Under The duration of the production cycle of a batch of products is understood as the period of time during which blanks (basic materials) are transformed into finished parts .
The duration of the production cycle is one of the main indicators, which allows us to evaluate the organizational and technical level of production and determine the timing of the launch and release of products in conditions of single and serial production.
The amount of work in progress, which occupies a significant share in the composition, largely depends on the duration of the production cycle. working capital enterprises. Reducing work in progress leads to an acceleration of the turnover of working capital, which is of great importance economic importance for enterprise economics.
Let us introduce a number of more concepts.
An operating cycle is the time it takes to process a batch of parts in a specific operation.
The technological cycle is the time associated directly with the processing of a batch of parts in all operations technological process.
Considering that the duration of technological operations is standardized in most cases, the duration of the technological cycle can be calculated quite accurately. The time for performing auxiliary operations (control and transport) and laying down parts during the production process, as a rule, is not standardized, so their value is determined approximately taking into account the conditions of execution in the workshops of a machine-building enterprise.
Breaks associated with the accepted operating mode in the workshop are taken into account when the duration of the production cycle is determined in days (calendar or working).
The duration of the technological cycle for processing one batch of parts depends on the type of movement in production. There are three main (typical) types of movement of a batch of parts: sequential, parallel and parallel-sequential.
Sequential type of movement batches of parts for operations is characterized by the fact that a batch of parts is transferred to a subsequent operation after it has been completely processed in the previous operation. (TC AFTER)
TC PAST = p x , (1.1)
Where n – number of parts in the batch;
T- number of operations in the technological process;
ti- piece time i-th operations;
Ci– the number of parallel working machines (workstations) per operation.
In all cases ti should be determined taking into account the percentage of time standards fulfilled by workers.
Magnitude Shopping center does not include the time of breaks, preparatory and final time and the time of auxiliary operations, therefore it is always less than the actual duration of the production cycle of a batch of parts. The batch size of processed parts is assumed to be the same for all operations, although this condition is sometimes not met in practice.
Parallel-sequential type of movement of a batch of parts operations are characterized by the following characteristics:
1. The transfer of a batch of parts from operation to operation is carried out individually or in parts (transfer batches);
2. The start of processing a batch of parts at each operation is planned in such a way as to ensure continuity of processing of the entire batch at the operation;
3. Parallel processing of a batch of parts in separate operations is ensured.
Duration of the technological cycle for processing a batch of parts with this type of movement in operations (TC PP) will be determined by the formula
Tc PP = n x – (n-p) x , (1.2)
Where r – number of parts in the transfer batch.
Parallel view of the movement of a batch of parts operations are characterized by two characteristics:
1. The transfer of a batch of parts from operation to operation is carried out piece by piece or in transfer batches;
2. Each transfer batch enters processing at the subsequent operation immediately after its processing at the previous operation, i.e. Each transfer batch undergoes processing for all operations continuously and independently of other transfer batches.
Duration of the technological cycle for processing a batch of parts with this type of movement in operations (TC PAR) determined by the formula
TC PAR = p x + (n-p) x m ax (1.3)
From the formula it follows that the greatest influence on the value TC PAR in the parallel type of processing, the “leading” operation has the effect, i.e. operation with the longest duration operating cycle. In all operations (with the exception of the “leading”), breaks occur between the end of processing of the previous one and the beginning of processing of the next transfer batch, if the durations of the operations are not equal or multiples.
Problems with solutions
Task 1.1. Determine the duration of the technological cycle for processing a batch of 100 parts with sequential, parallel and parallel-sequential types of movement of workpieces during the production process. Parts for complex types of movement are transferred from operation to operation in transfer batches of 20 pieces.
The technological process of processing a part includes 5 operations with a duration of t 1 = 2 min. , t 2 = 6 min. , t 3 = 5 min. , t 4 = 12 min. , t 5 = 5 min. In the second operation two machines are used, the fourth operation is performed in three machines, in the remaining operations one machine is operated.
Construct movement schedules for a batch of parts for each type of movement.
Solution
The duration of the technological cycle for processing a batch of parts will be:
TC AFTER = n x = 100 x 
= 1900 min;
TC PP = p x - (n-p) x = 1900 – (100-20) x
X 
= 860 min;
TC PAR = p x + (n-p) x m ax = 20 x +
+ (100-20) x = 780 min.
The movement schedules for a batch of parts for each type of movement will look like:
| m | |||||||||||||
0 200 400 600 800 1000 1200 1400 1600 Hz (min)
Rice. 1.1. Schedule of sequential movement of a batch of parts by operation
The construction of a schedule for the parallel-sequential type of movement of a batch of parts through operations depends on the ratio of the duration of the operating cycles of related operations. If the duration of the operating cycle at the subsequent operation is longer than at the previous one, then processing of the batch of parts at the subsequent operation begins after receiving the first transfer batch from the previous operation.
If the duration of the operating cycle at a subsequent operation is less than at the previous one, then the processing of a batch of parts at the subsequent operation is based on the moment of receipt of the last transfer batch from the previous operation. In this case, relative to this moment in the subsequent operation, the processing time of one transfer batch (the last one) is shown to the right, and the processing time of the remaining transfer batches is shown to the left.
| m | |||||||||||||||||||||||||||
0 200 400 600 800 Hz (min)
Rice. 1.2. Parallel-sequential movement schedule of a batch of parts
The procedure for constructing a graph with a parallel type of movement of a batch of parts by operation is as follows: first, a graph is constructed for one transfer batch, as with a sequential type of movement, and then, relative to the operation with the maximum operating cycle, a graph for the remaining transfer batches is similarly constructed.
| m | ||||||||||||||||||
0 200 400 600 800 Hz (min)
Rice. 1.3. Parallel movement schedule of a batch of parts
Problem 1.2. Determine the duration of the production cycle for sequential, parallel-sequential and parallel types of movement. Indicate the possible dates for launching the entire batch into production for these types of movement.
The size of the processed batch is 500 pcs., the transfer batch is 50 pcs., the release date of the entire batch of parts is September 1st. Production operates in two 8-hour shifts with two days off. The time limits for operations are as follows:
Time associated with transportation and inter-operational care, take 10 % on the duration of the technological cycle.
Solution
1. The duration of the technological cycle for processing a batch of parts will be:
a) with a sequential type of movement
TC AFTER = 500 x 
= 1100 hours;
b) with a parallel-sequential type of movement
TC PP = 1100 – (500-50) x 
= 560 hours;
c) with a parallel type of movement
TC PAR = 50 x + (500-50) x = 470 hours.
2. Duration of the production cycle for processing a batch of parts (tpc) in hours will be:
a) with a sequential type of movement
Tpts LAST = 1100 x 1.1 = 1210 hours;
b) with a parallel-sequential type of movement
Tpts PP = 560 x 1.1 = 616 hours;
c) with a parallel type of movement
Tpts PAR = 470 x 1.1 = 517 hours.
3. The duration of the production cycle for processing a batch of parts in working days will be:
a) with a sequential type of movement
Tpts AFTER = 1210: 16 = 75.6 days, we accept 76 working days;
b) with a parallel-sequential type of movement
TPC PP = 616: 16 = 38.5 days, we accept 39 working days;
c) with a parallel type of movement
Tpts PAR = 517: 16 = 32.3 days, accept 33 working days
4. The launch period, taking into account the operating mode of the enterprise according to the 2003 calendar, will be:
Problem 1.3. Determine the duration of the production cycle for a sequential type of movement with the following initial data:
· total time of operational cycles in operations – 840 minutes;
· preparatory and final time for a batch of parts in all operations – 60 minutes;
· time associated with moving and storing a batch of parts – 420 minutes;
· the coefficient of compliance with standards on the site is 1.2.
Solution
Tpts LAST = + 60 + 420 = 1180 min.
Problem 1.4. A mechanism consisting of two units and three parts is assembled. The assembly diagram of the mechanism is shown in Fig. 1.4.
| M | |||||||||||||||||||||||
| SB-1 | SB-2 | ||||||||||||||||||||||
| D-11 | D-12 | D-21 | D-22 | D-23 | D-1 | D-2 | D-3 | ||||||||||||||||
Rice. 1.4. Mechanism assembly diagram
The duration of the cycles is as follows:
The duration of production cycles for assembling units is as follows:
Determine the total production time assembly units and the M mechanism as a whole.
Solution
If the production of parts and the assembly of components are carried out in parallel, the duration of production of assembly unit 1 will be 7 days, assembly unit 2 - 7 days, mechanism M as a whole - 12 days.
Individual assignment on topic I:
“Determination of the duration of the production cycle of processing
batch of parts."
Exercise. Batch needs to be processed "n" details. Workpieces are transferred from operation to operation in transfer batches equal to "p" details. The technological process of processing a part consists of 6 operations with a duration t 1, t 2, …, t 6. In the second and fifth operations, two machines are used, the fourth operation is performed on three machines, in the remaining operations one machine is used. Lot size of parts "n", transfer batch "p" , duration of each operation of the technological process "t" are taken from the tables given in Appendix 1 in accordance with the individual code.
Define:
a/ the duration of the technological cycle for processing a batch of parts with sequential, parallel-sequential and parallel types of movement;
b/ build processing schedules for a batch of parts by type of movement;
Practical lesson No. 1
Subject: Duration of the technological cycle for processing a batch of parts or products
Production batch– this is the number of parts (products) of the same name and standard size, launched into production within a certain time interval with the same preparatory and final time (Tp.z.) for the operation.
Depending on the simultaneity of related operations, there are three types of movement of parts through the operations included in a given process: sequential, parallel-sequential and parallel.
Sequential type of movement characterized by the fact that when manufacturing a certain batch of parts in a multi-operational technological process, each subsequent operation begins only after the previous operation has been completed on the entire batch being processed.
Parallel-serial(a more advanced type of movement compared to a sequential one) - such an order of transfer of objects of labor in a multi-operational production process in which the execution of a subsequent operation begins before the end of processing of the entire batch in the previous operation (this reduces the time it takes for parts to lie between operations; adjacent operations overlap in time , since they are executed in parallel for some time)
Parallel type of movement- such an order of transfer of objects of labor in a multi-operational production process, which is characterized by the absence of batch breaks, in which each copy is transferred to the subsequent operation immediately after completion of processing in the previous operation
Task 1. Determine the duration of the technological cycle for processing 20 parts with sequential, parallel-sequential and parallel types of movement in the production process. Construct a schedule for processing parts for each type of movement. The technological process of processing parts consists of four operations, the duration of which is t 1 =1, t 2 =4, t 3 =2, t 4 =6 minutes. The fourth operation is performed on two machines, and each of the others is performed on one. The size of the transfer lot is 5 pcs.
Solution
The duration of the technological cycle for processing a batch of parts with a sequential type of movement is calculated using the formula
T last = n ∙ ,
where n is the number of parts in the batch being processed;
m – number of operations in the technological process;
t pieces i – piece-calculation norm of time for an operation, min.;
C i is the number of pieces of equipment simultaneously employed in the i-th operation.
T last = 20 ∙ (1 + 4 + 2 + ) =200 min.
The duration of the technological cycle for processing a batch of parts with a parallel-sequential type of movement is determined by the formula
T pp = T last – 
,
Where 
– the sum of time intervals (τ i) during which adjacent operations are performed in parallel.
T pp = n ∙ 
– (n – p) ∙ 
,
where p is the number of parts in the transfer (transport) batch (parts into which the processed batch of parts is divided), pcs.;
(
) core i – the shortest operating cycle of each pair of adjacent operations, min.
T pp = 20 ∙ (1 + 4 + 2 + ) – (20 – 5) ∙ (1 + 2 + 2) = 125 min.
(τ 1 =(20-5)∙1=15 min.; τ 2 =(20-5)∙2=30 min.; τ 3 =(20-5)∙2=30 min.).
The duration of the technological cycle for processing a batch of parts with a parallel type of movement is calculated using the formula
T pairs = (n – p) ∙( 
) gl + p ∙ 
,
Where ( 
) hl – longest operating cycle, min.
T steam = (20 – 5) ∙ 4 + 5 ∙ (1 + 4 + 2 + ) = 110 min.
The duration of the technological cycle for processing a batch of parts is minimal with a parallel type of movement.
Rules for constructing a graph of a parallel type of motion
For the first transfer batch, a graph of the sequential type of movement is constructed.
For the main operation (with the longest operating cycle), a schedule is built for processing the entire batch without interruptions.
The processing of all transfer batches in operations located after the main and before the main operation is depicted, based on the required deadlines for submitting transfer batches to the main operation.
There are two possible cases of parallel-sequential combination of adjacent operations:
when the duration of the previous operation is less than the subsequent one. In this case, processing of a part (transfer batch) in a subsequent operation is possible immediately after the completion of processing of the first part (transfer batch) in the previous operation;
when the duration of the previous operation is longer than the subsequent one, immediately after processing the first part (transfer batch), it cannot be transferred to the subsequent operation (unlike case 1).
One of the most important components production activities is the production cycle. One of its main characteristics is production cycle duration.
The duration of the production cycle refers to the time it takes for raw materials to be transformed into finished products..
The production cycle includes:
Interoperational downtime can be reduced due to a reasonable type of transfer from one operation to another and methods for organizing product processing:
Organization production process 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 same party products. That is, until the entire batch of products is processed in one technological operation, no further processing is performed.
Cycle time of the sequential processing method details can be found using the formula:
n- number of parts in the batch being processed, pcs.
i- operation
m– number of operations in the technological process
ti
Ci
test
toexpect- waiting time for processing between technological operations (interoperational downtime and layovers)
Explanation of the formula for calculating the duration of the production cycle for sequential processing. Please note that the formula consists of three parts.
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 an operation by the number of machines that perform this operation and multiply it by the number of parts in the batch. We get the time during which a single operation will be completed for the entire batch of parts. The sum of the time for all operations gives us the time spent on processing parts without taking into account other factors.
Second part of the formula adds technologically necessary time to natural processes (for example, cooling, relieving internal stress, etc.). The total is cycle duration of technological operations. This value is displayed as a separate formula in the first line. We will need it later.
Addition third part of the formula, which takes into account waiting for processing and other time losses, gives the duration of the production cycle, which we can already take into account for planning purposes.
Parallel-serial processing method involves a partial combination of time for performing related operations, that is, processing in the following operations begins before the completion of the production of the entire batch in the previous operations, and it is necessary to maintain the conditions of continuity of processing of each operation.
This processing method 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 parts arrive at it at random times with random breaks. Therefore, we will need to start the heat treatment cycle in such a way that from the moment the batch begins to be processed until the end of the batch, the equipment runs continuously. The moment of the start of 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 awaiting processing.
The duration of the technological cycle with the parallel-serial method of transferring parts ( T c p-p) is calculated using the formula:
T cycle of pairs after– the total execution time of the technological process of processing parts during parallel-sequential processing
n
p
ti– unit execution time of the i-th operation, minutes
Ci– the number of machines on which the part is processed in the i-th operation
(t/c) core. – duration of execution of the shorter of two adjacent operations
test- duration of operations during which natural processes occur
Explanation formulas for calculating the duration of the production cycle for parallel-sequential processing. As can be seen from the first line of the block of formulas, time savings arising from the fact that the batch of parts lies only partially and its processing begins before the end of processing of the entire batch is subtracted from the time calculated for sequential processing of parts.
Second line of the formula block deciphers the first one. We divide the processing time of an operation by the number of machines that perform this operation and multiply it by the number of parts in the batch. We get the time during which a single operation will be completed for the entire batch of parts. The sum of the 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.
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 lot from the size of the entire batch, we get the number of parts that will actually be processed in parallel. We have the maximum, the transfer lot, which we subtracted. Now, by multiplying the number of parts processed in parallel by the time of their parallel processing (t/c), whichever is the smaller of the two operations, we will obtain the amount of time saved on processing with such an organization of production.
Fourth line of formula block it just supplements the time we calculated (see the second line of the block of formulas) with the time lost for waiting for processing details as a result of laying down.
Parallel movement of a batch of parts is characterized by the fact that different copies of a given item are processed simultaneously in all operations, and each sample is processed continuously in all operations. The transfer of parts from operation to operation is carried out individually or in transfer batches. In this case, the most labor-intensive operation (the “bottleneck”) is fully loaded, while others are waiting for processing.
The cycle duration for parallel processing of a batch of parts is found using the formula:
T cycle parallel– the total execution time of the technological process of processing parts during parallel processing
n– number of parts in the batch being processed, pcs.
p– size of the transport (transfer) lot pcs.
ti– unit execution time of the i-th operation, minutes
Ci– the number of machines on which the part is processed in the i-th operation
test- duration of operations during which natural processes occur
Explanation formulas for calculating the duration of the production cycle during parallel processing. Since processing is carried out continuously in the bottleneck itself, the batch processing time will increase only by the time of “stuck” parts exceeding the size of the transfer batch (n-p) in the bottleneck (t/c)max, which is what the formula shows us.
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, and multiply it by the number of parts in the transfer (!) batch.
Second part of the formula allows us to calculate the duration of a batch being stuck in a bottleneck. Since all other operations will be completed faster, the holding time will be equal to the number of waiting parts (n-p) multiplied by the processing time in the bottleneck (t/c)max.
Third part of the formula, which takes into account waiting for processing and other time losses, unless, of course, it is indicated in technological map as a technological operation
Parallelism– simultaneous execution of parts of the production process (stages, operations), that is, the implementation of processes with overlap.
Parallel production factor is found by the formula:
T parallel processing– cycle duration when organizing processing in a parallel way of moving parts
T fact– actual duration of the parts processing cycle.
Determining the duration of the production cycle is also possible graphically.
CALCULATION OF PRODUCTION CYCLE DURATION
Production cycle is a complex of basic, auxiliary and servicing processes organized in a certain way in time, necessary for the manufacture of a certain type of product. The most important characteristic of the production cycle is its duration.
The duration of the production cycle is the period of time during which a material, workpiece or other processed item goes through all the operations of the production process (or a certain part of it) and is transformed into a finished product.
A distinction is made 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 the product or assembly unit – complex . The cycle can be single-operational or multi-operational.
One-step production cycle for a batch of parts at i-th operation is determined by the formula:
n– number of parts in the production batch, pcs.;
https://pandia.ru/text/80/150/images/image003_90.gif" width="37" height="28 src=">- number of jobs (machines) per i-operations of the technological process.
Simple cycle calculation
The cycle time of a multi-operation process depends on the method of transferring parts from operation to operation. There are three types of movement of objects of labor in the process of their manufacture: sequential, parallel and parallel-sequential.
At sequential type of movement the entire batch of parts is transferred to the subsequent operation after finishing processing of all parts in the previous operation. The advantages of this method are the absence of interruptions in the operation of equipment and workers 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 activity of the workshop or enterprise.
At parallel type of movement parts are transferred to the next operation by a transport batch immediately after completion of its processing in the previous operation. In this case, the shortest cycle is ensured. But the possibilities of using parallel type of movement are limited, since prerequisite its implementation is the equality or multiple of the duration of operations. Otherwise, interruptions in the operation of equipment and workers are inevitable.
At parallel-sequential type of movement parts are transferred from operation to operation in transport batches or individually. In this case, there is a partial overlap of the execution time of adjacent operations, and the entire batch is processed at each operation without interruptions. Workers and equipment work without breaks. The production cycle is longer compared to a parallel one, 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="> - number of parts in the transport (transfer) batch, pcs.;
https://pandia.ru/text/80/150/images/image007_56.gif" width="825 height=376" height="376">
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 batches are transferred from the previous operation to the next one immediately upon completion of their processing at the previous one. This option allows you to minimize the total duration of the technological cycle.
On the other hand, continuity of processing of the entire batch of parts is ensured only in the longest operation. In other operations, equipment and workers stand idle waiting for the next shipment to arrive. In order to reduce the last drawback, you should try to reduce these downtimes to a minimum by changing the time standards 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 it has been processed in the previous operation, and uninterrupted processing of the entire batch of parts will be ensured.
Option 2:
Processing time for the subsequent operation is less than for the previous one
In this case, it is impossible to transfer the transport batch immediately after its processing at the previous operation, since there will be downtime at the subsequent workplace. To avoid downtime, you should accumulate the necessary stock of parts.
The amount of stock and the time when the transfer of the first transport batch to the subsequent operation can begin is found as follows: from the end of the processing time of all parts in the previous operation, a perpendicular is lowered, to the right of the perpendicular the processing time of the last transport batch is postponed, and to the left of the perpendicular - the processing time of the rest transport parties.
Thus, the condition is met that the last transport batch is processed at the subsequent operation without any waiting (sequentially), and all previous ones must be continuously processed by the time processing of the last one begins.
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 the manufacture and assembly of product A, the structure of which is shown in the diagram..gif" width="81" height="25">.gif" width="87" height="25">. In this case, it is generally accepted that various parts are manufactured simultaneously.
Building a complex cycle
Unlike previous constructions, this graph is constructed starting from the point of completion of the complete assembly of the product. On the graph, from right to left on a time scale, the cycles of the component processes are plotted, starting from the assembly of components, subassemblies 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 manufacturing parts and assembly units. That is, the duration of the complete production cycle of a product is determined by the longest chain.
|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____ days
Task 1
Determine the duration of the technological cycle for processing a batch of parts based on the movement of objects of labor:
- consistent;
- parallel;
- parallel-serial.
The graphical version of the calculation, drawn on a large scale, should be supplemented with an analytical calculation.
Task 2
Determine the total duration of the manufacturing cycle of machine “K”. Set the start date for manufacturing the machine if it must be delivered to the customer no later than the specified date.
With a sequential form of movement processing of a batch of parts at each subsequent operation begins only after the entire batch has been processed at the previous operation.
The analytical determination of the technological cycle for manufacturing batch n in m operations is calculated using the following formula:
m – number of processing operations;
With parallel movement, the transfer of objects of labor (parts) to the subsequent operation is carried out individually, or in a transport batch immediately after processing in the previous operation.
In the general case, when transferring parts from operation to operation by transport batch, the duration of the operating cycle is equal to:
;
(2)
n – number of parts in the batch;
m – number of processing operations;
t i – time standard for the i-th operation;
C i – number of jobs at the i-th operation;
t’, C’ – execution time and number of jobs in the longest operation, i.e. on operations max(ti/Ci);
Square brackets indicate rounding fractions to the nearest whole number.
With a parallel-sequential type of movement, parts are transferred to the next operation as they are processed in the previous one - individually or in a transport batch, while the execution times of adjacent operations are partially combined in such a way that a batch of parts is processed at each operation without interruptions.
The duration of the technological cycle for parallel-sequential movement can be determined using formula (3)
;
(3)
where: m – number of processing operations;
τ j - partial overlap of the execution time of each pair of adjacent operations, i.e. duration of the shorter operation from the considered pair of adjacent operations
;
(4)
where: n – number of parts in the batch;
t i – time standard for the i-th operation;
C i – number of jobs at the i-th operation;
p - size of the transport lot (or piece by piece), pcs;
Square brackets indicate rounding fractions to the nearest whole number.
Calculation of production cycle duration has a multi-purpose purpose. It is used when developing a production program for workshops, loading jobs and equipment, to calculate the size of work in progress (WIP), etc.
The duration of the production cycle is usually expressed in calendar time (days).
The structure of the PC is shown in Fig. 2.1
Rice. 2.1. Production cycle structure
With the analytical method, the duration of the production cycle of a simple process is determined by the formula
,
(5)
Tt – duration of technological operations, depending on the type of movement of production objects in time (h);
Тmo – average duration of interoperational break (hours);
m – number of operations in the technological process;
Dk – number of calendar days (days);
Dr – number of working days (days);
Ksm – number of work shifts (cm/day);
Psm – average shift duration (h/cm);
Te – duration of natural processes (hours).
