JP2010262426A - Method, program and device for preparing production plan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine an optimum product production configuration within a range of equipment capability even when fluctuation of an equipment load or fluctuation of demand occurs. <P>SOLUTION: In an arithmetic part of a computer, the following processing is performed. Basic information related to a period, a production route, occurrence cost, raw material and a selling price, a production amount, and equipment are read (S1). Calculation of an equipment load distribution ratio in each month is performed in each passage process set in a passage process route (S2). Conversion of load cost (a monthly equipment load consumption rate and limit profit rate) is performed in each passage process route (S3). Calculation of the optimum product production configuration by linear programming is performed (S4), and a calculation result is output (S5). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a production plan creation method for creating a production plan by calculating an optimum production amount for each product within a predetermined planning period when a plurality of types of products are produced on a multi-process production line. And a production plan creation program and a production plan creation apparatus.

  Conventionally, when a plurality of types of products are produced on a multi-process production line (for example, a production line of a material factory such as a copper plate), a production plan is determined as to how much and at what time it is produced. That is, in the production planning, the optimum production amount is calculated for each product while satisfying the constraints such as the capacity of each facility and the demand for each product within a predetermined planning period.

  In the calculation, the production plan is required at a certain range (order quantity), so that the various evaluation indexes are maximized within the range of the preset facility capacity. Determine the production volume of each product. At this time, in particular, in a multi-process / multi-order type production process, there is a degree of freedom of a passing process route (that is, a plurality of passing process routes exist for one manufacturing method, or in one passing process, There are multiple facilities that can be processed), and the optimal production plan (how many products will be produced at what time), taking into account various conditions such as seasonal fluctuations in demand and differences in manufacturing lead time depending on orders. It is required to decide.

In such a situation, there are the following problems.
• Develop a production plan that maximizes marginal profit and / or production volume.
・ Create a production plan that minimizes the amount of delay in delivery or the amount of preceding production (product inventory).
・ Create an optimal production plan at high speed.

  In order to solve the above-mentioned problem, when a plurality of types of products are manufactured in a multi-process production process, there are a plurality of procedures (passing process routes) for producing a product of one type. When there are multiple process designs, such as when there are alternative facilities in a specific process, considering the fluctuations in equipment load due to manufacturing lead time and fluctuations in demand, Technologies that can optimize the production amount have been proposed.

For example, the technique shown in Patent Document 1 makes a production plan based on the following steps.
1) Basic information such as important information of each type, correspondence information of passing process information of each order, generated cost information, information on raw materials and selling prices is set.
2) When production is performed over a plurality of periods, the facility load distribution ratio is calculated for each period based on the manufacturing lead time of the passing process corresponding to each type.
3) For each passing process, calculate the load cost (monthly equipment load intensity, marginal profit).
4) Calculate the optimal product manufacturing configuration by linear programming. At this time, three evaluation indices are considered: maximization of total marginal profit, maximization of total production, and maximization of total marginal profit and total production.
By calculating the load cost in the above steps, it is possible to optimally determine an alternative process route and an alternative facility to be used for production of each product type, production of each product type, based on a preset evaluation index. In addition, an optimal production plan can be created at high speed by using linear programming.

JP 2007-26046 A

However, the conventional load cost calculation technique described above has the following problems.
1) The maximum to minimum range of the required amount for each product type is determined, and the production amount of each product type in the planned production plan must be within that range. When the facility capacity of the factory is exceeded (that is, when the equipment load fluctuates), it cannot be handled.
2) When the order quantity is expected to increase in the future, which occurs frequently in actual factories, when an exceptional response such as “advance production and respond” or the requested quantity exceeds the capacity of the factory ( That is, it is not possible to consider a situation in which it is desired to reduce the exceptional response such as “respond by adjusting the delivery date” as much as possible, but allow the response.

  A problem to be solved by the present invention is a production plan creation method capable of determining an optimum product manufacturing configuration within the range of equipment capacity even when equipment load fluctuation or demand fluctuation occurs. A production plan creation program and a production plan creation apparatus are provided.

  In the production plan creation method according to the present invention, in a computer having a calculation unit, a storage unit, an input unit, and an output unit, a process executed by the calculation unit calculates an optimum product manufacturing configuration based on an evaluation index. A period information setting step for storing a period that is a unit to be registered, and one or more manufacturing routes to which equipment that can be processed for a plurality of processes for manufacturing a product is assigned for each product as a passing process route; For each passing process route, a manufacturing route information storage step for registering the processing capacity of each process and an inter-process lead time for each process, an equipment information storage step for registering an equipment capacity for each period of each equipment, A production quantity information storage step for registering a production quantity lower limit value and a production quantity upper limit value as a required production quantity range for each period of the product, and between the processes for each passing process route An equipment load distribution ratio calculating step for calculating an equipment load distribution ratio for each period before the predetermined period in each step for production in a predetermined period based on a production time, and the processing capacity and the equipment load distribution ratio. The facility capacity constraint that the total load for each period of each of the obtained facilities does not exceed the facility capacity, and the total production amount for each period of each product is greater than or equal to the production volume lower limit value and within the production volume upper limit value An optimal product manufacturing configuration calculation step for calculating a production amount for each period of each passing process route that maximizes a preset evaluation index while satisfying the upper and lower limit range restrictions on the production amount satisfying that it is within the range of It is characterized by providing.

  The production plan creation program according to the present invention processes a period information setting step for storing a period, which is a unit for calculating an optimum product manufacturing configuration based on an evaluation index, and a plurality of processes for manufacturing a product for each product. A manufacturing route information storage step for registering one or more manufacturing routes to which possible facilities are assigned as a passing process route, and for registering the processing capability of each step and the inter-process lead time for each passing step route; A facility information storage step for registering facility capacity for each period of each facility, and a production volume lower limit value and a production volume upper limit value as a required production volume range for each period of each product are registered. For each production process information storage step and for each passing process route, setting for each period prior to the predetermined period in each process for production in a predetermined period based on the inter-process lead time. A facility load distribution ratio calculating step for calculating a load distribution ratio, a facility capacity constraint that the total load for each period of each facility determined by the processing capacity and the facility load distribution ratio does not exceed the facility capacity, and While satisfying the upper and lower limit range restrictions of production amount that satisfy the total production amount of each product within the range of the production amount lower limit value and within the production amount upper limit value, the preset evaluation index is An optimum product manufacturing configuration calculation step for calculating a production amount of each passage process route that is maximized in each period, and the computer reads out the calculation unit to execute the process of each step.

  A production plan creation device according to the present invention is a production plan creation device that creates a production plan in a computer having a computation unit, a storage unit, an input unit, and an output unit, and the computation unit is based on an evaluation index. A period information setting unit that stores a period, which is a unit for calculating an optimum product manufacturing configuration, and a process that passes through one or more manufacturing routes in which equipment that can be processed for a plurality of processes for manufacturing a product is assigned for each product. In addition to registering as a route, for each passing process route, a manufacturing route information storage unit for registering the processing capacity of each process and the lead time between processes of each process, and registering the facility capacity for each period of each facility For each period of each product, a facility information storage unit, a production volume information storage unit that registers a production volume lower limit value and a production volume upper limit value as a range of required production volume, and for each passing process route, Between the processes An equipment load distribution ratio calculation unit for calculating an equipment load distribution ratio for each period before the predetermined period in each step with respect to production in a predetermined period based on a production time, and the processing capacity and the equipment load distribution ratio. The facility capacity constraint that the total load for each period of each of the obtained facilities does not exceed the facility capacity, and the total production amount for each period of each product is greater than or equal to the production volume lower limit value and within the production volume upper limit value An optimum product manufacturing configuration calculation unit that calculates the production amount of each period of each passing process route that maximizes the preset evaluation index while satisfying the upper and lower limit range restrictions of the production amount that satisfy the range of It is characterized by comprising.

According to this, the amount of production for each passing process route that is assigned as a processing route by assigning equipment that can be processed for a plurality of processes for manufacturing products is determined on a period basis, and the amount of production for each passing process route is The periodical load of each piece of equipment necessary to obtain is dependently determined. The production volume per period for each passing process route satisfies the equipment capacity constraint that the total load of each equipment calculated from the processing capacity and the equipment load distribution ratio does not exceed the equipment capacity, and each product After satisfying the upper / lower limit range of production volume, the total production volume for each period is within the range from the lower limit of production volume to the upper limit of production volume. Is done. Therefore, there are the following advantages.
-By changing the upper and lower limits of the production amount of each product for each period, it is possible to determine an optimal product manufacturing configuration against demand fluctuations.
-By considering the equipment load distribution ratio calculated based on the lead time between processes, the optimal product within the scope of equipment capacity against the seasonal equipment load fluctuation caused by the difference in the production lead time due to the production route The manufacturing configuration can be determined.
・ Even when multiple production routes are set for one product, by setting each route in advance, the production volume for each product route is maximized so that the preset evaluation index is maximized. Can be determined for each period.
・ If there is a small profit for a product, but you want to secure a strategic share, set the production lower limit to a large value to produce that product above a certain value and use the remaining capacity to produce the remaining product. Can be optimized.
・ By setting the upper limit of production volume, it is possible to prevent production that cannot be sold or stored just because profit is large, and optimize production volume including other products. Can do.
-By making the production volume upper limit value and the production volume lower limit value the same value, it is possible to always produce a product that needs to be produced in a certain amount, and then optimize the production amount of the remaining products.
The “equipment capacity” means the time that each piece of equipment can be used for the best production. “Processing capacity” means an ability to process a product or an intermediate product in each step, and represents, for example, a weight that can be processed within a predetermined time. The “total load” means the total load for each period of actual processing in each facility, and is expressed by the total required processing time.

  Here, the production plan creation method, the production plan creation program, and the production plan creation device according to the present invention relax the production lower limit constraint among the upper and lower limit range constraints of the production amount, The evaluation index regarding the production unachieved amount that is the sum of the values calculated from MIN (production amount−production amount lower limit value, 0) and the upper and lower limit range restrictions on the production amount In addition to the production volume in the period, the shipment volume is used as the basis for calculating the optimal product manufacturing configuration. The constraint that the shipment volume of each product must be greater than or equal to the lower limit of the production volume and the production volume of each product up to each period The constraint that the total production volume that is the sum of the upper limit value cannot be produced, the shipment amount of each product in each period cannot exceed the production volume upper limit value, and the total production amount over the entire planning period is the production upper limit System that does not exceed the sum of values While satisfying the door, in each period of each product - it may be set as the evaluation index at least one of the evaluation index with the prior production is the sum of the calculated values from the (production shipments).

According to this, the production quantity of each product for each period is minimized by using the evaluation index related to the unachieved quantity so as to minimize the unachieved quantity for the production quantity that must be produced in that period. Is determined for each passing process route. As a result, even if the production lower limit for a certain period is an amount that is impossible in terms of equipment capacity, the unachieved amount can be minimized and the optimum production amount can be determined.
In addition, by using an evaluation index related to the preceding production volume, each product for each period is minimized so that the production quantity that must be produced in that period is exceeded and the quantity stored as product inventory is minimized. Is determined for each passing process route. As a result, even if the production lower limit value in a certain period is an amount that is impossible in terms of equipment capacity, it is possible to determine the optimum production amount after allowing the preceding production.
The “planning period” means a period to be a production plan target.

  The production plan creation method and the production plan creation program according to the present invention include a raw material / sale price registration step for registering a raw material cost and a selling price for each product, and a generated cost generated in each process for each passing process route. And a generated cost registering step for registering the cost, and an evaluation index related to the total marginal profit, which is a sum of values calculated from (selling price−raw material cost−generated cost), may be further set.

  Further, in the production plan creation device according to the present invention, the calculation unit generates a raw material / sale price registration unit for registering a raw material cost and a selling price for each product, and a generated cost generated in each process for each passing process route. And a generated cost registering unit for registering the cost, and an evaluation index related to the total marginal profit, which is a sum of values calculated from (selling price−raw material cost−generated cost), may be further set.

  According to this, by using the total profit as the evaluation index, the production amount of each product for each period is determined for each passing process route so that the marginal profit is maximized. As a result, for example, even when a plurality of passage process routes are set for one product, it is possible to select a passage step route that gives the highest profit in consideration of the facility capacity. .

  In addition, the production plan creation method, the production plan creation program, and the production plan creation apparatus according to the present invention may further set an evaluation index related to the production amount that is the sum of the production amounts of all the products.

  According to this, by using the production amount as an evaluation index, the production amount of each product for each period is determined for each passing process route so that the production amount is maximized. As a result, for example, even when multiple passing process routes are set for one product, it is possible to select a passing process route that maximizes the production volume, taking into account the equipment capacity. Become.

  In addition, the production plan creation method and the production plan creation program according to the present invention are calculated by linear programming while using the weights of evaluation indexes set in advance when the optimum product manufacturing configuration calculation step uses a plurality of evaluation indexes. You can do it.

  In the production plan creation apparatus according to the present invention, the optimum product manufacturing configuration calculation unit may calculate by a linear programming method using weights of evaluation indexes set in advance when a plurality of evaluation indexes are used.

  Thereby, by using a plurality of evaluation indexes, a balanced production amount of each product in each period in consideration of each evaluation index is determined for each passing process route. For example, combining an evaluation index related to production unachieved quantity, an evaluation index related to preceding production volume, and an evaluation index related to gross profit will allow profits to be maximized while permitting preceding production and delaying delivery (while minimizing) In addition, the production amount of each product for each period can be determined for each passing process route.

  The production plan creation program according to the present invention can be distributed by being recorded on a removable recording medium such as a CD-ROM (Compact Disc Read Only Memory) or DVD (Digital Versatile Disk) or a fixed recording medium such as a hard disk. In addition, it can be distributed via a communication network such as the Internet by wired or wireless telecommunication means.

  The production plan creation method, production plan creation program, and production plan creation apparatus of the present invention provide an optimum product manufacturing configuration within the range of equipment capacity even when equipment load fluctuations or demand fluctuations occur. Can be determined.

  Hereinafter, the best mode for carrying out a production plan creation method, a production plan creation program, and a production plan creation apparatus according to the present invention will be described with reference to a specific example.

  First, an example of a production line targeted by the production plan creation method, the production plan creation program, and the production plan creation apparatus according to the present embodiment will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of a production line. In addition, what is demonstrated below is only what was illustrated and does not show the application limit of the production plan creation method, the production plan creation program, and the production plan creation device according to the present invention.

  As shown in Fig. 4, the production line from raw materials to shipment is composed of M01, M02M03, M04, and M05 equipment, and intermediate products and finished products in the middle of production are stored in buffers as needed. Is done. Here, the equipment used and the order thereof differ depending on the type of product (individual passage process routes will be described later based on Tables 1 and 4).

  In addition, “actual work rate” is defined as the facility capacity of each facility. Here, the actual work rate is a ratio of time that can be spent on net processing when the equipment is operated to the maximum, and is set statistically from the operation results of the equipment. For example, if the actual work rate is 80%, 19.2 hours (24 hours × 80/100) can be spent on the net processing in one day (24 hours), and the remaining time is used for work preparation and It means to be consumed for maintenance. In the present embodiment, the actual working rate to be used is 100% in all equipment for all periods.

  Next, Tables 1 to 3 show product information (hereinafter referred to as “product information”) used in the production plan creation method, the production plan creation program, and the production plan creation apparatus according to the present embodiment. As shown in Tables 1 to 3, there are five types of products ("product codes" shown in Tables 1 to 3), A01 to A05, each of three types of passage route (manufacturing procedure) (" There is a passing process route number "). For example, in product A03, there are three types of passage process routes with process design numbers 7-9. Further, as shown in Tables 2 and 3, each product has a lower limit amount (that is, a “production amount lower limit value”) to be produced in each period (in this embodiment, one month is assumed). And an upper limit amount that cannot be sold even if it is produced (that is, the “production amount upper limit value” and the “maximum production amount” shown in Table 3). Given monthly. Then, using any given (not necessarily one) passing process route, in each evaluation index to be described later, “production within the upper and lower limit amounts is necessary” or “in each period The production must be performed within the upper and lower limit amounts as much as possible, and the production within the upper and lower limit amounts must be performed as a whole. Further, as shown in Table 1, each product is given a “raw material cost” and a “selling price” per ton.

  Next, Table 4 shows information of each passing process route (hereinafter referred to as “passing process route information”) used in the production plan creating method, the production plan creating program, and the production plan creating apparatus according to the present embodiment. . Here, the information on the passing process route indicates the manufacturing procedure for each “passing process route number”, and the intermediate product is manufactured through the steps in the order of “process number” shown in Table 4 to obtain the final product. The finished product is manufactured. In each step, as shown in Table 4, “equipment (equipment code)” that can be processed is assigned from among the equipments M01, M02, M03, M04, and M05. And as shown in Table 4, as "equipment capacity", the weight (ton / hr) of the product (intermediate product) that can be processed per hour in each equipment ("equipment code" shown in Table 4) Is defined. In addition, as shown in Table 4, the cost generated for processing for 1 hour in each process is defined as “variable cost” (1,000 yen / hr). Furthermore, as shown in Table 4, the “process yield” which is the weight ratio between the exit side and the entrance side of the equipment, and the lead time (days) between the preceding and following processes are defined.

In Table 4, for example,
Based on the “equipment capacity”, the equipment M01 can process the product A01 having the passage process route number of 1 for 2 tons per hour.
Based on the “variable cost”, it can be seen that the equipment M01 requires a variable cost of 2,000 yen to process the product A01 having the passage process route number 1 for one hour.
-Based on the "process yield", the equipment M01 requires 10 tons of input to complete 8 tons of the product A01 having the passage process route number of 1 (2 tons of the difference is discarded as a defective part, for example) You can see how much).
-Based on the "inter-process lead time", the lead time between the first process (process number 1, equipment code M01) and the second process (process number 2, equipment code M05) having a passage process route number of 1 is used. It can be seen that it takes two days.
The inter-process lead time set in the final process is a lead time from completion of the final process to shipment. In addition, although the number of processes is set to three in all passing process route numbers, the present invention is not limited to this, and various process designs are possible.

  Next, the production plan creation apparatus according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram of the production plan creation apparatus according to the present embodiment. As shown in FIG. 2, the production plan creation device 1 includes a period information storage unit B1, an equipment load distribution ratio calculation unit B2, a manufacturing route storage unit B3, an generated cost information storage unit B4, and a load / cost information conversion. Unit B5, optimum product manufacturing configuration calculation unit B6, result output unit B7, evaluation index setting unit B8, raw material / sale price information storage unit B9, production volume information storage unit B10, equipment information storage unit B11, Is implemented on a computer. Here, each part B1-B11 of the production plan preparation apparatus 1 shown by FIG. 2 is comprised by computers, such as a general purpose personal computer, for example. Such a computer stores hardware such as a CPU, ROM, RAM, hard disk, and CD-ROM drive, and the hard disk includes a program (this program is a removable storage medium such as a CD-ROM or DVD). In this case, it is possible to install the software on various computers. The above-described units B1 to B11 are constructed by combining these hardware and software. In addition, information exchange of each of the above-described units B1 to B11 may be performed using a communication network.

  The period information storage part B1 is for storing information on a period, which is a unit for calculating an optimum product manufacturing configuration based on an evaluation index, as information on a period. In the present embodiment, the period is one month.

  The manufacturing route storage unit B3 includes, as information related to the manufacturing route (that is, the manufacturing order of the passing process route), the used equipment and the using order for each passing process route number, the processing capability of each process for each passing process route number, the process yield, And it is for memorize | storing the lead time between processes. In the present embodiment, it corresponds to the columns of “equipment code”, “processing capability”, “process yield”, and “inter-process lead time” in “process number” of the passing process route information in Table 4 described above. .

  The generated cost information storage unit B4 is for storing the generated variable cost unit price in each facility as information related to the generated cost. In the present embodiment, this corresponds to the “variable cost” column of the passage process route information in Table 4 described above. In this embodiment shown in Table 4, the unit price per hour (1,000 yen) of processing is used. However, the unit price per ton of processing may be used.

  The raw material / sale price information storage unit B9 stores information on the raw material cost and the selling price for each product as information on the raw material / sale price. In the present embodiment, it corresponds to the columns of “raw material cost” and “selling price” of the product information in Table 1 described above. In this embodiment, if the product is the same, the raw material cost and the selling price are the same even if the passing process route is different, but the raw material cost may be set for each process design.

  The production amount information storage unit B10 includes, as information on the production amount range, a pass process route number that can be used for each product, a minimum production amount for each period (that is, a “production amount lower limit value”), and a maximum production amount (that is, “ This is for storing information relating to the production upper limit value)). In this Embodiment, it is contained in the product information of Tables 1-3 mentioned above.

  The equipment information storage unit B11 is for storing information about equipment capacity of each equipment as information about equipment. In the present embodiment, it corresponds to the above-described actual work rate, and the total equipment is 100%.

  The evaluation index setting unit B8 is for setting a target evaluation index when determining the product configuration. In the present embodiment, a plurality of evaluation indexes are set, and the total marginal profit (hereinafter referred to as “total profit”) that is the sum of values calculated from (selling price−raw material cost−variable cost) in each period of each product. ), An evaluation index related to an unachieved amount that is the sum of values calculated from MIN (production volume-production volume lower limit, 0) in each period of each product, and each product in each period Consider a combination of an evaluation index relating to a preceding production amount, which is a sum of values calculated from (production amount−shipment amount).

The equipment load distribution ratio calculation unit B2 uses the process design based on the inter-process lead time for each process design registered in the production route information in the production route information storage unit B3. The facility load distribution ratio, which is the ratio of load distribution to each month for each process, is calculated. A specific calculation example of the equipment load distribution ratio will be described with reference to FIG. In FIG. 3, the manufacturing route (namely, manufacturing sequence of a passage process route) to the above-mentioned process 1-process 3 is shown. L1 to L3 are inter-process lead times between the post-processes of process 1 to process 3 (in the case of process 3, the post-process is shipping). Moreover, DT, DT-1, and DT-2 are the days of T month, T-January, and T-February, respectively. Further, the products are shipped evenly in T month, and the process in each process is executed at the same pitch as the shipment and preceded by the inter-process lead time. At this time, the processing time from step 1 to step 3 is a hatched portion in FIG. 3, and the load of the step is distributed according to the time of each month included in each hatched portion. For example, in step 1, the equipment load distribution ratio (r1, T-2) to T-February and the equipment load distribution ratio (r1, T-1) to T-Ju are as follows.
Facility load distribution ratio to T-February (r1, T-2)
r1, T-2 = {L1 + L2 + L3-DT-1} / DT
Equipment load distribution ratio to T-January (r1, T-2)
r1, T-1 = {DT + DT-1- (L1 + L2 + L3-DT-1)} / DT

  Table 5 shows the calculation result of the equipment load distribution ratio in the present embodiment calculated based on the example shown in the passing process route information of Table 4 described above. In the present embodiment, the period information is the number of days in each month, and is all 30 days.

The load / cost conversion unit B5 uses the processing capacity of each process stored in the manufacturing route information storage unit B3 and the facility load distribution ratio calculated by the facility load distribution ratio calculation unit B2 for each passing process route. 1) Required for production per ton of product in each period (each month) 1) Equipment load intensity by month (hr / product ton)
2) Marginal margin (1,000 yen / product ton)
Calculate 1) Each calculation method of 2) is shown below.

1) Unit load unit by month This is the load of T ′ month (T ′ ≦ T) at process k required for production per ton of product in T month, and the following is calculated for each passing process route.
Unit load unit of T 'month at process k for T month production (hr / product ton)
= T 'month equipment load distribution ratio at process k to T month production x load at process k required for production per ton of product (hr / product ton)
Table 6 shows the calculation result of the monthly equipment load basic unit in the present embodiment. In the case of this embodiment, the load (hr / product ton) required for production per ton of product is the weight in process k (that is, production per ton of product calculated from the process yield). Calculated as the required raw material weight) / equipment capacity of process k. Moreover, in this embodiment, in each passing process route, since the sum of the lead times between processes is shorter than one month, the equipment load intensity unit of T ′ month for T month production is only T month and T−1 month. Become.

2) Marginal margin (1,000 yen / product ton)
This is the profit obtained from sales per ton of product. The following is calculated for each passing process route.
Marginal margin (1,000 yen / product ton)
= Selling price (thousand yen / product ton)
-Raw material cost unit price (thousand yen / raw material ton) x raw material required for production per ton of product (ton / product ton)
-Sum of costs incurred in each process required for production per ton of product (thousand yen / product ton)
Table 7 shows the calculation result of the marginal profit rate in the present embodiment. In the embodiment shown in Table 7, the generated variable cost unit price (thousand yen / product ton) corresponds to the “generated cost in each process required for production per ton of product” in the above formula, and the weight in process k. (That is, the raw material weight required for production per ton of product calculated from the process yield) / equipment capacity of the process k × variable cost of each process. Further, in Table 7, the variable cost is the sum of the generated cost basic unit of each process in the passing process route. Further, in Table 7, the raw material cost means the raw material cost (raw material cost unit) of the product information shown in Table 1 and the weight in the process k (that is, the production per ton of product calculated from the process yield). It is a value multiplied by the raw material weight.

  The optimum product manufacturing configuration calculation unit B6 is configured to limit the total production amount upper and lower limit range for each product based on the production amount information stored in the production amount information storage unit B10 and the facility capacity constraint based on the actual operation rate stored in the facility information storage unit B11. The production volume for each period (monthly) for each passing process route that maximizes the evaluation index set by the evaluation index setting unit B8 (gross profit, unachieved production amount and preceding production volume) Determined by the planning method.

  In the present embodiment, the production amount for each period (monthly) for each passing process route is determined by solving the optimization problem of the following equation 1 using linear programming. In the present embodiment, as described above, the period is assumed to be one month (30 days). Further, in this embodiment, since the sum of the inter-process lead times is shorter than one month, it is only necessary to consider only the current month and the previous month as the equipment load unit for the current month production (corresponding to k = 0, 1).

  In the formula shown in Equation 1, α, β, and γ are weights of the evaluation indexes, and values can be freely set according to the priority of each evaluation index.

  Here, the formula shown in Equation 1 is a combination of three evaluation indices, and each evaluation index will be described below. First, the evaluation formula and the constraint formula when the gross profit is used as the evaluation index are the formulas shown in the following formula 2.

  Next, the evaluation formula and the constraint formula when the production unachieved amount is used as the evaluation index are the formulas shown in the following equation (3).

  When the production unachieved amount with respect to the production amount lower limit value is used as an evaluation index, the production amount lower limit constraint among the upper and lower limit range constraints on the production amount is relaxed. Here, the expression of MIN (a, b) is an expression in which the values of a and b are compared and the smaller value is selected. That is, MIN (10, 5) = 5. Therefore, this evaluation index returns the value when the situation where the production volume is below the production volume lower limit value, that is, the situation where the production volume does not reach the production volume lower limit value, occurs at each time. If not, the expression returns 0.

  Then, the evaluation formula and the constraint formula when the preceding production volume is used as the evaluation index are the formulas shown in the following equation (4).

When the preceding production volume is used as an evaluation index, the upper and lower limits of the production volume are relaxed so that the total production volume of each product is within the range of the production volume lower limit value and the production volume upper limit value. To do. Then, in each period of each product, it is not necessary to ship all products produced in the month (ie, it is allowed to be stored as product inventory), and in addition to the production amount of each product in each period, Consider the quantity of products shipped in each period (as a decision variable for the evaluation function). And the following restrictions are added.
1) In each period of each product, the lower production limit must be shipped.
2) Each product cannot be shipped in excess of the total production volume up to each period (that is, the total production volume upper limit value up to each period).
3) In each period of each product, the shipment volume cannot exceed the production volume upper limit.
4) During the entire planning period, the total production volume does not exceed the total production volume limit.

  The result output unit B7 is an output device (display, hard disk, printer, or the like) for displaying the calculation result in the optimum product manufacturing configuration calculation unit B6 via an output interface (not shown). As the calculation result, the optimized product manufacturing configuration for each period, the load status of the equipment, etc. are output. The output interface is a program or hardware for performing data conversion and communication for outputting the calculation result in the optimum product manufacturing configuration calculation unit B6 to the result output unit B7 (display, hard disk, printer, etc.). .

  In this embodiment, Table 8 shows the optimized production amount for each month / passing process route output in the result output unit B7.

  In addition, Table 9 shows the shipment volume by month (period) and product, and the preceding production volume.

  Further, Table 10 shows the required operation time for each month (period) and equipment for realizing the production amount shown in Table 8.

From Tables 8 and 9, the following can be understood.
1) The total monthly production amount of each product is determined within the range of the minimum and maximum production amounts defined by the product information shown in Tables 1 to 3. In addition, in the product code A01, it is understood that the intention of “production is performed although there is little direct profit” is reflected by setting the minimum production amount for each month.
2) The product codes A03 and A04 have a maximum production volume of 0 in January and February and a maximum production volume of 1000 in June, and are gradually increased. As a result, it can be seen that the intention of “advanced production in preparation for future expansion of demand for products with high profit margins” is reflected. In addition, from the middle to the second half of the planning period, product code A01 is pre-production in the first half of the planning period in order to secure equipment for production of product codes A03 and A04 with high profit margins. This shows that a flexible production plan has been drawn up.

Table 10 shows the following.
In any month, the working rate of three or more facilities is the largest. From March to June, there is more than one facility, but each product requires three different facilities for production, so the production volume of other products is not reduced and the production volume is increased. It is not possible. In other words, it can be seen that if production is performed as a problem setting, profits are increased (the evaluation value of the evaluation index is improved), and therefore production is performed to the limit of facility capacity as a factory.

Next, the processing procedure of the production planning method according to the present embodiment will be described with reference to FIG. FIG. 1 is a flowchart illustrating a processing procedure of the production planning method according to the present embodiment.
Note that the processing of the production planning method according to this embodiment described below can be read and executed by the CPU as a production planning program in the computer as well. The production planning program can be installed in various computer storage devices by recording it in a removable storage medium such as a CD-ROM or DVD.

As shown in FIG. 6, in a computer, a communication network such as the Internet is input by an input unit, recorded on a removable storage medium such as a CD-ROM or DVD, or wired or wireless telecommunication means. (S1: Period information storage step, manufacturing route information storage step, generated cost information storage step, raw material / sale price information storage step, production quantity information storage step, equipment information storage step).
In addition, the period information storage part B1, the production route information storage part B3, the generated cost information storage part B4, the evaluation index setting part B8, the raw material / sale price information storage part B9, the production amount information storage part of the production plan creation device 1 described above. The information stored in B10 and the facility information storage unit B11 is basic information. The details of this step are the same as those described, and a description thereof is omitted.

Next, the facility load distribution ratio for each month is calculated for each passage process set in the passage process route (S2: facility load distribution ratio calculation step).
The details of this step are the same as the description of the equipment load distribution ratio calculation unit B2 of the production plan creation apparatus 1 described above, and the description thereof is omitted.

In addition, load cost (monthly equipment load basic unit, marginal profit rate) is converted for each passing process route (S3).
The details of this step are the same as those described in the load / cost information conversion unit B5 of the production plan creation apparatus 1 described above, and a description thereof is omitted.

Then, the optimal product manufacturing configuration is calculated by linear programming (S4: optimal product manufacturing configuration calculation step).
The details of this step are the same as the contents described in the optimum product manufacturing configuration calculation unit B6 of the production plan creation apparatus 1 described above, and the description thereof is omitted.

Finally, the calculation result is output (S5).
The details of this step are the same as those described in the result output unit B7 of the production plan creation apparatus 1 described above, and the description thereof is omitted.

  As described above, according to the production plan creation device, the production plan creation method, and the production plan creation program of the present embodiment, even if a change in equipment load or a change in demand occurs, within the range of equipment capacity. Can determine the optimal product manufacturing configuration

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims.

  In the above-described embodiment, the evaluation index setting unit B6 sets the evaluation index so as to maximize (total profit, unachieved production amount, and preceding production amount), but is not limited thereto. It may be set as an evaluation index so as to maximize (gross profit and production unachieved amount), or may be set as an evaluation index so as to maximize (gross profit and preceding production amount). Further, instead of the evaluation index of gross profit, for the purpose of maximizing the production volume, the total production that is the sum of the production quantities of all products may be set as the evaluation index. When total production is used as an evaluation index, the following equation 5 may be used. In such a case, it is possible to determine a product manufacturing configuration that places importance on the total production volume, as in the case of giving priority to share.

  In the present embodiment, the selling price of the product and the raw material cost depend on only the passage process route, but may differ depending on the manufacturing time. In this case, the selling price is defined as Pij and the raw material cost is defined as Mij in the equations shown in the above formulas 1-5.

It is the flowchart explaining the procedure of the process of the production plan preparation method which concerns on this embodiment. It is a block diagram of a production plan creation device concerning this embodiment. It is a figure which shows the specific calculation example of an equipment load distribution ratio. It is a figure which shows an example of the production line made into the object of this embodiment.

DESCRIPTION OF SYMBOLS 1 Production plan preparation apparatus B1 Period information storage part B2 Equipment load distribution ratio calculation part B3 Manufacturing route information storage part B4 Generated cost information storage part B6 Optimal product manufacturing structure calculation part B9 Raw material and selling price information storage part B10 Production amount information storage part B11 Equipment information storage unit S1 Period information storage step, production route information storage step, generated cost information storage step, raw material / sale price information storage step, production volume information storage step, equipment information storage step S2 equipment load distribution ratio calculation step S4 Optimal product manufacturing Configuration calculation step

Claims (15)

In a computer having an arithmetic unit, a storage unit, an input unit, and an output unit,
The processing executed by the computing unit is
A period information setting step for storing a period, which is a unit for calculating the optimum product manufacturing configuration based on the evaluation index;
For each product, one or more manufacturing routes to which equipment that can be processed for a plurality of processes for manufacturing the product are assigned are registered as passing process routes, and the processing capacity and each process for each passing process route are registered. Manufacturing route information storage step for registering the inter-process lead time;
For each period of each facility, a facility information storage step for registering facility capacity;
A production amount information storage step for registering a production amount lower limit value and a production amount upper limit value as a required production amount range for each period of each product;
A facility load distribution ratio calculating step for calculating a facility load distribution ratio for each period before the predetermined period in each process for production in a predetermined period based on the inter-process lead time for each passage process route; ,
The facility capacity restriction that the total load of each facility determined by the processing capacity and the facility load distribution ratio does not exceed the facility capacity, and the total production amount of each product for each period is the production. Production volume in each period of each passing process route that maximizes the preset evaluation index while satisfying the upper and lower limit range restrictions on production volume that satisfy the requirement that it is within the range between the lower limit value and within the upper limit production value An optimal product manufacturing configuration calculation step for calculating
A production plan creation method characterized by comprising: The production lower limit constraint among the upper and lower range constraints of the production amount is relaxed, and the production not yet being the sum of values calculated from MIN (production amount-production lower limit value, 0) in each period of each product An evaluation index for the amount achieved, and
Relaxing the upper and lower limit range restrictions on the production volume, and using the shipment volume in addition to the production volume in each period for each product as the basis for calculating the optimal product manufacturing configuration, the shipment volume in each period for each product is the production volume lower limit. Constraints that must be greater than the above, restrictions that each product cannot exceed the total production volume that is the sum of the production volume upper limit up to each period, and the shipment volume of each product in each period must exceed the production volume upper limit value The sum of the values calculated from (Production volume-Shipment volume) in each period of each product while satisfying the constraint that the total amount of production does not exceed the sum of the production volume upper limit value for the entire planning period The production plan creation method according to claim 1, wherein at least one of the evaluation indices relating to the preceding production amount is set as an evaluation index. Raw material and selling price registration step for registering raw material cost and selling price for each product,
An accrued cost registration step of registering an accrued cost generated in each process for each passing process route;
3. The production plan creation method according to claim 1, further comprising setting an evaluation index related to a total marginal profit which is a sum of values calculated from (sell price-raw material cost-generated cost).   3. The production plan creation method according to claim 1, further comprising setting an evaluation index related to a production amount that is a sum of production amounts of all the products.   5. The optimal product manufacturing configuration calculation step is performed by linear programming using weights of evaluation indexes set in advance when a plurality of evaluation indexes are used. 5. The production plan creation method described. A period information setting step for storing a period, which is a unit for calculating the optimum product manufacturing configuration based on the evaluation index;
For each product, one or more manufacturing routes to which equipment that can be processed for a plurality of processes for manufacturing the product are assigned are registered as passing process routes, and the processing capacity and each process for each passing process route are registered. Manufacturing route information storage step for registering the inter-process lead time;
For each period of each facility, a facility information storage step for registering facility capacity;
A production amount information storage step for registering a production amount lower limit value and a production amount upper limit value as a required production amount range for each period of each product;
A facility load distribution ratio calculating step for calculating a facility load distribution ratio for each period before the predetermined period in each process for production in a predetermined period based on the inter-process lead time for each passage process route; ,
The facility capacity restriction that the total load of each facility determined by the processing capacity and the facility load distribution ratio does not exceed the facility capacity, and the total production amount of each product for each period is the production. Production volume in each period of each passing process route that maximizes the preset evaluation index while satisfying the upper and lower limit range restrictions on production volume that satisfy the requirement that it is within the range between the lower limit value and within the upper limit production value An optimal product manufacturing configuration calculation step for calculating
A production plan creation program characterized by having a computer read out by a calculation unit and causing each step to be executed. The production lower limit constraint among the upper and lower range constraints of the production amount is relaxed, and the production not yet being the sum of values calculated from MIN (production amount-production lower limit value, 0) in each period of each product An evaluation index for the amount achieved, and
Relaxing the upper and lower limit range restrictions on the production volume, and using the shipment volume in addition to the production volume in each period for each product as the basis for calculating the optimal product manufacturing configuration, the shipment volume in each period for each product is the production volume lower limit. Constraints that must be greater than the above, restrictions that each product cannot exceed the total production volume that is the sum of the production volume upper limit up to each period, and the shipment volume of each product in each period must exceed the production volume upper limit value The sum of the values calculated from (Production volume-Shipment volume) in each period of each product while satisfying the constraint that the total amount of production does not exceed the sum of the production volume upper limit value for the entire planning period The production plan creation program according to claim 6, wherein at least one of the evaluation indexes relating to the preceding production amount is set as an evaluation index. Raw material and selling price registration step for registering raw material cost and selling price for each product,
An accrued cost registration step of registering an accrued cost generated in each process for each passing process route;
8. The production plan creation program according to claim 6, further comprising setting an evaluation index relating to a total marginal profit, which is a sum of values calculated from (sell price-raw material cost-generated cost).   8. The production plan creation program according to claim 6, further comprising setting an evaluation index relating to a production amount that is a sum of production amounts of all the products.   10. The optimal product manufacturing configuration calculation step is calculated by linear programming using weights of evaluation indexes set in advance when a plurality of evaluation indexes are used. The production plan creation program described. In a computer having a calculation unit, a storage unit, an input unit, and an output unit, a production plan creation device that creates a production plan,
The computing unit is
A period information setting unit for storing a period, which is a unit for calculating the optimum product manufacturing configuration based on the evaluation index;
For each product, one or more manufacturing routes to which equipment that can be processed for a plurality of processes for manufacturing the product are assigned are registered as passing process routes, and the processing capacity and each process for each passing process route are registered. Manufacturing route information storage unit for registering the inter-process lead time;
For each period of each facility, a facility information storage unit that registers facility capacity;
A production amount information storage unit for registering a production amount lower limit value and a production amount upper limit value as a required production amount range for each period of each product;
An equipment load distribution ratio calculation unit for calculating an equipment load distribution ratio for each period before the predetermined period in each process for production in a predetermined period based on the inter-process lead time for each passing process route; ,
The facility capacity restriction that the total load of each facility determined by the processing capacity and the facility load distribution ratio does not exceed the facility capacity, and the total production amount of each product for each period is the production. Production volume in each period of each passing process route that maximizes the preset evaluation index while satisfying the upper and lower limit range restrictions on production volume that satisfy the requirement that it is within the range between the lower limit value and within the upper limit production value An optimal product manufacturing configuration calculation unit for calculating
A production plan creation device characterized by comprising: The production lower limit constraint among the upper and lower range constraints of the production amount is relaxed, and the production not yet being the sum of values calculated from MIN (production amount-production lower limit value, 0) in each period of each product An evaluation index for the amount achieved, and
Relaxing the upper and lower limit range restrictions on the production volume, and using the shipment volume in addition to the production volume in each period for each product as the basis for calculating the optimal product manufacturing configuration, the shipment volume in each period for each product is the production volume lower limit. Constraints that must be greater than the above, restrictions that each product cannot exceed the total production volume that is the sum of the production volume upper limit up to each period, and the shipment volume of each product in each period must exceed the production volume upper limit value The sum of the values calculated from (Production volume-Shipment volume) in each period of each product while satisfying the constraint that the total amount of production does not exceed the sum of the production volume upper limit value for the entire planning period The production plan creation device according to claim 11, wherein at least one of the evaluation indices relating to the preceding production amount is set as an evaluation index. The computing unit is
For each product, a raw material / sale price registration unit for registering a raw material cost and a selling price;
For each passing process route, further comprising an generated cost registration unit that registers an generated cost generated in each process,
The production plan creation device according to claim 11 or 12, further comprising setting an evaluation index relating to a total marginal profit, which is a sum of values calculated from (selling price-raw material cost-generated cost).   The production plan creation device according to claim 11 or 12, further comprising setting an evaluation index relating to a production amount that is a sum of production amounts of all the products.   The said optimal product manufacturing structure calculation part is calculated by linear programming, using the weight of the evaluation index set beforehand, when using several evaluation index, It is any one of Claims 11-14 characterized by the above-mentioned. The production plan creation device described.

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