JPH06203037A - Device and method for devising production planning - Google Patents

Abstract

PURPOSE:To automatically devise production planning corresponding to a demand and supply plan in a short period by considering the actual condition of a production plant, and also, to automatically verify its optimality. CONSTITUTION:From a demand and supply plan inputted to a demand/supply plan input part 1, the required number of products is calculated at each of plural production plants based on information managed by a reference information part 2 and a production control information part 3, and with respect to production planning of each plant, by the knowledge of an expert stored in a scheduling restraint condition part 8 and a schedule evaluating information part 9 as a rule, rescheduling is repeated while verifying automatically optimality of a schedule in an inference part 4, and a practically optimal schedule is devised automatically in a short time.

Description

Detailed Description of the Invention

The present invention, in response to the demand and supply plan requested,
The present invention relates to a production plan formulation device and method for automatically producing a minimum required production plan that satisfies a supply and demand plan from required states of a plurality of producible production plants in a short time.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram schematically showing a conventional production planning apparatus. In FIG. 4, the conventional production plan formulation apparatus includes a demand / supply plan input unit 1 for manually inputting a demand / supply plan based on an order from a customer, a production capacity for each production item, a yield rate, a construction period, and a production factory. Standard information part 2 that manages the calendar that specifies the number of days that the factory operates, and process management information that manages the number of daily production completions and the number of work in progress (quantity in production) for each production item in each factory. Based on the department 3 and the demand and supply plan input from the demand and supply plan input unit 1, the number of completed achievements for each production item managed by the process management information unit 3, the construction period for each production item, and the yield rate are calculated as parameters to produce It has a processing unit 41 that creates a plan and a production plan output unit 5 that outputs the production plan created by the processing unit 41.

Next, the operation of the above conventional apparatus will be described with reference to the flowcharts of FIGS. First, a supply and demand plan in which the production quantity for each production item is specified is input to the supply and demand plan input unit 1 (step S1), and the actual number of completions for each production item managed by the process management information unit 3 from this supply and demand plan (production (The number of finished products) and the number of products in process (the number of products in production) are subtracted, and the required number of products is calculated in consideration of the non-defective rate and the construction period for each product item defined in the standard information section 2 (step S2), The required production quantity for each production item is distributed to the designated production factory registered in advance in the reference information section 2 in consideration of the production capacity of each factory (step S3).

For each of the factories thus distributed, the processing section 41 schedules as follows (step S4).
For each production item, from the production start date S where raw materials are prepared to the delivery date E specified in the supply and demand planning input section 1, the production date D excluding holidays of the factory calendar registered in the standard information section 2 is set. calculate. The required production number is divided by this producible number of days to calculate the required production number per day. This process is performed for all distributed production items.

The schedule result is output to the production plan output unit 1
It is displayed at 0 (step S5). Then, whether the output schedule satisfies the schedule of each factory,
Production capacity of each factory (that is, maximum producible amount by product type)
Considering the above, the expert determines whether or not the distribution rate of the production quantity of each factory is appropriate (step S6), and if it is determined that the adoption is possible, the process ends.

If not adopted, the expert performs exceptional processing such as supply / demand plan change (step S7), factory distribution plan change (step S8), schedule plan change (step S9), etc., and steps S2, S4, respectively. The operations after step S5 are performed in the same manner as the first time.

[0007]

Since the above-mentioned conventional production planning apparatus is configured as described above, it is necessary for a person other than the expert to make a judgment and adjustment of the production planning expert. Had the problem of being difficult to handle. In addition, when the number of items to be produced increases and the conditions become complicated, it is necessary to repeat trial and error to obtain the optimum value, and there is a problem that even an expert takes a long time. Furthermore, in recent years, there has been a particularly strong demand to automatically output an appropriate production plan in a short time as the number of production items rapidly increases and the delivery time is shortened as the production needs diversify. The present invention has been made to solve the above problems,
It is an object of the present invention to provide a production plan formulation device and method that can automatically formulate an appropriate production plan corresponding to a frequently changed supply and demand plan in a short time.

[0008]

According to a first aspect of the present invention, there is provided a production plan formulation device, a demand and supply plan input section for inputting a product supply and demand plan, a production capacity of each factory for each production item, and a non-defective rate. , Schedule, designation by production factory priority, factory calendar that regulates the operating days of each factory, standard information section that manages information such as setup change, and the number of daily completed achievements and work in progress for each production item at each factory The process control information section that manages the number of items, the weak constraint conditions that can be selected when scheduling is specified with priority, and the scheduling constraint condition section that specifies the indispensable strong constraint conditions and the scheduling A scheduling evaluation information section that defines the judgment criteria for judging whether or not to adopt the result,
An inference unit that takes in necessary information from the reference information unit and the process control information unit based on the input information of the demand and supply plan input unit and automatically infers an appropriate production plan in a short time, and created by the inference unit And a production plan output unit for outputting the created schedule plan. The inference unit calculates the necessary production quantity from the supply and demand plan input to the supply and demand plan input unit in consideration of the number of completed achievements for each production item managed by the process management information unit, and the reference information. A scheduling unit that performs factory allocation calculation based on standard information defined by the department and automatically creates one schedule proposal according to the weak constraint condition and the strong constraint condition defined by the scheduling constraint condition unit, and the scheduling unit. A schedule verification unit that verifies whether the schedule proposal created in 1. satisfies the criteria defined in the schedule evaluation information unit, and the schedule verification unit determines that the schedule proposal does not satisfy the criteria. , The weakness is considered in consideration of the priority defined by the scheduling constraint condition part. Change the application constraints, and a constraint condition changing unit for carrying out the re-scheduling in the scheduling unit under the condition again.

According to a second aspect of the present invention, there is provided a production planning method, which comprises a first step of inputting a supply and demand plan in which a required quantity and a delivery date for each production item are designated, and the number of completed achievements and specifications for each production item from the supply and demand plan. The required number of products is calculated by deducting the number of products in question and converting it to a non-defective product rate for each production item, and the completion date of the in-process is converted based on the construction period for each production item to derive the production start date for each factory. In consideration of the process, the predetermined priority of the production factories, and the production capacity corresponding to the number of production days from the production start date to the delivery date, the required monthly production quantity for each production item is allocated to each factory. Combining each production item under the process and all pre-specified selectable weak constraints, according to the necessary strong constraints,
Scheduling is performed so that the volume is maximized under such conditions, and the fourth step of creating a schedule proposal and whether the created schedule proposal satisfies the predetermined judgment criteria and the schedule is verified. For the fifth step of deciding whether or not to adopt the plan, and for the schedule plan that is judged to be for adoption or non-adoption, the weak constraint conditions are canceled from the ones with lower priority defined in advance, and rescheduling is performed under the conditions. It can be adopted even if the sixth step to be executed, the seventh step that automatically repeats the fourth to sixth steps until a schedule that can be adopted is obtained, and all the constraint conditions are released. If there is no schedule proposal, the eighth step of exceptionally adopting the schedule proposal in which all the constraint conditions are released and the adopted schedule proposal are output, and the process ends. Consisting of a 9 process.

According to a third aspect of the present invention, there is provided a production plan formulation method including a first step of inputting a supply and demand plan in which a required quantity and delivery date for each production item are designated, and the number of completed achievements and specifications for each production item from the supply and demand plan. The required number of products is calculated by deducting the number of products in question and converting it to a non-defective product rate for each production item, and the completion date of the in-process is converted based on the construction period for each production item to derive the production start date for each factory. Steps, a third step of calculating a priority coefficient for each production item, a fourth step of allocating to the facilities of each factory in descending order of priority coefficient and scheduling, and a schedule plan created in this way. The fifth step of calculating the evaluation index such as the capacity utilization rate and the production output in the case of production according to the above, and whether or not the evaluation index of the created schedule proposal satisfies the evaluation condition defined in advance, Sixth step of deciding whether or not to adopt the schedule proposal, and for the schedule proposal determined to be not or not to be adopted, after changing the application of the weak constraint condition in the order of the production items having the smaller priority coefficients, the rescheduling is carried out. Even if the process and the applicable schedule change process are performed, an eighth process that automatically repeats the above fourth to seventh processes until all the applicable conditions are changed until a schedule plan that can be adopted is obtained. If it does not exist, it includes a ninth step that exceptionally adopts the last schedule proposal and a tenth step that outputs the adopted schedule proposal and ends the process.

[0011]

The production planning apparatus according to the first aspect of the invention is
In consideration of the supply and demand plan and the actual situation of the production factory, the minimum necessary and feasible production plan is automatically formulated in a short time. In the production plan formulation method according to the inventions of claims 2 and 3, the production plan satisfying the supply and demand plan supported by the production capacity of each factory is automatically verified by automatically verifying the production plan formulated from the supply and demand plan and the actual situation of the production factory. Since the plan is automatically created, even non-specialists can formulate the production plan.

[0012]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram schematically showing a production planning apparatus according to this embodiment. In FIG. 1, the same parts as those of the conventional device of FIG. 4 described above are designated by the same reference numerals, and the production plan formulation device of the present invention is a supply and demand system for inputting a supply and demand plan based on an order from a customer. Plan input section 1
And the production capacity, yield rate, construction period, etc.
Standard information section 2 that manages specification by production factory priority, factory calendar that regulates the operating days of each factory, setup change information (information for changing production equipment and production process according to production item), and each In addition to defining the process control information section 3 that manages the number of daily completions and the current number of in-process items for each production item in the factory, and prioritizing weak constraint conditions that can be selected when carrying out scheduling, Scheduling constraint condition unit 8 that defines an indispensable strong constraint condition, and scheduling evaluation information unit 9 that defines a criterion for determining whether or not to adopt a scheduling result.
And an inference section 4 for automatically inferring an appropriate production plan in a short time by taking in necessary information from the reference information section 2 and the process control information section 3 based on the input information of the demand and supply plan input section 1, and its inference. And a production plan output unit 10 that outputs the schedule plan created by the unit 4.

The weak constraint condition defined by the scheduling constraint condition unit 8 is a condition for suppressing (inhibiting) production, and production is possible without ignoring or satisfying this condition. It is a condition. (1) 100% compliance with the delivery date for each production item. (2) The same item is manufactured in the same factory in an integrated manner (Products are not exchanged between the plants in the intermediate process.) (3) Setup change does not occur (Items are not switched in the same facility. That is, production of the same item will continue (4) Production will not be performed on holidays and breaks.

The strong constraint condition is a condition for not creating a schedule that is physically and temporally unexecutable, and is the following condition. (1) Do not assign the same equipment to two or more items at the same time. (2) Allocate the post process after the previous process (do not create a schedule to process the post process before the previous process for the same lot). (3) Be sure to consider the transfer time between factories (when the products are exchanged between the plants in the intermediate process, the process of the next process is not started during the predetermined transfer time). (4) Be sure to consider the setup change time (when items are switched in the same equipment, the corresponding equipment is not used during the preset setup change time).

The criterion for determining whether or not to adopt the scheduling result defined by the scheduling evaluation information unit 9 is an index of whether or not the prepared schedule plan is to be adopted (verification of whether or not the schedule can be executed as scheduled. Has been proved by the system side), and examples of such criteria include the following. (1) Whether or not multiple specific items are scheduled to complete production in the requested quantity on time. (2) Whether the operating rate of the equipment in the factory is above a certain level.

The inference unit 4 calculates the required number of productions from the supply and demand plan input to the supply and demand plan input unit 1 in consideration of the number of completed achievements for each production item managed by the process control information unit 3, A scheduling unit 5 that performs factory allocation calculation based on the standard information defined in the standard information unit 2 and automatically creates one schedule proposal according to the weak constraint condition and the strong constraint condition defined by the scheduling constraint condition unit 8. , A schedule verification unit 6 that verifies whether the schedule proposal created by the scheduling unit 5 satisfies the criteria defined in the schedule evaluation information unit 9, and the schedule proposal is determined by the schedule verification unit 6. If it is determined that the criteria are not satisfied, the priority defined by the scheduling constraint condition unit 8 is considered and weak. By changing the application of about conditions, and a constraint condition changing unit 7 for carrying out the re-scheduling in the scheduling unit 5 under the condition again.

Example 2. FIG. 2 shows a first method for automatically creating a production plan according to the invention, which is carried out using the apparatus shown in FIG.
It is a flow chart which shows an example.

Next, this automatic production plan creating method will be described with reference to the flowchart of FIG. First, the supply and demand plan input unit 1 inputs a supply and demand plan specifying the required quantity and delivery date for each production item (step X1).

Next, the number of completed products for each production item managed by the process management information unit 3 is subtracted from the supply and demand plan, and the number of work in progress managed by the process management information unit 3 is subtracted from the standard information unit 2 The required number of products is calculated by converting it to the non-defective product rate managed by, and the production start date is derived for each factory by converting the in-process completion date based on the construction period also managed by the standard information section 2. (Step X2).

The required monthly production quantity for each production item is taken into consideration in consideration of the priority order of the production factories managed by the standard information section 2 and the production capacity corresponding to the production possible days from the production start date to the delivery date. Allocate to factories (step X3).

Next, for each of the factories thus distributed, the inference unit 4 automatically creates a production plan in the following procedure. In the scheduling unit 5, it is common sense that each production item is combined under all the weak constraint conditions defined by the scheduling constraint condition unit 8 and two allocations are not made to the same device at the same time. According to such a strong constraint condition, the scheduling is performed so that the volume is maximized under the condition, and the schedule plan is prepared (step X4).

The schedule verification unit 6 verifies whether the created schedule proposal satisfies the criteria defined in the schedule evaluation information unit 9 and determines whether or not to adopt the schedule (step X5).

In the schedule proposal judged by the schedule verification unit 6 to be adopted or rejected, the weak constraint conditions at that time are selected by the constraint condition changing unit 7 from the lowest priority defined in the scheduling constraint unit 8 to all of them. The conditions are released in ascending order of weight, and the rescheduling is performed by the scheduling unit 5 under the conditions (step X6).

Thereafter, the operations after step X4 are automatically performed in the same manner as the first time until the schedule verification section 6 adopts the schedule proposal.

Even if all the constraint conditions are released by the constraint condition changing unit 7, if there is no schedule plan to be adopted by the schedule verification unit 6, the schedule plan in which all the constraint conditions are released is exceptionally processed. Adopt (Step X
7).

The schedule plan adopted by the schedule plan verification unit 6 is output to the production plan output unit 10 and the process is terminated (step X8).

Example 3. FIG. 3 is a flow chart showing a production plan automatic decision method according to another embodiment of the present invention, and this method is also carried out by the production plan automatic decision apparatus of FIG. 1 described above. Hereinafter, this method will be described with reference to the flowchart of FIG.

A demand / supply plan specifying the required quantity and delivery date for each production item is input to the demand / supply plan input unit 1 in FIG. 1 (step Z1).

From this supply and demand plan, the number of completed achievements for each production item managed by the process management information unit 3 is subtracted, and the number of work in progress managed by the process management information unit 3 is subtracted.
The required number of products is calculated by converting the rate of non-defective products managed by the standard information section 2, and the in-process completion date is also converted based on the construction period also managed by the standard information section 2 to produce at each factory. Derive the start date (step Z2).

A priority coefficient for each production item (priority order of production items that need to be newly input within the number of days remaining until the delivery date) is calculated (step Z3).

This priority coefficient is basically obtained as the quotient obtained by dividing the required remaining quantity (required quantity-the completed quantity up to the previous day) by the remaining producible days (delivery date-planning date).
As a specific example, it is calculated by the following equation 1. Formula 1 (remaining required quantity / remaining available production days) X (remaining input required quantity / remaining inputtable days) In the above expression 1, remaining input required quantity = (remaining required quantity)-(number of work-in-process scheduled to be completed by the delivery date) ) Remaining available days = (remaining production days)-(standard production days: construction period). Further, (remaining required quantity / remaining producible days) is the quantity that needs to be completed per day from the production formulation date (today) to the delivery date. The larger this value, the higher the urgency. Also, (required remaining quantity required / remaining available days)
Is the quantity that must be started (input) per day in order to quickly start production from the date of production formulation (today) and to meet the deadline, and the larger this is, the higher the urgency.
For production items in which any one of the above items is a negative item, the maximum value of other items or a predetermined priority coefficient excluded product treatment (priority coefficient 0) is applied.

In the scheduling section 5, the equipment having the largest coefficient is assigned to the ranked equipment and scheduling is performed (step Z4).

An evaluation index such as a facility operation rate and a production output when the production is performed according to the created schedule is calculated (step Z5).

The schedule evaluation information section 9 verifies whether or not the specified values of the specified evaluation functions are cleared, and determines whether or not to adopt the schedule proposal (step Z6).

The schedule proposal determined by the schedule verification unit 6 to be rejected is subject to restriction condition change unit 7
Rescheduling is performed after performing application change processing such as cutting the production quantity at a constant rate or delaying the delivery date in the order of the production items with the lowest priority coefficient (that is, low urgency or importance). ).

Hereinafter, the priority coefficient calculation step Z3 until the schedule proposal is adopted by the schedule verification unit 6.
The subsequent operation is performed similarly to the first time.

If there is no schedule plan to be adopted by the schedule verifying unit 6 even if all the application changing processes permitted by the constraint condition changing unit 7 are performed, the last schedule proposal is exceptionally adopted (step Z8). ).

The schedule plan adopted by the schedule plan verification unit 6 is output to the production plan output unit 10 and the process is terminated (step Z9).

[0039]

As described above, according to the automatic production plan formulation apparatus of claim 1, weak constraint conditions that can be selected when carrying out scheduling are defined by prioritizing, and at the same time, an indispensable strong condition. A scheduling constraint condition part that defines constraint conditions, a scheduling evaluation information part that defines a judgment criterion for determining whether or not to adopt a scheduling result, and necessary information from the reference information part and the process control information part based on the supply and demand plan. Equipped with an inference unit that automatically infers an appropriate production plan in a short time. The inference unit completes the production items managed by the process management information unit from the supply and demand plan input to the supply and demand plan input unit. Calculate the required production quantity in consideration of the actual number, calculate the factory allocation based on the standard information specified in the standard information section, and set it in the scheduling constraint section. The scheduling unit that automatically creates one schedule proposal according to the weak constraint condition and the strong constraint condition that are defined by the schedule, and whether the schedule plan created by the scheduling unit satisfies the criteria defined in the schedule evaluation information unit. If the schedule verification unit that verifies whether or not the schedule proposal does not satisfy the determination criterion, the weak constraint condition is applied in consideration of the priority defined by the scheduling constraint condition unit. Change
Since it has a constraint condition changing unit that causes the scheduling unit to perform rescheduling again under that condition, an appropriate production plan that corresponds to the frequently changed supply and demand plan,
It has the effect that it can be created automatically and in a short time without relying on specialists.

Further, according to the production planning method of claim 2, the production items are combined under all the weak restrictions defined in advance, and two allocations are not made to the same device at the same time. According to the strong constraint conditions of, the process of performing the scheduling to maximize the volume under those conditions and creating the schedule plan, and whether the schedule plan created in this way satisfies the predetermined judgment criteria. The process of verifying whether the schedule proposal is adopted or not, and the weak constraint conditions for the schedule proposal determined to be adopted or rejected are weighted for all conditions from the one with the lowest priority specified in advance. Steps that are canceled in the order of decreasing, and re-scheduling under that condition, and the above steps are automatically repeated until an acceptable schedule is obtained. As it is equipped with the 7th process, the expert knowledge can be ruled into constraint conditions and judgment criteria, and the optimization of the production plan can be automatically verified. Therefore, an appropriate production plan can be made by a person other than the expert in a short time. In addition to being easy to formulate, the production plan is formulated in consideration of the situation of the production factory, which has an effect of reducing unnecessary inventory in the factory.

Further, according to the production planning method of claim 3, a step of calculating a priority coefficient for each production item, and a step of allocating to the equipment of each factory in descending order of priority coefficient and scheduling , The process of calculating the evaluation index such as the capacity utilization rate and the production output when the production is carried out according to the schedule proposal created in this way, and the evaluation index of the created schedule proposal satisfies the predetermined evaluation condition. The process of verifying whether or not the schedule proposal is adopted, and for the schedule proposal determined to be not adopted, after performing the application change process of the weak constraint condition in the order of the production items having the smaller priority coefficient, the rescheduling is performed. And a step of automatically repeating the above steps until an employable schedule is obtained. Same effects as the effects obtained by the method of production planning claim 2 noted are those obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a production plan automatic formulation device according to an embodiment of the present invention.

FIG. 2 is a flow chart showing an automatic production planning method according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a production plan automatic decision method according to another embodiment of the present invention.

FIG. 4 is a block diagram showing a conventional production planning apparatus.

FIG. 5 is a flowchart showing a conventional production planning method.

[Explanation of symbols]

 1 Supply and Demand Planning Input Section 2 Standard Information Section 3 Process Management Information Section 4 Reasoning Section 5 Scheduling Section 6 Schedule Verification Section 7 Constraint Condition Change Section 8 Scheduling Constraint Condition Section 9 Schedule Evaluation Information Section 10 Production Plan Output Section

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[Procedure amendment]

[Submission date] February 1, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically prepares a minimum required production plan that meets the demand and supply plan from a state at a required time of a plurality of production plants capable of producing the required supply and demand plan in a short time. The present invention relates to an apparatus and a method for producing a production plan created in.

Claims (3)

[Claims] 1. A demand / supply plan input section for inputting a demand / supply plan for products, a production capacity of each factory for each production item, a non-defective rate, a construction period, designation by a priority of a production factory, and an operation date of each factory. A standard information section that manages information such as the prescribed factory calendar and setup changes, a process management information section that manages the number of completed daily records and the number of work in progress for each production item at each factory, and A weak constraint condition that can be selected is specified by prioritizing, a scheduling constraint condition part that defines an indispensable strong constraint condition, and a scheduling evaluation information part that defines a judgment criterion for deciding whether to adopt a scheduling result. , Based on the input information of the supply and demand plan input section, the necessary information is fetched from the standard information section and the process control information section to automatically make an appropriate production plan. An inference unit that infers in a short time, and a production plan output unit that outputs the schedule plan created by the inference unit, the inference unit, based on the supply and demand plan input to the supply and demand plan input unit, the process The required production quantity is calculated in consideration of the number of completed achievements for each production item managed in the management information section, and the factory allocation calculation is performed based on the standard information defined in the standard information section, and the scheduling constraint is set. The scheduling unit that automatically creates one schedule proposal according to the weak constraint condition and the strong constraint condition defined by the condition unit, and the schedule proposal created by the scheduling unit satisfies the criteria defined in the schedule evaluation information unit. A schedule verification unit that verifies whether or not the schedule plan is satisfied by the schedule verification unit. If it is determined not to do so, the application of the weak constraint condition is changed in consideration of the priority defined by the scheduling constraint condition unit, and the scheduling unit re-schedules under the condition again. A production planning apparatus having a condition changing unit. 2. A first step of inputting a supply and demand plan in which a required quantity and a delivery date are specified for each production item, and the number of completed achievements and work-in-progress for each production item are subtracted from the supply and demand plan to obtain a good product rate for each production item. Second, the production start date for each factory is derived by converting the in-process completion date based on the construction period for each production item.
Allocate the required monthly production quantity for each production item to each factory in consideration of the process, the predetermined priority of the production factory, and the production capacity equivalent to the number of production days from the production start date to the delivery date. Combine each process item with a process and all pre-defined, selectable weak constraints, and schedule according to the necessary and strong constraints to maximize yield under those conditions. A fourth step of executing and creating a schedule proposal, a fifth step of verifying whether the created schedule proposal satisfies a predetermined judgment criterion, and determining whether or not to adopt the schedule proposal; A sixth step of releasing the weak constraint conditions from the lower priority ones defined in advance for the determined schedule proposal, and performing rescheduling under the conditions; A seventh step of automatically repeating the above fourth to sixth steps until a possible schedule proposal is obtained, and when there is no applicable schedule proposal even if all the constraint conditions are released. A production plan formulation method comprising an eighth step for exceptionally adopting a schedule proposal in which all the constraint conditions are released and a ninth step for outputting the adopted schedule proposal and ending the processing. 3. A first step of inputting a supply and demand plan in which a required quantity and a delivery date are specified for each production item, and the number of completed achievements and the number of work-in-progress for each production item are subtracted from the supply and demand plan to obtain a good product rate for each production item. Second, the production start date for each factory is derived by converting the in-process completion date based on the construction period for each production item.
Processes, a third process for calculating the priority coefficient for each production item, a fourth process for assigning to the equipment of each factory in order from the one with the highest priority coefficient, and a schedule plan created in this way. Fifth step of calculating the evaluation index such as capacity utilization rate and production output in the case of normal production, and whether or not the evaluation index of the created schedule proposal satisfies the evaluation conditions specified in advance, and the schedule Sixth step of deciding whether or not to adopt the plan, and a seventh step of performing rescheduling after applying change processing of weak constraint conditions in the order of the production items having the smallest priority coefficient for the schedule plan judged to be not to be adopted. And an eighth step of automatically repeating the above fourth to seventh steps until an applicable schedule is obtained, and all applicable condition changing processes. If there is no schedule proposal that can be adopted even after applying the reason, it consists of a ninth step that exceptionally adopts the last schedule proposal and a tenth step that outputs the adopted schedule proposal and ends the process. Production planning method.