Calculation of production cycle duration. When calculating the duration of the production cycle Tp.c, only those time costs that do not overlap with time are taken into account. An example of calculating the duration of a technological cycle for sequential, pair

PRODUCTION PROCESS AND ITS ORGANIZATION

Practical work №1

(Option 81)

Goal of the work: consolidate and concretize students’ knowledge in the field of rational organization of the production process, analyze and evaluate the degree of influence of various organizational factors on the production cycle.

Task

Determine the duration of technological and production cycles for all three types of movement of objects of labor; how the duration of the technological cycle will change if the processing batch is doubled; what type of party movement and its size has the most significant impact on reducing the cycle. Construct graphs of technological cycles for parallel and parallel-sequential movement of objects of labor.

The work is carried out in two shifts of 8 hours each. There are no natural processes when processing a batch of parts. The initial data for option 81 are shown in Table 1.

Table 1 Initial data

Operation No.	Standard time t PC, min	Number of machines With, PC	Processing batch size n, PC	Transport package size p, PC	Average interoperative time t mo, min

Advance paynemt

Operation No.	Standard time t PC, min	Number of machines With, PC

Calculation of technological and production cycles of movement of parts

Sequential type of movement

The duration of the production process, that is, the calendar period of time during which the production process is carried out, is called the production cycle. The basis of the production cycle is the technological cycle, which in turn consists of operational cycles.

The operating cycle, i.e. the duration of processing a batch of parts (min) at one (given) process operation is equal to

,

Where P - batch size of parts, pcs.;

t m - piece-calculation standard time for an operation, min;

With- number of jobs per operation.

The combination of operational cycles in execution time significantly influences the production cycle and determines the order in which parts (batches) are transferred in the process. There are 3 types of combinations of operational cycles (types of movement of objects of labor through process operations): sequential, parallel and parallel-sequential.

A sequential type of movement, when the entire processed batch of parts is completely transferred to the subsequent operation after the complete completion of all work on the previous one. In this case, the duration of the technological process (min) is determined by the sum of operating cycles

Where m - number of operations in the process.

The duration of the production cycle (calendar days) additionally includes interoperational breaks (t mo ) and the time of natural processes ( T eating)

Where S- number of shifts;

q - shift duration, min;

f- coefficient for converting working days into calendar days (with 260 working days per year f = 260/365 = 0.71).

n=150pcs; R=15pcs

Figure 1 - Graph of the technological cycle in sequential form

Parallel type of movement

A parallel type of movement, when small transport batches p or individual pieces (p = 1) of parts are launched into a subsequent operation immediately after processing them in the previous operation, regardless of the entire batch. In this case, the most labor-intensive operation with the longest operating cycle is fully loaded; less labor-intensive operations have breaks.

Number of transport packs N, PC.:

.

Where R- number of parts in a transport batch (pack), pcs;

- operation cycle with maximum duration, min.

The duration of the production cycle (calendar days) will take the form

With double batch size (2n=300)

n=150pcs; R=15pcs

Figure 2 - Graph of the technological cycle in parallel mode

movements of a batch of parts in production

Parallel-sequential type of movement

Parallel-sequential type of movement, in which the next operation begins before the complete completion of work on the previous operation and is carried out without interruptions manufacturing a batch of parts. In this case, there is a partial overlap of the execution time of adjacent operational cycles. The transfer of manufactured parts from the previous to the subsequent operation is carried out not in whole batches, but in parts, transport batches R(in packs) or individually (p=1).

The duration of the technological cycle (min) will be correspondingly less than with a sequential type of movement by the amount of combining operating cycles.

Where
- the sum of short operating cycles from each pair of adjacent operations.

The duration of the production cycle (calendar days) with a parallel-sequential type of movement will take the form:

With double batch size (2n=300)

Figure 2 - Graph of the technological cycle with a parallel-sequential type of movement of a batch of parts in production

IN conclusions:

Having analyzed the calculations of technological and production cycles for three types of movement of parts, as well as graphs of technological cycles, we can clearly state that the longest is sequential movement (4800 min). This is explained by the fact that the entire batch of parts being processed is completely transferred to the subsequent operation after all work on the previous one has been completed. The fastest is the parallel type of movement (1830 min). This is due to the fact that small transport batches of parts are launched into the subsequent operation immediately after they have been processed in the previous operation, regardless of the entire batch. In this case, the most labor-intensive operation with the longest operating cycle is fully loaded; less labor-intensive operations have breaks. The serial-parallel type of movement turned out to be slightly longer than the parallel one (1965 min), because there is a partial overlap of the execution time of adjacent operational cycles, i.e. the next operation begins before the previous operation is completed and is carried out without interruptions manufacturing a batch of parts.

As for doubling the batch size, the parallel type of movement also turns out to be the most effective, because the technological cycle will end at 330 minutes. faster (3330 min) than if we repeated it twice (3660 min). The same situation is observed in series-parallel motion. Here the time gain would be 105 minutes. (3825 min. vs. 3930 min.). With sequential movement, the technological process time will not be reduced, and the duration of the production cycle will decrease by only 0.26 calendar days (versus 0.52 days with parallel and 0.19 calendar days with parallel-sequential movement of a batch of parts in production).

When calculating the duration of the production cycle T p.c, only those time costs that do not overlap with the time of technological operations are taken into account (for example, time spent on control, transportation of products). Breaks caused by organizational and technical problems (untimely provision of the workplace with materials, tools, violation of labor discipline, etc.) are not taken into account when calculating the planned duration of the production cycle. 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. Usually one of three types of combinations of operations is used: sequential, parallel, parallel-serial.

At sequential movement, the processing of a batch of items of labor of the same name at each subsequent operation begins only when the entire batch has been processed at the previous operation.

Example 1. Let's say you need to process a batch consisting of three products (n = 3); then the number of processing operations (t = 4), time standards for operations are: t 1 = 10, t 2 = 40, t 3 = 20, t 4 = 10 minutes.

For this case the cycle duration is:

T c. last = 3 (10 + 40 + 20 + 10) = 240 min.

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:

T c. last = , (2.14)

where t i is the piece rate of the i-th operation;

Ci- number of jobs.

At parallel in motion, the transfer of objects of labor to a subsequent operation is carried out individually or in a transport batch immediately after processing in the previous operation:

T c. par = , (2.15)

Where R - transport lot size, pcs;

t max - time to complete the longest operation;

C max - number of jobs in a long-running operation.

For the example above: R= 1.

T c. steam = (10 + 40 + 20 + 10) + (3 - 1) × 40 = 160 min.

At parallel type of movement, the duration of the production cycle is significantly reduced.

At parallel-serial In the form of movement, objects of labor are transferred to the subsequent operation as they are processed at the previous one individually or in a transport batch, while the time for performing related operations is partially combined in such a way that a batch of products is processed at each operation without interruptions. The transfer of a transport batch pt to the next operation can be carried out without waiting for work to be completed on the entire batch of products, subject to the condition of continuity of work on n ser,

When organizing parallel-sequential movement, two options for combining operations are possible:

a) from a previous short to a subsequent long operation;

b) from a previous long to a subsequent short operation;

In each of the options, a reduction in the technological cycle by the amount τ = (n ser - p t) × (t core / C about core) is achieved.

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 the sequential type of movement, due to the partial overlap of the execution time of each pair of adjacent operations:

T c.p-p = T c.p - = (2.16)

For example, 1 p = 1.

T c. steam-last = 240 - = 160 min.

With a parallel-sequential combination of technological operations, the cycle duration T c.p.p in calendar days is determined by the formula:

where 1/0.7 is the coefficient for converting working days into calendar days;

n and p - the number of products in the series and in the transport batch;

m is the number of technological operations performed;

T m.o - the duration of interoperational waiting and transportation time from the previous to the next workplace;

T eat - the duration of the natural process;

ΣТ pcs.cor - the total time standard for short operations, which is found during a sequential selection of operations, comparing them sequentially with each other in pairs, for all technological operations;

T cm - duration of shift, T cm = 8 hours;

f cm - number of shifts per day.

For clarity and precise execution, a graph of the production cycle duration is constructed, shown in Figure 2.7.

Figure 2.7 - Production cycle duration schedule

Rules for constructing a production cycle duration schedule.

1. Parallel-sequential type of movement:

a) in the case of a transition from a short previous operation to a longer one, the transfer is carried out after the first transport batch;

b) in the case of a transition from a previous long operation to a short one - the transfer is carried out from the last transport batch of the long operation, and the rest are completed by the amount:

τ = (n ser - r t) × t i.

2. Parallel type of movement:

a) first, the technological cycle of the 1st transport batch is built for all operations without technological waiting;

b) then the schedule of the “main” - the longest operation - is completed, taking into account its continuity;

Uninterrupted operation (with minimization of interoperational expectations) at technological operations can be achieved by synchronizing all other operations subject to the following conditions:

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 labor 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 therefore their duration), and standards for work in progress. 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, which 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.

Production capacity of the enterprise

The production capacity of an enterprise or workshop directly depends on the duration of the production cycle. Under 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 production 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 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.

Introduction

The purpose of the workshop on production organization is to expand and deepen theoretical knowledge, to instill the necessary skills for solving the most frequently encountered problems in practice regarding the organization and planning of production.

The workshop includes tasks for the main sections of the course. At the beginning of each topic, brief methodological instructions and theoretical information, typical problems with solutions and problems for independent solution are presented.

The presence of methodological instructions and brief theoretical information in each topic allows you to use this workshop for distance learning.

Calculation of production cycle duration

The duration of the production cycle serves as an indicator of the efficiency of the production process.

Production cycle– the period of stay of objects of labor in the production process from the moment of launching raw materials until the moment of release of finished products.

The production cycle consists of working hours, during which labor labor is expended, and break times. Breaks, depending on the reasons that caused them, can be divided into:

1) on natural or technological - they are determined by the nature of the product;

2) organizational(breaks between shifts).

The duration of the production cycle consists of the following components:

T cycle = t those + t eats + t tr + t k.k. + t m.o. + t m.ts.

Where t those– time of technological operations;

t eats - time of natural processes (drying, cooling, etc.);

t tr – transportation time of objects of labor;

t k.k. – quality control time;

t m.o – interoperative care time;

t m.c. – storage time in inter-shop warehouses;

(t three t k.k. can be combined with t m.o).

The calculation of the production cycle time depends on the type of production. In mass production, the duration of the production cycle is determined by the time the product is in production, i.e.

T cycle = t in M,

Where t V– release stroke;

M- number of workplaces.

Under release stroke it is necessary to understand the time interval between the release of one manufactured product and the next product.

The release stroke is determined by the formula

t in = Teff /V,

Where Tef– effective fund of worker time for the billing period (shift, day, year);

IN– volume of output for the same period (in natural units).

Example: T cm = 8 hours = 480 min; T per = 30 min; → Teff = 480 – – 30 = 450 min.

B = 225 pcs; → t in = 450/225 = 2 min.

In serial production, where processing is carried out in batches, the duration of the technological cycle is determined not per unit of product, but for the entire batch. Moreover, depending on the method of launching a batch into production, we get different cycle times. There are three ways of moving products in production: sequential, parallel and mixed (series-parallel).

I. At sequential When moving parts, each subsequent operation begins only after the previous one has finished. The cycle duration for sequential movement of parts will be equal to:

Where n – number of parts of the batch being processed;

t pcsi- piece rate of time for an operation;

C i– number of jobs per i th operation;

m– number of technological process operations.

A batch of products consisting of 5 pieces is given. The batch is passed sequentially through 4 operations; the duration of the first operation is 10 minutes, the second is 20 minutes, the third is 10 minutes, the fourth is 30 minutes (Fig. 1).

Picture 1

T cycle = T last = 5·(10+20+10+30) = 350 min.

The sequential method of moving parts has the advantage that it ensures the operation of the equipment without downtime. But its disadvantage is that the duration of the production cycle in this case is the longest. In addition, significant stocks of parts are created at work sites, which requires additional production space.

II. At parallel During the movement of the batch, individual parts are not detained at work stations, but are transferred individually to the next operation immediately, without waiting for the processing of the entire batch to be completed. Thus, with the parallel movement of a batch of parts, at each workplace various operations are simultaneously performed on different parts of the same batch.

The processing time of a batch with parallel movement of products is sharply reduced:

dl .

Where n n– number of parts in transfer batch(transport batch), i.e. the number of products simultaneously transferred from one operation to another;

Length – the longest operating cycle.

When launching a batch of products in parallel, the parts of the entire batch are processed continuously only at those workplaces where long operations follow short ones. In cases where short operations follow long ones, i.e. longer (in our example, the third operation), these operations are performed discontinuously, i.e. equipment is idle. Here, a batch of parts cannot be processed immediately, without delays, since the previous (long) operation does not allow this.

In our example: n= 5, t 1 = 10; t 2 = 20; t 3 = 10; t 4 = 30; With= 1.

T steam = 1·(10+20+10+30)+(5-1)·30=70+120 = 190 min.

Let's consider the diagram of parallel movement of parts (Fig. 2):

Figure 2

III. To eliminate interruptions in the processing of individual parts of a batch in all operations, use parallel-serial or mixed a launch method in which parts (after processing) are transferred to the next operation one by one, or in the form of “transport” batches (several pieces) in such a way that the execution of operations is not interrupted at any workplace. In the mixed method, the continuity of processing is taken from the sequential method, and the transition of the part from operation to operation immediately after its processing is taken from the parallel method. With a mixed method of launching into production, the cycle duration is determined by the formula

core .

where is the cor. – the shortest operating cycle (from each pair of adjacent operations);

m-1 – number of combinations.

If the subsequent operation is longer than the previous one or equal in time, then this operation is started individually, immediately after processing the first part in the previous operation. If, on the contrary, the subsequent operation is shorter than the previous one, then interruptions occur here during piece transfer. To prevent them, it is necessary to accumulate a transport reserve of such a volume that is sufficient to ensure work at the subsequent operation. To practically find this point on the graph, it is necessary to transfer the last part of the batch and move the duration of its execution to the right. The processing time for all other parts in the batch is plotted to the left on the graph. The beginning of processing of the first part indicates the moment when the transport backlog from the previous operation must be transferred to this operation.

If adjacent operations are the same in duration, then only one of them is considered short or long (Fig. 3).

Figure 3

T last pairs = 5·(10+20+10+30)-(5-1)·(10+10+10) = 350-120 = 230 min.

The main ways to reduce the production cycle time are:

1) Reducing the labor intensity of manufacturing products by improving the manufacturability of the manufactured design, using computers, and introducing advanced technological processes.

2) Rational organization of labor processes, arrangement and maintenance of workplaces based on specialization and cooperation, extensive mechanization and automation of production.

3) Reduction of various planned and unplanned breaks at work based on the rational use of the principles of scientific organization of the production process.

4) Acceleration of reactions as a result of increasing pressure, temperatures, transition to a continuous process, etc.

5) Improving the processes of transportation, storage and control and combining them in time with the processing and assembly process.

Reducing the duration of the production cycle is one of the serious tasks of organizing production, because affects the turnover of working capital, reducing labor costs, reducing storage space, the need for transport, etc.

Tasks

1 Determine the duration of the processing cycle of 50 parts with sequential, parallel and serial-parallel types of movement in the production process. The process of processing parts consists of five operations, the duration of which is, respectively, min: t 1 =2; t 2 =3; t 3 =4; t 4 =1; t 5 =3. The second operation is performed on two machines, and each of the others on one. The size of the transfer lot is 4 pieces.

2 Determine the duration of the processing cycle of 50 parts with sequential, parallel and serial-parallel types of movement in the production process. The process of processing parts consists of four operations, the duration of which is, respectively, min: t 1 =1; t 2 =4; t 3 =2; t 4 =6. The fourth operation is performed on two machines, and each of the others on one. The size of the transfer lot is 5 pieces.

3 A batch of parts of 200 pieces is processed with parallel-sequential movement during the production process. The process of processing parts consists of six operations, the duration of which is, respectively, min: t 1 =8; t 2 =3; t 3 =27; t 4 =6; t 5 =4; t 6 =20. The third operation is performed on three machines, the sixth on two, and each of the remaining operations on one machine. Determine how the duration of the processing cycle for a batch of parts will change if the parallel-sequential version of the movement in production is replaced by a parallel one. The size of the transfer lot is 20 pieces.

4 A batch of parts of 300 pieces is processed with parallel-sequential movement during the production process. The process of processing parts consists of seven operations, the duration of which is, respectively, min: t 1 =4; t 2 =5; t 3 =7; t 4 =3; t 5 =4; t 6 =5; t 7 =6. Each operation is performed on one machine. Transfer lot – 30 pieces. As a result of improving production technology, the duration of the third operation was reduced by 3 minutes, the seventh - by 2 minutes. Determine how the processing cycle of a batch of parts changes.

5 A batch of blanks consisting of 5 pieces is given. The batch goes through 4 operations: the duration of the first is 10 minutes, the second is 20 minutes, the third is 10 minutes, the fourth is 30 minutes. Determine the cycle duration by analytical and graphical methods with sequential movement.

6 A batch of blanks consisting of four pieces is given. The batch goes through 4 operations: the duration of the first is 5 minutes, the second is 10 minutes, the third is 5 minutes, the fourth is 15 minutes. Determine the cycle duration by analytical and graphical methods with parallel movement.

7 A batch of blanks consisting of 5 pieces is given. The batch goes through 4 operations: the duration of the first is 10 minutes, the second is 20 minutes, the third is 10 minutes, the fourth is 30 minutes. Determine the cycle duration by analytical and graphical methods for serial-parallel motion.

8 Determine the duration of the technological cycle for processing a batch of products of 180 pieces. with parallel and sequential variants of its movement. Build processing process graphs. The size of the transfer lot is 30 pcs. Time standards and number of jobs in operations are as follows.

Guidelines for performing practical work

on the topic “Calculation of the duration of the production and technological cycle”

Purpose of practical work: study the essence of the production cycle, learn how to calculate the duration of the production cycle, identify the main ways to reduce the duration of the production cycle.

Introduction

The production process is a collection 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. Competent organization of the production process is the basis of the activities 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 cycle is one of the most important technical and 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 process takes place in time and space, so the production cycle can be measured by the length of the movement path of the product and its components, as well as the time during which the product goes through the entire processing path.

Basic concepts about the production and technological cycle

Production cycle- the calendar period of time from the moment raw materials are launched into production until the finished product is released, accepted by the technical control service and delivered to the finished product warehouse, which is measured in days and hours.

There are simple and complex production cycles.

A simple production cycle is the cycle of manufacturing a part. Complex production cycle – product manufacturing cycle.

The structure of the production cycle includes the time for performing main and auxiliary operations, natural processes and breaks in the manufacture of products (Fig. 1).

Figure 1 – Structure of the production cycle

The production cycle has two stages:

1) time of the production process;

2) time of breaks in the production process.

The production process time, which is called the technological cycle, or working period, includes:

Time for preparatory and final operations;

Time for technological operations;

Time for natural processes to occur;

Transportation time during the production process;

Time for technical control.

The time of breaks in the production process is the time during which there is no impact on the subject of labor and there is no change in its quality characteristics, but the product is not yet finished and the production process is not completed.

Break times during production include:

Interoperative follow-up time;

Time between shifts.

Preparatory-final time is spent by the worker (or team) on preparing himself and his workplace to complete the production task, as well as on all actions to complete it. It includes the time for obtaining work orders, materials, special tools and devices, setting up equipment, etc.

The time of technological operations is the time during which a direct impact on the subject of labor is carried out either by the worker himself or by machines and mechanisms under his control.

The time of natural technological processes is the time during which the object of labor changes its characteristics without the direct influence of man and technology (drying a painted product in air, cooling a heated product, etc.).

Time for technical control and time for transportation during the production process constitutes maintenance time, which includes:

Product processing quality control;

Control of operating modes of machines and equipment;

Transportation of workpieces, materials, acceptance and cleaning of processed products.

There are regulated and unregulated breaks. Regulated breaks are divided into interoperational and intershift.

Interoperational (intra-shift) breaks are divided into:

Batch breaks (occur when processing parts in batches: each part, arriving at the workplace as part of a batch, lies twice - before the start and at the end of processing, until the entire batch goes through this operation);

Waiting breaks (caused by inconsistency (non-synchronization) in the duration of adjacent operations of a technological process and occur when the previous operation ends before the workplace is freed up to perform the next operation);

Breaks in completion (occur in cases where parts and assemblies are lying around due to the incomplete production of other parts included in one set).

Breaks between shifts are determined by the work schedule (number and duration of shifts) and include breaks between work shifts, weekends and holidays, and lunch breaks.

Unregulated breaks include:

1) breaks due to disruption of the production process - this is the time of breaks for organizational and technical reasons (equipment malfunction and troubleshooting; lack of workpieces, parts, materials at the workplace; lack of electricity, steam, gas, water; lack of tools, equipment; waiting crane, electric vehicle);

2) breaks depending on the performer, which in turn are divided into two types:

Breaks caused by violation of labor discipline (lateness to work, unauthorized absences from the workplace, premature departure from work, etc.);

Breaks for valid reasons (absence of the performer with the permission of the administration, sudden illness, injury, visiting a first-aid post, teaching a student, etc.).

Calculation of production and technological cycle

The production cycle duration is calculated using the formula:

where T p.c. , T tech. - respectively, the duration of the production and technological cycles;

T est.pr. - time of natural processes;

T per. - duration of breaks.

When calculating the duration of the production cycle T p.c. Only those time costs that are not covered by the time of technological operations are taken into account (for example, time spent on control, transportation of products). Breaks caused by organizational and technical problems (untimely provision of the workplace with materials, tools, violation of labor discipline, etc.) are not taken into account when calculating the planned duration of the production cycle.

The main component of the production cycle is the duration of technological operations, which constitutes the technological cycle. The duration of the technological cycle largely depends on the method of transferring parts from operation to operation. There are three types of movement of parts during their manufacturing process: sequential; parallel-serial; parallel.

1. With a sequential type of movement of objects of labor, parts at each operation are processed in a whole batch. The parts are transferred to the next operation after the processing of all parts in a given batch has been completed.

With a sequential type of movement, the technological cycle T is subsequent. processing a batch of parts n at operations m is equal to:

where n is the number of parts in the batch, pcs.;

i - number of operations (i = 1…m);

t i - piece processing time of one part at the i-th operation, min;

RM i is the number of parallel workstations at the i-th operation.

With a sequential type of movement of objects of labor, a batch of parts is delayed at each operation until all parts from the batch are completely processed (i.e., batch breaks are observed). This leads to an increase in work in progress and a lengthening of the technological part of the production cycle. This type is used in single and small-scale production.

The duration of the technological cycle for processing a batch of parts at the i-th operation is equal to:

The duration of the technological cycle with a sequential type of movement of objects of labor is the sum of the time it takes to complete a batch of parts at each operation, i.e. from operating cycles:

To reduce the duration of the technological cycle, other types of movement of objects of labor are used.

Operation No.	t pcs., min.	RM	Time, min.
0 20 40 60 80 100 120 140 160
n= 20 pcs.
			40
			60
			20
			40

Figure 2 - Technological cycle for sequential movement of a batch of parts

The advantages of this method: no interruptions in the operation of equipment and workers during each operation; the possibility of their high load during the shift; simplicity of organization.

Disadvantages of this method: parts lie for a long time due to interruptions in batching, which results in the creation of a large volume of work in progress; Due to the lack of parallelism in the processing of parts, the duration of the technological cycle is the longest.

The sequential type of movement is used, as a rule, in single and small-scale production.

2. Parallel-sequential type of movement is such an order of transfer of objects of labor in which the execution of the subsequent operation begins before the end of processing of the entire batch in the previous operation, i.e. there is parallelism in the execution of operations. In this case, the processing of parts of the entire batch at each operation is carried out continuously.

There are 2 options for parallel-sequential movement:

a) The duration of the operating cycle in the previous operation is less than in the subsequent one. In this case, the start of processing in the subsequent operation is possible immediately after the completion of processing of the first piece or transfer lot in the previous operation. Parts are transferred to the subsequent operation one by one as they are ready, while they (except for the first) will lie waiting for the workplace to become free for the subsequent operation.

b) The duration of the operating cycle in the previous operation is longer than in the subsequent one. In this case, the start of processing at the subsequent operation is determined from the condition that the last piece or transfer lot, having been completed by processing at the previous operation, immediately begins to be processed at the subsequent one. To ensure continuous operation during the subsequent (short) operation, a backlog of finished parts is created on the previous ones. When transferring parts to a subsequent operation, they focus on the last part. By the time work on it begins, the subsequent operation must finish processing all the other parts in the batch.

For large batches, parts are transferred not individually, but by transport (or transfer) batch R.

The total duration of the technological cycle with parallel-sequential movement T p-p is reduced compared to sequential movement by the sum of those time intervals τ , during which adjacent operations are performed in parallel, i.e.:

, (5)

In practical calculations, this savings can be calculated using the shortest of two adjacent operations:

, (6)

Thus we get:

, (7)

If the transfer of objects of labor is carried out piece by piece, then instead of R 1 is substituted.

Operation No.	t pcs., min.	RM	Time, min.
0 10 20 30 40 50 60 70 80 90 100
n= 20 pcs., p= 5 pcs.
			10 10 10 10
			15 15 15 15
			5 5 5 5
			10 10 10 10

Figure 3 - Technological cycle for parallel-sequential movement of a batch of parts

This method is used for significant production of products of the same name in areas with uneven equipment capacity at enterprises with serial and large-scale production of products with large batches of parts and significant labor-intensive operations. Its use requires constant maintenance of minimum stocks of labor items between operations, careful preliminary calculations, clear planning and regulation of production.

The advantages of this method: no downtime for equipment and workers; significant reduction in the duration of the technological cycle compared to the sequential type of movement.

This type of movement is widely used in medium-scale and large-scale production when processing labor-intensive parts.

3. A parallel type of movement is an order of transfer of objects of labor in which each part (or transport batch) is transferred to the subsequent operation immediately after completion of processing in the previous operation.

With a parallel type of movement of objects of labor, an even greater reduction in the technological cycle is achieved.

Thus, the processing of batch parts is carried out simultaneously in many operations. There is no lingering of parts due to batch breaks, which leads to a reduction in the duration of the technological part of the production cycle and a reduction in work in progress.

When constructing a graph of a parallel type of movement, the technological cycle for the first part or transport batch p is first noted. Then, based on the operation with the longest operating cycle (t chapter - the main operation), a cycle of work is built on the entire batch n without interruptions. For all parts (transport batches), except the first, operational cycles are completed for all other operations.

The total duration of the technological part of the production cycle is T pairs. determined by the formula:

, (8)

where is the time of the longest operation (main).

For piece transfer p = 1.

Task. Determine the duration of the technological cycle for processing a part

Determine the duration of the technological cycle of processing a part using different types of transfer of objects of labor. The planned batch is 30 pieces. The operations per unit and the number of machines per operation are given below:

Solution.

In order to find the cycle duration using the sequential method of transferring parts, you need to use the formula:

n– number of parts in the batch being processed pcs.

i- operation

m– number of operations in the technological process

WITH і – the number of machines on which the part is processed in the i-th operation.

t i – unit time to perform the i-th operation, minutes

t eats - the duration of natural processes (we do not have them and are taken equal to zero)

Let's substitute the values ​​into the formula

T c. last= 30*(5/1 + 9/1 + 18/1 + 6/2 + 5/1 + 3/2) = 30*(5 + 9 + 18 + 3 + 5 + 1.5)=1245 minutes

T cycle.– total processing time of the technological process

R– size of the transfer lot pcs.

(t/c) core. – duration of execution of the shorter of two adjacent operations.

Let's substitute the values ​​into the formulas.

τ = (30-5) * (5/1 + 9/1 + 6/2 + 6/2 + 3/2) = 25*(5 + 9 + 3 + 3 + 1.5) = 25 * 41, 5 = 537.5 min.

Now let's find the duration of the parallel-sequential cycle.

T cycle = 1245 - 537.5 = 707.5 minutes

The task of a parallel sequential cycle is to pass the products of labor through all stages of production as quickly as possible while the machines are continuously operating.

In order to find the duration of the parallel cycle of parts transfer, we use the formula:

Let's substitute the values ​​into the formula.

T c pairs = 5*(5/1+9/1+18/1+6/2+5/1+3/2)+(30-5)*(18/1)=5*(5+9 +18+3+5+1.5)+

25*18=5*41.5+25*18=207.5+450=657.5 minutes

The task of the parallel cycle of movement of parts is to pass the products of labor through all stages of production as quickly as possible.

We can find the parallelism factor using the formula:

T c steam - cycle duration using parallel movement of parts

T ts last – cycle duration in a sequential way of moving parts.

Let's substitute the values ​​into the formula.

K pairs = 657.5/1245 = 0.528

Answer: T c. last =1245 min. , T c p-p = 707.5 min. , Tc steam =657.5 min.

Task. Determine the change in the duration of the parts processing cycle

A batch of parts consists of 10 parts, which are processed using a parallel sequential type of motion. The technological process of processing parts consists of 6 operations t 1 = 2, t 2 = 9, t 3 = 6, t 4 = 2, t 5 = 3, t 6 = 4 min. It is possible to combine the fifth and sixth operations into one without changing the duration of each. The size of the transport batch is 1. Determine how the duration of the technological cycle for processing parts will change.

In order to find the time of a parallel sequential cycle of movement of parts, we use the formula.