Pre-production network planning. Network planning of construction production Network planning of pre-production

Network planning and management of technical preparation of production.

The process of creating and mastering new technology. Stages of technical preparation for the production of new products. Design preparation of production. Technological preparation of production.

Scientific and technological progress presupposes a change in generations of machines, devices, mechanisms. The feasibility study for attributing a particular new product to the next generation is its ability to provide a sharp increase in labor productivity. The process of mastering production and developing new products is called technical preparation of production for the release of new products.

The technical preparation of production is understood as a set of processes of a scientific, technical and organizational-economic nature.

Technical training production includes the following stages:

1. Research works:

Comprehensive research of the market, customers and competitors;

Searching for an idea for a new product.

This stage in the enterprise is carried out by the marketing department.

2. Research and development

Complex of works to create design documentation for new products, manufacturing and testing of its samples.

3. Technological:

Works on creation and improvement technological processes;

Development of the design of tools͵ equipment, special equipment;

Execution of layouts of workshops of sites.

4. Organizational and economic

A complex of interrelated processes of organization, planning, accounting and control, logistics of sales and financing, ensuring the readiness of the enterprise for the release of new products.

Design preparation of production- a set of interrelated processes for the creation of new or improvement of existing product designs in accordance with the requirements of the customer (consumer).

Stages of design preparation for production:

1. Preparation of technical specifications together with representatives of the customer. It should contain everything technical requirements, conditions and modes of operation, connection dimensions, transportability, resource, safety and so on.

2. Calculation of a technical proposal- contains calculations of technical parameters and economic efficiency that substantiate the possibility and feasibility of developing a new product. Calculations are performed according to several options for manufacturing a product, from which the optimal ( the best option the one with the higher economic coefficient).

3. Development of a draft design... The draft design is not carried out to scale, but in compliance with the required proportions. Drawings of basic assembly units and general view, kinematic, pneumatic and hydraulic circuits. The draft design should give a general idea of ​​the device and the principles of operation of the new device.

4. Development of technical project ... It is carried out strictly to scale in compliance with the requirements of the standard and norms. All types, cuts, sections are carried out in it, general drawings are specified, specifications are drawn up, strength and stiffness calculations are performed, and so on. A selection of materials is made and instructions for use are drawn up.

5. Preparation of working design documentation... Conducting norm control, patent and metrological examination.

6. Production and testing of a prototype.

7. Correction of the working draft and release of the initial batch of products.

8. Checking the approval of amendments, approval and reproduction of the working draft. Transfer of documents to the department of the chief technologist.

Technological preparation of production- a set of works that determine the sequence of the production process of a new product in the most rational ways, taking into account specific production conditions of this enterprise.

Stages technological preparation production:

1. Technological analysis of working drawings and their control for the manufacturability of the design of the part and assembly units.

2. Development of progressive technological processes. It begins with the definition of technological routes for the movement of parts and assembly units. Then technological processes for obtaining blanks, their processing and assembly are developed.

3. Design of special tools, tooling and equipment.

4. Execution of layouts of workshops and production areas with the arrangement of equipment according to the developed technological routes.

5. Reconciliation, debugging and implementation of technological processes.

6. Calculation of the production capacity of the enterprise with the standard of consumption of tools, material and energy resources.

Network planning- one of the forms of graphic representation (reflection) of the content of work and the duration of the implementation of strategic plans and long-term complexes, design, planning, organizational and other types of activities of enterprises. Network planning serves as the basis for economic and mathematical calculations, graphic and analytical calculations, organizational and management decisions, operational and strategic plans that provide not only an image, but also modeling, analysis and optimization of projects for the implementation of complex technical objects and design developments. The network model of a set of works is usually called directed graph.

Graph- ϶ᴛᴏ a conditional scheme, consisting of given points (vertices), interconnected by a certain system of lines (segments connecting the vertices - edges or arcs of the graph).

Directed graph- a graph on which arrows indicate the directions of all its edges. Graphs are called maps, mazes, networks, and diagrams.

Way- a sequence of arcs or works, when the end of each previous segment coincides with the beginning of the next one.

Work- any production processes or other actions that lead to the achievement of certain results, that is, events.

Work is waiting requires labor time without using resources.

Fictitious work- a logical connection or dependence between some final processes that do not require time-consuming. On the graph, it is represented by a dotted line.

Event- the final result of the previous work.

In any graph, it is customary to distinguish the following paths:

1. The path from the initial event to the final one - full path;

2. The path preceding the given event from the initial one;

3. The path following this event to the final one;

4. Path between several events;

5. The critical path is the full path of maximum duration.

Stages of network planning:

1. Dividing the whole complex of works into separate parts and assigning them to the responsible executors.

2. Identification and elimination of all events necessary to achieve the goal.

3. Construction of primary network diagrams and specification of works.

4. Stitching of private networks and building a consolidated network schedule.

5. Clarification or justification of the execution time of each work in the network schedule.

In order to carry out the stitching of the network schedule, it is extremely important to have a list of the work performed.

Example: Checklist design work

Rules for building a network diagram:

1. Building a network can begin both from the initial event to the final one, and vice versa.

2. The initial event is located on the left side of the network, the final event on the right side.

3. The event is indicated by a circle with the number, the work is done with an arrow, the duration of the work is put above the arrow.

4. Each work must be concluded between 2 events and have its own code.

5. There should be no dead-end events in the network, a large number of final ones (otherwise the results of previous work will not be possible to use, the schedule is not built accurately).

6. The network schedule should not have more than one start event.

7. The network should not allow closed loops (subsequent events are connected to the previous ones).

8. In the network model, it is not allowed to depict connections between adjacent events of 2 or more works.

Calculation of planned parameters of network schedules

The main planned parameters are:

The duration of the work;

Critical path;

Time reserves for the occurrence of events and so on.

In network models, tense and non-tense paths are distinguished.

Tense path- the critical path.

Unstressed path- full path, less than critical in duration.

From the unstressed paths, the subcritical path is distinguished, that is, the closest in duration to the critical one.

Time reserve the execution of an event is such a period of time for which the execution of this event can be delayed without violating the deadlines for the completion of work planned by the network schedule. The time reserve is defined as the difference between the late date of the event and the early date of the event:

Early term the occurrence of an event characterizes the earliest possible time of the event. The time of its occurrence is determined by the value of the longest segment of the path from the initial to the considered one:

At t 0- i = max

Late date the occurrence of an event - such a period of admissible time, exceeding which causes a corresponding delay in the occurrence of the final event. The calculation of the late date of the event is carried out from the final to the initial one and is determined by the difference between the duration of the critical path and the maximum duration of the paths following the given event to the final one:

T P i = L cr - t i - c at t i - c = max

Time reserves are available not only for events, but also for all paths of the network model, except for the shortest one. The slack for critical path events is always zero. The difference between the length of the critical path and any other full path is usually called full reserve of time:

R p = L cr - L i

The total reserve of time shows how much the total duration of all jobs belonging to this path can be increased.

R p1 = 48 - 18 = 30

R p2 = 48 - 40 = 8

R p3 = 48 - 24 = 24

R p4 = 48 - 29 = 19

An important planning property of a full slack is the fact that it can be used in part or in full to increase the duration of some work. At the same time, the reserve of time for all other jobs on this path decreases.

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After the calculation of the marked numerical parameters has been made for each of the network diagrams, the SPU service on this basis compiles a calendar schedule for the execution of work due to the preparation for mass production of all products of the planned quarter. If at the same time it is possible to obtain such a schedule in which the process of preparing the production of each of the products is completed within an acceptable time frame, then one of the acceptable schedules is obtained. If not, then an analysis is made of a possible reduction in the preparation time for the production of individual products by changing the composition or sequence of work in order to reduce the duration of the critical paths of the corresponding network schedules, reduce the duration of execution individual works(first of all, works on critical paths), more rational use or attraction of additional resources, varying the start and end dates of works on critical paths, taking into account a more rational use of resources.

As a result of repeated sequential improvement of the initial work plan, it is possible either to obtain an acceptable schedule, or to come to the conclusion that, given these constraints, due primarily to the actual availability of resources, all products cannot be prepared within the agreed time frame. The latter is the basis for revising individual directives for the preparation of production of specific products or serves as a prerequisite for attracting additional resources. In this regard, the corresponding most acceptable for the given production association(enterprises) final decisions on the timing of the completion of the preparation of production of products and the use of resources and a project is drawn up calendar plan... On its basis, the recommended start and end dates of work related to the preparation for the production of each specific product are determined, a schedule-recommendation for the performance of work by each of the performers for a certain period of time, a schedule of resource consumption, time parameters of the degrees of freedom indicators necessary for analyzing and adjusting the plan -recommendations when making management decisions. After the SPU service has drawn up a schedule for the preparation of production of products of a new assortment and, in order to implement it, have issued corresponding task plans for the performance of work by each of the performers, the service monitors and records the progress of the planned work, identifies and analysis of deviations arising between planned and actual progress of work. On this basis, appropriate control actions are provided, ensuring the elimination of the deviations that have arisen, i.e., operational regulation progress of work. Daily collection of information on the actual implementation of the planned work is carried out by the SPU service. To do this, at the beginning of each working day, one of the service employees looks through all the control cards and examines the actual state of the work on the current day specified in these control cards. performers. This information is issued only in cases where there are some deviations of the actual progress of work from the planned, namely, when new work appears or the need to perform previously envisaged work disappears, the wording of existing work and events changes, and the duration of work and actual their start and end dates. In all these cases, the responsible executor informs the SPU service about the changes that have occurred (Form 4). All information collected by the SPU service is processed, and on this basis, appropriate changes are made to the schedule and operational decisions are made aimed at eliminating deviations of the actual progress of work from the planned one. If at the same time it is not possible to eliminate the deviations that have arisen, then the SPU service adjusts the schedule for preparing the production of new products and the corresponding changes are communicated to the responsible executors. Thus, it is shown in detail how all the main tasks of managing the preparation of the production of new products are solved based on the use of network diagrams. Further improvement of the described production preparation management system would be the use of computers and economic and mathematical methods to find solutions to the problems described above. At the same time, as the experience of industrial associations and enterprises shows, computers for solving the problems of managing the preparation of the production of new products in each specific enterprise should be used in stages, gradually relieving a significant number of employees of the administrative apparatus from labor-intensive work on the primary processing of information. Ultimately, with the use of a computer, the problem of finding the optimal schedules for preparing the production of new products must be solved. Their determination and correction should be made in the computer center (CC) on the basis of information received from the SPU service, as well as from the responsible executors. When drawing up scheduling plans, it is advisable to use determined specific situations methods and algorithms for finding solutions to problems scheduling, due to the appropriate formulation of each specific problem, which was described in detail above. The draft of the optimal schedule for preparing the production of new products calculated in the computer center is issued to the SPU service, after which it is coordinated by the employees of this service with the responsible executors and approved by the chief engineer of the given enterprise or production association. From the moment of its approval until the completion of the entire complex of work, provided for by the preparation of the production of new products in accordance with the drawn up plan, operational regulation of the progress of the work performed is carried out. To do this, the computing center receives daily operational information about the actual implementation of the planned work. On its basis, the center compiles various summaries and documents in the actual performance of work. This output information is sent to the SPU service and is used by the heads of various departments when making decisions aimed at eliminating bottlenecks that have arisen. The output information is constructed in such a way that each manager receives only the information that is necessary for him and is sufficient for analysis and management decisions. In addition to issuing various summaries and documents on the actual progress of work, once a month in the computer center, in accordance with the assessment of the status of the progress of work, operational schedules for the preparation of production of products for the next one or two months are formed. After approval, the schedules are communicated to the responsible executors through the SPU service.

Network planning is a management method based on the use of the mathematical apparatus of graph theory and a systematic approach to display and algorithmize complexes of interrelated works, actions or activities to achieve a clearly defined goal. The most famous are the practically simultaneously and independently developed method of the critical path - MCP and the method of assessing and revising plans - PERT. They are used to optimize the planning and management of complex branched work complexes that require the participation of a large number of performers and the cost of limited resources. The main goal of network planning is to minimize project duration. The task of network planning is to graphically, visually and systematically display and optimize the sequence and interdependence of works, actions or activities that ensure the timely and systematic achievement of the ultimate goals. To display and algorithmize certain actions or situations, economic and mathematical models are used, which are usually called network models, the simplest of which are network diagrams. With the help of the network model, the manager of a work or operation has the ability to systematically and scaled up the entire course of work or operational activities, to manage the process of their implementation, as well as to maneuver resources. The most common uses for network planning are:

• · Targeted research and development of complex objects, machines and installations, in the creation of which many enterprises and organizations are involved;
• · Planning and management of the main activities of developing organizations;
• · Planning of a complex of works on preparation and development of production of new types of industrial products;
• · Construction and installation of industrial, cultural and household and residential facilities;
• · Reconstruction and repair of existing industrial and other facilities;
• Planning of training and retraining of personnel, verification of performance decisions taken, organization of a comprehensive audit of the activities of enterprises, associations, construction and installation organizations and institutions.

The use of network planning methods helps to reduce the time for creating new objects by 15-20%, ensuring rational use labor resources and technology.

In network modeling construction production There are two basic concepts used: network models and network graphics. Network models are different depending on the nature of the construction object, goals and a number of other indicators. Network models are classified according to the following main features:

• 1. by the type of goals - single-purpose models and multi-purpose (for example, during the construction of different objects erected by the same construction organization; 2. by the number of coverage of objects: a particular model and a complex model (for example, for one object and for the whole industrial complex factory);
• 3. by the nature of the estimates of the parameters of the model: deterministic (with pre-determined and fully determined data) and probabilistic (taking into account the influence of random factors);
• 4. models taking into account the target orientation (time, resource, cost).

Elements of the network diagram are (for the type "vertices - events") are:

• 1.work - a process that requires time and resources (for example, digging pits, concreting foundations, installing columns, etc.;
• 2. event - the fact of the completion of one or several works, necessary and sufficient to start one or several subsequent works, requiring neither time nor resources (for example, the end of digging pits, concreting foundations, roofing, etc.);
• 3. expectation - a technological and organizational break between works, requiring only time expenditures (for example, concrete hardening, plaster drying, etc.);
• 4.dependency (or fictitious work) - an element of the network schedule, which is introduced to reflect the correct technological relationship between the works, which does not require the expenditure of either time or labor of performers (such as, for example, the completion of digging a trench at the 1st stage and the possibility of starting the laying of foundation blocks on the same capture);

The following designations are adopted for the elements of the network schedule: Work and expectations are depicted by solid lines with arrows directed along the technological process (from left to right); events are shown with circles, and dependencies are shown with dotted lines with arrows. Events are numbered one number, and works - two (the number of the previous and subsequent events).

The length of the lines with arrows can be taken as arbitrary, but sometimes the network diagram is built on a time scale, i.e. tied to calendar days of work. The name of the work is indicated above the arrow, and the duration of work (n) is indicated below the arrow.

Elements of the network diagram are shown in Table 3.

Table 3 - the main elements of the network schedule.

"St. Petersburg State Technological Institute

(Technical University)"

UGS (code, name) ________________________________________

Specialty (specialization) __________________________________

Faculty_____________________________________________________

Department ______________________________________________________

COURSE PROJECT

Topic "Network planning and management of technical training

production of new products by example

Student _________________ __________________

Supervisor,

position ________________ ___________________

(signature, date) (initials, surname)

3) Subprogramme for the design and manufacture of non-standard equipment and tooling;

4) Subprogram of technological development of the production of new products up to the stipulated design level.

For each subprogram, local network diagrams are built, which are then stitched into a general network diagram of the target scientific and technological program.

Decisions made under the subprogram 1. The decisions on the subprogram provide for the use of science-intensive technological processes, its implementation should begin after receiving a completely revised technological documentation based on the results of testing prototypes of new products. Depending on the novelty of technological processes, decisions are made on the reconstruction of workshops and the layout of production areas.

The most important decisions for updating production technology should be considered the widespread use of CNC equipment in combination with robotic devices. Accordingly, the management system is also subject to changes, as production becomes more flexible, focused on individual orders of product consumers. The primary organizational element in the management of flexible automated manufacturing (FAC) is the flexible manufacturing module (FMC), which operates offline. Several technologically connected PMGs and an automated transport and storage system (ATSS) form a flexible automated section (GAU). In turn, GAUs of various technological purposes, united by common production tasks, are included in organizational structure flexible automated workshop (GAC).

In the conditions of frequent turnover of manufactured products, production flexibility is complemented by functional computer-aided design (CAD) systems and an automated process preparation system (ASTPP). At the same time, the possibilities of effective application of ASTPP depend on the informativeness of design and technological classifiers, determined by the level of continuity of design solutions in CAD.

Methodical instructions for practical work №3

"NETWORK PLANNING OF SCIENTIFIC AND TECHNICAL PREPARATION OF PRODUCTION"

Developed by Assoc., Ph.D. Prokhorov Yu.K.

Network planning of scientific and technical preparation of production

Formulation of the problem

A team of developers (researchers, designers, technologists, programmers, etc.) was given a task to develop a project and a deadline was set for the completion of the development. It is necessary to plan the development progress using the network planning and management (NMS) method, which would ensure the completion of all work within a given deadline.

The task

According to the proposed list of works, it is necessary to draw up a network model (network graph) of project development, determine the expected duration of work, calculate the parameters of the network model, determine the likelihood of the project being completed within a given deadline and assess the quality of the developed network model, optimize the network model, develop a work distribution schedule ...

1. Basic concepts and definitions

The network model is a graphical representation of the technological sequence and the connection of events that represent the result of one or more activities.

An event cannot be expressed in time - it represents the end of the work included in it.

In the network model, an event is represented by a circle with an indication of the event number.

Work is any process that precedes the occurrence of an event. Work in the network model is depicted by an arrow.

Distinguish:

The work is valid, i.e. requiring labor and time;

Waiting work that only requires time;

Fictitious work - a logical connection between two events, indicating that the data obtained during the occurrence of a previous event is necessary for the occurrence of a subsequent event. In this case, time and resources are not spent. Fictitious work is shown with a broken arrow.

All work through intermediate events leads to the final event, which means the achievement of the goal outlined in the program.

Any continuous sequence of activities and events forms the paths of the network model.

Critical path is the full path (from the start to the end event) of the maximum duration.

2. Rules for constructing the topology of the network model

A schematic representation of events and activities, showing their interrelationships, forms a topological model of the development process.

In order to avoid errors and related further incorrect decisions when building a network model, the following rules must be observed:

1. The network model is built from left to right: from the initial event to the final one.

2. The length of the arrow representing the work does not represent the duration of the work (the model is built out of scale).

3. The expected duration of work is put down in the corresponding time estimates (days, weeks) above the arrow.

4. It is impractical to depict on the model of work with a duration less than the accepted unit of measurement (one day, one week), since this granularity makes ongoing management over the network difficult.

5. Works are coded with the numbers of the initial ( ith) and final ( j гo) events, and the code j гo work events cannot be less than code ith work events.

6. The network model should not contain a single event, except for the initial one, which would not include any work.

7. In the network model there should not be a single event, except for the final one, from which no work would come out.

8. On the network model there should be no works with the same codes, ie. with common start and end events. If works ATo (k = 1, 2 ..., n) begin and end with events common for these works (Fig. 1), then in order for all these works to have different codes, it is necessary to enter into the network model (n-1) fictitious works B t (t = l, 2 ..., n-1) (fig. 2)

9. When building a network model, you should avoid crossing arrows whenever possible.

3. Determination of the duration of work

One of the most important steps in building a network model is to obtain correct estimates of the duration of the work. The duration of the work can be determined either according to the existing standards, or using expert probabilistic estimates.

Formulas for determining the expected duration of work by the second method, depending on the number of expert assessments, are presented in table. one.

Table 1

Calculated dependencies to establish the expected duration of work

and its variance based on expert assessments

Legend for the table:

t min- the minimum duration of work, selected from the condition that the performance of the work will proceed under the most favorable circumstances;

t HB- the most probable duration of work, chosen under average conditions, under which no unexpected difficulties arise;

t max- the maximum duration of work, selected from the condition of performing this work under the most unfavorable combination of circumstances.

4. Calculation of the parameters of the network model