Production planning system and production planning method

Abstract

To calculate, at a factory that produces various kinds but small-lot products, a layout of permanent parts which reduces a part mounting time and a preparation time.SOLUTION: A production planning system includes an arithmetic unit and a storage unit. The storage unit stores production plan information, design information, and mounting facility information. The arithmetic unit calculates, on the basis of the production plan information, one or more candidates of a changing timing for permanent parts, and calculates, on the basis of the production plan information, the design information, and the mounting facility information, a production efficiency in a period after each candidate of the changing timing for the permanent parts when the permanent parts are not changed at each candidate of the changing timing for the permanent parts and a production efficiency in a period after each candidate of the changing timing for the permanent parts when the permanent parts are changed at each candidate of the changing timing for the permanent parts.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a system for supporting planning of part change timing, part types and part placement in a factory that manufactures products, which will improve the production efficiency of the production line. [Background technology]

[0002] Background art includes JP 2016-42523 A (Patent Document 1). This publication states that "the method includes a step (ST1) of identifying the production frequency of each of a plurality of types of mounting boards in a predetermined period, a step (ST2) of dividing the plurality of types of mounting boards into a plurality of groups that can be produced without changing the arrangement of the component supply means based on the production frequency, and a step (ST3) of determining, for each of the plurality of groups, the arrangement in the component mounting device of the component supply means that supplies components necessary for the production of the mounting boards belonging to each group." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-42523 A Summary of the Invention [Problem to be solved by the invention]

[0004] Social infrastructure system products such as control panels are produced in small quantities and with a wide variety of products, and the products produced change irregularly. For example, in the process of mounting components on printed circuit boards, setup is required to change the components to be installed on the equipment according to the products to be put into the production line. In the mounting process of printed circuit boards in the production of small quantities and wide varieties, a production line configuration that improves production efficiency is one in which multiple mounting equipment units are connected, enabling the production of many printed circuit boards with a single setup. In addition, methods for improving production efficiency in production planning include a method of improving component mounting time by determining component placement so as to level the workload among multiple mounting equipment, and a method of reducing setup time for component replacement by fixing specific components to mounting equipment (hereinafter referred to as permanent components).

[0005] In response to this, Patent Document 1 describes a method for dividing several types of mounting boards into multiple groups that can be produced without changing the arrangement of component supply means based on the production frequency during a given period. However, these methods improve production efficiency only from the perspective of reducing setup time, and are unable to improve production efficiency from the perspective of both component mounting time and setup. In addition, in high-mix, low-volume production where input products are changed irregularly, it is necessary to appropriately review the component arrangement of the mounting equipment in order to maintain production efficiency, but Patent Document 1 does not describe any technology that solves this problem.

[0006] Therefore, the present invention provides a production planning system that improves production efficiency even in a production form in which products input into the production line are changed irregularly. [Means for solving the problem]

[0007] In order to achieve at least one of the above objects, the present invention provides a production planning system comprising a calculation unit and a storage unit, wherein the storage unit holds production plan information, design information, and mounting equipment information, wherein the production plan information includes information indicating a production period for each product, the design information includes information indicating components used in each of the products, and the mounting equipment information includes information indicating the number of mounting machines that mount the components on the products, information indicating the number of supply devices for the components that can be mounted on each of the mounting machines, information indicating the items and arrangement of the components supplied by each of the supply devices that are already mounted on each of the mounting machines, and information indicating the items and arrangement of the components supplied by each of the supply devices that are already mounted on each of the mounting machines. The information includes information indicating whether the parts supplied by the supply device are non-replaceable parts that are subject to replacement or permanent parts that are not subject to replacement, and the calculation unit calculates one or more candidate times for the change of the permanent parts based on the production plan information, and calculates, based on the production plan information, the design information, and the mounting equipment information, the production efficiency for a period after each of the candidate times for the change of the permanent parts in a case where the permanent parts are not changed to each of the candidate times for the change of the permanent parts, and the production efficiency for a period after each of the candidate times for the change of the permanent parts in a case where the permanent parts are changed to each of the candidate times for the change of the permanent parts. Effect of the Invention

[0008] According to one aspect of the present invention, even in a factory that produces a wide variety of products in small quantities, it is possible to plan the timing and content of changes to the types and arrangement of permanent components to improve the production efficiency of the production line. As a result, even in a wide variety of products in small quantities, it is possible to realize an arrangement of permanent components that can reduce component mounting time and setup time, and highly efficient component mounting can be realized. Problems, configurations, and effects other than those described above will be made clear by the explanation of the following embodiment. [Brief description of the drawings]

[0009] [Figure 1A] 1 is a block diagram showing an example of a component mounting line that is a target of processing in a production planning system according to an embodiment of the present invention; [Figure 1B]FIG. 2 is an explanatory diagram illustrating an example of a configuration of a mounting facility included in a component mounting line according to an embodiment of the present invention. [Diagram 2] 1 is a block diagram showing an example of a production planning system according to an embodiment of the present invention. [Diagram 3] FIG. 2 is an explanatory diagram illustrating an example of a production plan held by the production planning system according to the embodiment of the present invention. [Figure 4] FIG. 2 is an explanatory diagram illustrating an example of design information held by the production planning system according to the embodiment of the present invention. [Diagram 5] FIG. 2 is an explanatory diagram illustrating an example of mounting equipment master information held by the production planning system according to an embodiment of the present invention. [Figure 6] FIG. 2 is an explanatory diagram illustrating an example of mounting equipment setting information held by the production planning system according to an embodiment of the present invention. [Figure 7] FIG. 2 is an explanatory diagram illustrating an example of trend information of a planned production item held by the production planning system according to the embodiment of the present invention. [Figure 8] FIG. 2 is an explanatory diagram illustrating an example of used parts information held by the production planning system according to the embodiment of the present invention. [Figure 9] FIG. 2 is an explanatory diagram illustrating an example of part placement information held by the production planning system according to the embodiment of the present invention. [Figure 10] FIG. 2 is an explanatory diagram illustrating an example of component mounting time information held by the production planning system according to the embodiment of the present invention. [Figure 11] FIG. 2 is an explanatory diagram illustrating an example of setup time information held by the production planning system according to the embodiment of the present invention. [Figure 12] 1 is an explanatory diagram illustrating an example of permanent component placement change timing information held by the production planning system according to an embodiment of the present invention; [Figure 13] 4 is a flowchart illustrating an example of a process executed by the production planning system according to the embodiment of the present invention. [Figure 14] FIG. 2 is an explanatory diagram illustrating an example of an input screen displayed by the production planning system according to the embodiment of the present invention. [Figure 15A] 11 is a flowchart illustrating an example of a process for calculating an analysis period based on product information by the production planning system according to the embodiment of the present invention. [Figure 15B] 11 is a flowchart illustrating an example of a process for calculating an analysis period based on part information used by the production planning system according to the embodiment of the present invention. [Figure 16] FIG. 11 is an explanatory diagram illustrating an example of an output screen displayed by the production planning system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

[0011] FIG. 1A is a block diagram showing an example of a component mounting line that is a target of processing by a production planning system according to an embodiment of the present invention.

[0012] The component mounting line is composed of one or more mounting equipment 101 connected to the preceding and succeeding processes by a transport mechanism 105 such as a conveyor. A printed circuit board 104 is fed into the mounting equipment 101 by the transport mechanism 105, and components 106 are mounted on the printed circuit board 104. Each mounting equipment 101 in the component mounting line is connected to a mounting equipment control device 103 via a network 102, and mounting conditions are set and operation is controlled.

[0013] FIG. 1B is an explanatory diagram showing an example of the configuration of a mounting facility 101 included in a component mounting line according to an embodiment of the present invention.

[0014] The mounting equipment 101 is composed of a feeder 107 on which components 106 are mounted, a cart 108 on which the feeder 107 is mounted, a nozzle 109 that picks up the components 106, a nozzle transport mechanism 110, and a fixing mechanism 111 that mounts a printed circuit board. Of the components 106, component types called reel products and stick products are attached to the feeder 107 and then placed on the cart 108. Component types called tray products are placed on trays corresponding to the component shapes, and then placed on the mounting equipment 101.

[0015] When mounting a component 106 on a printed circuit board 104, a nozzle 109 is transported by a nozzle transport mechanism 110 to the position of a feeder 107 on which the component 106 to be mounted is attached. The nozzle 109 transported to the predetermined position picks up the component 106, which is then transported by the transport mechanism 110 to a component mounting position on the printed circuit board 104 and mounted on the printed circuit board 104.

[0016] FIG. 2 is a block diagram showing an example of a production planning system according to an embodiment of the present invention.

[0017] The production planning system 200 is a device including a PC (Personal Computer) such as a server or a terminal, and software implemented in the PC, and is equipped with an input / output unit 201, a storage unit 202, and a calculation unit 203. The production planning system 200 is connected to systems such as a design system 205 and a work instruction device 206 via a network 204.

[0018] The input / output unit 201 is used to obtain data necessary for processing by the calculation unit 203 and display the processing results, and is configured to have, for example, input devices such as a keyboard and mouse, a communication device for communicating with the outside, a recording / playback device for disk-type storage media, and an output device such as an LCD monitor.

[0019] The storage unit 202 includes input information 207 used in the processing of the calculation unit 203 and output information 208 for storing the processing results, and is configured with a storage device such as a hard disk drive and memory.

[0020] The input information 207 includes a production plan 209, product design information 210, mounting equipment master information 211, and mounting equipment setting information 212. These pieces of information will be described below.

[0021] FIG. 3 is an explanatory diagram showing an example of the production plan 209 held by the production planning system 200 according to the embodiment of the present invention.

[0022] The production plan 209 is information for managing the production plan of a product, and for example, as shown in Fig. 3(a), is composed of information such as product ID 301, product category 302, production quantity 303, production start date 304, and production end date 305. In the production plan shown in Fig. 3(a), for example, the product ID "P001" corresponds to product category A, and indicates that the plan is to produce the entire production quantity in the period "10 / 1 to 10 / 5".

[0023] A product is composed of multiple boards, and the production plan for each board can be confirmed, for example, in the production plan for each board shown in Fig. 3(b). Fig. 3(b) shows a production plan for multiple boards that make up a product with product ID "P001" as an example, but the actual production plan 209 also includes production plans for each board of other products.

[0024] The production plan for each board shown in Fig. 3(b) is managed by information such as product ID 311, board name 312, input group 313, mounting start date 314, and mounting end date 315. Since there is a limit to the types of boards that can be input to the component mounting line in one setup, the boards are grouped into units on which components can be mounted in one setup. For example, the input group "Group_1" is composed of board names "Board1" and "Board3" of product ID "P001", and indicates that component mounting will be performed on "10 / 1".

[0025] FIG. 4 is an explanatory diagram showing an example of the design information 210 held by the production planning system 200 according to the embodiment of the present invention.

[0026] Design information 210 is information for managing the components and drawings of a product, and is composed of information such as product ID 401, board name 402, number of boards 403, and drawing 404, as shown in Fig. 4(a). For example, it is shown that five boards with board name "Board1" of product ID "P001" need to be produced, and that the drawing for that board is stored under drawing number "Drawing_P001_Board1".

[0027] Furthermore, component information for each board is held, for example, as shown in Fig. 4(b). Fig. 4(b) shows component information for a board named "Board1" as an example, but actual design information 210 also includes component information for other boards. The board component information shown in Fig. 4(b) is composed of information on board name 411, component type 412, component name 413, and number of components mounted 414. For example, it is shown that the board named "Board1" uses a reeled component "Comp_001", and that the number of components mounted is 10.

[0028] FIG. 5 is an explanatory diagram showing an example of the mounting equipment master information 211 held by the production planning system 200 according to the embodiment of the present invention.

[0029] Mounting equipment master information 211 is information for managing the production line configuration and the like, and is composed of information such as production line name 501, installation position in the production line 502, mounting equipment name 503, and product model 504, as shown in Fig. 5. The mounting equipment master information 211 shown in Fig. 5 indicates, for example, that the name (mounting equipment name) of the first mounting equipment (i.e., the installation position is "1") in the production line name "Line_1" is "SMT_1", and its product model is "Model_001".

[0030] FIG. 6 is an explanatory diagram showing an example of the mounting facility setting information 212 held by the production planning system 200 according to the embodiment of the present invention.

[0031] The mounting equipment setting information 212 is information for managing the setting information of the mounting equipment registered in the mounting equipment master information 211. For example, as shown in Fig. 6(a), the mounting equipment setting information 212 is composed of information on the mounting equipment name 601, the cart 602, the maximum number of channels 603 indicating the number of components that can be placed on the cart, whether components can be allocated to the mounting equipment for each component type (reel, stick, tray) 604, and options 605 such as the upper limit of component height. For example, the information in the first row of Fig. 6(a) indicates that the front cart of the mounting equipment "SMT_1" has a maximum number of channels of 100 channels, can allocate only reel products, and can allocate components up to a height of 5.0 mm.

[0032] Also, Fig. 6(b) shows an example of component information currently allocated in each mounting equipment. The currently allocated component information shown in Fig. 6(b) is composed of information on the mounting equipment name 611, cart 612, channel number 613, allocated component name 614, component type 615, and whether or not the component is permanently installed in the mounting equipment 616. For example, the information in the first row of Fig. 6(b) indicates that the component name "Comp_002" is allocated as a permanent component to channel number 1 of the front cart of the mounting equipment "SMT_1".

[0033] 2 includes planned production product trend information 213, component usage information 214, permanent component layout information 215, component mounting time information 216, setup time information 217, and permanent component layout change timing information 218. These pieces of information will be described below.

[0034] FIG. 7 is an explanatory diagram showing an example of the planned production product trend information 213 held by the production planning system 200 according to the embodiment of the present invention.

[0035] The planned production product trend information 213 is information for managing the trends of planned production products in the production planning system 200, and is composed of a planned production product trend 701, a product classification 702, a production start date 703, and a production end date 704 of the target product, as shown in FIG. 7, for example. The planned production product trend information 213 in FIG. 7 shows a group of products grouped by product classification and part information. In the example of FIG. 7, the trends of planned production products are classified based on product classification, and for example, product classification A is grouped as a planned production product trend "T1", which indicates that the product will be produced in the period "10 / 1 to 10 / 15". A method for acquiring the trends of planned production products will be described later.

[0036] FIG. 8 is an explanatory diagram showing an example of the parts used information 214 held by the production planning system 200 according to the embodiment of the present invention.

[0037] The used parts information 214 is information for managing the number of parts used and the frequency of use calculated based on the production plan 209 and the design information 210 in the production planning system 200. Here, the number of parts used indicates, for example, the total number of parts used when producing a product with production ID "P001". Also, the frequency of use of a part indicates, for example, when the product ID "P001" is composed of multiple boards with board names such as "Board1" and "Board2", how many of those boards the part is used in.

[0038] The number of parts used is composed of a usage number ranking 801, a part name 802, and a usage number 803, as shown in Fig. 8(a), for example. For example, the information in the first row of Fig. 8(a) indicates that the number of uses of the part name "Comp_002" is 1,000, ranking it first in terms of usage number. The frequency of part use is composed of a usage frequency ranking 811, a part name 812, and a usage frequency 813, as shown in Fig. 8(b), for example. For example, the information in the first row of Fig. 8(b) indicates that the part name "Comp_002" is used in 25 boards, ranking it first in terms of usage frequency.

[0039] FIG. 9 is an explanatory diagram showing an example of the part placement information 215 held by the production planning system 200 according to the embodiment of the present invention.

[0040] The component placement information 215 is information for managing allocation information of permanent components to mounting equipment calculated when the production system is executed. For example, as shown in Fig. 9(a), the component placement information 215 is composed of information on the installation position 901 of the mounting equipment on the production line, the equipment name 902, the cart 903, and whether or not the equipment is to be permanently installed over the entire surface 904.

[0041] Here, "fully permanently installed" refers to a configuration in which all parts installed on the trolley are permanently installed. When the entire surface of the trolley is permanently installed, even when the input group is changed, there is no need to replace the trolleys and feeders, i.e., no setup is required. The example in Figure 9(a) shows that the front trolley of equipment name "SMT_1" at installation position "1" and the rear trolley at installation position "2" are fully permanently installed.

[0042] Next, Fig. 9(b) shows an example of information for managing the correspondence between channel numbers and permanent parts. For example, the information shown in Fig. 9(b) is composed of information on equipment name 911, cart 912, channel number 913, and part name 914. The example of the first line in Fig. 9(b) shows that part name "Comp_001" is assigned as a permanent part to channel number "4" of the front cart of equipment name "SMT_1". The method of calculating part placement will be described later.

[0043] FIG. 10 is an explanatory diagram showing an example of the component mounting time information 216 held by the production planning system 200 according to the embodiment of the present invention.

[0044] The component mounting time information 216 is information for managing the component mounting time calculated when the production planning system 200 is executed. Here, the component mounting time is defined as the time from when a board is carried into the first mounting equipment until it is carried out from the rearmost mounting equipment. For example, the component mounting time information 216 is composed of information on a product ID 1001, a board name 1002, the number of boards 1003, and component mounting time 1004, as shown in FIG. 10. The example of the first row in FIG. 10 indicates that the component mounting time for five boards with the board name "Board1" that constitute a product with a product ID "P001" (i.e., the total component mounting time for the five boards) is 10 minutes. The method of calculating the component mounting time will be described later.

[0045] FIG. 11 is an explanatory diagram showing an example of the setup time information 217 held by the production planning system 200 according to the embodiment of the present invention.

[0046] The setup time information 217 is information for managing the setup time for part replacement calculated when the production planning system 200 is executed. For example, as shown in Fig. 11, the setup time information 217 is composed of an input group 1101, an operation date 1102, and a setup time 1103. The example of the first row in Fig. 11 indicates that the operation of the input group "Group_1" is performed on "10 / 1", and the setup time is 10 minutes. The method of calculating the setup time will be described later.

[0047] FIG. 12 is an explanatory diagram showing an example of permanent component location change timing information 218 held by the production planning system 200 according to the embodiment of the present invention.

[0048] The permanent component layout change timing information 218 is information for managing the change timing of the permanent component layout calculated when the production planning system 200 is executed. For example, as shown in Fig. 12(a), the permanent component layout change timing information 218 is composed of information on permanent component layout change timing candidate 1201, permanent component replacement time 1202, permanent component layout 1203, and production efficiency improvement effect 1204. The example of the first row in Fig. 12(a) shows that if the permanent component layout is changed on 10 / 1, the work time for replacing the permanent component is 1 hour, and the production efficiency is improved by 20 hours compared to production with the current permanent component layout.

[0049] 12(b), the detailed information for calculating the improvement effect of production efficiency is composed of permanent component layout change timing candidate 1211, component mounting time 1212 and setup time 1213 calculated using the current permanent component layout (current layout), and component mounting time 1215 and setup time 1216 calculated using the permanent component layout (optimization result) calculated by this production system, and replacement time 1217 when changing the layout of permanent components, and a total of these 1218. A method for calculating the permanent component layout change timing, and a method for calculating the component mounting time, setup time, and replacement time when changing the layout of permanent components will be described later.

[0050] Referring again to Fig. 2, the calculation unit 203 has a memory unit 220 and a calculation processing unit 221. The memory unit 220 is for temporarily storing data acquired from the input / output unit 201 and the input information 207 of the storage unit 202, or the results of processing by the calculation processing unit 221.

[0051] The calculation processing unit 221 is made up of a data acquisition unit 222 , a product tendency estimation unit 223 , a permanent component layout optimization model creation unit 224 , a permanent component layout calculation unit 225 , a permanent component layout change timing calculation unit 226 , and a display control unit 227 .

[0052] The data acquisition unit 222 acquires information required for the processing of the calculation processing unit 221 from the input information 207 based on information such as the target period input by the user from the input / output unit 201, and stores the information in the memory unit 220. The product tendency estimation unit 223 acquires product IDs, product classifications, and information on parts used from the production plan 209 and the design information 210 of the products to be produced during the target period, and estimates the time when the tendency of the products to be produced will change from changes in the product classification to be produced and changes in the number and frequency of parts used. The permanent component placement optimization model creation unit 224 creates an optimization model of the permanent component placement for determining the permanent component placement, using the product changeover time acquired by the product tendency estimation unit 223 as the analysis period. The permanent component placement calculation unit 225 calculates the permanent component placement using the model created by the permanent component placement optimization model creation unit 224 and the information of the input information 207 stored in the data acquisition unit 222. A permanent component layout change timing calculation unit 226 calculates the timing to change the permanent component layout based on the component mounting time calculated by the permanent component layout calculation unit 225, the setup time for component replacement occurring for each input group, and the setup time for replacing the permanent components. A display control unit 227 stores the results obtained, calculated, or determined by each of the above processing units in output information 208, and displays them on the input / output unit 201.

[0053] Next, the operation of each function in the production planning system 200 shown in FIG. 2 will be described with reference to the flowchart shown in FIG.

[0054] FIG. 13 is a flowchart showing an example of processing executed by the production planning system 200 according to the embodiment of the present invention.

[0055] First, in order to reflect the period used to calculate the timing of changing the permanent component allocation and the target production line in the production planning system 200, the user inputs or selects the period to be analyzed, the name of the target production line, the method for determining the analysis period for determining the permanent component allocation, and the maximum number of permanent components from an input screen such as that shown in Fig. 14. The production planning system 200 can start processing by reading from the input screen.

[0056] FIG. 14 is an explanatory diagram showing an example of an input screen displayed by the production planning system 200 according to the embodiment of the present invention.

[0057] 14 is an example of a screen displayed for the user to input data, and includes an analysis period input section 1401, a production line input section 1402, an analysis period determination method input section 1403, a maximum number of parts that can be permanently installed input section 1404, and an execute button 1405. In each of the above input sections, the user may directly input a value by operating the input / output section 201, or may select a value from a plurality of options.

[0058] 14, "10 / 1-3 / 31" is input as the analysis target period in analysis period input section 1401, "Line_1" is selected as the target production line in production line input section 1402, "product information" is selected as the analysis period determination method in analysis period determination method input section 1403, "product classification" is selected as the classification method, and the maximum number of permanently installed parts "100" is input in maximum permanently installable part number input section 1404. When execute button 1405 is operated in this state, the processes from S001 onwards, which will be described later, are executed, and in S002, the process of FIG. 15A is executed.

[0059] On the other hand, "parts information" may be selected as the method for determining the analysis period in the analysis period determination method input section 1403. In this case, the judgment order of the number of parts used, the judgment order of the frequency of use of the parts, the judgment threshold value of the number of parts used, and the judgment threshold value of the frequency of use of the parts can be further input. In the example of Fig. 14, "50", "50", "5", and "5" are input, respectively. When the execute button 1405 is operated in this state, the processes from S001 onwards, which will be described later, are executed, and in S002, the process of Fig. 15B is executed.

[0060] 13 again. The data acquisition unit 222 acquires input information 207 based on the analysis period and the conditions of the target production line input by the user from the input / output unit 201 such as a terminal, and stores the information together with the input information 207 in the memory unit 220 (S001). In this embodiment, the following description will be given assuming that the production plan 209, design information 210, mounting equipment master information 211, and mounting equipment setting information 212 shown in FIGS. 3 to 6 are acquired as the input information 207.

[0061] The product tendency estimation unit 223 calculates the tendency of input products based on the product information scheduled to be produced during the analysis period and the parts used information acquired from the production plan 209 and the design information 210, and calculates the analysis period used to calculate the permanent component allocation (S002). At this time, the product tendency estimation unit 223 calculates the analysis period used to calculate the permanent component allocation based on either the product information or the parts used information according to the user's selection. Details of this process will be described with reference to Figs. 15A and 15B.

[0062] FIG. 15A is a flowchart showing an example of a process in which the production planning system 200 according to the embodiment of the present invention calculates an analysis period based on product information.

[0063] The process in Fig. 15A is executed when "product information" is selected in analysis period determination method input section 1403 on input screen 1400 shown in Fig. 14. Here, the explanation will be given on the assumption that "product information" is selected in analysis period determination method input section 1403 and "product classification" is selected as the classification method.

[0064] The product trend estimation unit 223 acquires a product ID and a product classification as product information in the production plan 209 (S101). Next, the product trend estimation unit 223 acquires the time when the input product will be switched using the product information (S102). In this embodiment, since the product classification is selected in the analysis period determination method input unit 1403 in Fig. 14, the product trend estimation unit 223 acquires the time when the product classification will be switched. Then, the product trend estimation unit 223 sets the period up to the acquired switching time as the analysis period to be used in the calculation of permanent component placement (S103).

[0065] Thereafter, the product tendency estimation unit 223 determines whether the analysis period has been set for all products included in the analysis period set in FIG. 14 (S104), and if not complete, returns to S102, and if complete, ends the setting of the analysis period.

[0066] In this embodiment, for example, when determining the product changeover time based on the product classification, in Fig. 3(a), "10 / 1 to 10 / 15" when product classification A is produced is the trend of the first input product, i.e., the first analysis period T1. Then, "10 / 15 to 11 / 10" when product classification C is produced, and "11 / 10 to 11 / 30" when product classification B is produced are set as analysis periods T2 and T3, respectively, and are output as trend information 213 of the planned production product in the output information.

[0067] According to the process of FIG. 15A, when products with adjacent production periods belong to the same classification, those production periods are combined into one analysis period. In general, even if products are different, if they belong to the same classification, the tendency of the parts used is often similar, such as parts that are frequently used in each product being common, or parts that are used in many boards being common. Therefore, even when the products being produced are switched, if those products belong to the same classification, it is considered that there is little need to review the permanent parts at that timing. Therefore, in the process of FIG. 15A, the period during which products of the same classification are produced is treated as one analysis period, and the timing of switching of products of the same classification is excluded from the candidates for the review timing of the permanent parts, thereby reducing the processing load for reviewing the permanent parts.

[0068] FIG. 15B is a flowchart showing an example of a process for calculating an analysis period based on part information used by the production planning system 200 according to the embodiment of the present invention.

[0069] The process in Fig. 15B is executed when "parts information" is selected in analysis period determination method input section 1403 on input screen 1400 shown in Fig. 14. Here, it is assumed that "parts information" is selected in analysis period determination method input section 1403, "product classification" is selected as the classification method, the number of uses "50" and the frequency of use "50" are input as the judgment rank, and the number of uses "5" and the frequency of use "5" are input as the judgment threshold.

[0070] The product tendency estimation unit 223 acquires a product ID and a product classification as product information (S201). Next, the product tendency estimation unit 223 acquires the number of parts used and the frequency of use in units of the classification method selected in Fig. 14 (S202). For example, when product classification is selected as the classification method, the number of parts used and the frequency of use are acquired and stored in the memory unit 220.

[0071] The product tendency estimation unit 223 acquires information on the number of uses and the frequency of use for all products within the period set in Fig. 14, creates a list of the number of parts and the frequency of use, and then calculates the difference between the list of parts information for the product to be produced most recently and the list of parts information for the product to be produced next (S203). In this embodiment, the top 50 in terms of number of uses and the top 50 in terms of frequency of use are set as the target range of parts for which the difference is to be calculated, as shown in the analysis period determination method input unit 1403 in Fig. 14. The upper limit of the judgment rank is set so that the sum of the set values ​​of the judgment rank for the number of uses and the frequency of use is equal to or less than the maximum number of permanent parts shown in Fig. 14. The maximum number of permanent parts may be set, for example, to the number of feeders available for permanent parts.

[0072] Next, the product trend estimation unit 223 determines whether the calculated difference is equal to or greater than the threshold value input in Fig. 14 (S204). If the difference is equal to or less than the threshold value, the product trend estimation unit 223 integrates the compared lists and compares them with a list of information on parts to be produced next (S205). If the difference is equal to or greater than the threshold value, the product trend estimation unit 223 sets the period during which the products included in that list are produced as the analysis period (S206).

[0073] Thereafter, the product tendency estimation unit 223 determines whether the analysis period has been set for all products included in the analysis period set in FIG. 14 (S207), and if not complete, returns to S203, and if complete, ends the setting of the analysis period.

[0074] According to the process of FIG. 15B, when the difference between the number of parts used and the frequency of use of the top parts used in products with adjacent production periods is small, those production periods are combined into one analysis period. Even if the timing of product changeover occurs, if the tendency of the parts used in those products is similar, it is considered that there is little need to review the permanent parts at that timing. Therefore, in the process of FIG. 15B, the period in which products with similar tendency of parts used are produced based on the number of parts used and the frequency of use is treated as one analysis period, and the timing of product changeover is excluded from the candidates for the review of permanent parts, thereby reducing the processing load for reviewing permanent parts.

[0075] Returning to the flowchart in Fig. 13, after the setting of the analysis period in S002 is completed, the permanent component placement optimization model creation unit 224 creates an optimization model for determining the permanent component placement using the set analysis period and information on the products included in that period (S003), and the permanent component placement calculation unit 225 calculates the placement of the permanent components using the created optimization model (S004).

[0076] In this embodiment, a mathematical programming model is used to select permanent components that satisfy the constraint conditions shown in the following formulas (1) to (4), and their placement in the mounting equipment is calculated. This specification method may be performed by determining whether or not all combinations of components to be analyzed satisfy the constraint conditions shown in formulas (1) to (4), but it may also be solved using a branch and bound method, which is a well-known technique. Since the branch and bound method is well-known, a description thereof will be omitted.

[0077]

number

[0078] Here, formula (1) requires that the parts used in the calculation of permanent parts be allocated to any mounting equipment or cart as either permanent or non-permanent parts. In other words, the system determines whether or not a part should be a permanent part for a part that needs to be allocated to any cart of any mounting equipment and mounted on a product.

[0079] Equation (2) requires that the number of components that can be allocated to the mounting equipment must be equal to or less than the maximum number of channels of the cart.

[0080] Equations (3) and (4) require that, for example, a component that cannot be allocated to a mounting equipment due to the component allocation availability and upper component height limit of the mounting equipment shown in FIG. 6(a) cannot be allocated to that mounting equipment.

[0081] If a combination of the permanent component selection results and mounting equipment allocation results that satisfy the constraints shown in these equations (1) to (4) cannot be found, it is determined that there is no feasible solution, and if there is only one solution that satisfies these constraints, that solution is the optimal solution. If there are multiple solutions that satisfy these constraints, the one that minimizes the objective function shown in equation (5) is the optimal solution.

[0082]

number

[0083] Here, the first term in formula (5) represents an estimate of the component mounting time, the second term represents the feeder changeover time that occurs as a setup when switching input groups, and the third term represents the tray item changeover time.As shown in formula (5), by minimizing the value of the objective function, it is possible to obtain a list of permanent components with small estimates of component mounting time and small setup times for feeders and tray items, and their placement on the mounting equipment.

[0084] When the objective function shown in formula (5) is used, permanent components are selected and allocated so that the sum of the component mounting time and the setup time for non-permanent components (feeder replacement time and tray product replacement time) is minimized. However, this is just one example, and at least one of the component mounting time and the setup time can be used as the objective function.

[0085] Here, the constraint conditions for satisfying the objective function of equation (5) are expressed by the following equations (6) to (8).

[0086]

number

[0087] Equation (6) is a calculation formula for estimating the time required to mount components on board l in mounting equipment j.

[0088] Equation (7) is used to calculate the component mounting time of mounting equipment j, which is a bottleneck in the process of mounting components onto board l to be input into the production line (for example, when multiple mounting equipment 101 are installed in series as shown in Figure 1, the longest component mounting time among them).

[0089] Equation (8) is a constraint equation for calculating the number of trolleys that are permanently installed on the entire surface.

[0090] The calculated component mounting time and setup time information are stored in the memory unit 220.

[0091] Next, the permanent component placement calculation unit 225 determines whether or not the list and placement of permanent components have been calculated for all conditions of the analysis period set in S002 (S005), and if complete, the permanent component placement change timing calculation unit 226 determines the change timing of the permanent components (S006).

[0092] In this embodiment, an example will be described in which the improvement effect of production efficiency is calculated by comparing the total of the component mounting time and setup time calculated using the current permanent component layout with the total of the component mounting time, setup time, and time to replace the permanent component layout calculated using the permanent component layout calculated by the optimization model created in S003, and the timing to change the permanent component layout is determined based on this value.

[0093] First, the permanent component layout change timing calculation unit 226 acquires the design information 210 to be analyzed and the current permanent component layout information 212 from the input information 207, and calculates the component mounting time PTcs using a line simulator or the like. Then, the component setup time STcs is calculated using the method explained in the creation of the optimization model in S003. Next, the component mounting time PTopt and setup time STopt are similarly calculated for the permanent component layout calculated using the optimization model, and the time STperm for replacing the permanent component is calculated. The time for replacing the permanent component is calculated using the following formula (9).

[0094]

number

[0095] The method of acquiring each task time can be a method of estimating by measuring the on-site task with a stopwatch, etc. Also, the quantity of the target feeders and sticks can be calculated by comparing the current placement with the component placement information 215 of the optimization result.

[0096] Using the time calculated by the above method, permanent component layout change timing calculation unit 226 calculates the production efficiency improvement effect PE according to the following formula (10).

[0097]

number

[0098] If PE is positive, it can be determined that the component mounting time and setup time can be reduced by optimization. The permanent component placement change timing calculation unit 226 calculates the improvement effect of production efficiency in the analysis period set in Fig. 14, and for example, the time when PE is maximum in the target period can be set as the permanent component change timing.

[0099] Finally, the display control unit 227 stores each data of the product trend, the component used information, the permanent component placement, the component mounting time information, the setup time, and the permanent component placement change timing information stored in the memory unit 220 in planned production product trend information 213, component used information 214, component placement information 215, component mounting time information 216, setup time information 217, and permanent component placement change timing information 218, respectively, and displays them on the input / output unit 201 (S007).

[0100] FIG. 16 is an explanatory diagram showing an example of an output screen displayed by the production planning system 200 according to the embodiment of the present invention.

[0101] At the top of the output screen 1600, planned production product trend information 1601 is displayed in table format. This information corresponds to planned production product trend information 213 shown in Fig. 7, and displays a list of all cases in the analysis target period, but has sorting and filtering functions according to the planned production product trend, product classification, and production start and end dates. This allows the user to check the trend of input products for any product or period.

[0102] Next, the calculation result 1602 of the improvement effect of production efficiency is displayed on the lower left side of this screen. This is a graph showing the candidate timings for changing the permanent parts layout shown in FIG. 12(a) and the improvement effect of production efficiency. Furthermore, the upper part of the graph shows the product classification to be produced during the period and the period showing the trend of the planned production items shown in the upper part of this screen. This allows the user to visually confirm the improvement effect of production efficiency and the product classification and the trend of the planned production items that are being input at that time, making it easier to understand the relationship between the input products and the improvement effect of production efficiency.

[0103] 16, the boundary between analysis period T1 and the previous analysis period (not shown) (which may be read as the start of analysis period T1 or the end of the previous analysis period; similarly below), the boundary between analysis periods T1 and T2, the boundary between analysis periods T2 and T3, and the boundary between analysis period T3 and the subsequent analysis period (not shown) are each calculated as a candidate for the permanent part change timing, and the improvement effect of production efficiency calculated for each candidate is displayed. The improvement effect of production efficiency calculated for the boundary between analysis periods T1 and T2 (i.e., 10 / 15) is the largest.

[0104] Then, on the lower right side of this screen, a permanent component layout change time 1603 is displayed based on the improvement effect of production efficiency. In this embodiment, the time when the improvement effect of production efficiency is the largest (10 / 15, which corresponds to the boundary between analysis periods T1 and T2 in the example of FIG. 16) is set as the permanent component layout change time, and the date is displayed in the date column of the permanent component layout change time 1603. Also, the replacement time of the permanent components when changing the permanent component layout under the input change time conditions is displayed in the change work time column with reference to the permanent component layout change time information in FIG. 12(a). Also, when the display section of the permanent component layout information is selected, the component layout information for the corresponding conditions shown in FIG. 9 is displayed.

[0105] The user checks the improvement effect of production efficiency on this screen, the time when the permanent component placement is changed, and the change work time, and if there is no problem with the contents, the user selects the confirm button 1604 at the bottom right of this screen to confirm the time when the permanent component placement is changed. In this embodiment, the method of determining the time when the production efficiency is most improved as the time when the permanent components are changed has been described, but the user may check the screen shown in FIG. 16 and change it to another candidate date. When changing it, for example, it is possible to change it by selecting another candidate date from the date field on the lower right side of FIG. 16. For example, if 11 / 10 is selected as the time when the change is made, the work time (permanent component replacement time 1217) when changing the permanent component placement shown in FIG. 12 is referenced, and "1.5 hours" corresponding to "11 / 10" is displayed. In addition, as for the permanent component placement information, the value "part placement_3" of the permanent component placement 1203 can be referenced as the placement information when the permanent component placement is changed on 11 / 10. This makes it possible to respond to cases where the permanent component placement is changed on a date other than 10 / 15 due to the user's convenience, such as a shortage of workers.

[0106] The system according to the embodiment of the present invention may be configured as follows, for example.

[0107] (1) A production planning system (e.g., production planning system 200), comprising a calculation unit (e.g., calculation unit 203) and a storage unit (e.g., storage unit 202), the storage unit holds production plan information (e.g., production plan 209), design information (e.g., design information 210), and mounting equipment information (e.g., mounting equipment master information 211 and mounting equipment setting information 212), the production plan information includes information indicating a production period of each product (e.g., production start date 304 and production end date 305), the design information includes information indicating components used in each product, the mounting equipment information includes the number of mounting machines that mount components on the products (e.g., mounting equipment master information 211), information indicating the number of component supply devices (e.g., feeders or trays) that can be mounted on each mounting machine (e.g., maximum channel number 603), and information indicating the items of components supplied by each supply device already mounted on each mounting machine. and information indicating the placement of the permanent parts (for example, mounting equipment name 611, trolley 612, channel number 613, component name 614, and component type 615), and information indicating whether the parts supplied by each supply device already attached to each mounting machine are non-replaceable parts to be replaced or permanent parts not to be replaced (for example, permanent / non-replaceable 616).The calculation unit calculates one or more candidates for the timing of changing the permanent parts based on the production plan information (for example, S002), and calculates the production efficiency in a period (for example, an analysis period) after each of the candidates for the timing of changing the permanent parts in a case where the permanent parts are not changed to each of the candidates for the timing of changing the permanent parts, and the production efficiency in a period after each of the candidates for the timing of changing the permanent parts in a case where the permanent parts are changed to each of the candidates for the timing of changing the permanent parts (for example, S003 and S004), based on the production plan information, design information, and mounting equipment information.

[0108] This makes it possible to plan the timing and content of changes to the types and layout of permanent parts that will improve the production efficiency of the production line, even in factories that produce a wide variety of small quantities of products.As a result, even in high-mix, low-volume production where the input products change irregularly, it is possible to realize a permanent part layout that can reduce part mounting time and setup time, making it possible to achieve highly efficient part mounting.

[0109] (2) In the above (1), the calculation unit calculates at least one of the periods when the products being produced are switched as one or more candidates for the changeover period of the permanent parts.

[0110] This makes it possible to appropriately calculate candidates for the replacement time of permanent parts.

[0111] (3) In (2) above, the production plan information further includes information indicating the classification of each product (e.g., product classification 302), and when the products before and after the product to be produced belong to the same classification at the time when the product to be produced is changed, the calculation unit does not calculate the time when the product to be produced is changed as a candidate for the time to change the permanent part (e.g., S101 to S104).

[0112] This makes it possible to appropriately calculate candidates for the replacement time of permanent parts.

[0113] (4) In (2) above, if at least one of the number of uses and the frequency of use of each part used in the products before and after the change in the product to be produced satisfies a predetermined condition, the calculation unit does not calculate the change in the product to be produced as a candidate for the change in the permanent parts (e.g., S201 to S207).

[0114] This makes it possible to appropriately calculate candidates for the replacement time of permanent parts.

[0115] (5) In (4) above, if the calculation unit determines that there is a high similarity between the parts used in the products before and after the change in the product being produced based on at least one of the number of parts used and the frequency of use of each part item used in the products before and after the change in the product being produced, the calculation unit does not calculate the time when the product being produced is changed as a candidate for the time to change the permanent parts (e.g., S201 to S207).

[0116] This makes it possible to appropriately calculate candidates for the replacement time of permanent parts.

[0117] (6) In (1) above, the calculation unit calculates the items and arrangement of the changed permanent parts based on at least one of the time required to install the parts and the time required to replace the non-installed parts, and calculates the production efficiency for the period after each of the candidate dates for the change of the permanent parts in the case where the permanent parts are changed to each of the candidate dates for the change of the permanent parts based on the calculated items and arrangement of the changed permanent parts.

[0118] This allows proper selection of permanent component items and arrangements that improve production efficiency.

[0119] (7) In (6) above, the calculation unit calculates the items and placement of the permanent components after the change so as to maximize production efficiency based on the time required to implement the components and the time required to replace the non-permanent components (e.g., calculation based on formulas (1) to (5)).

[0120] This allows proper selection of permanent component items and arrangements that improve production efficiency.

[0121] (8) In (1) above, the calculation unit calculates an improvement effect of production efficiency in a period after each of the candidate dates for changing the permanent parts when the permanent parts are changed to each of the candidate dates for changing the permanent parts, compared to the production efficiency in a period after each of the candidate dates for changing the permanent parts when the permanent parts are not changed to each of the candidate dates for changing the permanent parts, and outputs the improvement effect of production efficiency (e.g., S003 and S004).

[0122] This allows appropriate evaluation of improvements in production efficiency resulting from changing permanent parts.

[0123] (9) In the above (8), the calculation unit determines the candidate replacement timing for the permanent part that maximizes the effect of improving production efficiency as the replacement timing for the permanent part (for example, determination based on formula (10)).

[0124] This makes it possible to realize a permanent component arrangement that can reduce component mounting time and setup time, thereby enabling highly efficient component mounting.

[0125] (10) In the above (1), the calculation unit calculates the production efficiency in the period after the candidate times for changing the permanent parts if the permanent parts are not changed to the candidate times for changing the permanent parts by calculating the time required for mounting parts and the time required for replacing non-installed parts in the period after the candidate times for changing the permanent parts based on the types and arrangement of parts before the change of the permanent parts (for example, the first term of formula (10)), and calculates the production efficiency in the period after each of the candidate times for changing the permanent parts if the permanent parts are changed to each of the candidate times for changing the permanent parts by calculating the sum of the time required for mounting parts and the time required for replacing non-installed parts in the period after the candidate times for changing the permanent parts and the time required for replacing parts for the change of the permanent parts to the candidate times for changing the permanent parts based on the types and arrangement of parts after the change of the permanent parts (for example, the second term of formula (10)).

[0126] This makes it possible to appropriately determine whether the component mounting time and setup time can be reduced.

[0127] The present invention is not limited to the above-mentioned embodiment, and various modifications are included. For example, the above-mentioned embodiment has been described in detail for better understanding of the present invention, and is not necessarily limited to those having all the configurations described. Also, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Also, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0128] In addition, the above-mentioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole by hardware, for example, by designing them as integrated circuits. In addition, the above-mentioned configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function. Information such as programs, tables, files, etc. that realize each function can be stored in a storage device such as a non-volatile semiconductor memory, a hard disk drive, or an SSD (Solid State Drive), or in a computer-readable non-transitory data storage medium such as an IC card, an SD card, or a DVD.

[0129] In addition, the control lines and information lines are shown as those considered necessary for the explanation, and not all control lines and information lines in the product are shown. In reality, it can be considered that almost all components are connected to each other. [Explanation of symbols]

[0130] 101 Mounting Equipment 102 Network 103 Mounting equipment control device 104 Printed Circuit Board 105 Transport mechanism 106 parts 107 Feeder 108 Trolley 109 Nozzle 110 Conveyor mechanism 111 Fixing mechanism 200 Production Planning System 201 Input / output section 202 Storage section 203 Arithmetic section 204 Network 205 Design System 206 Work instruction device 207 Input information 208 Output Information 220 Memory section 221 Processing unit

Claims

1. A production planning system, The apparatus includes a calculation unit and a storage unit, The storage unit holds production plan information, design information, and mounting equipment information, The production plan information includes information indicating a production period of each product, the design information includes information indicating parts to be used in each of the products, The mounting equipment information includes information indicating the number of mounting machines that mount the components on the product, information indicating the number of supply devices for the components that can be attached to each of the mounting machines, information indicating the items and arrangement of the components supplied by each of the supply devices already attached to each of the mounting machines, and information indicating whether the parts supplied by each of the supply devices already attached to each of the mounting machines are non-replaceable parts that are subject to replacement or permanent parts that are not subject to replacement; The calculation unit is Calculating one or more candidates for the changeover time of the permanent parts based on the production plan information; A production planning system characterized by calculating, based on the production plan information, the design information, and the mounting equipment information, a production efficiency for a period after each of the candidate times for changing the permanent components in a case where the permanent components are not changed to each of the candidate times for changing the permanent components, and a production efficiency for a period after each of the candidate times for changing the permanent components in a case where the permanent components are changed to each of the candidate times for changing the permanent components.

2. The production planning system according to claim 1, The production planning system is characterized in that the calculation unit calculates at least one of the periods when the products to be produced are changed as one or more candidates for the period when the permanent parts are changed.

3. The production planning system according to claim 2, The production plan information further includes information indicating a classification of each of the products, The production planning system is characterized in that, when the products before and after the product to be produced belong to the same classification at the time when the product to be produced is changed, the calculation unit does not calculate the time when the product to be produced is changed as a candidate for the time to change the permanent part.

4. The production planning system according to claim 2, The production planning system is characterized in that, when at least one of the number of parts used and the frequency of use of each part item used in the product before and after the change in the product to be produced satisfies a predetermined condition, the calculation unit does not calculate the time when the product to be produced is changed as a candidate for the time to change the permanent parts.

5. The production planning system according to claim 4, The production planning system is characterized in that when it is determined that there is a high similarity between parts used in the products before and after the switch at the time when the product to be produced is switched based on at least one of the number of parts used and the frequency of use of each item of parts used in the products before and after the switch, the calculation unit does not calculate the time when the product to be produced is switched as a candidate for the time to change the permanent parts.

6. The production planning system according to claim 1, The calculation unit is Calculating the items and arrangement of the permanent components after the change based on at least one of the time required for mounting the components and the time required for replacing the non-permanent components; A production planning system characterized by calculating production efficiency in a period after each candidate for the change time of the permanent parts when the permanent parts are changed to each candidate for the change time of the permanent parts based on the items and arrangement of the permanent parts after the calculated change.

7. The production planning system according to claim 6, A production planning system characterized in that the calculation unit calculates the items and placement of the permanent components after the change so as to maximize production efficiency based on the time required to implement the components and the time required to replace the non-installed components.

8. The production planning system according to claim 1, The calculation unit calculates an improvement effect of production efficiency in a period after each of the candidate times for changing the permanent parts when the permanent parts are changed to each of the candidate times for changing the permanent parts, compared to production efficiency in a period after each of the candidate times for changing the permanent parts when the permanent parts are not changed to each of the candidate times for changing the permanent parts, and outputs the improvement effect of production efficiency.

9. The production planning system according to claim 8, The production planning system is characterized in that the calculation unit determines, as the change timing for the permanent part, a candidate for the change timing for the permanent part that maximizes the effect of improving the production efficiency.

10. The production planning system according to claim 1, The calculation unit is Calculating the time required to mount the components and the time required to replace the non-installed components in a period following the candidate time for changing the permanent components based on the items and arrangement of the components before the change of the permanent components, thereby calculating the production efficiency in the period following the candidate time for changing the permanent components in a case where the permanent components are not changed to the candidate time for changing the permanent components; A production planning system characterized by calculating the production efficiency in the period after each candidate for the permanent part change time when the permanent parts are changed to each candidate for the permanent part change time by calculating the sum of the time required to implement the parts and the time required to replace the non-installed parts in the period after the candidate for the permanent part change time based on the items and placement of the parts after the change of the permanent parts, and the time required to replace the parts to change the permanent parts at the candidate for the permanent part change time.

11. A production planning method executed by a computer system, comprising: The computer system includes a calculation unit and a storage unit, The storage unit holds production plan information, design information, and mounting equipment information, The production plan information includes information indicating a production period of each product, the design information includes information indicating parts to be used in each of the products, The mounting equipment information includes information indicating the number of mounting machines that mount the components on the product, information indicating the number of supply devices for the components that can be attached to each of the mounting machines, information indicating the items and arrangement of the components supplied by each of the supply devices already attached to each of the mounting machines, and information indicating whether the parts supplied by each of the supply devices already attached to each of the mounting machines are non-replaceable parts that are subject to replacement or permanent parts that are not subject to replacement; The production planning method includes: a step of the calculation unit calculating one or more candidates for the changeover time of the permanent part based on the production plan information; a step of calculating, based on the production plan information, the design information, and the mounting equipment information, an improvement effect of production efficiency in a period after each of the candidate times for changing the permanent components when the permanent components are changed to each of the candidate times for changing the permanent components, relative to the production efficiency in a period after each of the candidate times for changing the permanent components when the permanent components are not changed to each of the candidate times for changing the permanent components.

Images