working capital.
The production cycle consists of two parts: from the working period, i.e. the period during which the object of labor is directly in the manufacturing process, and from the time of breaks in this process.
The working period consists of the time for performing technological and non-technological operations; the latter include all control and transport operations from the moment the first production operation is performed until the delivery of the finished product.
Production cycle structure(the ratio of its constituent parts) is not the same in different branches of mechanical engineering and at different enterprises. It is determined by the nature of the products manufactured, technological process, the level of technology and production organization. However, despite the differences in structure, opportunities for reducing production cycle times lie in both reducing working hours and reducing break times. The experience of leading enterprises shows that at every stage of production and at every production site Opportunities for further reductions in production cycle times may be identified. It is achieved by carrying out various activities, both technical (design, technological) and organizational.
The implementation of production processes is closely related to the methods of their implementation. There are three main types of organization of the movement of production processes over time:
¨ sequential, characteristic of single or batch processing or assembly of products;
¨ parallel, used in continuous processing or assembly conditions;
¨ parallel-series, used in direct-flow processing or product assembly.
With a sequential type of movement, a production order - one part, or one assembled machine, or a batch of parts 1 (series of machines 2) - in the process of their production is transferred to each subsequent operation of the process only after the completion of processing (assembly) of all parts (machines) of this batch ( series) on the previous operation. In this case, the entire batch of parts is transported from operation to operation simultaneously. In this case, each part of a machine batch (series) lies in each operation, first waiting for its processing (assembly) turn, and then waiting for the completion of processing (assembly) of all machine parts of a given batch (series) for this operation.
A batch of parts is the number of parts of the same name that are simultaneously put into production (processed with one set-up of equipment). A series of machines is the number of identical machines simultaneously launched into an assembly.
In Fig. Figure 1 shows a graph of the sequential movement of objects of labor through operations. The processing time for the sequential type of movement of objects of labor Tpos is directly proportional to the number of parts in the batch and the processing time of one part for all operations, i.e.
Tpos = Et * n,
where Еt is the processing time of one part for all operations in minutes; n – number of parts in the batch.
With a parallel type of movement, the processing (assembly) of each part (machine) in the batch (series) at each subsequent operation begins immediately after the end of the previous operation, regardless of the fact that the processing (assembly) of other parts (machines) in the batch (series) at this operation not finished yet. With such an organization of the movement of objects of labor, several units of the same batch (series) can simultaneously be processed (assembled) in different operations. The total duration of the processing (assembly) process of a batch of parts (series of machines) is significantly reduced compared to the same process performed sequentially. This is a significant advantage of the parallel type of movement, which can significantly reduce the duration of the production process.
The processing (assembly) time of a batch of parts (series of machines) with a parallel type of movement Tpar can be determined by the following formula:
Tpar = Еt + (n – 1) * r,
where r is the release stroke, corresponding in this case to the longest operation, in min.
However, with a parallel type of movement, during the processing (assembly) of a batch of parts (machines), downtime of people and equipment may occur at some workplaces (Fig. 2), the duration of which is determined by the difference between the cycle and the duration of individual operations of the process. Such downtime is inevitable if operations following one another are not synchronized (not aligned in their duration), as is usually done on production lines. That's why practical use The parallel type of movement of objects of labor turns out to be absolutely expedient and economically beneficial in the continuous organization of the production process.
The need to equalize (synchronize) the duration of individual operations significantly limits the possibility of widespread use of parallel type of movement, which promotes the use of the third - parallel-sequential type of movement of objects of labor.
The parallel-sequential type of movement of objects of labor is characterized by the fact that the process of processing parts (assembling machines) of a given batch (series) at each subsequent operation begins earlier than the processing of the entire batch of parts (assembling machines) at each previous operation is completely completed. Parts are transferred from one operation to another in parts, transport (transfer) batches. The accumulation of a certain number of parts in previous operations before the start of sodium processing in subsequent operations (production backlog) allows you to avoid downtime.
The parallel-sequential type of movement of objects of labor can significantly reduce the duration of the production processing (assembly) process compared to the sequential type of movement. The use of a parallel-sequential type of motion is economically feasible in cases of manufacturing labor-intensive parts, when the duration of process operations varies significantly, as well as in cases of manufacturing low-labor parts in large batches (for example, normals of small standardized parts, etc.).
With a parallel-sequential type of movement of objects of labor, there can be three cases of combining the duration of operations:
1) the previous and subsequent operations have the same duration (t 1 = t 2);
2) the duration of the previous operation t2 is greater than the duration of the subsequent operation t3, i.e. t2 > t3;
3) the duration of the previous operation t3 is less than the duration of the subsequent one t 4, i.e. t 3< t 4 .
In the first case, the transfer of parts from operation to operation can be organized individually; For reasons of convenience of transportation, simultaneous transfer of several parts (transfer batch) can be used.
In the second case, a subsequent, shorter operation can be started only after finishing processing of all parts in the previous operation included in the first transfer batch. In Fig. 3 this has mine when moving from the first operation to the second.
In the third case (in Fig. 3 - the transition from the 3rd to the 4th operation) there is no need to accumulate parts from the previous operation. It is enough to transfer one part to a subsequent operation and begin processing it without any fear of downtime. In this, as in the first case, the transfer lot is established only for transport reasons.
The moment of starting work at each subsequent operation (workplace) is determined according to the schedule or by calculating the minimum displacements c.
The minimum offset c 2 is determined by the difference between the durations of the previous larger t 2 and the subsequent smaller operations t 3, namely:
c 2 = n * t 2 – (n – n tr) * t 3,
where n tr is the value of the transfer (transport) batch, which for the second case of a combination of operation durations is determined from the ratio c 1 / t 1 (c 1 is the minimum displacement of the first operation), in all other cases - from the conditions of ease of transportation.
The minimum calculated offset is included in the total duration of the production process T for the combination of operation durations related to the second case. In the first and third cases, the minimum displacement is set equal to the time required to form the transfer batch.
When determining the total duration of the production process with a parallel-sequential type of movement of objects of labor, one should take into account the calculated value of the displacement E c:
T pl = E s + n * t k,
where tk is the duration of the last (final) operation in a given production process.
Example. Determine the total duration of the processing process for a batch of parts when various types movement, if the number of parts in the batch is n = 40, and the processing time of one part (in minutes) for operations is: t 1 = 1.5; t 2 = 1.5; t 3 = 0.5; t 4 = 2.5; release stroke r = 2.5 min.
A. In conditions of sequential movement of parts
E t = t 1 + t 2 + t 3 + t 4 = 1.5 + 1.5 + 0.5 + 2.5 = 6.0;
T pos = E t * n = 6.0 * 40 = 240 min = 4 hours.
B. In conditions of parallel type of movement of parts
T steam = E t + r * (n – 1) = 6.0 +2.5 * (40 – 1) = 103.5 minutes, or 1.725 hours.
IN. In conditions of parallel-sequential movement of parts
T p.p = E s + n * t = 65 + 40 * 2.5 == 165 min == 2.7 hours.
First you need to determine the value of E c . Taking the size of the transfer batch, convenient for transportation, n tr = 10 pcs., we can find the minimum displacements for operations:
s 1 = n tr * t 1 = 10 * 1.5 = 15 min;
s 2 = n * t 2 – (n – n tr) * t 3 = 40 * 1.5 – (40 – 10) * 0.5 = 45 min;
s 3 = n tr * t 3 = 10 * 0.5 = 5 min.
To determine the amount of displacements E c, it is necessary to know the number of transport batches when transferring parts from the second to the third operation, which will be equal to
k = s 2 / (n tr * t 2) = 45 / (1.5 * 10) = 3;
then the sum of the displacements will be E c = 15 + 45 + 5 = 65 min.
Thus, the use of parallel and parallel-sequential types of movement of objects of labor makes it possible to reduce the duration of the production process, or, in other words, to reduce the production cycle of manufacturing an object of labor.
Organizational measures are aimed at improving the maintenance of workplaces with tools, workpieces, improving the operation of the control apparatus, intra-shop transport, storage facilities, etc. Restructuring the production structure of a plant, workshop, for example, organizing subject-closed production areas, helping to reduce the time of interruptions in the production process by reducing the time of inter-operational storage and transportation, it leads to a reduction in the duration of the production cycle; A particularly significant economic effect comes from the introduction of flow forms of organizing the production process.
Reducing the duration of the production cycle is one of the most important tasks in organizing production at an enterprise, on the proper solution of which its effective, cost-effective operation largely depends.
Types of production
Type of production is a comprehensive characteristic of the technical, organizational and economic features of mechanical engineering production, due to its specialization, volume and consistency of the product range, as well as the form of movement of products to workplaces.
The level of specialization of jobs is expressed by a number of indicators characterizing the design-technological and organizational-planning features of products and production. Such indicators include specific gravity specialized jobs in the department; the number of names of detail operations assigned to them; the average number of operations performed at a workplace over a certain period of time. Among these indicators, the last one most fully characterizes the organizational and economic features corresponding to a specific type of production and level of specialization-jobs. This level is determined coefficient of consolidation of operations Kz.o.
Coefficient Kz.o shows the ratio of the number of various technological operations performed or to be performed by a department during a month to the number of jobs. Because Kz.o reflects the frequency of changes in various operations and the associated frequency of servicing the worker with various information and material elements of production, then Kz.o is assessed in relation to the attendance number of workers of the unit per shift. Thus,
,
Where R issue– coefficient of fulfillment of time standards; Fp– the worker’s time fund when working for the planned period in one shift; Nj – release program i-th product name for the planned period; Тj – labor intensity i-th product name; m – the total number of different operations performed during the planned period; h – the number of workers in the unit performing these operations. If externally implicit, the indicator Kz.o combines a significant number of factors that determine the degree of stability of production conditions in the workplace. All parameters affecting Kz.o , conditionally can be combined into three groups: the first group – parameters of the constructive and technological order that determine the basis of the production process; the second – volumetric parameters characterizing the “statics” of the production process; the third is calendar parameters that determine the “dynamics” of the production process.
The first group includes such parameters as: coefficient of preparatory-final time, number of operations, norms of operation time, number of product items.
The second group of parameters includes: the turnout number of main workers, the worker’s time fund, the production program, the rate of fulfillment of time standards, the number of jobs.
The third group includes the following parameters: the size and rhythm of a batch of products, the rhythm of product release, the coefficient of interoperational time, the duration of the production cycle of a batch of products.
A series of simple substitutions, substitutions and transformations can be used to connect these parameters with Kz.o .
Coefficient Kz.o. shows the average frequency of changes in technological operations for the site. Consequently, a change in the KZ.O. affects the specialized skills of workers, the labor intensity of processing and wages of site workers, the costs of changeovers and the frequency of maintenance on the part of the foreman, planner, adjuster, as well as the wages of workers waiting for service, i.e. cost of manufactured products.
Coefficient Kz.o characterizes the average time to complete one operation or a set of similar operations using group technology; therefore, it is related to the batch size of products that are produced continuously in each operation. Changing the batch size, in turn, affects the duration of the production cycle and the amount of work in progress. The presence of both increasing and decreasing costs with unidirectional change Kz.o indicates the need to search for the optimal value Kz.o.
The range of products manufactured at workplaces can be constant or variable. The permanent range includes products the production of which continues for a relatively long time, i.e. a year or more. With a constant nomenclature, the production and release of products can be continuous and periodic, repeated at certain intervals. With variable nomenclature, the production and release of products is repeated at indefinite intervals.
According to the degree of specialization, size and consistency of the range of products manufactured, all workplaces are divided into the following groups: 1) mass production jobs, specialized to perform one continuous repeating operation; 2) serial production workplaces, on which several different operations are performed, repeated at certain intervals: time; 3) single production jobs, on which a large number of different operations are performed, repeated at indefinite intervals or not repeated at all.
Depending on the value Kz.o batch production jobs are divided into large-, medium- and small-scale: with 1<= Kz.o< 10 рабочие места относятся к крупносерийному производству, при 10 <= Kz.o < 20 рабочие места соответствуют среднесерийному производству, при 20 <= Kz.o <= 40 – small-scale production.
The type of production is determined by the predominant group of jobs.
Mass type production is characterized by the continuous production of a limited range of products at highly specialized workplaces.
Serial type production is determined by the production of a limited range of products in batches (series), repeated at certain intervals at workplaces with broad specialization. The serial type of production is also divided into large-, medium- and small-scale, depending on the predominant group of jobs.
Unit type production is characterized by the production of a wide range of products in single quantities, repeated at indefinite intervals or not repeated at all, at workplaces that do not have a specific specialization.
The large-scale type of production is close in its characteristics to the mass production, and the small-scale type is closer to the single type of production.
The movement of parts (products) through workplaces (operations) can be: in time - continuous and discontinuous; in space – direct-flow and indirect-flow. If workplaces are located in the order of the sequence of operations performed, i.e., along the technological process of processing parts (or products), then this corresponds to direct-flow movement, and vice versa.
Production in which the movement of products through workplaces is carried out with a high degree of continuity and direct flow is called continuous production.
In this regard, depending on the form of movement of products through workplaces, mass and serial types of production can be in-line and non-in-line, that is, there can be a mass, mass-in-line, serial and serial-in-line type of production. In a single type of production, it is usually difficult to ensure continuity and direct flow of all products manufactured at a group of workplaces, and therefore a single type of production cannot be continuous.
The type of site, workshop and plant as a whole is determined by the predominant type of production.
In mass production factories, the mass type of production is predominant, but there may be other types of production. At such factories, the assembly of products is carried out according to the mass type, the processing of parts in machine shops is carried out according to the mass and partially serial type, and the production of blanks is carried out according to the mass and serial (mainly large-scale) types of production. Mass production factories are, for example, automobile, tractor, ball bearing and other factories.
In factories where the serial type of production predominates, the assembly of products can be carried out using mass and serial types of production, depending on the labor intensity of the assembly and the number of products produced. Processing of parts and production of blanks is carried out according to the serial type of production.
Unit production plants are characterized by the predominance of a single type of production. Serial and sometimes even mass production are found in the production of standard, normalized and unified parts and assembly units. This is also facilitated by the typification of technological processes and the introduction of group processing methods.
As the degree of specialization of workplaces increases, the continuity and direct flow of products through workplaces, i.e., during the transition from single to serial and from serial to mass types of production, the possibility of using special equipment and technological equipment, more productive technological processes, advanced methods of labor organization, mechanization and automation of production processes. All this leads to increased labor productivity and reduced production costs.
The main factors contributing to the transition to serial and mass types of production are an increase in the level of specialization and cooperation in mechanical engineering, the widespread introduction of standardization, normalization and unification of products, as well as the unification of technological processes.
When transforming production items into a specific product, they go through a variety of basic, auxiliary and servicing processes occurring in parallel, parallel-sequentially or sequentially in time, depending on the existing production structure at the enterprise, type of production, level of specialization of production units, forms of organization of production processes and other factors. The set of these processes that ensure the manufacture of a product is usually called production cycle, the main characteristics of which are its duration and structure.
Production cycle time production of products (regardless of the number of simultaneously manufactured parts or products) is the calendar period of time during which raw materials, basic materials, semi-finished products and finished components are transformed into finished products, or, in other words, this is the period of time from the moment the production process begins until the release of the finished product or batch of parts, assembly units.
The duration of the production cycle is usually expressed in calendar days or hours (with low labor intensity of products).
Knowledge of the duration of the production cycle for the manufacture of all types of products (from the manufacture of blanks, parts to assembly of products) is necessary: 1) to draw up a production program for the enterprise and its divisions; 2) to determine the timing of the start of the production process (launch) based on the timing of its completion (release); 3) for calculating the normal value of work in progress.
The duration of the production cycle depends on the time of labor and natural processes, as well as on the time of breaks in the production process. During labor processes, technological and non-technological operations are performed. The time required to perform technological operations in the production cycle is the technological cycle (Tc). The time it takes to complete one operation, during which one part, a batch of identical parts, or several different parts are manufactured, is called the operating cycle (T op).
Non-technological operations include operations for transporting objects of labor and monitoring product quality.
Processes that are associated with cooling of parts after heat treatment, drying after painting parts or other types of coating, and aging of the metal are considered natural.
Breaks, depending on the reasons that caused them, can be divided into inter-operational (intra-cycle), inter-shop and inter-shift.
Interoperational breaks are caused by batching and waiting time and depend on the nature of the processing of a batch of parts in operations. Breaks in batching occur because each part, arriving at the workplace as part of a batch of similar parts, lies twice: once before the start of processing, and a second time after the end of processing, until the entire batch goes through this operation.
Waiting interruptions are caused by inconsistent durations of adjacent process operations. These breaks occur in cases where the previous operation ends before the workplace is freed up for the next operation.
Inter-shop breaks are due to the fact that the completion dates for the production of component parts of assembly units in different shops are different and the parts lie waiting for completeness. This maintenance (breaks in picking) occurs with a complete-unit planning system, i.e. when finished blanks, parts or assemblies must “stay” due to the unfinished state of other blanks, parts, and assemblies included in one set together with the first ones. As a rule, such interruptions occur during the transition of products from one stage of production to another or from one workshop to another.
Inter-shift breaks are determined by the operating hours of the enterprise and its divisions. These include weekends and holidays, breaks between shifts (in a two-shift mode, the third shift) and lunch breaks (conditionally).
The structure and duration of the production cycle depend on the type of production, the level of organization of the production process and other factors. Mechanical engineering products are characterized by a high share of technological operations in the total duration of the production cycle. Reducing the latter is of great economic importance. As a rule, the duration of the production cycle is determined for one part, a batch of parts, one assembly unit or batch of units, one product. It should be borne in mind that a product is any item or set of items to be manufactured at an enterprise or in its divisions.
When calculating the duration of the production cycle for manufacturing a product, only those time costs for transport and control operations, natural processes and breaks that are not overlapped by the operational cycle are taken into account.
Reducing production cycle times is of great economic importance. The shorter the duration of the production cycle, the more products per unit of time, other things being equal, can be produced at a given enterprise, workshop or site; the higher the use of fixed assets of the enterprise; the less the enterprise needs for working capital invested in work in progress; the higher the capital productivity, etc.
In factory practice, the production cycle is reduced simultaneously in three directions: the time of labor processes is reduced, the time of natural processes is reduced, and various breaks are completely eliminated or minimized.
Loading...