JP2007102684A - Method, device for drawing up periodical work plan and program therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To draw up a reasonable periodical work plan in short time. <P>SOLUTION: The method for drawing up the periodical work plan performs processes for determining work intervals by every periodical work, a work period which is a common multiple of the work intervals by every periodical work and a unit work interval which is a common factor of the work intervals by every periodical work. In addition, the method has a process for assigning each periodical work to work points set by every unit work interval in the work intervals according to each work period. In the assignment process, each periodical work is sequentially assigned. In addition, in the assignment process, (1) the periodical works are temporarily assigned to each of all the assignment patterns by every periodical work to be assigned, standard deviation of "the total work hour of an assigned periodical work group" by every work point is calculated for each of all the temporarily assigned assignment patterns and (2) the periodical work is assigned to the assignment pattern whose standard deviation becomes minimum. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for preparing a periodic work plan for maintaining and managing a system.

  For example, in a product production site, a product is produced by sequentially processing materials with a plurality of machine tools. Various tools are used on the production site. Each tool has a unique life. For example, there is a tool that has a lifetime when the material is processed 1000 times, while there is a tool that has a lifetime when the material is processed 200 times. If the number of times a tool processes a material to produce one product is one, the former tool must be replaced before producing 1000 products, and the latter tool is 200 products. Must be replaced before producing. In a product production site where a large number of tools are used, replacement of each tool must be performed within the tool life. In the above-described product production system, the former tool needs to be changed regularly and the latter tool needs to be changed periodically. There are many systems that require multiple types of regular work for maintenance management.

Some conventional product production sites perform tool change work as follows. This will be described with reference to the drawings. FIG. 14 is a graph showing a tool change work plan designed by a conventional method. In the graph of FIG. 14, the horizontal axis represents the number of products produced, and the vertical axis represents the working time.
The example of FIG. 14 exemplifies a tool change work plan executed during the production of 1200 products, and the tool change work is executed every time 100 products are produced. Every time when 100 products are produced, the working time required for the tool change work performed at that timing is stacked in the vertical direction. For example, the time required for the tool change operations A, D, B, and E is accumulated because the tool change operations A, D, B, and E are planned to be performed when the cumulative product production number is 100. . In FIG. 14, only the tool change operations A to E are denoted by reference numerals. The tool change work shown in the graph has a height corresponding to the work time required to perform the tool change work. Tool change work with a long work time is high, and tool change work with a short work time is low. The total height of the tool change work group at each tool change timing is the total work time required to execute all the tool change work groups executed at that timing.
The tool change interval is determined for each tool. For example, the replacement work of the tool A is assigned at a timing when the cumulative product production number becomes 100, 400, 700, and 1000. The tool A is replaced every time 300 products are produced. Each tool is planned to be replaced before the end of its life.

The tool change work plan shown in FIG. 14 is executed as follows. One work card is generated that indicates the tool change work group A, D, B, E to be executed at the timing when the cumulative product production number is 100. Similarly, for each of other timings (200, 300, etc.), one work card is created in which a tool change work group that needs to be performed at that timing is entered. In the example of FIG. 14, twelve work cards are created. Twelve work cards are arranged in the order of 100, 200, and so on. When 100 products are produced, the worker looks at the first work card. The first work card shows tool change operations A, D, B, and E that should be performed when the cumulative production number is 100. The worker performs the tool change work A, D, B, E shown on the first work card. When the tool change work A, D, B, E instructed by the first work card is completed, the first work card is turned to the last of the 12 work cards. As a result, the second work card comes to the top. When 100 products are produced (that is, when a total of 200 products are produced), the worker looks at the first work card (second work card). The second work card shows a tool change operation C and the like to be performed at a timing when the cumulative production number is 200 pieces. The worker performs the tool change work C of the second work card. When the tool change work is finished, the second work card is turned last. Each time 100 products are produced, the worker looks at the top work card, performs the tool change work group indicated on the work card, and when those tool change work is completed, the work card is displayed. Turn to the end.
When the tool change work C shown on the 12th work card (the tool change work group at 1200 positions) is completed and the work card is turned last, the first work card is again at the top. come. When 1300 products are produced in a cumulative manner, the first work card is used again. As a result, the tool change operations A, D, B, and E assigned to the 100 positions are performed again. A series of tool change operations shown on the 12 work cards are repeated at a cycle of 1200 product production numbers. This cycle is called “work cycle”. Further, the position of every 100 manufactured products is called “work point”. That is, the work point is the timing when the tool change work group is performed. An interval between two adjacent work points (in the example of FIG. 14, the number of product production is 100) is referred to as a “unit operation interval”.

The tool change work plan shown in FIG. 14 is created manually by a person who manages the product production site. The creator assigns each tool change operation so that each tool is changed before the end of the life of each tool. For example, the tool change operation A in FIG. 14 is assigned to every 300 pieces (every three work points) because the life of the tool change operation A is about 300 pieces.
Further, the creator assigns each tool change work so that the total work time variation of the tool change work group at each work point is reduced. When the total work time of each work point is leveled, the tool change work group can be completed within the same time by the same number of workers at any work point. When the total work time of each work point is leveled, it is easy to grasp the number of workers required to perform all tool change work at the product production site.
There is a work cycle in the above-described tool change work plan. If the work cycle is eliminated and the tool change work group is assigned according to the increasing number of product productions, the work plan must be continuously created. The burden on the creator is very large. In addition, when there is a work cycle, it is possible to fix the work point that each worker is in charge of. For example, an odd-numbered work point in FIG. 14 can be assigned to one worker, and an even-numbered work point can be assigned to another worker. In this case, since the worker repeatedly performs the same tool replacement work, the skill of the worker is easily improved, and the work load on the worker is reduced.

The creator of the tool change work plan exemplified above must assign each tool change work so that the total work time at each work point is leveled. In order to pursue leveling, tool replacement work is irregularly assigned within a range that does not exceed the life of each tool. For example, the tool exchanged in the tool exchange operation B in FIG. 14 has a life when 500 products are produced. The creator of the tool change work plan assigns with an emphasis on leveling within a range in which the interval from the previous tool change work B to the next tool change work B does not exceed 500 product production numbers. As a result, the tool change work B is assigned to the first work point, the sixth work point, and the eleventh work point. The distance from the first work point to the sixth work point and the distance from the sixth work point to the eleventh work point are 500. However, the interval from the eleventh work point to the first work point is 200. Further, for example, in FIG. 14, the tool change work E is assigned to the first work point, the third work point, the sixth work point, the eighth work point, and the eleventh work point. The tool change operation E is performed alternately at intervals of 200 pieces and 300 pieces.
Since it is allowed to assign the tool change work irregularly, the number of patterns to which the tool change work is assigned becomes enormous. For this reason, it takes enormous time and labor to find an allocation pattern in which the total work time at each work point is leveled.
As long as it takes time, it seems possible to create a rational tool change work plan in which the total work time at each work point is leveled. However, a tool change work plan created by the creator's experience and intuition without clear logic often does not equalize the total work time at each work point, no matter how much time is spent. In the example of FIG. 14, the total work time at the sixth work point (600) is considerably longer than the total work time at other work points. At the sixth work point (600 pieces), the load on the worker is larger than other work points.

  The present invention has been created in view of the above circumstances. Provided is a technique capable of creating a periodic work plan that is more rational than that of a conventional system in a short time for a system in which a plurality of types of periodic work that must be periodically performed.

The inventors of the present invention have created the following method in order to create a reasonable periodic work plan in a short time. In this method, a regular work plan is created for a system that requires a plurality of kinds of regular work. The method will be described with reference to FIG. The unit of the horizontal axis of the graph of FIG. 1 is the unit of the work interval, work cycle, and unit work interval of regular work. As this unit, elements that change over time (for example, time, the above-mentioned cumulative product production number, etc.) can be employed. The vertical axis of the graph in FIG. 1 is the total work time. Box-shaped items stacked in the graph indicate regular work. One box corresponds to one regular work. The vertical width of each regular work corresponds to the work time required for the regular work.
In this method, one work interval is determined for each type of periodic work. The work interval of the regular work is an interval at which the kind of regular work should be performed. For example, in the case of a tool change work, the work work interval is set shorter than the tool life. The table of FIG. 1 exemplifies the regular work interval for each work type. In this example, the regular work interval for work type A is 6 (the unit is arbitrary), the regular work interval for work type B is 3, and the regular work interval for work type C is 4. In this method, the work cycle is determined. The work cycle is set to be a common multiple of the regular work interval for each work type. In the example of FIG. 1, 12 is determined as the work cycle. This work cycle (12) is a common multiple of the regular work intervals (6, 3, 4) of the regular work A, B, C. In this method, the unit work interval is also determined. The unit work interval is set to be a common divisor of the regular work intervals (6, 3, 4) of the regular work A, B, and C. In the example of FIG. 1, 1 is determined as the unit work interval.
The regular work interval for each work type, the work cycle, and the order for determining the unit work intervals can be freely determined. For example, the regular work interval for each work type may be determined first, and the work cycle and unit work interval may be determined based on the fixed work interval. For example, the work cycle and the unit work interval may be determined first, and the regular work interval for each work type may be determined based on the work cycle and the unit work interval.
In this method, a work point is set by dividing a period into unit work intervals within a work cycle. In the example of FIG. 1, twelve work points are set.

When the regular work interval, work cycle, and unit work interval for each work type are determined and the work points are set, the regular work intervals for each work type are set according to the regular work intervals for each work type. The process of assigning work is performed. In this allocation process,
(1) tentatively assign regular work of each work type according to all assignment patterns that satisfy the regular work interval of that work type,
(2) For each combination of assignment patterns for each work type, the variation for each work point in the “total work time of the periodic work group assigned for each work point” is quantified,
(3) Allocate periodic work to work points according to a combination of assignment patterns that minimizes variation.
For example, it is assumed that the periodic work of work types A and B in FIG. 1 is assigned to work points. First, the regular work A is temporarily allocated according to all allocation patterns that satisfy the regular work interval of the work A (in this case, 6). For example, periodic work A is assigned to work points 1 and 7. In this case, even if the regular work A is assigned to the work points 2 and 8, the regular work interval of the work A can be satisfied. However, the only difference is that the start numbers of the work points are different, and they are the same if the start numbers of the work points are aligned. The allocation pattern is the same. Therefore, if work A is assigned to work points 1 and 7, all assignment patterns satisfying the regular work interval of work A are assigned.
Next, the regular work B is provisionally assigned according to all assignment patterns that satisfy the regular work interval of the work B (in this case, 3). For example, as shown in the pattern B1, the regular work B is assigned to the work points 1, 4, 7, and 10. As shown in the pattern B2, even if the regular work B is assigned to the work points 2, 5, 8, and 11, the regular work interval of the work B can be satisfied. Similarly, as shown in the pattern B3, even if the regular work B is assigned to the work points 3, 6, 9, and 12, the regular work interval of the work B can be satisfied. In this case, since the combination with the assignment pattern of the work A becomes a problem, the patterns 1, 2, and 3 cannot be identified. There are patterns B1, B2, and B3 in the allocation patterns that satisfy the regular work interval of the work type B, and all patterns are considered only after all are considered.
In the present invention, the periodic work to be assigned is temporarily assigned according to all assignment patterns that satisfy the regular work interval of the work. In the above case, each of the patterns B1, B2, and B3 is temporarily allocated. Then, for each of all the assigned patterns, the variation for each work point in the “total work time of the periodic work group assigned for each work point” is quantified, and according to the combination of assignment patterns that minimizes the variation. Assign regular work to work points. For this reason, the regular work can be assigned to an assignment pattern that minimizes the variation. If all the periodic tasks are assigned in order according to the procedure described above, a reasonable periodic task plan is completed.

When the work types are A, B, C, and D, the regular work A is assigned according to all the allocation patterns that satisfy the regular work interval of the regular work A, and the regular work is performed according to all the assignment patterns that satisfy the regular work interval of the regular work B B may be assigned, the regular work C may be assigned according to all the assignment patterns that satisfy the regular work interval of the regular work C, and the regular work D may be assigned according to all the assignment patterns that satisfy the regular work interval of the regular work D. Of these, one allocation pattern for periodic work may be considered on the basis of it, and therefore one type of allocation pattern may be considered. If periodic work A is used as a reference, there are multiple types of allocation patterns for periodic work B, multiple types of allocation patterns for periodic work C, and allocation patterns for periodic work D. There are multiple types.
In this case, for each combination of assignment patterns when the work types are A, B, C, and D, there is a variation for each work point of “total work time of the periodic work group assigned for each work point”. Periodic work may be assigned to the work points according to a combination of assignment patterns that are digitized and have the smallest variation.

On the other hand, a combination of allocation patterns that minimizes the variation may be searched step by step.
In this case, the work types are ordered in the order of long work time, and all the assignment patterns of the regular work of the next work type are combined with the regular work assignment pattern of the work type with the longest work time. A step of adopting a combination of allocation patterns that minimizes the variation and a combination of allotment patterns of the periodic work of the next order work type to the combination of the employed allocation patterns, and the variation is the smallest in the combination The process of adopting a combination of allocation patterns is implemented. In this case, the latter process is repeated until the next-order work type becomes the work type with the shortest work time.
For example, it is assumed that the work types are A, B, C, and D in descending order of work time. In that case, the periodic work A is first assigned to the work point. As described above, since the first periodic work may be considered based on the assignment pattern, one kind of assignment pattern may be considered. Next, periodic work B is assigned. As described above, in the case illustrated in FIG. 1, there are patterns B1, B2, and B3. At this stage, “the combination that the work type B is assigned to the assignment pattern B1 with respect to the work type A assignment pattern” and “the work type B that is assigned to the work pattern B is the assignment pattern B2. Three combinations of “combination” and “a combination in which the assignment pattern of work type B is B3 with respect to the assignment pattern of work type A” are obtained. In this method, for each of the three combinations obtained at this stage, the variation for each work point of “the total work time of the regular work A and the regular work B assigned to each work point” is quantified. Then, the regular work B is assigned to the work point according to the combination of assignment patterns that minimizes the variation. As a result, the allocation pattern for the regular work of the work type B with the next longest work time is determined with respect to the regular work allocation pattern for the work type A with the longest work time.
Next, the “work type C assignment pattern” having the next longest work time is determined with respect to the previously determined “combination of work type A assignment pattern and work type B assignment pattern”. For example, assume that patterns C1, C2, C3, and C4 exist for work type C. In this case, for the determined “combination of assignment pattern of work type A and assignment pattern of work type B”, the combination of assignment pattern of work type C is C1, the combination of C2, and the combination of C3 , Four combinations of C4 are obtained. In this method, among the four combinations obtained at this stage, the variation for each work point of “the total work time of the regular work A, the regular work B, and the regular work C assigned to each work point” is quantified. The regular work C is assigned to the work points according to the combination of the assignment patterns that minimizes the variation. As a result, the assignment pattern of the work type A with the longest work time and the assignment pattern of the work type C with the next longest work time are determined with respect to the assignment pattern of the work type B with the longest work time.
By continuing this, the variation for each work point of “the total work time of the regular work A, the regular work B, the regular work C, and the regular work D assigned to each work point” is quantified, and the variation is minimized. It is possible to determine stepwise combinations of the allocation patterns of the regular work A, the regular work B, the regular work C, and the regular work D.
In this method, since it is determined step by step, the calculation amount is small. It is possible to prevent unnecessary calculation even for combinations with large variations. On the other hand, there is really no possibility of failing to find a combination with the least variation. Since this method searches for combinations with the least variation in order of work time, even if there is a search omission, the degree of variation due to the searched combination and the variation when the variation is the least. It is possible to search for a combination that does not have a large difference between the degrees.

When a work cycle that is a common multiple of the regular work interval for each work type is set and a unit work interval that is a common divisor of the regular work interval for each work type is set, each periodic work is repeated at each work interval. Only such an allocation pattern exists. Since work is not assigned at irregular intervals as in the prior art, the number of assignment patterns can be reduced.
Above the graph of FIG. 1, all the allocation patterns B1, B2, and B3 of the regular work B are shown. As shown in FIG. 1, there may be three allocation patterns B1, B2, and B3 in the regular work B. The assignment pattern for the regular work B may be selected from the three assignment patterns B1, B2, and B3. Similarly, there may be four allocation patterns C1, C2, C3, and C4 in the regular operation C. The assignment pattern for the regular work C may be selected from the four assignment patterns C1, C2, C3, and C4.
In the present invention, for every periodic work to be assigned, all assignment patterns satisfying the regular work interval of the periodic work are temporarily assigned. In the case of the regular work B described above, all three allocation patterns B1, B2, and B3 are temporarily allocated. Then, for each of all the assignment patterns B1, B2, and B3 assigned temporarily, the variation for each work point of “the total work time of the periodic work group assigned for each work point” is quantified. Since the variation is quantified for each allocation pattern, an allocation pattern that minimizes the variation can be selected. For this reason, the regular work can be assigned to an assignment pattern that minimizes the variation. If all the periodic tasks are assigned in order according to the procedure described above, a reasonable periodic task plan is completed.

Conventionally, work is allowed to be assigned at irregular intervals, and the number of assignment patterns is enormous. For this reason, all allocation patterns that satisfy the regular work interval are not considered, and an allocation pattern that is considered to have relatively little variation is selected by the creator's subjectivity. There is a case where a regular work plan that is not leveled due to a large variation in work points of the total work time for each work point is created. On the other hand, in the method of the present invention, a work cycle that is a common multiple of the regular work interval for each work type is set, and a unit work interval that is a common divisor of the regular work interval for each work type is set. For this reason, the number of allocation patterns for each work type is small. Since the number of allocation patterns is small, all combinations of allocation patterns for each work type can be considered. For this reason, the variation can be quantified for each combination of all allocation patterns for each work type, and the combination of allocation patterns with the smallest variation can be selected by comparing the results. According to the method of the present invention, it is possible to make a regular work plan with less variation and leveling than in the past in a short time. A reasonable periodic work plan can be made automatically in a short time.
According to the present invention, since the number of assignment patterns to be examined for each work type is small, the regular work group can be assigned to work points in a short time. In order to create a regular work plan in a shorter time, it is preferable to carry out the assignment step by a computer.
In the present invention, “the periodic work of each work type is provisionally assigned according to all assignment patterns satisfying the regular work interval of the work type” is executed. This “all allocation pattern” means an allocation pattern that affects the total work time for each work point. For example, the periodic work that is initially assigned does not affect the above-described variation regardless of the pattern assigned to the work point. In such a case, one type of allocation pattern can be set to “all allocation patterns”.

When regular work having a long work time must be assigned to the final stage, it may be difficult to maintain leveling due to variations caused by the assignment of the regular work. For this reason, when assigning in stages, it is preferable to assign in order from the periodic work having a long work time.
In this way, the variation in the total work time at each work point can be further reduced. Standardized regular work plans can be drawn up.

In the above-described assignment step, the periodic work groups having the same work interval may be combined into one type of regular work and assigned.
In this way, it is possible to reduce the number of types of periodic work to be assigned. The allocation process can be performed in a shorter time.

The above-mentioned periodic work plan planning method can be suitably used as a method for creating a tool change work plan for a system that uses a plurality of tools and requires tool change work at intervals determined for each tool. it can. In this tool change work planning method, a tool change work interval for each tool, a work cycle that is a common multiple of the tool change work interval for each tool, and a unit work interval that is a common divisor of the tool change work interval for each tool are determined. The process to perform is implemented. In addition, a step of assigning each tool replacement work according to the tool replacement work interval for each tool is performed on the work points set for each unit work interval in the work cycle. In the assignment step, (1) a tool change work for each tool is temporarily assigned according to all assignment patterns satisfying the tool change work interval of the tool, and (2) for each combination of assignment patterns for each tool, (3) Allocate tool change work to work points according to a combination of assignment patterns that minimizes the variation.
According to this method, a rational tool change work plan can be made in a short time.

  The method of creating a tool change work plan can be used in a product production system that produces a plurality of types of products. In such a product production system, the type of tool used may vary depending on the type of product to be produced. For example, in the case of a product production system that produces the product X and the product Y, the tool A may be used when the product X is produced, but the tool A may not be used when the product Y is produced. In this case, the work interval for each tool change work may be determined in units of the total production number of all types of products produced in the product production system. In the case of the above example, the work interval for each tool change work is set based on the total production number of the product X and the product Y. In this case, the work interval for each tool change work is preferably determined based on the production ratio of the types of products produced in the product production system. For example, when the life of the tool A is 100 times and the product X and the product Y are produced at a ratio of 1: 1, the tool A is planned to be periodically replaced every time 200 products are produced. Work can proceed.

The present invention provides an apparatus for creating a regular work plan for a system that requires multiple types of regular work. This periodical work planning device is a commitment for regular work time for each work type, regular work interval for each work type, work cycle that is a common multiple of the regular work interval for each work type, and regular work interval for each work type. The apparatus which memorize | stores the unit work interval which is a number is provided. In addition, a device is provided that assigns regular work of each work type to work points set for each unit work interval in the work cycle in accordance with the regular work interval of each work type. This allocation apparatus tentatively allocates (1) periodic work of each work type according to all allocation patterns satisfying the periodic work interval of that work type, and (2) “work point” for each combination of assignment patterns for each work type. The variation for each work point of the “total work time of the regular work group assigned to each” is quantified, and (3) the regular work is assigned to the work point according to the combination of the allocation patterns that minimizes the variation.
According to this periodic work plan planning device, a reasonable periodic work plan can be created in a short time.

The present invention also provides a program for creating a regular work plan for a system that requires a plurality of types of regular work. This program performs the following processing on a computer, that is, a regular work time for each work type, a regular work interval for each work type, a work cycle that is a common multiple of the regular work intervals for each work type, and a regular work period for each work type. A process of specifying a unit work interval that is a common divisor of the work intervals and a work point obtained by dividing the work cycle by the unit work interval is executed. Furthermore, according to the regular work interval of each work type, a process of assigning the regular work of each work type to the work point is executed. In this assignment process, (1) a process of allocating a regular work of each work type according to all assignment patterns satisfying the regular work interval of that work type, and (2) a combination of assignment patterns for each work type, A process for quantifying the variation for each work point of “the total work time of the periodic work group assigned for each work point”, and (3) a process for allocating the periodic work to the work point according to a combination of allocation patterns that minimizes the variation. Let it run.
According to this program, a reasonable periodic work plan can be made in a short time.
In any of the above apparatuses and programs, a combination may be searched in a stepwise manner, or a combination with the smallest variation among all the combinations of work types may be searched in a lump.

First, the main features of the techniques described in the following examples are summarized.
(Mode 1) For every periodic task to be newly allocated, all allocation patterns satisfying the periodic task interval of the periodic task are temporarily allocated. Then, a total work time for each work point is calculated for each combination of all assignment patterns temporarily assigned. For each combination of allocation patterns, the standard deviation of the total work time for each work point is calculated. Select the combination of assignment patterns with the smallest standard deviation.
(Mode 2) The work cycle and the unit work interval are determined first. Next, the work interval for each regular work is determined. In the case of tool change work, the work interval is determined to be shorter than the tool life.
(Mode 3) The unit work interval is the greatest common divisor of the regular work intervals for each work type. In this way, the number of work points set in the work cycle can be reduced.
(Mode 4) Two or more types of tools may be used in one machine. In this case, there are two or more types of tool change work for one machine. If these tool change operations have the same work interval, the tool change operations are grouped.

First Embodiment An embodiment of the present invention will be described with reference to the drawings. In this embodiment, a regular work plan (mainly a tool change work plan) for a product production system that uses a plurality of types of tools is created. FIG. 2 is a schematic diagram of the product production system 10 of the present embodiment. Reference numerals M1 to M20 denote machine tool groups used in the product production line. The material 2 is completed as a product 4 by being processed through the machines M1 to M20 in order. Various tools are used in the machines M1 to M20. There is a machine M1 or the like in which one type of tool is used, and a machine M1 or the like in which a plurality of types of tools are used. Each tool has a unique life. The tool change operation for each tool is performed before the end of the tool life. Moreover, in the product production system 10 of the present embodiment, the quality check operation of the produced product 4 is also performed.

In the product production system 10, work cards are used for various regular work (tool change work and quality check work). FIG. 3 shows an example of a work card. In this embodiment, 30 cards are used. Each of the 30 work cards has a card No. Any one of 1-30 is attached. Card No. Work cards are arranged in the order of. Card No. 1 is placed at the top and the card No. 30 is placed last.
Each work card has a work No. And information in which the machine number and the work content are associated with each other. Work No. Is a number for identifying the periodic work. The machine number is a number for identifying the machine tools M1 to M20 (see FIG. 2). The machine number is not associated with the quality check work WX. The work content indicates an outline of each work. For example, the column of work W4 indicates that two tools Y1 of machine number M2 are to be replaced.
When a total of 1000 products have been produced in the product production system 10 since the previous regular work, the worker is given a card no. Draw 1 work card. Then, work W4, W5, etc. shown on the work card are carried out in order from the top. Card No. When all the operations shown in 1 are completed, the work card is turned to the back of the work card group. Therefore, the card No. 2 comes to the top. When 1000 more products are produced in the product production system 10 (when a total of 2000 products are produced), the card No. Workers carry out regular work according to the contents of work card 2. When the regular work is completed, the card No. Turn 2 work card to the back. Every time 1000 products are produced, the worker performs a regular work according to the work card at the head, and turns the work card last when the regular work is completed.
Card No. When regular work is carried out according to the work card of No. 30, the card no. 30 turns last. Card No. 1 comes to the top again. Next, when 1000 products are produced (that is, when 31000 products are produced), the worker will receive the card No. 1. Perform regular work according to the work card shown in 1. In this embodiment, one work card is used for every 1000 products produced. Since there are a total of 30 work cards, all work cards are used when 30000 products are produced. When more than 30000 products are produced, No. It uses in order from 1 work card. That is, in this embodiment, a work card group is used with 30000 pieces as one cycle. A regular work plan with 30000 pieces as one cycle is drawn up. Hereinafter, this cycle (30000) is referred to as a work cycle. The interval (1000) from the use of one work card to the use of the next work card is called a unit work interval.

In this embodiment, there are a plurality of types of regular work such as tool change work and quality check work. Create a work plan and create a card for these periodic tasks to be carried out reasonably. A device for this purpose will be described next.
FIG. 4 shows a schematic configuration diagram of the apparatus 20 for making a periodic work plan. The regular work planning apparatus 20 includes a computer 22, a keyboard 40, a monitor 42, and a printer 44. The computer 22 is connected to a keyboard 40, a monitor 42, and a printer 44. The computer 22 includes a CPU, a ROM, a RAM, and the like (not shown). The ROM stores programs for the CPU to execute various processes. In this embodiment, a program for creating a reasonable periodic work plan is stored. In the computer 22, each unit 24 to 34 is configured by a CPU, a ROM, a RAM, and the like functioning. These parts 24-34 will be described in detail.

FIG. 5 shows the stored contents of the actual tool data storage unit 24. The administrator of the product production system 10 stores information in the actual tool data storage unit 24 using the keyboard 40 shown in FIG.
The actual tool data storage unit 24 stores the work NO. The machine number, work content, work time, life, coefficient, and actual life are stored in association with each other. Work No. Is a number for identifying the periodic work. Work No. Is set for each type of tool used in one machine tool M1 or the like. For example, since three kinds of tools X1, X2, and X3 are used for the machine M1, the machine M1 has three work Nos. (W1, W2, W3) is set. In the product production system 10 of the present embodiment, the quality check operation WX of the produced product 4 is performed at a predetermined interval. Information stored in the actual tool data storage unit 24 includes information on the quality check work WX.
The machine number is a machine tool number. M1 to M20 (see FIG. 2) are used as the machine numbers. No machine number is assigned to the quality check work WX.
The work content shows an outline of each regular work. For example, it is stored that one tool X1 of machine number M1 is exchanged in association with work W1.
The work time is the time required to perform the regular work. For example, in order to perform the operation W1 (that is, to change one tool X1 in the machine M1), it means that a time of 240 seconds is required. The administrator of the system 10 determines the work time of each work based on the past results.
Life is the life of the tool. For example, it means that the tool X1 associated with the work W1 has a life when it is used for processing for producing 10,000 products. The life column of the quality check operation WX does not indicate the life, but indicates the frequency with which the quality check must be performed. In the present embodiment, the quality check work WX must be performed every time 1000 products are produced.

The coefficient and actual life will be described. In the product production system 10 of this embodiment, two types of products are produced alternately. When one type of product is produced, the other type of product is produced next. Therefore, if 10,000 products are produced in the product production system 10, two types of products are produced, 5000 pieces each. For example, the tool X1 associated with the work W1 is used when producing one product, but is not used when producing the other product. For this reason, even if 10,000 products are produced together in the product production system 10, the tool X1 is used only for producing 5000 products. The tool X1 reaches the end of its life when used for processing to produce 10,000 products, as shown in the life column. If this tool life is applied as it is and the tool X1 is replaced when 10,000 products are produced, the tool X1 is replaced even though only 5000 products are processed. The tool X1 that can still be used sufficiently will be replaced. Therefore, the concept of real life is used. The actual lifetime is the lifetime for all products produced in the product production system 10. The actual life is obtained by multiplying the life by a factor. In the case of the tool X1, by using the coefficient 2, the actual life becomes 20000 pieces. When 20000 pieces of two kinds of products are produced together in the product production system 10, the tool X1 is used to produce 10,000 products. The numerical value of 10,000 corresponds to the life of the tool X1.
The coefficient is set according to the production ratio of the product. For example, when the product L1, the product L2, and the product L3 are produced at a ratio of 1: 2: 3 and there is a tool that is used only for the production of the product L1, the coefficient of the tool is 6 Become. In this example, if there is a tool that is used for the production of the products L2 and L3 but is not used for the production of the product L1, the coefficient of the tool is 6/5.
In this embodiment, a life corresponding to the production ratio of various products in the product production system 10 (that is, an actual life) is set for each tool.

Next, the contents stored in the basic data storage unit 26 in FIG. 4 will be described. FIG. 6 shows the stored contents of the basic data storage unit 26.
The basic data storage unit 26 stores unit work intervals and work points. The unit work interval is an interval from using a certain work card (see FIG. 3) to using the next work card. In the present embodiment, the smallest actual life (or frequency of quality check work) among the actual life (or frequency of quality check work) of each tool is selected as the unit work interval. As shown in FIG. 5, in this embodiment, the frequency (1000 pieces) of the quality check work WX is the smallest. For this purpose, 1000 unit work intervals are adopted.
The number of work points is the number of work points. The work point is the timing at which the worker performs the work group indicated on one work card within the work cycle. In the present embodiment, work points are set every 1000 pieces within 30000 work cycles. That is, in the present embodiment, there are 30 work points. The number of work points matches the number of work cards. In this embodiment, the number of work points (that is, the number of work cards) is set to 30. Any number can be selected as the number of work points. If the number of work points is large, the number of cards increases. It is preferable to set the number of work points within a range where the number of cards does not become excessive.

The contents stored in the used tool data storage unit 28 in FIG. 4 will be described. FIG. 7 shows the stored contents of the used tool data storage unit 28.
The use tool data storage unit 28 stores the work NO. The machine number, the work content, the work time, and the work interval are stored in association with each other. Work No. Since the machine number, work content, and work time are the same as those stored in the actual tool data storage unit 22 (see FIG. 5), description thereof is omitted here. The work interval is set as follows.
FIG. 8 is a flowchart of the process for determining the work interval. This process is executed by the calculation unit 32 shown in FIG. First, the calculation unit 32 calculates a divisor of the number of work points (step S2). In this embodiment, 30 is employed as the number of work points, and 1, 2, 3, 5, 6, 10, 15, and 30 are calculated in step S2. The calculated divisor is stored in the temporary storage space 30 shown in FIG.
Subsequently, the divisor calculated in step S2 is multiplied by the unit work interval. In this embodiment, since 1000 is adopted as the unit work interval, 1000, 2000, 3000, 5000, 6000, 10000, 15000, 30000 are calculated in step S4. The calculated number is stored in the temporary storage space 30.
Subsequently, step S6 is executed. In step S6, for each work, the largest number that is equal to or less than the actual life of the work is selected from the numbers obtained in step S4. For example, the work W1 shown in FIG. The largest number among the numbers less than 20000 and calculated in step S4 is 15000. For this reason, in step S6, 15000 is selected for the work W1. Further, for example, the work W2 shown in FIG. Since 6000 is among the numbers calculated in step S4, 6000 is selected for the work W2. Similarly, numerical values are selected for other operations.
In step S <b> 8, the numerical value selected in step S <b> 6 is stored as a work interval in the utilization tool data storage unit 28. For example, 15000 is stored as the work interval of work W1. 6000 is stored as the work interval of work W2.
By performing the above-described processes, work intervals corresponding to the work in the use tool data storage unit 28 are set.

The temporary storage space 30 shown in FIG. 4 temporarily stores the calculation result of the calculation unit 32 and the like. The calculation unit 32 performs various calculations and other processes. The output control unit 34 comprehensively controls data output to the monitor 42 and the printer 44.
As described above, the administrator of the system 10 can input various information using the keyboard 40. The monitor 42 displays the data output from the output control unit 34. The printer 44 prints the data output from the output control unit 34. The above-described work card (see FIG. 3) is printed by the printer 44.

  Next, processing for creating a regular work plan will be described. This process is performed by the calculation unit 32. FIG. 9 shows a flowchart of the regular work planning process. The calculation unit 32 first executes the process of step S10. In step S10, work groups having the same machine number and the same work interval are grouped. This process is executed by searching the stored contents (see FIG. 7) of the used tool data storage unit 28. Taking FIG. 7 as an example, work W4 and work W5 are associated with the same machine number M2, and the work intervals of these works W4 and W5 are both 2000. For this reason, in the process of step S10, the work W4 and the work W5 are grouped into one group. The grouped work group (W4, W5, etc.) is treated as one work in the subsequent processing. In step S10, the storage content of the tool utilization data storage unit 28 is rewritten to the content including information in which work groups are grouped. FIG. 10 shows the storage contents of the used tool data storage unit 28 after rewriting. As shown in FIG. 10, in the used tool data storage unit 28 after rewriting, the work W4 and the work W5 are grouped and rewritten as one work WM1. The work time corresponding to the work WM1 is the sum (440 seconds) of the work time (204 seconds) of the work W4 and the work time (236 seconds) of the work W5. The used tool data storage unit 28 is configured so that information on each grouped work is not lost even after rewriting in step S10. In other words, it can be seen that the work WX1 is a grouping of the work W4 and the work W5. Further, the machine number, the work content, the work time, and the work interval corresponding to each of the work W4 and the work W5 are stored.

  When step S10 of FIG. 9 is finished, step S12 is executed. In step S12, the contents stored in the tool utilization data storage unit 28 are rewritten so that the working time is in descending order. FIG. 11 shows the stored contents of the used tool data storage unit 28 after rewriting in step S12. In FIG. 11, the work order is rearranged so that the work with the long work time is at the top of the table. Work W20 has the longest work time (520 seconds). Next, work W2 (460 seconds) and work WM1 (440 seconds) are continued. In step S12, the work having the longest work time is set as T0, and numbers are assigned so that the work time becomes T1, T2,.

Subsequently, the processes of steps S14 to S20 in FIG. 9 are executed. Here, the following graph is referred to so that the processing of steps S14 to S20 can be easily understood. FIG. 12 is a graph in which the horizontal axis represents the cumulative production number of products (total production number of two types of products) and the vertical axis represents the total work time.
The working cycle of this embodiment is 30,000. The work cycle can be obtained by multiplying the unit work interval (1000 pieces) by the work point (30). The work cycle is a common multiple of the work interval of each work. This is apparent from the fact that, in the process of FIG. 8, the work interval of each work is set by multiplying one of the divisors of the work points by the unit work interval.
The unit work interval is a divisor of the work cycle. The unit work interval is the greatest common divisor of the work intervals of each work. It is clear that the unit work interval becomes a common divisor of the work intervals of each work because the work interval of each work is set by multiplying one of the divisors of the work points by the unit work interval.
Each work point is set for each unit work interval (1000 pieces) in the work cycle (30000 pieces). The first work point is at 1000 positions, and the 30th work point is at 30000 positions. Hereinafter, the nth work point (n is 1 to 30) is referred to as the nth work point. Each work point is assigned a work group. Each work is assigned to each work point in a pattern according to the work interval of the work. That is, since the work interval of the work W20 is 10,000 (see FIG. 11), the work W20 is assigned every 10,000 (every ten work points).
The vertical length of each work corresponds to the work time of the work. The work W20 with the longest working time is the longest.

In steps S14 to S20 in FIG. 9, each work is assigned in order. The processing of steps S14 to S20 will be described with reference to the above graph.
In step S14, an assignment pattern of work W20 indicated by T0 (see FIG. 11) is determined. The work interval of the work W20 is 10,000. The work W20 is assigned so that 10,000 work intervals are maintained. At the stage of executing step S14, no work is assigned. The work W20 is assigned with an arbitrary assignment pattern. In this embodiment, the work W20 is assigned to the sixth work point, the sixteenth work point, and the twenty-sixth work point. 10,000 work intervals are allocated so as to be maintained. It is not necessary to consider a plurality of assignment patterns of work W20 in order to consider assignment patterns of other work with respect to assignment of work W20.
When the assignment pattern of the work W20 is determined in step S14, the assignment pattern of the work W2 (see FIG. 11) indicated by T1 is subsequently determined (step S16). The process of step S16 will be described in detail with reference to FIG. FIG. 13 shows a flowchart embodying the process of step S16 of FIG. As shown in FIG. 13, first, an assignment pattern of work (W2 at the current stage) indicated by Ti (T1 at the current stage) is provisionally determined (step S30). With reference to FIG. 12, a state where the allocation pattern is provisionally determined will be described. Here, not the manner in which the assignment pattern of the work W2 of T1 is provisionally determined, but the manner in which the assignment pattern of the work W30 is provisionally determined after a plurality of work has already been assigned will be described. The work pattern of T1 and other work assignment patterns are also provisionally determined in the same manner. In the upper part of the graph of FIG. 12, three allocation patterns of the work W30 are shown. Since the work interval of work W30 is 3000, there are three patterns for assigning work W30 to each work point. That is, there are pattern 1, pattern 2, and pattern 3 shown in FIG. In pattern 1, work W30 is assigned to each of the three work points starting from the first work point. Pattern 2 is the entire pattern 1 shifted to the right by one work point, and work W30 is assigned to each of the three work points starting from the second work point. Pattern 3 is the entire pattern 2 shifted to the right by one work point, and work W30 is assigned to each of the three work points starting from the third work point. If pattern 3 is shifted to the right by one work point, pattern 1 is obtained. Therefore, there are three patterns for assigning the work W30 to each work point.
In step S30, one allocation pattern is provisionally determined from all possible allocation patterns. In the case of the above-described operation W30, any one of pattern 1, pattern 2, and pattern 3 is provisionally determined. The work W2 indicated by T1 has a work interval of 6000 (see FIG. 11), and there are six assignment patterns. In step S30, one of the six allocation patterns is selected.

In step S32, an objective function value when work is assigned according to the assignment pattern provisionally determined in step S30 is calculated. In this embodiment, the standard deviation of the distribution of the total work time at each work point is adopted as the objective function value. In step S32, first, the total work time for each work point is calculated. Next, the standard deviation is calculated from the total work time for each work point. The calculated standard deviation is stored in the temporary storage space 30 (see FIG. 4).
In step S34, it is determined whether or not standard deviations of all allocation patterns have been calculated. For example, in the case of work W30 in FIG. 12, it is determined whether or not the respective standard deviations when assigned according to three patterns are calculated. If the standard deviations of all the allocation patterns have not been calculated (NO in step S34), the process returns to step S30 to tentatively determine different allocation patterns, and the process of step S32 is executed to calculate the standard deviation.
If the standard deviation of all the allocation patterns has been calculated (YES in step S34), the process proceeds to step S36. In step S36, an assignment pattern having the smallest standard deviation is selected from the assignment patterns, and work is assigned using the assignment pattern. For example, in the work W30 of FIG. 12, when the variation of the total work time for each work point when the pattern 2 is selected from the patterns 1 to 3 is small (when the standard deviation according to the pattern 2 is the smallest). Assigns work W30 with pattern 2. That is, the work W30 is assigned to every three work points starting from the second work point. In the graph of FIG. 12, a state where the work W30 is assigned in the pattern 2 is indicated by a broken line.
In the case where two or more allocation patterns have the same standard deviation and the standard deviation is smaller than other allocation patterns, any allocation pattern may be selected from them.
By executing the processes of steps S30 to S36, a work assignment pattern is determined.

When the process in step S16 in FIG. 9 (the process in FIG. 13) ends, the process proceeds to step S18, and 1 is added to “i” of Ti. That is, if the assignment pattern of the work W2 of T1 is determined in step S16, “2” is obtained in step S18. In step S20, it is determined whether or not “i” is larger than m (see step S12 and FIG. 11). That is, it is determined whether or not the allocation pattern has been determined for all the operations. If it is determined NO in step S20, a process (step S16) for determining an assignment pattern for the next work is executed. If the assignment pattern of the work W2 of T1 is determined in step S16 and the determination in step S20 is made, NO is determined in step S20 and the process returns to step S16. In this case, in step S16, an allocation pattern of the work WM1 (see FIG. 11) of T2 is determined.
If YES is determined in the step S20, the grouped work is released (step S22). For example, the work WM1 assigned to the first work point or the like in FIG. 12 is divided into work W4 and work W5. In step S22, the grouping is canceled for all the grouped operations.
When the grouping is canceled, the work group assigned to each work point is assigned the work No. It rearranges in order (step S24). For example, when work W4, work W5, work W30, work W15, and work W1 are assigned in this order at a certain work point, the work W1, work W4, work W5, work W15, and work W30 are rearranged in this order.
When step S24 is completed, step S26 is executed. In step S26, the information of the work group assigned to one work point is printed on one work card. Since there are 30 work points, 30 work cards are printed. This process is executed by the output control unit 34 outputting data to the printer 44. The work card shown in FIG. 3 is created by executing the process of step S26. The work card has a work No. Work is arranged in the order of. The worker selects the work No. indicated on the work card. Work in this order. Work No. Are arranged in the order of machines M1 to M20. For this purpose, the operation No. When the operations are performed in this order, the worker turns around in order of the machines M1, M2,. The walking distance of the worker can be made constant. In the process of step S26, the contents of each work card may be displayed on the monitor 42.
By executing the processes of S10 to S26 described above, a regular work plan is drawn up and a work card is created. According to the above-described embodiment, a reasonable periodic work plan can be made in a short time.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
In the above-described embodiment, a method of assigning each periodic work W1 and the like in stages is adopted. However, the technical idea of the present invention can also be applied to a method for searching for a combination having the smallest variation from a combination of all allocation patterns of each periodic operation.
The technique of the present embodiment can also be used when creating a work plan for periodic work other than tool change work and quality check work. For example, it can also be used to create periodic work plans for nursing care service patrol work, system regular maintenance work, regular sales (outside) work, patrol work, patient examination work at hospitals, etc. it can.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

It is a figure for demonstrating the content of this invention. A graph is shown in which values that change over time (time, number of products produced, etc.) are plotted on the horizontal axis, and total work time is plotted on the vertical axis. The schematic of the product production system of an Example is shown. A work card group is shown. 1 shows a configuration of a periodic work plan planning apparatus of an embodiment. The storage contents of the actual tool data storage unit are shown. The storage contents of the basic data storage unit are shown. The storage content of a utilization tool data storage part is shown. The flowchart of a work interval determination process is shown. The flowchart of a regular work planning process is shown. The storage content of the utilization tool data storage part after two or more regular work is grouped is shown. The storage content of the utilization tool data storage part after rearranging in order of work time is shown. It is a figure for demonstrating a mode that the allocation pattern of a regular work is determined. The graph shows the number of product production on the horizontal axis and the total work time on the vertical axis. The flowchart of an allocation pattern determination process is shown. The figure for demonstrating a prior art is shown. The graph shows the number of product production on the horizontal axis and the total work time on the vertical axis.

Explanation of symbols

10: Product production system 20: Periodic work planning device 22: Computer 24: Actual tool data data storage unit 26: Basic data storage unit 28: Tool data storage unit 30: Temporary storage space 32: Calculation unit 34: Output control unit 40: Keyboard 42: Monitor 44: Printer

Claims (7)

A method for creating a regular work plan for a system that requires multiple types of regular work,
A step of determining a regular work interval for each work type, a work cycle that is a common multiple of the regular work interval for each work type, and a unit work interval that is a common divisor of the regular work interval for each work type;
A step of assigning a regular work of each work type to a work point set for each unit work interval in the work cycle according to a regular work interval of each work type,
In the allocation process,
(1) tentatively assign regular work of each work type according to all assignment patterns that satisfy the regular work interval of that work type,
(2) For each combination of assignment patterns for each work type, the variation for each work point in the “total work time of the periodic work group assigned for each work point” is quantified,
(3) A periodic work planning method characterized in that periodic work is assigned to work points according to a combination of assignment patterns that minimizes variation. In the allocation step, the work types are ordered in descending order of work time,
Combine all the allocation patterns of the periodic work of the next order work type with the allocation pattern of the periodic work of the work type with the longest work time, and adopt the combination of the allocation patterns that minimizes the variation among the combinations. ,
The step of combining all the assigned patterns of the periodic work of the work order of the next order with respect to the adopted assignment pattern combination, and adopting the assignment pattern combination that minimizes the variation in the combination, The method according to claim 1, wherein the work type is repeated until the work type becomes the work type having the shortest work time.   3. The regular work plan planning method according to claim 1 or 2, wherein, in the assigning step, the periodic work groups having the same regular work interval are collectively assigned as one kind of regular work. A method of creating a tool change work plan for a system that uses a plurality of tools and requires tool change work at intervals determined for each tool.
Determining a tool change work interval for each tool, a work cycle that is a common multiple of the tool change work interval for each tool, and a unit work interval that is a common divisor of the tool change work interval for each tool;
A step of assigning each tool replacement work according to the tool replacement work interval for each tool, for work points set for each unit work interval in the work cycle;
In the allocation process,
(1) The tool change work for each tool is temporarily assigned according to all assignment patterns that satisfy the tool change work interval of the tool,
(2) For each combination of allocation patterns for each tool, the variation for each work point in the “total work time of the tool change work group allocated for each work point” is quantified,
(3) A tool change work planning method characterized by assigning tool change work to work points according to a combination of assignment patterns that minimizes variation. The method according to claim 4, wherein a tool change work plan for a product production system for producing a plurality of types of products and changing a tool to be used according to the type of product to be produced is prepared.
In the determining step, a tool change work planning method for determining a tool change work interval for each tool based on a production ratio for each type of product. It is a device that creates a regular work plan for a system that requires multiple types of regular work,
Memorizes the regular work time for each work type, the regular work interval for each work type, the work cycle that is a common multiple of the regular work interval for each work type, and the unit work interval that is the common divisor of the regular work interval for each work type With the device
A device for allocating the periodic work of each work type according to the periodic work interval of each work type to the work point set for each unit work interval in the work cycle,
The allocation device is
(1) tentatively assign regular work of each work type according to all assignment patterns that satisfy the regular work interval of that work type,
(2) For each combination of assignment patterns for each work type, the variation for each work point in the “total work time of the periodic work group assigned for each work point” is quantified,
(3) A periodic work planning apparatus characterized in that periodic work is assigned to work points according to a combination of assignment patterns that minimizes variation. It is a program that creates a regular work plan for a system that requires multiple types of regular work.
Regular work time for each work type, regular work interval for each work type, work cycle that is a common multiple of the regular work interval for each work type, unit work interval that is a common divisor of the regular work interval for each work type, A process for identifying a work point obtained by dividing a work cycle by a unit work interval;
According to the regular work interval of each work type, the process of assigning the regular work of each work type to work points is executed.
In the allocation process,
(1) A process of temporarily allocating the periodic work of each work type according to all allocation patterns satisfying the regular work interval of the work type;
(2) For each combination of assignment patterns for each work type, a process for quantifying the variation for each work point of “the total work time of the periodic work group assigned for each work point”;
(3) A periodic work planning program characterized by executing a process of assigning periodic work to work points according to a combination of assignment patterns that minimizes variation.

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