Creation system, creation method, program, and storage medium

Abstract

To provide a generation system, a generation method, a program, and a storage medium that can generate a production plan in a more accurate manner.SOLUTION: An embodiment relates to a generation system that generates a production plan for producing products of multiple product types in multiple processes using multiple production lines. The generation system comprises an optimization calculation part, an input plan generator, and a verification part. The optimization calculation part generates a processing plan indicating a production plan amount for each of the product types, each of the production lines, and each of the processes by an optimization calculation using first input data that includes the production plan amount of each of the product types and processing performance for each equipment. The input plan generator generates an input plan indicating timings to input workpieces to the multiple production lines using second input data that includes an input amount of the workpieces to each of the production lines for each of the product types, and a processing path in the multiple processes for each of the product types. The verification part determines an appropriateness of the processing plan and the input plan by simulation on the basis of the processing plan and the input plan.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a creation system, a creation method, a program, and a storage medium. [Background technology]

[0002] There is a system that automatically creates production plans. There is a need for technology that can create production plans with greater accuracy for this system. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-098509 [Overview of the project] [Problems that the invention aims to solve]

[0004] The problem that this invention aims to solve is to provide a production system, production method, program, and storage medium that can create production plans with higher accuracy. [Means for solving the problem]

[0005] The embodiment relates to a production system for creating a production plan for producing multiple types of products using multiple production lines and multiple processes. The production system comprises an optimization calculation unit, an input plan creation unit, and a verification unit. The optimization calculation unit uses first input data, including the planned production quantity for each product type and the processing capacity of each piece of equipment, to create a processing plan showing the planned production quantity for each product type, each production line, and each process by performing an optimization calculation including an objective function and constraints. The input plan creation unit uses second input data, including the number of workpieces to be input to each production line for each product type and the processing paths in the multiple processes for each product type, to create an input plan showing the timing of inputting the workpieces to the multiple production lines. The verification unit determines the validity of the processing plan and the input plan by performing a simulation based on the processing plan and the input plan. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic diagram showing the configuration of the creation system according to the embodiment. [Figure 2] This is a schematic diagram showing the model used in optimization calculations. [Figure 3] This is a schematic diagram illustrating the processing performed by the calculation department. [Figure 4] This is a schematic diagram illustrating the processing performed by the calculation department. [Figure 5] This is a schematic diagram illustrating the processing performed by the calculation department. [Figure 6] This is a schematic diagram illustrating the processing performed by the calculation department. [Figure 7] This is a schematic diagram illustrating the processing performed by the calculation department. [Figure 8] This is a schematic diagram illustrating the processing performed by the calculation department. [Figure 9] This is a schematic diagram illustrating the processing performed by the input planning unit. [Figure 10] This is an example of data used in creating an input plan. [Figure 11] This is an example of data used in creating an input plan. [Figure 12]Data that illustrates the processing result by the input plan creation unit. [Figure 13] Data that illustrates the processing result by the input plan creation unit. [Figure 14] Data that illustrates the processing result by the input plan creation unit. [Figure 15] Data that illustrates the processing result by the input plan creation unit. [Figure 16] Data that illustrates the processing result by the input plan creation unit. [Figure 17] Data that illustrates the processing result by the input plan creation unit. [Figure 18] It is a schematic diagram showing the components of the simulation model. [Figure 19] It is an example of the data used in the simulation. [Figure 20] It is an example of the data used in the simulation. [Figure 21] It is an example of the data used in the simulation. [Figure 22] It is an example of the data used in the simulation. [Figure 23] It is an example of the data used in the simulation. [Figure 24] It is an example of the data used in the simulation. [Figure 25] It is an example of the data used in the simulation. [Figure 26] It is a flowchart showing the operation of the simulation by the verification unit. [Figure 27] It is a flowchart showing the operation of the simulation by the verification unit. [Figure 28] It is a flowchart showing the operation of the simulation by the verification unit. [Figure 29] It is a graph illustrating the created production plan. [Figure 30] It is a flowchart showing the outline of the creation method according to the embodiment. [Figure 31]This is a schematic diagram illustrating the hardware configuration. [Modes for carrying out the invention]

[0007] The embodiments of the present invention will be described below with reference to the drawings. In this specification and in the drawings, elements similar to those already described are denoted by the same reference numerals, and detailed descriptions will be omitted as appropriate.

[0008] One embodiment of the present invention relates to a production system. The production system creates a production plan. Products are produced according to the production plan.

[0009] First, let's explain the overview of product production. Multiple products are produced at a production site (factory, manufacturing plant, etc.). Each product is produced through multiple processes. A series of processes constitutes a production line. Each production line is optimized to efficiently transport workpieces between processes. For example, the processing equipment in each process is placed close to each other to reduce workpiece transport time. A production site has multiple production lines, and products are produced on each production line.

[0010] Generally, multiple product varieties are produced in manufacturing plants. Different product varieties differ in form, structure, or characteristics. The processes required to produce each product also vary. Furthermore, multiple production lines are generally not identical and have differences. For example, some production lines have dedicated equipment for specific product varieties. Other production lines have superior equipment with higher processing capacity compared to others. High processing capacity means being able to process many workpieces simultaneously or process workpieces in a short amount of time.

[0011] When producing multiple product varieties using multiple production lines, a production plan is necessary. As mentioned above, there are differences between production lines, and the required processes also differ for each product variety. Therefore, a production plan is created to efficiently operate each piece of equipment on the production floor. The production plan includes data such as which production line to use, which equipment to use, and when to produce each product.

[0012] Figure 1 is a schematic diagram showing the configuration of the creation system according to the embodiment. As shown in Figure 1, the creation system 1 includes a processing unit 10 and a storage device 20. The processing unit 10 functions as an optimization calculation unit 11, a trial calculation unit 12, an input plan creation unit 13, and a verification unit 14.

[0013] The optimization calculation unit 11 creates a processing plan to achieve the target production quantity for each product type. The processing plan indicates, for each product type, which production line, which process, and to what extent the workpieces will be processed.

[0014] Figure 2 is a schematic diagram showing the model used in the optimization calculation. A concrete example of optimization calculation is explained. Equation 1 is used as the objective function. Equations 2 to 6 are used as constraints. In equations 1 to 6, i represents the product type, as shown in Figure 2. j represents a resource. A resource is the equipment that processes the workpiece in each process and corresponds to a production line. For example, a production line containing resource j is different from a production line containing resource j+1. k represents a process.

[0015] d ik x is the required number of workpieces of variety i in the k-th process. ijk This indicates the usage ratio of variety i to resource j in process k. Usage ratio x ijk The number of requests is d ik This shows the ratio of the number of workpieces processed by each resource to the total number of workpieces. ijk This indicates the allocation ratio in which workpieces of type i are processed by each resource j in process k. ijk This indicates the processing capacity of resource j in process k for variety i. Processing capacity sijk As such, the maximum number of workpieces of variety i that can be processed by only resource j is set. n is the upper limit of the total usage ratio that can be processed by resource j in process k, and means the number of available resources. z ijk For resource j that processes workpieces of variety i, z indicates the difference in the allocation ratio between process k and process k + 1, and corresponds to the number of transports. The difference z in the allocation ratio between processes ijk is represented by Equation 7. The required quantity d ik , variety i, resource j, process k, processing capacity s ijk , transport constraint b k The input data (the first input data) including is prepared in advance by the user.

[0016]

Number

Number

Number

Number

Number

Number

Number

[0018] In Equation 1, l is the smallest integer that satisfies Equation 8. Depending on the product type, not all processes on a particular production line may be executed. That is, some processes may be skipped. In this case, the number of requests d for the skipped processes for that product type is set to 0. Consequently, the allocation ratio of each resource in the skipped processes for that product type becomes 0. If the number of requests for the skipped processes is used in the calculation of Equation 1, an incorrect transport count will be calculated. The value l is used to exclude the skipped processes (processes with a request count of 0) from the transport count calculation.

number

[0019] Figures 3(a) to 3(c), 4(a), and 4(b) show examples of data used to generate models used in optimization calculations. Figure 3(a) is a table that defines the process. The table 100 shown in Figure 3(a) includes process 101, group 102, sequence 103, and constraint 104. Group 102 indicates the group to which each process 101 belongs. Group 102 represents a set of processes. Even if they are different processes, if the same equipment is used, those processes belong to the same group. Sequence 103 indicates the order in which process 101 is executed. Constraint 104 indicates whether transport between groups (production lines) is possible. If transport to another production line is not possible after process 101, "1" is set.

[0020] The table 110 shown in Figure 3(b) includes equipment 111, process 112, and resources 113. Equipment 111 indicates an available processing unit. Process 112 indicates the process in which equipment 111 is used. Resources 113 indicate the number of resources for equipment 111 and correspond to "n" in formula 5. "1" corresponds to 100%, indicating that equipment 111 can process in process 112. In addition to "1", a value such as "0.99" may be set according to the operating status of equipment 111. "0" indicates that equipment 111 cannot process in process 112.

[0021] Table 120, shown in Figure 3(c), shows the number of workpieces that can be processed per unit time. Table 120 includes item 121, equipment 122, process 123, and capacity 124. Item 121 indicates the product type. Capacity 124 indicates the number of workpieces that item 121 can process per unit time.

[0022] The table 130 shown in Figure 4(a) includes product type 131, equipment 132, process 133, and availability 134. Availability 134 indicates whether equipment 132 is available in process 133 of the production of product type 131. In this example, "1" indicates availability, and "0" indicates unavailability.

[0023] Table 140, shown in Figure 4(b), includes variety 141, process 142, and required quantity 143. The required quantity 143 indicates the number of variety 141 to be produced in process 142.

[0024] The optimization calculation unit 11 generates the model shown in Figure 2 based on the data in the tables shown in Figures 3(a) to 3(c), Figure 4(a), and Figure 4(b). The optimization calculation unit 11 uses the model to solve an optimization problem that includes an objective function and constraints. This calculates which production line should process each type of workpiece at each stage in order to minimize the number of items transported. Based on the results of the optimization calculation, the optimization calculation unit 11 outputs the allocation ratio between production lines for each stage and the number of items transported between production lines.

[0025] If a solution cannot be obtained, the optimization calculation unit 11 outputs data indicating this. In that case, the user changes the input data or constraints. For example, the production plan quantity may be reduced, or the constraints may be relaxed. Relaxation of constraints may involve removing some transport constraints or increasing the resource processing capacity.

[0026] Figure 5 is a schematic diagram showing the processing plan created by the optimization calculation unit. In the example shown in Figure 5, processes 1-11, 13-15, 17, and 19-22 are executed in each of the production lines a-c. Workpieces of varieties A-D are processed in production lines a-c. The proportion of each variety processed in each production line is shown. The optimization calculation unit 11 outputs the created processing plan to the estimation unit 12.

[0027] Note that the objective function and constraint functions are not limited to the examples above and can be changed as appropriate. For example, instead of minimizing the number of transports, the objective function could be set to keep the number of transports below a threshold. The threshold is set by the user. Other factors include the usage ratio x ijk A limit may be set for this.

[0028] The calculation unit 12 estimates whether the processing capacity required by the equipment at each process will exceed the upper limit when the processing plan created by the optimization calculation unit 11 is executed. The calculation unit 12 uses the allocation ratio included in the processing plan and the input data (third input data) to perform the estimation. Equipment refers to devices for carrying out the process. The input data is prepared in advance by the user.

[0029] The input data includes production plan quantities, cumulative yield rate, and equipment data. Production plan quantities are the planned production numbers for each product. The cumulative yield rate is the overall yield rate for each process. Equipment data includes operating days, operating hours, utilization rate, batch size, and processing time. Operating days are the number of days in a month that the equipment was in operation. Operating hours indicate the daily operating time of the equipment. For example, the average operating time of the production site is set as the operating time. The utilization rate indicates the percentage of time the equipment was actually in operation. The product of operating days, operating hours, and utilization rate indicates the actual monthly operating time of the equipment. Batch size indicates the number of workpieces that can be processed per batch. Processing time indicates the time required to perform one process. Equipment data is set for each piece of equipment.

[0030] The calculation unit 12 calculates the number of workpieces to be processed, the processing capacity, and the load factor for each piece of equipment based on the calculation results. The load factor is the ratio of the number of workpieces assigned to the equipment to the number of workpieces that the equipment can process. The calculation unit 12 determines whether each calculated load factor exceeds a predetermined threshold. For example, the threshold is set to 100%. In other words, the calculation unit 12 determines whether any of the pieces of equipment will experience a load exceeding the maximum processing capacity. The threshold may be set to 99% or other values ​​to take into account equipment maintenance, etc.

[0031] If any load rate exceeds a threshold, the calculation unit 12 determines that the solution (processing plan) calculated by the optimization calculation unit 11 is invalid. Based on this determination, the optimization calculation unit 11 performs the optimization calculation again. At this time, the input data or constraints are changed. Both the input data and constraints may be changed, or only one of them may be changed. The input data or constraints are changed by the user. The optimization calculation unit 11 may also automatically change the input data or constraints according to pre-set rules.

[0032] The optimization calculation unit 11 calculates an alternative processing plan by performing an optimization calculation using different input data or different constraints. The estimation unit 12 estimates the load factor for that alternative processing plan and determines the validity of that alternative processing plan. For example, the optimization calculation unit 11 repeats the process of creating processing plans until the estimation unit 12 determines that the processing plan is valid.

[0033] If all load rates are below the threshold, the calculation unit 12 adds the calculated load rates to the processing plan. This provides a processing plan that shows how much work will be processed for each product type, production line, process, and piece of equipment. The calculation unit 12 outputs the processing plan with the added load rates to the input plan creation unit 13.

[0034] Figures 6 to 8 are schematic diagrams illustrating the processing performed by the calculation unit. The specific method for calculation is as follows. First, as shown in Figure 6, the calculation unit 12 calculates the production plan number for each process based on the input production plan number and the cumulative good product rate for each process. The production plan number for each process corresponds to the number of workpieces processed in each process. The production plan number for each process is obtained by multiplying the production plan number, which has been increased according to the yield, by the cumulative good product rate for each process. Alternatively, the production plan number for each process may be calculated by dividing the production plan number, which has not been increased, by the cumulative good product rate for each process. By multiplying the production plan number for each process by the allocation ratio of each production line to that process, the allocation number for each production line in each process can be obtained. Furthermore, for each production line, the number of items transported between production lines can be calculated from the difference in the allocation numbers of the preceding and succeeding processes.

[0035] As shown in Figure 7, the calculation unit 12 calculates the processing capacity for each piece of equipment from the batch size, operating days, operating hours, equipment utilization rate, and processing time of each piece of equipment. For example, the score S, which indicates the processing capacity, is calculated using formula 9 with the batch size s1, operating days s2, operating hours s3, utilization rate s4, and processing time s5.

number

[0036] The calculation unit 12 calculates the processing capacity of each production line and each process by adding up the processing capacity of each piece of equipment according to the number of pieces of equipment in each process. The calculation unit 12 calculates the processing capacity ratio of each piece of equipment by dividing the processing capacity of each piece of equipment by the processing capacity of the equipment group.

[0037] As shown in Figure 8, the calculation unit 12 calculates the allocated load for each equipment for each product type by multiplying the number of items allocated for each process and product type by the processing capacity ratio. The calculation unit 12 calculates the load rate for each product type and each equipment by dividing the allocated load by the processing capacity of each equipment. The calculation unit 12 calculates the sum of the load rates for each product type. This calculates the load rate for each equipment when all allocated product types are processed. The calculation unit 12 compares the calculated load rates for each equipment with a threshold value.

[0038] The input data and calculation methods used for the estimation are not limited to the examples described above and can be modified as appropriate. For example, to simplify calculations, batch size, actual operating time, and processing time may be set commonly across equipment. However, from the standpoint of improving the accuracy of the estimation, it is preferable to have this data available. In addition, the production plan quantity may be set considering the cumulative good product rate. In this case, setting the cumulative good product rate becomes unnecessary.

[0039] The input plan creation unit 13 calculates the number of each product type to be input to each production line. Based on the input number, the input plan creation unit 13 calculates the input interval for each product type, taking into account the batch size. Furthermore, based on the input number, the input plan creation unit 13 calculates the input frequency for each product type. The input plan creation unit 13 then creates an input plan from the input interval and input frequency.

[0040] Figure 9 is a schematic diagram showing the processing performed by the input plan creation unit. The specific processing performed by the input plan creation unit 13 will now be explained. First, the input plan creation unit 13 refers to the input data (second input data). As shown in Figure 9, the input data includes the input plan for each product type, the number of batch input lots, the operating time, the allocation ratio for the first process, and the allocation route. This input data is prepared in advance by the user.

[0041] Figures 10(a), 10(b), 11(a), and 11(b) are examples of data used in creating an input plan. Figure 10(a) is a table illustrating the input quantity and batch input lot size. Table 150 in Figure 10(a) includes product type 151, input lot size 152, and batch input lot size 153. Input lot size 152 indicates the total number of lots input to the production line for each product type 151. Batch input lot size 153 indicates the number of lots input to the production line at one time. Batch input lot size 153 is set considering the batch size of bottleneck processes, etc.

[0042] Figure 10(b) is a table illustrating the allocation ratios for the initial process. Table 160 in Figure 10(b) includes product type 161 and allocation ratios 162-164. Allocation ratios 162-164 are the allocation ratios for each production line in the initial process for each product type 161.

[0043] Figure 11(a) is a table illustrating operating hours. Table 170 in Figure 11(a) includes operating days 171, operating hours 172, and monthly operating hours 173. Operating days 171 represents the average number of operating days per month. Operating hours 172 represents the average operating hours per day. Monthly operating hours 173 represents the average operating hours per month.

[0044] Figure 11(b) is a table showing the allocation route. Table 180 in Figure 11(b) shows the variety 181, lot number 182, route 183, and input line 184. Route 183 shows the processing route through multiple processes for producing each variety 181. Each number in route 183 indicates a specific processing route. Input line 184 shows the production line to which the lot is first input.

[0045] Figures 12 to 17 show data illustrating the processing results by the input plan creation unit. The input plan creation unit 13 calculates the number of inputs to each production line from the input data. The number of inputs can be calculated using the formula: "(Number of input lots × allocation ratio for the first process) / Number of batch input lots". For example, as shown in Figure 12, data for Table 190 is calculated, including product type 191, input number 192, and input number 193. Table 190 shows the number of inputs for each product type 191 and for each production line.

[0046] The input planning unit 13 calculates the input interval for each production line. The input interval is calculated as "monthly operating hours / total number of inputs for each production line". For example, if each production line operates for 28 days per month and 24 hours per day, the input interval for "production line a" shown in Figure 12 is calculated as 28 days × 24 hours / 83 times. As a result of the calculation, the input interval for "production line a" is once every 8.1 hours. The input interval for "production line b" is once every 7.6 hours.

[0047] The input planning unit 13 calculates the input frequency for each production line. The input frequency indicates how often each product type is input. The input frequency is calculated as "number of inputs to the production line / number of inputs for each product type". As a result of the calculation, for example as shown in Figure 13, for product type "690", lots are input to "production line a" every two or three times. Lots are input to "production line b" every one or two times.

[0048] The input plan creation unit 13 plans the input sequence. The input plan creation unit 13 randomly assigns routes to each variety so that lots are not processed intensively on a specific route during a specific time period. Figure 14 shows a table that adds input frequency and random numbers to some of the data shown in Figure 11(b). In Table 200 shown in Figure 14, only data related to "production line b" and variety "690" are exemplified. Table 200 includes variety 201, input frequency 202, batch lot size 203, and route 204, in addition to random numbers 205.

[0049] The input plan creation unit 13 sorts the data obtained by adding random numbers based on the random numbers. Table 200a in Figure 15 shows the result of sorting the variety 201, input frequency 202, batch lot size 203, and root 204 based on the random number 205. Sorting based on random numbers results in a random order for the root 204. The input plan creation unit 13 generates similar data with added random numbers for each variety and each production line.

[0050] The input plan creation unit 13 compiles data for each variety and production line, adding random numbers to each. The input plan creation unit 13 assigns lot numbers sequentially to each variety and production line, and then adds random numbers to them. The input plan creation unit 13 calculates a score for the input of each variety using the input frequency, lot number, and random number. The input plan creation unit 13 sorts the data based on the score and determines the input order.

[0051] Figure 16 shows Table 220, which summarizes the data with random numbers added. Table 220 includes variety 221, input frequency 222, batch lot size 223, root 224, lot number (No.) 225, random number 226, and score 227. Lot number 225 is assigned sequentially from the top of the table for each variety 221. The score 227 is calculated as the product of input frequency, lot number, and random number. Table 220 shows the results sorted based on score 227. This provides a leveled input order to prevent any particular variety from being input intensively.

[0052] The input plan creation unit 13 adds the input timing calculated based on the input interval to the obtained input order. This results in an input plan that specifies when, which type of workpiece, and which route to input.

[0053] Figure 17 shows Table 220a, which is obtained by adding sequence 228 and input timing 229 to the product type 221, input frequency 222, batch lot size 223, and route 224 of Table 220. Input timing 229 indicates when each work in sequence 228 is input, relative to the input timing of the first work.

[0054] Based on the above, the input plan creation unit 13 creates an input plan that indicates the timing of inputting lots (workpieces) into multiple production lines. More specifically, the input plan indicates which type of lot to input, to which processing path, and when. The input lots are processed according to the processing plan. The input plan creation unit 13 transmits the created input plan and the processing plan with the load rate added to it to the verification unit 14.

[0055] The input data used to create the input plan is not limited to the examples described above and can be changed as appropriate. For example, to simplify the preparation of input data, the batch input lot size may be set to be the same for all varieties, or the minimum value of "1" may be automatically set. However, from the viewpoint of improving the accuracy of the input plan, it is preferable to set the batch input lot size for each variety. In addition, the input order may be standardized using methods other than random numbers.

[0056] The verification unit 14 verifies the validity of the created input plan and processing plan. Based on the input, the verification unit 14 sets each element of the simulation model. The verification unit 14 operates the simulation model according to the input plan and processing plan.

[0057] Figure 18 is a schematic diagram showing the components of the simulation model. As shown in Figure 18, the simulation model 300 includes an input unit 301, a buffer 302, equipment 303, a shift 304, a worker 305, resources 306, and an output unit 307. The input unit 301 inputs a lot consisting of multiple workpieces into the production line. The buffer 302 is a buffer that holds lots awaiting processing. The equipment 303 is the equipment that executes each process and processes the lots. The processing capacity of the equipment 303 is set based on input data (fourth input data). The shift 304 indicates the operating time of the equipment and workers. Worker 305 is a worker. Each worker is assigned a set of processes they can handle. Resources 306 are available jigs. In the example shown in Figure 18, for the convenience of the simulation, jigs are also treated as workers. The output unit 307 is the unit that outputs the lots. Once processing is complete, the output unit 307 removes the lot.

[0058] Figures 19 to 25 show examples of data used in the simulation. The input unit 301 generates lots based on a pre-prepared table and an input plan created by the input plan creation unit 13. A lot consists of multiple lots. For example, as shown in Figure 19, the table 400 includes product type 401, processing ID 402, and quantity 403. The table 400 sets which processing will be performed for each lot of product type 401.

[0059] Equipment 303 processes each lot based on the processing table and flow table. Equipment 303 that processes a lot in each process is allocated according to the processing plan. Workers 305 and resources 306 involved in each process are allocated based on the allocation table.

[0060] Figure 20 shows an example of a processing table. The processing table 420 shown in Figure 20 includes product type 421, processing ID 422, processing name 423, processing time 424, and equipment 425. Processing time 424 indicates the time required to execute the processing specified by each processing ID 422. Equipment 425 indicates the equipment used when executing the processing.

[0061] Figure 21 shows an example of a flow table. The flow table 440 shown in Figure 21 includes product type 441, processing ID 442, processing name 443, pre-processing ID 444, and pre-processing name 445. Pre-processing ID 444 indicates a process that is executed before the process corresponding to processing ID 442. That is, the process corresponding to processing ID 442 is executed after the process corresponding to pre-processing ID 444 is executed.

[0062] Figure 22 shows an example of an allocation table. The allocation table 460 shown in Figure 22 includes a product type 461, a processing ID 462, a processing name 463, a resource 464, a type 465, and a quantity 466. Resource 464 indicates the resource to be allocated to the process indicated by the processing ID. Resources include workers, jigs, etc. Type 465 indicates the type of work that resource 464 can perform. For example, "Work A" indicates that a jig for Work A will be used in the process identified by processing ID "P1_02". Quantity 466 indicates the number of resources 464 required in the process indicated by the processing ID. For example, it indicates that one worker capable of performing Work A is required to process the process indicated by processing ID "P1_02".

[0063] Worker 305 performs their duties according to the data set in the shift table and worker table. Figure 23 is an example of a shift table. The shift table 480 shown in Figure 23 includes the shift type 481, start time 482, end time 483, and break time 484. The start time 482, the end time 483, and the break time 484 between the start time 482 and the end time 483 are set for each shift type 481.

[0064] Figure 24 shows an example of a worker table. The worker table 500 shown in Figure 24 includes the worker name 501, shift type 502, and target tasks 503-505. Shift type 502 indicates the shift in which the worker identified by worker name 501 will work. Target tasks 503-505 indicate the tasks that each worker will perform. "1" indicates that the worker will perform that task. A blank space indicates that the worker will not perform that task.

[0065] Equipment 303 operates in accordance with the actual operating conditions of the equipment. For example, to reflect the actual operating conditions of the equipment, an equipment failure table 520, as shown in Figure 25(a), is prepared. The equipment failure table 520 includes the equipment name 521, number 522, capacity 523, shift type 524, Mean Time Between Failure (MTBF) 525, and Mean Time To Repair (MTTR) 526. Capacity 523 indicates the number of lots that can be processed simultaneously. MTBF 525 indicates the average operating time before failure. MTTR 526 indicates the average time taken from failure to recovery. By setting MTBF 525 and MTTR 526, the validity of the processing plan and input plan can be verified considering the actual operating conditions of the equipment.

[0066] For resource 306, for example, a fixture table 540 is provided, as shown in Figure 25(b). The fixture table 540 includes a name 541, a number 542, and a shift type 543. The number of available fixtures and the time slots (shifts) are set using the fixture table 540.

[0067] Figures 26 to 28 are flowcharts showing the operation of the simulation by the verification unit. The flowchart in Figure 26 illustrates the operation of sending a lot from buffer 302 to equipment 303. First, when a lot arrives at buffer 302, the operation begins. Buffer 302 sorts the product types in buffer 302 in the order of first-in, first-out (FIFO) and earliest delivery date (EDD) (step S11). Buffer 302 then determines which lot to start processing based on the sorting results (step S12). For example, lots that arrived at buffer 302 earlier and have shorter delivery dates are given priority for processing. Once the lot to be processed is determined, it is determined whether there are enough consolidation parts (step S13). Multiple parts processed in multiple preceding processes may be used in a single process. Here, these multiple parts are called consolidation parts. In step S13, it is determined whether all the parts necessary for starting processing have been consolidated.

[0068] If there are enough merging parts, it is determined whether there is equipment available to start work (step S14). If there is equipment available to start work, it is determined whether there are enough workers and resources (step S15). If there are enough workers and resources, buffer 302 sends the lot to equipment 303 (step S16). Next, it is determined whether there is still capacity in the equipment (step S17). If there is still capacity in the equipment, it is determined whether there is a lot available to start work in buffer 302 (step S18). If there is a lot available to start work, that lot is sent to equipment 303 (step S19). The operation ends if there are not enough merging parts in step S13, if there is no equipment 303 available to start work in step S14, if there are not enough workers and resources in step S15, if there is no capacity in the equipment in step S17, if there is no lot available to start work in step S18, or if step S19 is completed.

[0069] As shown in Figure 26, if there is a lot ready for processing in buffer 302, that lot is sent to equipment 303.

[0070] The flowchart in Figure 27 shows another operation for sending a lot from buffer 302 to equipment 303. If equipment 303 is available, the operation shown in Figure 27 is initiated. First, it is determined whether there are any product types that can be processed in buffer 302 (step S21). Product types that can be processed refer to product types that can be processed by equipment 303. If there are product types that can be processed, it is determined whether there are enough consolidation parts (step S22). If there are enough consolidation parts, it is determined whether there are enough workers and resources (step S23). If there are enough workers and resources, buffer 302 sends the lot to equipment 303 (step S24). It is determined whether there is still capacity in the equipment (step S25). If there is still capacity in the equipment, it is determined whether there is a lot that can be processed in buffer 302 (step S26). If there is a lot that can be processed, that lot is sent to equipment 303 (step S27). The operation terminates if there are insufficient merging parts in step S22, insufficient workers and resources in step S23, insufficient equipment capacity in step S25, no lots available to start work on in step S26, or when step S27 is completed.

[0071] As shown in Figure 27, once the equipment 303 becomes ready to process a lot, the varieties waiting in the buffer 302 are started.

[0072] The flowchart in Figure 28 shows yet another operation for sending a lot from buffer 302 to equipment 303. If worker 305 and resource 306 are available, the operation shown in Figure 28 is initiated. First, it is determined whether there are any product types that can be processed in buffer 302 (step S31). If there are product types that can be processed, it is determined whether there are enough consolidation parts (step S32). If there are enough consolidation parts, it is determined whether there is available equipment that can process the product (available equipment) (step S33). If there is available equipment that can process the product, it is determined whether there are enough workers and resources required (step S34). If there are enough workers and resources required, buffer 302 sends the lot to equipment 303 (step S35). Next, it is determined whether there is still capacity in the equipment (step S36). If there is still capacity in the equipment, it is determined whether there is a lot that can be processed in buffer 302 (step S37). If there is a lot that can be processed, that lot is sent to equipment 303 (step S38).

[0073] The operation terminates if there are no product varieties that can be processed in step S31, if there are insufficient consolidation parts in step S32, if there is no equipment that can be processed in step S33, if there are insufficient workers and resources in step S34, if there is insufficient capacity in step S36, if there are no lots that can be started in step S37, or if step S38 is completed.

[0074] As shown in Figure 28, once the worker 305 and resource 306 are ready to process the lot, the varieties waiting in buffer 302 are started.

[0075] The simulation calculates how much of each product lot will be produced and by when. The verification unit 14 determines from the simulation results whether the predetermined production plan quantity of products will be produced by the delivery date. If the production plan quantity of products cannot be produced by the delivery date, the verification unit 14 determines that the created processing plan and input plan are not valid. If the production plan quantity of products can be produced by the delivery date, the verification unit 14 determines that the created processing plan and input plan are valid.

[0076] The verification unit 14 may calculate evaluation values ​​that indicate the evaluation of the processing plan and the input plan. For example, the more positive the evaluation, the higher the evaluation value calculated. When the production plan quantity is achieved, the evaluation value is calculated to be higher. Also, the smaller the difference between the equipment utilization rate and the estimated load rate, the higher the evaluation value is calculated. In addition, the evaluation values ​​of the processing plan and the input plan may be calculated based on the period during which the production plan quantity of products is produced and the period until the delivery date. The verification unit 14 may also judge the validity of the processing plan and the input plan based on the evaluation value. For example, the evaluation value is calculated according to the difference between the period during which the products are produced and the period until the delivery date. The shorter the production period is compared to the period until the delivery date, the more positively the processing plan and the input plan are evaluated, and the higher the evaluation value is calculated.

[0077] If the verification unit 14 determines that the processing plan and input plan are not valid, the optimization calculation unit 11 performs the optimization calculation again. For example, similar to when the trial calculation unit 12 determines that the processing plan is not valid, the optimization calculation unit 11 calculates an alternative processing plan by performing an optimization calculation using different input data or different constraints. Then, the trial calculation unit 12 determines the validity of the alternative processing plan. The input plan creation unit 13 creates an alternative input plan based on the alternative processing plan. At this time, the input data for creating the input plan may be changed. For example, the processing path for processing the workpiece may be changed. The verification unit 14 verifies the validity using the alternative processing plan and the alternative input plan.

[0078] For verification, Siemens Plant Simulation can be used as the simulator. In Siemens Plant Simulation, the input unit 301, buffer 302, equipment 303, shift 304, worker 305, resources 306, and discharge unit 307 can be set, and various input data can be prepared to verify the input plan.

[0079] The process described above yields a production plan, including a processing plan and an input plan. By producing according to this production plan, the planned number of products can be produced by the deadline.

[0080] In the example above, all the data was provided in a table format. However, the data may be provided in formats other than tables. Formulas or other methods may be used to calculate data usable for production planning from other data.

[0081] Figure 29 is a graph illustrating the production plan that was created. In Figure 29, the horizontal axis represents the date, and the vertical axis represents the number of lots processed. For each of the three production lines a to c, the plan outlines which product types will be processed, when, and in what quantities. By processing the workpieces according to the created production plan, the predetermined number of products can be produced by the deadline.

[0082] The processing unit 10 outputs the created production plan. For example, the processing unit 10 sends the production plan data to an external server using File Transfer Protocol (FTP) or the like. The processing unit 10 may also perform database communication and insert the data into an external database server using Open Database Connectivity (ODBC) or the like. The processing unit 10 may output the data in a predetermined file format such as Comma Separated Value (CSV) and write it to a recording medium such as flash memory. The processing unit 10 may also output the production plan to an output device such as a monitor. For example, the processing unit 10 displays the production plan shown in Figure 29 on a graphical user interface.

[0083] Figure 30 is a flowchart illustrating the overview of the manufacturing method according to the embodiment. The optimization calculation unit 11 acquires input data for optimization calculation (first input data) (step S1a). Based on the input data, the optimization calculation unit 11 creates a processing plan through optimization calculation (step S1b). The estimation unit 12 acquires input data for load factor estimation (third input data) (step S2a). Based on the processing plan and input data, the estimation unit 12 estimates the load factor for each piece of equipment (step S2b). The estimation unit 12 determines whether any of the load factors exceed a threshold (step S2c). If any of the load factors exceed the threshold, the optimization calculation is executed again. If none of the load factors exceed the threshold, the estimation unit 12 adds the load factor for each piece of equipment to the processing plan (step S2d). The input plan creation unit 13 acquires input data for the input plan (second input data) (step S3a). Based on the input data, the input plan creation unit 13 creates an input plan (step S3b). The verification unit 14 acquires input data for simulation (step S4a). The verification unit 14 verifies the processing plan and input plan through simulation (step S4b). Based on the simulation results, the verification unit 14 verifies the validity of the processing plan and input plan (step S4c). If the processing plan and input plan are deemed invalid, the optimization calculation is performed again. Alternatively, the input plan may be created again. If the processing plan and input plan are deemed valid, the verification unit 14 outputs a production plan including the processing plan and input plan (step S4d).

[0084] The advantages of the embodiment will be explained. In typical manufacturing environments, the processing capacity of equipment varies from line to line. Traditionally, it has been difficult to create production plans that take these differences into account. Furthermore, creating production plans involves considering numerous factors, such as equipment load, load balance between production lines, and the number of transfers between lines. Consequently, creating production plans has been a time-consuming process.

[0085] To address these challenges, the production system 1 according to this embodiment creates a processing plan that shows the planned production quantity for each product type, production line, and process through optimization calculations. Furthermore, using input data such as the number of lots (workpieces) to be input to each production line for each product type and the processing route for each product type, an input plan is created that shows the timing of lot input to each production line. In addition, the validity of these plans is verified by simulation based on the processing plan and input plan. Through this series of processes, a production plan can be created with greater accuracy. Good accuracy means, for example, that when production is actually carried out according to the production plan, there is little error between the planned schedule and the actual production schedule. Moreover, since the production system 1 can create a production plan once the input data is prepared, there is no need for a person to spend a lot of time creating the production plan.

[0086] To further improve the accuracy of the production plan, it is preferable to estimate the load factor for each piece of equipment, as shown in Figure 30. In some cases, multiple pieces of equipment may be prepared to perform a certain process. In this case, if any piece of equipment is required to process more workpieces than it can handle, that piece of equipment will not be able to process the requested number of workpieces. The estimation allows for determining whether the processing plan is feasible when considering the load on each piece of equipment.

[0087] Figure 31 is a schematic diagram illustrating a hardware configuration. As the processing unit 10, for example, the computer 90 shown in Figure 31 can be used. The computer 90 includes a CPU 91, ROM 92, RAM 93, storage device 94, input interface 95, output interface 96, and communication interface 97.

[0088] ROM92 stores programs that control the operation of computer 90. ROM92 contains the programs necessary for computer 90 to perform each of the processes described above. RAM93 functions as a memory area where the programs stored in ROM92 are loaded.

[0089] The CPU 91 includes processing circuits. The CPU 91 uses RAM 93 as a batch memory and executes programs stored in at least one of ROM 92 or storage device 94. During program execution, the CPU 91 controls each component via the system bus 98 and performs various processes. Through program execution, the computer 90 functions as the optimization calculation unit 11, the trial calculation unit 12, the input plan creation unit 13, and the verification unit 14 described above.

[0090] The memory device 94 stores data necessary for program execution and data obtained through program execution.

[0091] The input interface (I / F) 95 connects the processing unit 10 and the input device 95a. The input I / F 95 is, for example, a serial bus interface such as USB. The CPU 91 can read various data from the input device 95a via the input I / F 95.

[0092] The output interface (I / F) 96 connects the processing unit 10 and the output device 96a. The output I / F 96 is a video output interface such as Digital Visual Interface (DVI) or High-Definition Multimedia Interface (HPMI®). The CPU 91 can transmit data to the output device 96a via the output I / F 96 and display an image on the output device 96a.

[0093] The communication interface (I / F) 97 connects the processing unit 10 to a server 97a located outside the processing unit 10. The communication I / F 97 is, for example, a network card such as a LAN card. The CPU 91 can read various data from the server 97a via the communication I / F 97.

[0094] The storage device 94 includes one or more selected from Hard Disk Drives (HDDs) and Solid State Drives (SSDs). The input device 95a includes one or more selected from a mouse, keyboard, microphone (voice input), and touchpad. The output device 96a includes one or more selected from a monitor, projector, printer, and speaker. Devices that have the functions of both input device 95a and output device 96a, such as a touch panel, may also be used.

[0095] The functions of the optimization calculation unit 11, the estimation unit 12, the input plan creation unit 13, and the verification unit 14 may be implemented by a single computer 90, or by the cooperation of multiple computers 90. For example, the creation system 1 includes multiple processing units 10 (computers 90). Each of the multiple processing units 10 may function as the optimization calculation unit 11, the estimation unit 12, the input plan creation unit 13, and the verification unit 14, respectively.

[0096] The processing of the various data described above may be recorded as a program that can be executed by a computer on a magnetic disk (flexible disk and hard disk, etc.), an optical disk (CD-ROM, CD-R, CD-RW, DVD-ROM, DVD±R, DVD±RW, etc.), a semiconductor memory, or another non-transitory computer-readable storage medium.

[0097] For example, information recorded on a recording medium can be read by a computer (or embedded system). The recording format (storage format) of the recording medium is arbitrary. For example, a computer reads a program from the recording medium and has the CPU execute the instructions written in the program based on this program. In a computer, program acquisition (or reading) may be performed via a network.

[0098] According to the embodiments described above, a production system, production method, program, and storage medium are provided that can create production plans with higher accuracy.

[0099] Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Furthermore, the embodiments described above can be implemented in combination with each other. [Explanation of symbols]

[0100] 1: Creation system, 10: Processing unit, 11: Optimization calculation unit, 12: Trial calculation unit, 13: Input plan creation unit, 14: Verification unit, 20: Storage device, 90: Computer, 91: CPU, 92: ROM, 93: RAM, 94: Storage device, 95: Input interface, 95a: Input device, 96: Output interface, 96a: Output device, 97: Communication interface, 97a: Server, 98: System bus, 300: Simulation model, 301: Input unit, 302: Buffer, 303: Equipment, 304: Shift, 305: Worker, 306: Resources, 307: Dispensing unit

Claims

1. A production system for creating production plans for producing multiple types of products using multiple production lines and multiple processes, An optimization calculation unit creates a processing plan that shows the planned production quantity for each product, each production line, and each process by performing an optimization calculation that includes an objective function that aims to minimize the number of transports between the multiple production lines and constraints that include constraints on transports between the multiple production lines, using first input data including the planned production quantity for each product and the processing capacity of each piece of equipment. An input plan creation unit creates an input plan indicating the timing of inputting the workpieces into the multiple production lines, using second input data which includes the number of workpieces to be input to each production line for each type and the processing paths in the multiple processes for each type. A verification unit that determines the validity of the processing plan and the input plan by simulating based on the processing plan and the input plan, A creation system equipped with this.

2. If the verification unit determines that the processing plan and the input plan are not valid, the optimization calculation unit creates an alternative processing plan by optimization calculation using alternative first input data or alternative constraints, according to claim 1.

3. If the verification unit determines that the processing plan and the input plan are not valid, the input plan creation unit creates another input plan by optimization calculation using different second input data, according to claim 1 or 2.

4. The aforementioned processes are carried out by multiple pieces of equipment, A creation system according to any one of claims 1 to 3, further comprising a calculation unit that refers to a third input data including equipment data for each of the aforementioned pieces of equipment, estimates the load rate for each piece of equipment when the processing plan is executed using the processing plan and the third input data, and determines the validity of the processing plan based on the load rate.

5. If the calculation unit determines that the processing plan is not appropriate, the optimization calculation unit creates an alternative processing plan by optimization calculation using alternative first input data or alternative constraints, according to claim 4.

6. A method for creating a production plan for producing multiple types of products using multiple production lines and multiple processes, An optimization calculation is performed using first input data including the planned production quantity for each product type and the processing capacity of each piece of equipment, to create a processing plan that shows the planned production quantity for each product type, each production line, and each process, by performing an optimization calculation that includes an objective function that aims to minimize the number of transports between the multiple production lines and constraints that include constraints on transports between the multiple production lines. Using second input data including the number of workpieces to be fed into each production line for each type and the processing paths in each of the multiple processes for each type, an input plan is created to indicate the timing of feeding the workpieces into the multiple production lines. Verification is performed to determine the validity of the processing plan and the input plan through simulation based on the processing plan and the input plan, How to create a prepared document.

7. A program that causes a computer to execute the creation method described in claim 6.

8. A storage medium storing the program described in claim 7.

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