The schedule of the technological cycle with a sequential type of movement. Production cycle: the duration of the production cycle, components, calculation. Parallel-sequential movement

The production cycle- one of the most important technical and economic indicators, which is the starting point for calculating many indicators of the production and economic activities of the enterprise. On its basis, for example, the timing of the launch of the product is established, taking into account the timing of its release, it is calculated, the volume of work in progress is determined, and other planned production calculations are carried out.

The manufacture of a product (batch) is a calendar period of its being in production from the launch of raw materials and semi-finished products into the main production to receiving finished product(parties).

Cycle structure

The structure of the production cycle includes the execution time of the main, auxiliary operations and breaks in the manufacture of products (Fig. 8.2).

Rice. 8.2. Production cycle structure

The execution time of the main operations of processing products is technological cycle and determines the time during which the direct or indirect impact of a person on the subject of labor is carried out.

The breaks can be divided into two groups:

  • breaks associated with the work schedule established at the enterprise - non-working days and shifts, between shift and lunch breaks, in-shift regulated breaks for rest of workers, etc.;
  • breaks due to organizational and technical reasons - waiting for a vacant workplace, waiting at the assembly of components and parts, inequality of production rhythms in adjacent, i.e. dependent on each other, workplaces, lack of energy, materials or Vehicle etc.:

Calculation of the duration of the production cycle

  • T p.ts,T tech - accordingly, the duration of the production and technological cycles;
  • T lane- duration of breaks;
  • T eats. etc- the time of natural processes.

When calculating the duration of the production cycle T p.ts only those costs of time are taken into account that do not overlap with the time of technological operations (for example, time spent on control, transportation of products). Interruptions caused by organizational and technical malfunctions (untimely provision of the workplace with materials, tools, violation 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 in the operations existing at the enterprise. Usually one of three types is used: serial, parallel, parallel-serial.

At consistent movement processing of a batch of similarly named objects of labor at each subsequent operation begins only when the entire batch has been processed at the previous operation.

Example 8.1.

Let's say you want to process a batch of three items (n = 3); the number of processing operations (m = 4), the time norms but operations are: = 10, = 40, = 20, = 10 minutes.

For this case, the cycle time

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

Since a number of operations can be performed not in one, but in several workplaces, the duration of the production cycle with sequential movement in general case has the form

where, is the number of jobs.

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

where R- the size of the transport batch, pcs; t max- time to complete the longest operation, min; C max- the number of jobs in the longest operation. For the above example: p = 1.

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

With a parallel movement mode, the production cycle is significantly reduced.

With a parallel-sequential type of movement, objects of labor are transferred to the next operation according to their processing at the previous piece or transport batch, while the execution time of adjacent operations is partially combined in such a way that the batch of products is processed at each operation without interruption.

The duration of the production cycle can be defined as the difference between the cycle time 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:

For example 8.1: p = 1.

240 - (3 - 1) (10 + 20 + 10) = 160 min.

Cycle time

The duration of the production cycle is influenced by many factors: technological, organizational and economic. Technological processes, their complexity and diversity, technical equipment predetermine the processing time of parts and the duration of assembly processes. Organizational factors of the movement of objects of labor in the process of processing are associated with the organization of jobs, the work itself and its payment. Organizational conditions further affect the duration of ancillary operations, service processes and breaks.

Economic factors determine the level of mechanization and equipment of processes (and, consequently, their duration), standards of work in progress.

The faster it is done (the shorter the duration of the production cycle), which is one of the elements of the circulation working capital, the greater will be the rate of their turnover, the greater the number of revolutions they make during the year.

As a result, there is a release monetary resources that can be used to expand production at this 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 circulating assets in their material form, i.e. in the form of specific material resources.

The production capacity of an enterprise or workshop directly depends on the duration of the production cycle. Under production capacity means the maximum possible production output in the planning period. And therefore, it is clear that the less time is spent on the production of one product, the more of them can be produced in the same period of time.

With a reduction in the duration of the production cycle, it 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 work of auxiliary workers in a unit of production, as well as the share of labor of specialists and employees.

With a reduction in the production cycle, it decreases due to a decrease in the unit cost of production, the share of general plant and workshop costs with an increase in production capacity.

Thus, reducing the duration of the production cycle is one of the most important sources of intensification and increasing 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, the deepening of specialization and cooperation, the introduction of methods scientific organization labor and maintenance of workplaces, robotics.

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

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

Solution.

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

n- the number of parts in the processed batch, pcs.

i- operation

m- the number of operations in the technological process

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

t i - piece 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)

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 technological process

R- the size of the transfer batch pcs.

(t / c) cor... - the duration of the execution of the smallest of two adjacent operations.

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 minutes

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

Cycle T = 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 with continuous operation of machines.

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

Let's plug in 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 a 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 coefficient of parallelism using the formula:

T c steam - the duration of the cycle in a parallel way of movement of parts

T c post. - the duration of the cycle in a sequential way of movement of parts.

Let's plug in the values ​​into the formula.

K pairs = 657.5 / 1245 = 0.528

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

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

A batch of parts consists of 10 parts that are machined in parallel sequential 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 minutes. 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 of parts processing will change.

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

The production cycle

One of the most important components production activities is the production cycle. One of its main characteristics is duration of the production cycle.

The duration of the production cycle is understood as the time after which the raw materials turn into finished products..

The production cycle includes:

  • Time of technological operations
  • Interoperative simple
  • Time for the course of natural processes (cooling of the metal, hardening of concrete).

Interoperational downtime can be reduced by a reasonable type of transfer from one operation to another and methods of organizing product processing:

  • sequential processing
  • parallel-serial processing
  • parallel product processing

Determination of the duration of the production cycle

The formula for the duration of the cycle of sequential processing of parts

The organization of the production process by the method of sequential processing of parts is carried out in the case when one technological operation is performed after the completion of the previous one and there is no possibility of their combination (simultaneous execution) during processing the same party products. That is, until the end of the processing of the entire batch of products in one technological operation, further processing is not performed.

Cycle time for sequential processing details can be found by the formula:

n- the number of parts in the processed batch, pcs.

i- operation

m- the number of operations in the technological process

ti

Сi

test

wait- the duration of waiting for processing between technological operations (interoperative downtime and lying)

Explanation of the formula for calculating the duration of the production cycle for sequential processing... Please note that the formula has three parts.
The first part of the formula allows you to directly determine the time during which the part (product) is subjected to direct active processing. We divide the processing time of the operation by the number of machines that perform this operation, multiply by the number of parts in the batch. We get the time for which a separate operation will be performed for the entire batch of parts. The sum of time for all operations gives us the time spent on processing parts without taking into account other factors.
The second part of the formula adds technologically necessary time to natural processes (for example, cooling, removal of internal stresses, etc.). The sum is duration of the cycle of technological operations... This value is displayed in a separate formula on the first line. It will be useful to us later.
Adding third part of the formula, which takes into account the waiting time for processing and other waste of time, gives the duration of the production cycle, which we can already take into account for planning purposes.

Parallel-Serial Cycle Time Formula

Parallel-serial processing method involves a partial overlapping of time for the execution of adjacent operations, that is, processing in subsequent operations begins before the end of the production of the entire batch in previous operations, while it is necessary to maintain the conditions of continuous processing of each operation.

This method of processing is used when the equipment can only operate in a continuous cycle. For example, heat treatment of a batch will not be economically feasible if the parts arrive at it at arbitrary points in time with arbitrary interruptions. Therefore, we will need to start the heat treatment cycle in such a way that from the moment the batch starts processing until the moment it ends, the equipment would work continuously. The moment of starting processing on such equipment should be calculated in such a way that the start time of processing at the current operation would be such that the part that came out last from the previous operation was immediately sent for processing at the current one or was already waiting for processing.

The duration of the technological cycle with a parallel-serial method of transferring parts ( T c p-p) is calculated by the formula:

T cycle of pairs last- the total execution time of the technological process of processing parts in parallel-sequential processing

n

p

ti- piece execution time of the i-th operation, minutes

Сi- the number of machines on which the part is processed at the i-th operation

(t / c) cor... - duration of execution of the smallest of two adjacent operations

test- the duration of operations during which natural (natural) processes occur

Explanation formulas for calculating the duration of the production cycle for parallel-serial processing... As you can see from the first line of the block of formulas, from the time calculated for the sequential processing of parts, the time savings arising from the fact that the batch of parts lies only partially and its processing begins until the end of processing of the entire batch is subtracted.
Second line of the formula block decrypts the first. We divide the processing time of the operation by the number of machines that perform this operation, multiply by the number of parts in the batch. We get the time for which a separate operation will be performed for the entire batch of parts. The sum of time for all operations gives us the time spent on processing parts without taking into account other factors. Then we add the time required for the natural processes of cooling, hardening, etc. and subtract the time savings resulting from the earlier start time of processing parts in the next operation.
The third line of the formula block shows us how the batch reduction time is calculated. Please note that the first operation may be shorter than the second, or vice versa. Therefore, from two adjacent operations, we need to choose the one whose processing time is shorter. Now, when we subtract the size of the transfer batch from the size of the entire batch, we get the number of parts that, in fact, will be processed in parallel. We have the maximum, the transfer batch, which we subtracted. Now, multiplying the number of parallel processed parts by the time of their parallel processing (t / s), with the smaller of the two operations, we will get the amount of time savings for processing with such an organization of production.
The fourth line of the formula block only supplements the time we calculated (see the second line of the formula block) with the time of waiting with details of processing as a result of lying.

The formula for the cycle time of parallel processing of a batch of parts

Parallel movement of a batch of parts characterized by the fact that simultaneously at all operations different copies of this name are processed, and each sample is processed continuously for all operations. The transfer of parts from operation to operation is carried out individually or in transfer batches. In this case, the most time-consuming operation ("bottleneck") is fully loaded, while others are waiting for processing.

The cycle time for parallel processing of a batch of parts is found by the formula:

T loop parallel- the total execution time of the technological process of processing parts in parallel processing

n- the number of parts in the processed batch, pcs.

p- the size of the transport (transfer) batch, pcs.

ti- piece execution time of the i-th operation, minutes

Сi- the number of machines on which the part is processed at the i-th operation

test- the duration of operations during which natural (natural) processes occur

Explanation formulas for calculating the duration of the production cycle in parallel processing... Since at the "bottleneck" the processing is performed continuously, the batch processing time will increase only for the time of the "jam" of parts exceeding the size of the transfer batch (n-p) in the "bottleneck" (t / s) max, which is what the formula shows us.
The first part of the formula allows you to directly determine the time during which the part (product) is subjected to direct active processing. We divide the processing time (t) of the operation by the number of machines (C) that perform this operation, multiply by the number of parts in the transfer (!) Batch.
The second part of the formula allows us to calculate how long a batch is stuck in a bottleneck. Since all other operations will be performed faster, the duration of soak will be equal to the number of waiting parts (n-p) multiplied by the duration of processing in the bottleneck (t / s) max.
The third part of the formula, which takes into account the waiting time for processing and other waste of time, unless, of course, it is specified in technological map as a technological operation

Coefficient of parallelism of the production process

Parallelism- simultaneous execution of parts of the production process (stages, operations), that is, the implementation of processes with overlapping.

Coefficient of parallelism of production is found by the formula:

T parallel processing- the duration of the cycle when organizing processing in a parallel way of movement of parts

Fact- the actual duration of the processing cycle of parts.

Determination of the duration of the production cycle is also possible graphically.

5.2.1. Calculation of the duration of the production cycle simple process with sequential, parallel - sequential and parallel modes of movement

The production cycle is based on the technological cycle, which in turn consists of operating cycles.

Operating cycle Is the duration of processing a part or batch of parts in one operation of the production process.

V general view duration i -th operating cycle is determined by the formula:

where P - the size of the batch of parts, pcs;

- by piece - the calculation rate of time for i -th operation, min .;

- the number of jobs per i th operation.

The combination in the execution time of operating cycles significantly affects the duration of the technological and, therefore, the production cycle.

There are three types of combinations of operating cycles, which determine the type of movement of products (parts) by operations: sequential, parallel-sequential and parallel.

At sequential motion, the entire batch of parts is transferred to the next operation only after finishing the processing of all parts in the previous operation. Batch of parts- this is the number of parts of the same name, launched into production with a one-time cost of preparatory - final time.

The duration of the technological cycle with a sequential type of movement is determined by the sum of operating cycles according to the formula:

, (5.2.2.)

where m - the number of operations in the technological cycle.

A graphical method for determining the duration of a technological cycle with a sequential form of movement of parts is shown in Fig. 5.2.1.

Rice. 5.2.1. Technological cycle with a sequential form of movement of objects of labor by operations

Duration production cycle with sequential movement determined by the formula:

, (5.2.3)

where is the time of natural processes, min;

- duration of interoperative breaks, min .;

- the duration of breaks associated with the operating mode of the enterprise.

The production cycle expressed in calendar days , is determined by the formula:

, (5.2.4.)

where is the duration of the shift in minutes;

f- the number of shifts per day;

- the coefficient taking into account the mode of operation of the enterprise is determined by the formula:

where and - the number of working and calendar days in a year.

The advantages of the sequential movement of parts are:

the relative simplicity of the organization of work;

no interruptions in the work of equipment and workers;

the possibility of their high load during the shift.

However, the production cycle with a sequential type of movement has the greatest duration, since each part is delayed (lies) at the workplace awaiting processing of the entire batch of parts. Therefore, the sequential type of movement can be recommended when processing small batches of parts with low labor intensity in operations, which is typical for single and small-scale production.

To shorten the technological cycle, apply parallel-sequential motion... Its essence lies in the fact that the entire batch of parts to be processed is divided into transport batches of “p” parts each or piece by piece (p = 1). The transportation lot is processed at each operation without interruption and it can be transferred to the next operation without waiting for the end of processing for other transportation lots. In this case, the condition must be met continuous work at each operation when processing the entire batch “n”.

The duration of the technological cycle will be less than in the case of a sequential type of movement by the total value of the combination of operating cycles (), which is determined by the formula:

, (5.2.6.)

where P - the number of parts in the batch being processed, pcs;

R- the number of parts in the transport batch, pcs;

- the minimum value of the operating cycle for two adjacent operations.

The duration of the technological cycle with a parallel - sequential type of movement determined by the formula:

The duration of the production cycle in calendar days for a parallel - sequential type of movement is determined by the formula:

. (5.2.8.)

A graphical method for determining the duration of a technological cycle with a parallel - sequential type of movement is shown in Fig. 5.2.2.

When constructing a schedule, one should take into account the ratio of operating cycles on adjacent operations. If the operating cycle in the previous operation is less than or equal to that of the next one, i.e. , then the transport batch after processing it in the previous operation can be immediately transferred to the next operation. Continuity of processing is achieved due to the fact that the productivity at the previous operation is higher than at the next one.

Fig.5.2.2. Technological cycle with a parallel - sequential form of movement of objects of labor in operations

If the operating cycle in the previous operation is longer than in the next one, i.e. , then after processing the first transport batch at the previous operation, it cannot be immediately transferred to the next one, since the productivity on i -th operation is less and the continuity of operation of the equipment on ( i + 1) th operation.

Continuity of batch processing in a subsequent operation can be achieved only when it accumulates the minimum required backlog of parts before the start, and, therefore, the subsequent operation can be started at a later date. Graphically, the start of processing at a subsequent operation is determined from the condition that the last transport batch, after processing it at a previous operation, is transferred immediately to the next one.

Parallel - the sequential type of movement has a shorter cycle, but leads to an increase in the number of accounting and planning units, to a higher rate of operation of vehicles. It is advisable to use it for large batches and high labor intensity of products, which is characteristic of large-scale production. However, there is also a latency of parts waiting for processing due to the out of sync in the time of operations.

Parallel view of movement of parts transport batches are transferred to the next operation immediately after the end of their processing at the previous one. In this case, the lying of parts between operations is eliminated, all operations of the technological cycle are performed in parallel, as a result of which the duration of the technological cycle is reduced to a minimum. Downtime of equipment and workers occurs due to asynchronous operating cycles in time. If the duration is equal, there will be no downtime.

The duration of the technological cycle with a parallel type of movement determined by the formula:

. (5.2.9.)

Duration of the production cycle with a parallel movement mode determined by the formula:

. (5.2.10.)

A graphical method for determining the duration of a technological cycle with a parallel form of movement is shown in Fig. 5.2.3.

Rice. 5.2.3. Technological cycle with a parallel view of the movement of objects of labor in operations

The rules for constructing a schedule of a technological cycle with a parallel form of movement are formulated as follows:

1. A technological cycle is built for the first transport batch at all operations without interruptions between them.

2. The operation with the longest cycle is determined and a cycle is built for it over the entire processed batch “n” without interruptions.

3. For the rest of the transport batches, except for the first one (for which it has already been constructed according to item 1.), operating cycles are completed on all operations, except for the longest one (for which it is constructed according to item 2.).

CALCULATION OF PRODUCTION CYCLE DURATION

Production cycle is called a complex of the main, auxiliary and service processes, organized in a certain way in time, necessary for the manufacture of a certain type of product. The most important characteristic the production cycle is its duration.

The duration of the production cycle is the period of time during which a material, workpiece or other workpiece goes through all the operations of the production process (or a certain part of it) and turns into a finished product.

Distinguish between the production cycle of individual parts and the production cycle of an assembly unit or product as a whole. The production cycle of a part is usually called simple , and a product or assembly unit - complicated ... The cycle can be single-stage and multi-stage.

One-step production cycle for a batch of parts for i-th operation is determined by the formula:

n- the number of parts in a production batch, PC.;

https://pandia.ru/text/80/150/images/image003_90.gif "width =" 37 "height =" 28 src = "> - the number of workplaces (machines) for i-th operation of the technological process.

Simple cycle calculation

The cycle time of a multi-step process depends on the way parts are transferred from one operation to another. There are three types of movement of objects of labor in the process of their manufacture: sequential, parallel and parallel-sequential.

At sequential movement the entire batch of parts is transferred to the next operation after finishing the processing of all parts in the previous operation. The advantages of this method are the absence of interruptions in the work of the equipment and the worker at each operation, the possibility of their high load during the shift. But the production cycle with such an organization of work is the largest, which negatively affects the technical and economic indicators of the workshop, enterprise.


At parallel movement the parts are transferred to the next operation by the transport batch immediately after the end of its processing at the previous operation. In this case, the shortest cycle is ensured. But the possibilities of using the parallel type of movement are limited, since a prerequisite its implementation is the equality or multiplicity of the duration of operations. Otherwise, interruptions in the operation of equipment and workers are inevitable.

At parallel-serial motion parts from operation to operation, they are transferred in transport batches or piece by piece. In this case, there is a partial overlapping of the execution time of adjacent operations, and the entire batch is processed at each operation without interruption. Workers and equipment work without interruption. The production cycle is longer in comparison with the parallel, but shorter than with the sequential movement of objects of labor.

https://pandia.ru/text/80/150/images/image005_74.gif "width =" 17 "height =" 20 src = "> - the number of parts in the transport (transfer) batch, PC.;

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https://pandia.ru/text/80/150/images/image010_45.gif "width =" 45 "height =" 24 src = ">.

Parallel movement of batches of parts

The parallel option is characterized by the fact that small transport lots are transferred from the previous operation to the next one immediately after the end of their processing at the previous one. This option allows you to minimize total duration technological cycle.

On the other hand, the continuity of processing of the entire batch of parts is ensured only during the longest operation. At other operations, equipment and workers are idle awaiting the arrival of the next transport batch. In order to reduce the latter disadvantage, it is necessary to try to reduce these downtime to a minimum by changing the norms of time or the number of jobs.

https://pandia.ru/text/80/150/images/image015_35.gif "width =" 609 height = 277 "height =" 277 ">

In this case, the transport batch can be transferred immediately after its processing at the previous operation, and the continuity of processing of the entire batch of parts will be ensured.


Option 2:

Processing time on the next operation is less than on the previous one

In this case, you cannot transfer the freight lot immediately after it has been processed in the previous operation, since there will be a downtime at the subsequent workstation. In order to avoid downtime, the necessary stock of parts should be accumulated.

The amount of stock and the time when it is possible to start transferring the first transport batch to the next operation are found as follows: from the end of the processing time of all parts in the previous operation, the perpendicular is lowered, the processing time of one last transport batch is set to the right of the perpendicular, and the processing time of the rest is to the left of the perpendicular transport consignments.

Thus, the condition is satisfied that the last transport batch is processed in the next operation without any waiting (sequentially), and all the previous ones must be continuously processed by the time the last one starts processing.

https://pandia.ru/text/80/150/images/image020_27.gif "width =" 75 "height =" 64 src = "> - time to perform the shortest operation (from each pair of two adjacent operations).

Complex cycle calculation

A complex cycle is a combination of simple cycles and individual operations that strictly follow a given technological process.

Let's consider an example of making and assembling a product A, the structure of which is shown in the diagram..gif "width =" 81 "height =" 25 ">. Gif" width = "87" height = "25">. It is generally accepted that different parts are manufactured at the same time.

Building a complex cycle

Unlike the previous constructions, this graph is built starting from the point of completion of the complete assembly of the product. On the graph from right to left, in a time scale, the cycles of the constituent processes are plotted, starting from the assembly of assemblies, sub-assemblies and ending with the manufacture of parts.

The total duration of a complex cycle is determined by the largest sum of sequentially interconnected processes for the manufacture of parts and assembly units. That is, the duration of the complete manufacturing cycle of a product is determined by the longest chain.

|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____ days

Exercise 1

Determine the duration of the technological cycle of processing a batch of parts at the sight of the movement of objects of labor:

- consistent;

- parallel;

- parallel-serial.

The graphic version of the calculation, drawn on a large scale, should be supplemented with an analytical calculation.

Assignment 2

Determine the total duration of the manufacturing cycle of the machine "K". Establish the start date for the manufacture of the machine, if it must be handed over to the customer no later than the specified date.

 

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