JPH0877278A - Method for stabilizing various activities accompanying production of material preparation schedule, process schedule, or the like against variation of production schedule - Google Patents

Abstract

PURPOSE: To make various activities, accompanying the production of the material preparation schedule, process schedule, etc., as stable as possible by providing a variation permissible range for absorbing variation of the material preparation schedule and process schedule accompanying variation of the product schedule of a product. CONSTITUTION: The volume of inventories in an ordering lead time period is calculated from the varying production schedule of the product, the preparation schedule for materials which are already ordered, and the process schedule, and compared with the 'variation permissible range of inventories' per day which is set by materials. Then when the daily volume of inventories is within the 'variation permissible range of the inventories' per day, the preparation schedule for the materials which are already ordered and the process schedule are unchanged. When the daily volume of inventories exceeds the 'variation permissible range of the inventories', on the other hand, the preparation schedule for the materials which are already ordered and the process schedule are varied on the day.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for stabilizing various activities associated with production, such as a material procurement plan and a process plan, against changes in the production plan, and particularly when the production plan changes. It relates to a method of stabilizing those activities as much as possible.

[0002]

2. Description of the Related Art Conventionally, in the manufacturing industry, in the production of products, first, a production plan is created, and in accordance with this production plan, necessary raw materials, parts, materials such as processed products are provided. It had to be procured and supplied to the production site. Therefore, conventionally, in order to supply the necessary materials, the material procurement plan has been prepared so that the materials can always be supplied systematically.

[0003] Conventionally, as a method of calculating a material requirement amount for creating this material procurement plan, a material requirement amount planning method (MRP = Material Requirmen) is used.
tsPlanning) was proposed.

However, in the above-mentioned conventional "material requirement calculation method", when the procurement plan for each material requirement is calculated, since there is no buffer function for absorbing fluctuations in the production plan, There was a problem that the material procurement plan had to be changed every time the plan changed.

This method will be illustrated below based on an actual example. Date 1 2 3 4 5 6 7 8 9 9 10 A production plan 11 12 13 14 15 A plan change + 3-2 X procurement plan 11 12 13 14 15 X change plan + 3-2 In the case of the above example, please explain. For simplicity, product A is X
It is assumed that it must be obtained one day before the day on which the two types of parts X and Y are used for producing the product A.

Then, only the part X is taken up.

The parts X do not have to be ordered in a batch.

However, the conventional “material procurement plan calculation method” has a problem that the material procurement plan must be changed in this way when the quantity of the product production plan increases or decreases.

Further, even if the timing of the product production plan changes, the material procurement plan also changes in the same manner.

Now, when the "time to use for production" is called the "necessary time", the "period necessary to obtain a few days before the required time" is referred to as the "chasing period". I will call it.

Among the conventional calculation methods, there is a function of calculating a material procurement plan by performing a retroactive calculation of a "follow-up period" with respect to a "required time".

However, in the conventional "material procurement plan calculation method", since it is handled uniformly, if the time of the production plan of the product changes, the time of the material procurement plan must be changed accordingly. There was a problem.

An example of this is as follows. Date 1 2 3 4 5 6 7 8 9 9 10 A production plan 11 12 13 ← 13 14 → 14 15 A plan change X procurement plan 11 12 13 ← 13 14 → 14 15 X change plan Next, conventional Among the calculation methods, there is the concept of "safety stock", and a "procurement plan for material requirements" that always secures the set "safety stock" was calculated.

At this time, the "leading stock" in the procurement plan calculation period
And "safety stock" were compared, and the quantity of the material procurement plan was adjusted so as to approach "safety stock", and the material procurement plan was calculated.

This method will be illustrated below based on an actual example. Date 1 2 3 4 5 6 7 8 9 9 10 A production plan 11 12 13 14 15 X required quantity 11 12 13 14 15 X procurement plan 13 12 13 14 15 X initial inventory = 8 and X inventory quantity 10 10 10 10 10 10 10 10 10 10 10 In the above example, the “safety stock” of the part X is 10,
If the "initial stock" is 8, adjust the material procurement quantity by +2 minutes with respect to the required quantity of the product X so that the stock of the product X becomes "safety stock" on the first day. To calculate.

In the conventional calculation method, the material procurement plan is always calculated so that the stock of the material is always "safe stock".

Therefore, there is still a problem that the material procurement plan must be changed every time the production plan changes, as in the above-described embodiment.

"Procurement plan for material requirements" in the above description
Can be referred to in the same manner even in the process plans of various processing steps after the material is procured, and there is a problem that the material procurement plan must be changed due to the change in the production plan.

As a result of this, in the case of the conventional method,
There is a problem in that it is difficult to change the production plan of the product and it is difficult to quickly respond to changes in demand.

[0020]

In view of the problems of the prior art, the main object of the present invention is to provide a material procurement plan for arranging materials such as raw materials and parts and a process plan for arranging processing steps. Even if the production plan of the product changes when various activities associated with production are performed, the various activities associated with production such as the material procurement plan and process plan are stabilized as much as possible. Is to provide a method that can.

[0021]

According to the present invention, such an object is to produce a material procurement plan and a product for arranging materials such as raw materials and parts necessary for producing a product. When carrying out various activities associated with production, such as a process plan for arranging each processing process required for the product, set a permissible range for fluctuations in the materials and processes, and make a production plan for the product after arranging the materials and processes. In the case of fluctuations, if the fluctuations that affect the materials and processes due to the fluctuations fall within the allowable range of fluctuations above, leave the material procurement plans and process plans that have already been arranged unchanged. This is achieved by providing a method for stabilizing various activities associated with production such as a characteristic material procurement plan and process plan against fluctuations in the production plan.

[0022]

According to the present invention, the calculation is performed by providing a "variable allowable range" (buffer) that absorbs the variation of the material procurement plan and the process plan due to the variation of the production plan of the product.

In the present invention, two types of fluctuation allowable ranges are provided.

One is a fluctuation allowable range for inventory.

This is to set a reference value such as a minimum inventory amount (minimum retained inventory amount) and a maximum inventory amount (allowable maximum inventory amount) for each material, and if the inventory of the material is more than the minimum inventory amount every day during the calculation period. Yes If it is less than the maximum inventory quantity, do not change the material procurement plan already arranged.

When the intermediate processing step is completed and the state before being used for the next step is called "work-in-process inventory", "work-in-process inventory" is calculated even in the process plan of the intermediate processing step. If it is within the range of the minimum inventory amount and the maximum inventory amount every day during the period, the process plan already arranged will not be changed.

The second is a fluctuation allowable range for the "follow-up period".

This is the "follow-up period before arrangement" for each material.
And "the follow-up period after arrangement" and two "follow-up periods"
To provide.

The "follow-up period after arrangement" is a net (minimum) necessary "follow-up period" with respect to the required period.

Further, the "follow-up period before arrangement" is a "follow-up period" which is larger than the "follow-up period after arrangement" by an allowable range.

Therefore, when arranging a material procurement plan or a process plan, a follow-up calculation should be made with a margin for the allowable range.

At this time, even if the production plan of the product is moved forward after the arrangement, if the advance is within the allowable range, the material procurement plan is not changed.

As described above, the present invention is a method for stabilizing an arranged material procurement plan or process plan against fluctuations in the product production plan.

Next, the operation of these two allowable fluctuation ranges will be described.

First, the effect of the fluctuation allowable range on the inventory will be described.

First, when the production plan of the product fluctuates and the production amount decreases after the material procurement plan and the process plan have already been arranged, the stock of materials and work-in-progress increases but the maximum stock is not exceeded. Does not change the already-procured material procurement plan or process plan.

This is because these materials and work-in-process may be used for the next production, and the stock may temporarily increase.

Next, when the production plan of the product fluctuates and the production amount increases, the stock of materials and work-in-process decreases, but if the stock does not fall below the minimum stock, the already-procured material procurement plan or process plan is used. No need to change.

In this way, even if the production plan of the product fluctuates and the production amount fluctuates, if it is within the fluctuation allowable range, the already-procured material procurement plan or process plan cannot be changed.

Next, the operation of the fluctuation allowable range with respect to the "follow-up period" will be described.

First, after the material procurement plan and the process plan are already arranged, even if the production plan of the product fluctuates and the production time fluctuates, if it goes back, there will be almost no problem. Do not change the arranged material procurement plan or process plan.

This is because the stock of materials and work-in-process is only temporarily increased, and it is only necessary to use it later.

Next, when the production plan of the product fluctuates and the production period is advanced, it is necessary to plan the procurement period of the material and the process schedule.

However, according to the present invention, since the follow-up calculation is made in advance with a margin for the follow-up period before the arrangement at the time of arrangement,
If the advancing time of the production time of the product production plan is equal to or less than the fluctuation allowable range (margin period), the material procurement plan or process plan already arranged is not changed.

In this way, the present invention provides two types of allowable fluctuation ranges, the allowable fluctuation range for the stock and the allowable fluctuation range for the "follow-up period", and after arranging the material procurement plan and the process plan, Even if the production plan fluctuates, if it is within the allowable range, the material procurement plan and the process plan are stabilized by using the calculation method that does not change the material procurement plan and the process plan.

[0046]

Next, the first embodiment of the present invention will be described in detail.

That is, the present invention is a method for stabilizing various activities associated with production such as a material procurement plan and a process plan against fluctuations in the production plan.

In the manufacturing industry, when a product (product) is produced in accordance with a product production plan, raw materials and parts necessary for producing the product are always supplied to the production site without excess or deficiency. Therefore, it is required to procure raw materials and parts necessary for producing the product in a timely manner.

At this time, a predetermined period of time called "order lead time" is required from the time when the raw materials and parts are ordered to the time when they are actually obtained.

However, the production plan of the product may change during the "ordering lead time".

The factors that change the production plan of the product are as follows. (1) New order from a new customer. (2) Advance shipment time from customers. (3) Strong sales results. (4) Fluctuations in shipping.

When the production plan of such a product fluctuates, it is necessary to deal with it in a timely manner. (1) Miss sales opportunities. (2) We cannot meet customer requirements. (3) Efficient production cannot be achieved.

Therefore, when the production plan of the product changes, it is necessary to timely procure raw materials and parts necessary for the production of the product.

In this case, according to the present invention, a material procurement plan for arranging materials such as raw materials and parts necessary for producing the product and arrangement of each processing step necessary for producing the product When performing various activities associated with production such as a process plan, etc., when a "variable allowance range" is set for the material or process and the production plan of the product changes after arranging the material or process, Changes caused by changes in materials and processes,
If it falls within the "variable allowable range", the already-arranged material procurement plan and process plan are left unchanged, so that the complexity of the process and the adverse effects of the change are avoided. Of.

Further, in the present invention, even if the production plan of the product fluctuates, even if the fluctuation causes changes in materials, processes and the like to exceed the above "variable allowable range",
When the production volume decreases or the production period is delayed, the materials and components can be used for the next production, so the arranged material procurement plan and process plan can be left unchanged. By doing so, the complexity of the paperwork is avoided and the labor is saved.

When the production plan of the product fluctuates, and the fluctuation causes changes in materials, processes, etc. to exceed the above "variable allowable range", the production amount increases or the production time is If it is carried forward, it is necessary to consider the need to change the material procurement plan, process plan, etc. that have been arranged for the first time.

That is, for production of a material procurement plan for arranging materials such as raw materials and parts necessary for producing a product, and a process plan for arranging each processing step required for producing a product. When carrying out various activities that accompany it, the production plan of the product fluctuates, compared to the already-procured material procurement plan and process plan,
It is necessary to change "when the production volume increases" or "when the production period is advanced" compared to the arranged material procurement plan or process plan, the arranged material procurement plan or process plan, etc. Will be considered.

At this time, in the present invention, a "variation allowable range" (buffer) is provided to absorb the variation of the material procurement plan and the process plan due to the variation of the production plan of the product.

In the present invention, two types of "variable allowable ranges" are provided.

One is "variable allowable range (allowable stock amount) with respect to stock".

For this purpose, reference values such as "minimum stock amount (minimum holding stock amount)" and "maximum stock amount (allowable maximum stock amount)" are set for each material, and "stock amount of material" is "predetermined period". "Every day in" is greater than or equal to "Minimum inventory" and "Maximum inventory"
In the following cases, do not change the material procurement plan already arranged.

Further, when the state before the intermediate processing step is completed and used in the next step is called "work-in-process inventory", the "work-in-process inventory" is "in-process inventory" in the process plan of the intermediate processing step. If it is within the range of "minimum inventory amount" and "maximum inventory amount" for "every day in a predetermined period", the already arranged process plan is not changed.

As described above, the "allowable stock amount" which is the "range between the minimum stock amount and the maximum stock amount" becomes the "variable allowable range for the stock".

The second variation allowable range is the "variation allowable range (margin period) for the follow-up period".

In the case of material procurement, this "follow-up period" is "a period in which the time when the material is obtained is traced back from the time when the material is produced."
Therefore, in the process arrangement, it is a "period in which the processing time is traced back from the production time" and is provided for each material and each process.

[Performance period before arrangement] for each material
And "the follow-up period after arrangement" and two "follow-up periods"
To provide.

The "follow-up period after arrangement" is a net (minimum) necessary "follow-up period" with respect to the required period.

Further, the “follow-up period before arrangement” is a “follow-up period” which is larger than the “follow-up period after arrangement” by “allowable range (margin period)”.

Therefore, when arranging a material procurement plan or a process plan, the “follow-up period” is calculated with a margin of “variable allowable range (margin period) with respect to the follow-up period”.

At this time, even if the production plan of the product is moved forward after the arrangement, if the advance is within the allowable range, the material procurement plan is not changed.

Next, the operation of this "variable allowable range (allowable stock amount) with respect to inventory" will be described.

At this time, according to the changed production plan,
If the production volume increases or decreases compared to the material procurement plan or process plan that has already been arranged, change the "allowable inventory amount", which is the range between the "minimum inventory amount" and the "maximum inventory amount", to "variation with respect to inventory". If the production plan of the product fluctuates, it is possible to deal with it by setting it as `` tolerance range '' and keep it as much as possible without changing the arranged material procurement plan or process plan. The various activities associated with production, such as process plans and process plans, are stabilized as much as possible, and the complication of processing due to those changes and the harmful effects due to the changes are avoided.

That is, in the case where the production plan of a product fluctuates after arranging materials, processes, etc., when the change given to the materials, processes, etc. exceeds the above “variable allowable range”, the production amount is When increasing or decreasing, do not change the material procurement plan or process plan that has already been arranged immediately. (1) First, the minimum inventory amount of materials and processes that should be kept and the maximum inventory amount The "maximum inventory amount", which is the limited inventory amount, is provided for each daily material and each process. (2) Next, the "allowable inventory amount", which is a range between the "minimum inventory amount" and the "maximum inventory amount", is set as the "variable allowable range". (3) Then, if the increasing / decreasing production amount is within the "allowable stock amount" which is the "variable allowable range", the arranged material procurement plan and process plan are left unchanged. . (4) Further, when the increasing / decreasing production amount exceeds the range of the "allowable stock amount" which is the "variable allowable range", the arranged material procurement plan, process plan, etc. are changed. (5) Next, if the material exceeds the "allowable stock" range, which is the "variable allowance", and if it falls below the "minimum stock quantity", materials that have already been arranged to secure the "minimum stock quantity". Increase the number of procurement plans and process plans. (6) Next, if the material exceeds the "allowable stock" range, which is the "variable allowance", and if it exceeds the "maximum stock quantity," the materials that have already been arranged to secure the "maximum stock quantity" Either reduce the number of arrangements such as procurement plans or process plans, or cancel the arrangements.

By doing so, various activities associated with the production such as the material procurement plan and the process plan are stabilized against the fluctuation of the production plan.

Next, the operation of the "permissible fluctuation range (margin period) with respect to the follow-up period" will be described.

At this time, according to the changed production plan,
When the production period is advanced earlier than the arranged material procurement plan or process plan, it is uniquely dealt with by setting multiple "chase period", and the production plan of the product changes Even if there is, the existing material procurement plan and process plan are left unchanged as much as possible, and the labor of having an extra inventory is saved, and the adverse effects of increasing inventory are avoided and the procurement of those materials The various activities associated with production, such as plans and process plans, are stabilized as much as possible, and the complexity of the processing associated with those changes and the adverse effects associated with the changes are avoided.

That is, in the case where the production plan of a product fluctuates after arranging materials, processes, etc., and when the production period is advanced, immediately without changing the arranged material procurement plan, process plan, etc. (1) First, an appropriate “follow-up period” according to various activities involved in production (in the case of material procurement, it is “a period in which the point of time when the material was obtained is traced back from the point of production”) "Is a period in which the processing time is traced back from the production time") is provided for each material and each process. (2) Next, this "follow-up period" is the net necessary follow-up period, "the post-arrangement follow-up period".
Or a "follow-up period before arrangement", which is a larger follow-up period for the "allowable range" than the "follow-up period after arrangement".
Provide multiple. (3) Subsequently, the "margin period", which is the difference between the "follow-up period before arrangement" and the "follow-up period after arrangement", is defined as the "variable allowable range". (4) Furthermore, if the period in which the production period is moved forward is within the "margin period" which is the "variable allowance range" above, the arranged material procurement plan, process plan, etc. will not be changed. And (5) Next, if the period in which the production period is advanced earlier exceeds the "margin period", which is the "variable allowance" above, consider changes to the material procurement plan or process plan that has already been arranged. To do.

Furthermore, if the period in which the production period is advanced earlier exceeds the range of the "margin period" which is the "variable allowance range", the arranged material procurement plan or process plan should be immediately changed. No, (1) First, by further providing a “catch-up period in case of emergency” that is shorter than the “catch-up period after arrangement”, the “catch-up period” is further increased by one. (2) Next, the period during which the production period is moved forward is the "maximum margin period" which is the "variable allowable range" which is the difference between the "follow-up period before arrangement" and the "follow-up period in case of emergency". If it is within the range of “”, the material procurement plan and process plan that have already been arranged will remain unchanged. (3) Furthermore, the period during which the production period is moved forward is the "maximum margin period" which is the "variable allowance range", which is the difference between the "follow-up period before arrangement" and the "follow-up period in case of emergency". If it exceeds the range of “”, the arranged material procurement plan and process plan are changed.

By doing so, various activities associated with production, such as the material procurement plan and the process plan, are stabilized against variations in the production plan.

In practice, these processes are calculated at once for several thousand to tens of thousands of parts, raw materials, etc., so that there is a case where the procurement plan fluctuates more than necessary as in the past, and a case where the procurement plan changes to the minimum required. There is a very large difference between the case where only the fluctuation of is calculated and the calculation is performed.

When the amount of data becomes large, it becomes impossible to check manually as a daily work, and in reality, materials are procured as calculated by the computer system.

On the contrary, if it cannot be done, there is no point in using the computer system.

Considering from the viewpoint of actual business, much less can be easily changed in the procurement of the material itself. Therefore, the conventional calculation method in which the procurement plan is changed more than necessary and the minimum required location. With the calculation method of the present invention in which only the change is made, it becomes clear how large the difference is.

The present invention will be described in detail below with reference to the drawings for specific embodiments.

FIG. 3 is a diagram for explaining the movement of the material procurement plan and the process plan in time series, and is a graph showing the inventory of work in progress of a certain specific material or process. That is, first, today, the order lead time ahead (t1) is arranged.

At this time, the number of arrangements is calculated and arrangements are made so as to satisfy the set standard stock.

Within the already arranged period (from t0 to t1), even if the production plan of the product fluctuates and the inventory of the material and work-in-process varies, the "minimum inventory amount" and the "maximum inventory amount" are "Allowable inventory", which is the range between
Then, if it is within the range of the "allowable stock amount" that is the "variable allowable range", the material procurement plan and process plan already arranged are not changed.

However, the production plan of the product varies greatly, and only when the production plan exceeds this range, the already-procured material procurement plan or process plan is changed.

In the next embodiment, the production plan of the product, the material procurement plan and the process plan, and the inventory thereof are displayed.

In the case of this embodiment, in order to simplify the explanation, the product A is made up of two kinds of parts, X and Y.
It suffices to obtain the same kind of parts X and Y used for producing the product A on the same day, but only X will be taken up.

Further, it is assumed that X does not have to be ordered in a lot.

In this case, the standard stock is 5, the minimum stock is 1,
The maximum inventory is 1,000. Schedule 1 2 3 4 5 6 7 8 9 9 10 Production plan for product A 5 3 1 1 0 3 5 2 0 2 4 Procurement plan for parts X 5 3 1 0 3 5 2 2 0 2 4 Inventory for parts X 8 8 8 8 8 8 8 8 8 8 8 Here, it is assumed that arrangements such as material procurement have already been completed by the 7th.

Next, the production plan of the product A is changed by +5 on the 3rd day and by -2 on the 6th day depending on the demand trend. Then
In the present invention, the material procurement plan is calculated as follows. Schedule 1 2 3 4 5 6 7 8 9 10 10 + 5-1 for product A 5 3 6 0 3 4 4 2 0 2 4 Parts X procurement plan 5 3 3 1 0 3 5 2 1 2 4 4 Parts X inventory 8 8 8 3 3 3 4 4 5 5 5 In this calculation example, the stock of X decreases because the required number of products A has increased on the 3rd, but it is not below the minimum stock quantity, so 3
The daily material procurement plan will not be changed.

Also, since the required number of product A decreased on the 6th,
The inventory of X increased by 1 compared to 5th, but since it does not exceed the maximum inventory, the material procurement plan on 6th will not be changed.

Further, by 7th, since the arrangement has already been completed, the inventory is below the standard inventory, but the material procurement plan and the process plan are not changed.

However, since the 8th is the time when no arrangement is made yet, the material procurement plan is calculated so as to become the standard stock, and the arrangement of 1 is made in this case.

That is, in the present invention, even if the production plan of the product fluctuates, the production amount may decrease or the production period may be delayed as compared with the arranged material procurement plan or process plan. In this case, do not change the arranged material procurement plan, process plan, etc. as they are, avoiding the complexity of clerical work and saving labor, compared to the arranged material procurement plan or process plan. Then, when the production volume increases, it is considered to change the contents of various activities associated with the production such as the material procurement plan and the process plan.

That is, if the production plan of the product changes after the material procurement plan or the process plan is arranged, immediately, without changing the arranged material procurement plan or the process plan, (1) The daily stock quantity within the order lead time period (from t0 to t1) is calculated from the production plan of the manufactured product and the already-arranged material procurement plan and process plan. (2) Next, the stock amount is compared with the “permissible fluctuation range with respect to the stock” per day set for each material. (3) Then, if the daily stock amount falls within the above-mentioned "permissible fluctuation range for stock" per day, the material procurement plan and process plan already arranged are left unchanged. (4) On the other hand, when the daily stock quantity exceeds the above-mentioned “permissible fluctuation range for stock” per day, the material procurement plan or process plan already arranged is changed for that day.

In this case, "allowable fluctuation range for stock"
The term "allowable stock amount", which is a range between the "minimum stock amount (minimum holding stock amount)" and the "maximum stock amount (allowable maximum stock amount)", means the "minimum stock amount (minimum stock amount)". If the quantity is less than the “holding stock amount”, the quantity of the material procurement plan or process plan that has already been arranged is increased to make an additional arrangement.

When the "maximum inventory amount (allowable maximum inventory amount)" is exceeded, the arrangement (order) that exceeds the above is canceled or the arrangement (order) is changed.

A flowchart of this method is shown in FIG.
As shown in.

However, this flowchart describes the processing after the necessary plan for a certain material or process is calculated, as in the above calculation example.

Next, the permissible range of the “chasing period” of the present invention will be described in detail with reference to its examples.

In the case of the present embodiment, in order to simplify the explanation, the product A is made by processing the material Z. Material Z
Should be obtained one day before the processing of the product A is started. In this case, the “tracking period” after the arrangement of the present invention is 1.

At this time, assuming that the fluctuation allowable range of the "follow-up period" is 2 days, the "follow-up period" before arrangement is 3 days.

Further, the order lead time is set to 10 days in the following description. Schedule 1 2 3 4 5 6 7 8 8 9 10 11 12 12 13 10 pieces of product A Production plan Pursuit period before parts Z is arranged = 3 days Procurement plan 10 pieces This method plans to produce product A on the 13th And there is a material Z procurement plan in accordance with the above. For simplification of the explanation, let us consider a case where there is no inventory and lots are not grouped.

Since the order lead time for the material Z is 10 days, 10 pieces of the material Z are ordered (arranged) with the specified delivery date of 10 days per day.

Next, at the time when today is the 4th, it is assumed that what was planned to be produced on the 13th is moved up by 2 days to produce on the 11th. Schedule 1 2 3 4 5 6 7 8 8 9 10 11 12 13 13 Product A 10 ← 10 pcs Production plan 10 parts Z ← 10 pcs Procurement plan × In this calculation example, the product plan is advanced 10 days before Only when it changes, the procurement plan of material Z is changed. This is because it corresponds to the case where it exceeds two days which is the “allowable range of fluctuation” of the “tracking period”.

However, if the setting of the “urgent follow-up period” is set to 0 days, it is not necessary to give an instruction to advance the material Z even if it is advanced to 10 days.

According to the present invention, when the production period is advanced by the changed production plan as compared with the arranged material procurement plan or process plan, the "follow-up period" is uniquely set. It is dealt with by providing a plurality of.

That is, in the case where the production plan of a product fluctuates after arranging materials, processes, etc., and when the production time is advanced, immediately without changing the arranged material procurement plan, process plan, etc. (1) First, an appropriate “track-up period” is set for each material and each process. (2) Next, the "follow-up period" is a net necessary follow-up period "after-arrangement follow-up period" and a "permissible range" larger follow-up period "before-arrangement follow-up period". Period ", etc.
Provide multiple. (3) Subsequently, the "margin period" which is the difference between the "follow-up period before arrangement" and the "follow-up period after arrangement" is defined as the "variable allowance range". (4) Furthermore, if the period in which the production period is moved forward is within the “margin period” which is the “variable allowance range”, the arranged material procurement plan, process plan, etc. are left unchanged. To do. (5) Next, if the period in which the production period is moved forward exceeds the “margin period”, which is the “variable allowance”, change the arranged material procurement plan, process plan, etc. for the first time. In consideration of the above, in this case as well, by setting an "emergency follow-up period" that is shorter than the above "post-arrangement follow-up period", the arranged material procurement plan, process plan, etc. can be changed as much as possible. By leaving it as it is, various activities associated with production, such as material procurement plans and process plans, are stabilized against changes in production plans.

A flowchart of this method is shown in FIG.
As shown in.

[0113]

As described above, according to the present invention, a material procurement plan for arranging materials such as raw materials and parts necessary for producing a product and each processing step required for producing a product Even if the production plan of the product changes after making the arrangements of materials and processes when carrying out various activities associated with production, such as process planning, such fluctuations may occur for each material or process. Within the set "variable allowance", do not change the arranged material procurement plan or process plan, and change only those whose fluctuation exceeds the "variable allowance" set for each material or process. Even if it exceeds the "variable allowance range", if the production period is delayed or the production quantity decreases, keep it as much as possible and stabilize those activities as much as possible. It is the one to try.

Therefore, there are the following excellent effects. (1) Even if the production plan of the product is changed, it does not affect the arranged material procurement plan or process plan, so that the production plan can be easily changed as a result of not causing confusion. Like

Therefore, the production plan of the product can be changed according to the fluctuation of the demand, and the product can be supplied in a timely manner according to the demand without having the product inventory. As a result, there is an advantage that the money does not need to be spent unnecessarily, the inventory interest rate can be held down to a small amount, and the deterioration of products that occur during the inventory period can be prevented. (2) Being able to change the production plan of a product will not let you miss a sales opportunity due to a product being out of stock, which will increase sales and profit, and as a result you can change the production plan of a product without confusion at the production site. It has a very large effect on the aspect. (3) Since the production plan of the product can be changed without changing the arrangement of the many parts and materials necessary for producing the product or the many processing steps as much as possible, the material procurement plan and the process. There is an advantage that stable production can be achieved by avoiding the diffusion of problems in production activities and the difficulty of management that accompany changes in plans, enabling proper management by focusing on problem areas. (4) It is not necessary to change the material procurement plan and the process plan every time when the production plan of the product after the arrangement is changed, unlike the conventional method. Therefore, there is a problem that a material or a process that cannot follow the change occurs. In addition, since the feasibility of the plan is unknown at the time of making the plan, problems such as problems that make the ordering company unmotivated for the production activity are solved, and the motivation for the production activity accompanying the change of the production plan of the product There is an advantage that the decrease of (5) The method of the present invention is actually performed using a computer and calculates a plan for a large number of parts and processes at one time.
Since it is possible to deal with the fluctuation of the production plan of the product while isolating the problem according to a certain rule, there is a great advantage that complexity of the office work is eliminated. (6) Since extra paperwork is eliminated, there is an advantage that the office work efficiency is improved. (7) Since it is possible to cope with the advance of the production period without having an extra inventory, there is an advantage that the adverse effects due to the increase in inventory can be eliminated.

[Brief description of drawings]

FIG. 1 is a method for providing an “allowable range of inventory fluctuation” among methods for stabilizing various activities associated with production such as a material procurement plan and a process plan according to an embodiment of the present invention against variations in a production plan. It is a flowchart showing.

FIG. 2 shows a method of providing a plurality of “follow-up periods” among the methods for stabilizing various activities associated with production such as a material procurement plan and a process plan according to an embodiment of the present invention against variations in the production plan. It is a flowchart shown.

[Fig. 3] Fig. 3 shows a time series of a material procurement plan and a process plan in a method for stabilizing various activities associated with production such as a material procurement plan and a process plan according to an embodiment of the present invention against variations in the production plan. It is a graphic representation of the inventory of in-process inventory of specific materials or processes.

Claims (6)

[Claims] 1. A material procurement plan for arranging materials such as raw materials and parts necessary for producing a product, and a process plan for arranging each processing step necessary for producing a product. When carrying out various activities that accompany it, if there is a "variable allowance" for the materials and processes, and the production plan of the product changes after the materials and processes are arranged, the changes will be given to the materials and processes. If the change is within the above-mentioned "variable tolerance range", the material procurement plan or process plan, etc., characterized in that the arranged material procurement plan or process plan is left unchanged. A method for stabilizing various activities associated with production against fluctuations in production plans. 2. When the production plan of a product fluctuates after arranging materials, processes, etc., the amount of production is increased even if the fluctuation causes changes in the materials, processes, etc., above the "variable allowable range". In the case where the number of products is reduced or the production period is delayed, the already arranged material procurement plan, process plan, etc. are left unchanged.
A method to stabilize various activities associated with production such as the stated material procurement plan and process plan against fluctuations in the production plan. 3. When the production plan of a product fluctuates after arranging materials, processes, etc., and if the fluctuations in the materials, processes, etc. exceed the above "variable allowable range", the production volume The production of the material procurement plan or the process plan according to claim 1, wherein the arranged material procurement plan, the process plan, or the like is changed when the production time increases or when the production period is advanced. A method for stabilizing the accompanying activities against changes in production plans. 4. When the production plan of a product fluctuates after arranging materials, processes, etc., and when the change caused in the materials, processes, etc. exceeds the above "variable allowable range", the production amount is When increasing or decreasing, do not change the material procurement plan or process plan that has already been arranged immediately. (1) First, the minimum inventory amount of materials and processes that should be kept and the maximum inventory amount The "maximum inventory amount", which is the limited inventory amount, is provided for each daily material and each process. (2) Next, the “allowable inventory amount”, which is a range between the “minimum inventory amount” and the “maximum inventory amount”, is set as the “variable allowable range”. (3) Then, if the increasing / decreasing production amount is within the "allowable stock amount" which is the "variable allowable range", the arranged material procurement plan and process plan are left unchanged. . (4) Further, when the increasing / decreasing production amount exceeds the range of the "allowable stock amount" which is the "variable allowable range", the arranged material procurement plan, process plan, etc. are changed. (5) Next, if the material exceeds the "allowable stock" range, which is the "variable allowance", and if it falls below the "minimum stock quantity", materials that have already been arranged to secure the "minimum stock quantity". Increase the number of procurement plans and process plans. (6) Next, if the material exceeds the "allowable stock" range, which is the "variable allowance", and if it exceeds the "maximum stock quantity," the materials that have already been arranged to secure the "maximum stock quantity" Reduce the number of procurement plans or process plans, or cancel the order. A method for stabilizing various activities associated with production such as a material procurement plan and a process plan according to claim 1 against variations in the production plan. [Claim 5] When the production plan of a product fluctuates after arranging materials and processes, and when the production period is advanced, immediately without changing the arranged material procurement plan or process plan, (1) First, an appropriate “follow-up period” according to various activities involved in production (in the case of material procurement, it is “a period in which the point of time when the material was obtained is traced back from the point of production”) "Is a period in which the processing time is traced back from the production time") is provided for each material and each process. (2) Next, this "follow-up period" is the net necessary follow-up period, "the post-arrangement follow-up period".
Or a "follow-up period before arrangement", which is a larger follow-up period for the "allowable range" than the "follow-up period after arrangement".
Provide multiple. (3) Subsequently, the "margin period", which is the difference between the "follow-up period before arrangement" and the "follow-up period after arrangement", is defined as the "variable allowable range". (4) Furthermore, if the period in which the production period is moved forward is within the "margin period" which is the "variable allowance range" above, the arranged material procurement plan, process plan, etc. will not be changed. And (5) Next, if the period in which the production period is advanced earlier exceeds the "margin period", which is the "variable allowance" above, consider changes to the material procurement plan or process plan that has already been arranged. To do. A method for stabilizing various activities associated with production such as a material procurement plan and a process plan according to claim 1 against variations in the production plan. 6. When the production period is advanced earlier than the "margin period", which is the "variable allowance", the material procurement plan or process plan that has already been arranged should be changed immediately. No, (1) First, by further providing a “catch-up period in case of emergency” that is shorter than the “catch-up period after arrangement”, the “catch-up period” is further increased by one. (2) Next, the period during which the production period is moved forward is the "maximum margin period" which is the "variable allowable range" which is the difference between the "follow-up period before arrangement" and the "follow-up period in case of emergency". If it is within the range of “”, the material procurement plan and process plan that have already been arranged will remain unchanged. (3) Furthermore, the period during which the production period is moved forward is the "maximum margin period" which is the "variable allowance range", which is the difference between the "follow-up period before arrangement" and the "follow-up period in case of emergency". If it exceeds the range of “”, change the arranged material procurement plan or process plan. A method for stabilizing various activities associated with production such as a material procurement plan and a process plan according to claim 5 against variations in the production plan.