JP2007279998A - Inventory balance simulation system of type taking change to prior plan into account - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for calculating a highly accurate inventory balance by taking into account such a business characteristic as periodic corrections to a sales plan and a parts procurement plan. <P>SOLUTION: When a computer forwards to the future a point of time that serves as a starting point for MRP calculations, it also changes the time of a parts procurement plan/a product sales plan. Once the time is forwarded to the future, the number of parts stocked is calculated from the new plan on an as-needed basis to calculate a future inventory. A plurality of parts procurement plans and/or product sales plans reflecting possible future plan changes are prepared. Using the plans, an inventory balance that takes into account plan discrepancies caused by future plan changes is calculated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a simulation method, a system, a program, and a storage medium for calculating a previous inventory balance using a plurality of plans that differ from time to time.

  There is a material planning method called MRP (Material Requirements Planning) that was proposed in the United States in the 1970s and whose application range has expanded in recent years. In MRP calculation, necessary items (items) for parts, raw materials, etc. are required when necessary (delivery date) based on the planned product level production plan (hereinafter referred to as MPS). An arrangement plan for purchasing or manufacturing as much (required amount) as possible is calculated. Specifically, by subtracting the lead time of each process from the product delivery date (product level production plan), the required time and quantity (items at the process level) for items such as parts and raw materials Plan). In this MRP calculation, normally, three types of information of MPS data, a bill of materials, and inventory / remaining data are required.

  MPS data is generally the production of items at the top level (that is, the final product) in the part development diagram that shows the relationship between the parts that make up the product basically in accordance with the manufacturing procedure. This is data indicating the plan (how many products will be required by when). MPS is also called a standard production plan.

  The bill of materials usually consists of two master data, “item data” and “product configuration data”. The item data is a table including information peculiar to the item such as a time required for manufacturing or purchasing the part (hereinafter referred to as a lead time). The product configuration data indicates the relationship between items such as products and parts, parts and parts, and parts and raw materials. Specifically, a certain item (referred to as a parent item) and the production of the parent item. Necessary parts (referred to as child items because they are subordinate parts to the parent item) and the number of child items required to produce one parent item (this is the number of child items) Information).

  The inventory / remaining data is data indicating the current inventory and the number of work in progress for each item, or the delivery date and planned number (order information) that have already been ordered and will be delivered in the future.

In the MRP calculation, the following five types of calculations are performed for each item based on these pieces of information.
(1) Total requirement calculation The requirement data of the processing target item is read, the requested amount is compiled by period, and the total requirement by period is calculated. Hereinafter, in order to simplify the description, a case where the period is one day, that is, a case of daily planning will be described.
(2) Net requirement calculation Based on the calculated total requirement, reserves are made for inventory and backlog, and the actual required amount, that is, net requirement, is subtracted daily by subtracting inventory and backlog. calculate.
(3) Lot Summary Based on the calculated daily net requirements, the lots are summed up using the lot size set for the item.
(4) Start date calculation The lead time is subtracted from the delivery date of the quantity of lots, and the order date or start date is calculated to create an order.
(5) Requirement expansion Expand the created order to the subordinate items using the BOM. Specifically, using the day before the start date of the order as the request date, the required amount of each child item is calculated based on the number of child items and the number of child items required for one parent item in the product configuration data.

By performing the processes (1) to (5), a plan for one item is made. Hereinafter, these processes will be collectively referred to as component expansion calculation. MRP calculation refers to all the products set by MPS, from the highest item registered in the BOM to the lowest item in order for all items required for manufacturing the product. This is a calculation process for performing part development calculation (MRP development).
In the conventional inventory simulator, for the purpose of early measures against surplus inventory and the prevention of shortage, this MRP is used to calculate the inbound and outbound quantities of each material at a predetermined time in the future, and calculate the inventories at each time point. (See Patent Document 1).

  In addition, Patent Document 2 describes the MRP using a sales forecast plan instead of a product sales record in order to accurately estimate inventories etc. even if the parts procurement plan and the product sales record differ. Other inventory balance simulation systems are shown that have the characteristics of performing development, obtaining the amount of goods received and delivered based on the initial stock quantity at a required future time point, and calculating the stock quantity at the end of the period.

JP-A-11-306252 JP 2004-161437 A

  However, as mentioned above, it is not sufficient to calculate a high-accuracy inventory balance by using only two types of plans: a parts procurement plan and a product sales forecast plan. This is because the sales prospect plan and the parts procurement plan are regularly revised by the planner's planning work. In other words, the current sales forecast plan and the sales forecast plan after one month are often not exactly the same. It is common to re-plan sales prospects and procurement plans by using actual shipment status for one month and adding differences in sales prospects and procurement plans to the plan for the next month.

  Therefore, the present invention predicts and prepares a plurality of parts procurement plans and product sales forecast plans that will be re-planned in advance based on the above-mentioned business characteristics. Then, the MRP calculation is performed at each future plan re-planning time, the stock quantity at each time point is calculated, and the quantity that is insufficient with only the stock quantity is obtained by recalculating the new order quantity. The purpose is to provide a mechanism capable of calculating the preceding inventory balance based on actual difficult business characteristics with high accuracy.

  The preceding plan change considering inventory balance calculation simulation system of the present invention that achieves the above object simulates the inventory balance of the preceding period using a plurality of plans that take into account plan changes that will change in the future using a computer. When the computer advances the time point that is the base point of MRP calculation to the future, the computer also changes the time point of the plan at the same time, and calculates the amount of parts received at any time from the new plan at each time point advanced to the future. And a system including a step of calculating a future inventory amount. The feature of this system is that it prepares multiple parts procurement plans and product sales forecast plans that reflect planned changes that will change in the future, and uses these plans to take inventory that takes into account plan deviations caused by future planned changes. It is to provide a mechanism capable of calculating the balance.

  According to the present invention, it is possible to calculate an inventory outlook / incoming / outgoing outlook that takes into account a plan deviation due to a change in a procurement plan or a shipping outlook plan. In addition, using the inventory forecast / entry / entry forecast and the standard unit price / purchase unit price forecast thus determined, the advance payment unit price is calculated using the inventory quantity, thereby calculating a highly accurate inventory balance amount. Is possible.

  Further, by showing the deviations and fluctuations of the previous procurement plan and the shipping forecast plan used when calculating the inventory balance in a table and a graph, the user can easily consider the fluctuation factors of the inventory balance. In addition, in order to make a management decision as to whether it is possible to reduce the inventory balance amount and reduce opportunity loss when the plan change is made during the preceding period, the procurement plan and the shipping forecast are determined in advance. It can be said that the present invention in which the inventory balance is calculated using a plurality of plans is effective.

Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is an example of a hardware system configuration that can be used in an inventory balance calculation simulation system. As an embodiment of the present invention, an input device 1001, an arithmetic device 1002, an external storage device 1003, and an output device 1004 are connected, and an inventory balance is calculated using input data and data held in the external storage device 1003. , A system for outputting a result, and the output device 1004 outputs the result. Such an inventory balance calculation simulation system assists a decision maker who reviews a procurement plan or a sales prospect plan or decides a review timing.

  Here, as illustrated, the output device 1004 and the input device 1001 may be connected via a network or directly connected to the arithmetic device 1002.

  The arithmetic device 1002 includes a central processing unit (CPU) 1005, a read only memory (ROM) 1006 for storing programs and data, and a random access memory (RAM) 1007. The arithmetic device 1002 executes the inventory balance calculation process of the present invention by loading the program stored in the external storage device 1003 into the RAM 1007 and executing it. The program is provided in a state that the arithmetic device 1002 can read, that is, in the form of a signal. For example, although not shown, a program held by a recording medium such as a CD-ROM is read out via a CD-ROM reader and installed in the external storage device 1003 or via a network. The transmitted program can be provided by being received by a communication device or the like and installed in the external storage device 1003.

  FIG. 2 is an overall system flow of a system related to the inventory balance simulation system. First, various initial data and various parameter information are acquired (step 2001). Next, the inventory balance simulation system is executed (step 2002). In this process, the previous warehousing / shipping / inventory outlook is calculated. Next, the inventory balance amount is calculated (step 2003). Then, the inventory balance and procurement / shipment forecast plan screen output and confirmation work are performed (step 2004). As a result, if it is necessary to change the initial data or parameters, the process returns to step 2001, the input file is corrected, and the processes after step 2001 are performed again. If it is not necessary to change the parameter, the process is terminated (step 2005).

FIG. 3 is an overall system configuration diagram of the inventory balance simulation system.
First, as input, a base date definition file 3001, an N-point procurement plan file 3002, a scheduled warehousing file 3003, an SCM master DB 3004, an initial inventory file 3005, and an N-time shipment forecast plan file 3006 are used. Hereinafter, n is an integer of 1 to N.

  Then, the inventory balance simulation system 3007 is executed to calculate the warehousing prospect 3008 for the N time point, the leaving outlook 3009 for the N time point, and the inventory prospect 3010 for the N time point.

Here, functions of the inventory balance simulation system will be described.
First, the various input data described above are read into the system. The reference date definition file 3001 is for the reference date change processing function 3011, the n procurement plans 3002 are for the procurement plan n point function 3012, the scheduled receipt file 3003 is for the scheduled receipt function 3013, and the SCM master DB information 3004 is for SCM. In the master function 3014, the initial inventory file 3005 stores data in the initial inventory function 3015, and the n shipping forecast plan files 3006 store data in the shipping forecast planning function 3016.

  First, an MRP calculation 3017 for parts procurement is performed using the first time point plan of the procurement plan. As a result, the warehousing schedule of the parts that must be ordered within one period (parts in the order LT) is calculated as a new order quantity and stored in the new order quantity function 3018. Next, the production / shipment MRP calculation 3019 is performed using the plan at the first time point of the shipping forecast plan. By this processing, the end-of-period inventory quantity / inventory forecast / shipment forecast at the first time point are stored in the end-of-period inventory quantity function 3020, inventory forecast function 3021, and delivery forecast function 3022. The above is a series of processes at one time point.

Next, the base date change process 3011 is used to advance the time point by one and to move to the second time point process.
At the second time point, first, the new order quantity 3018 calculated at the first time point is set as the scheduled storage quantity 3013 at the second time point, and the final stock quantity 3020 calculated at the first time point is set as the initial stock 3015 at the second time point. Perform processing, and carry on the information on the amount of goods received and the amount of inventory to the next time point.

  Next, the part procurement MRP calculation 3017 is performed using the second time point plan of the procurement plan, and the warehousing schedule of parts that must be ordered within the period of the two time points is calculated as a new order quantity. Next, the production / shipment MRP calculation 3019 is performed using the shipping forecast plan. The process described above is repeated for N time points. When the work is completed up to time N, information on the warehousing prospect 3023, the warehousing prospect 3022, and the inventory prospect 3021 is collectively output as a warehousing / inventory prospecting file 3024. The contents of the warehousing / inventory forecast file 3024 are divided into a warehousing prospect 3008 for time N, a warehousing prospect 3009 for time N, and a stock prospect 3010 for time N.

  Fig. 4 shows the standard date definition file. This file defines the timing of parts order suppression (weekly, monthly, etc.) when the shelf-remaining simulation system is executed. The date is defined by an 8-digit number. To do.

  FIG. 5 is a procurement plan file, consisting of data records consisting of item code, quantity, and completion date.

  Fig. 6 shows the shipping forecast plan file, which consists of data records consisting of item code, quantity, and completion date.

  FIG. 7 shows an initial inventory file, which consists of data records consisting of item codes and inventory quantities.

  FIG. 8 shows a planned receipt amount file, which is composed of data records including item codes, receipt amounts, and receipt dates.

  FIG. 9 shows a storage / inventory amount file, which is composed of data records including item codes, inventory amounts, storage amounts, output amounts, period start dates, and period end dates. The period start date matches the date in the reference date definition file, and the period end date is the day before the next reference date defined in the reference definition file.

  FIG. 10 is a system configuration diagram for calculating the remaining amount of shelf. This system uses quantity information such as stock / inventory / inventory forecast 4001 calculated by the inventory balance simulation system 3007, standard price 4002 at this time, and price information such as prospective purchase price 4003 at each time. A unit price forecast 4005 is calculated. There are various methods for calculating the payout unit price, such as the individual method, the first-in first-out method, the last-in first-out method, the total average method, the moving average method, the simple average method, the final purchase cost method, and the selling price reduction method. Therefore, the corresponding calculation method is adopted, and the payout unit price at each time point is calculated. Finally, the inventory / incoming / outgoing prospects at each time point are multiplied by the payout unit price at each time point to create a shelf remaining amount prospect 4006.

  FIG. 11 shows a payout unit price file, which consists of data records consisting of item code, year, month, and payout unit price. The year and month are 6 digits (YYYYMM).

  FIG. 12 shows a shelf remaining amount forecast file, which includes data records including at least an item code, an inventory amount, an inventory amount, a receipt amount, a receipt amount, a delivery amount, and a delivery amount.

  FIG. 13 summarizes the inventory balance simulation system results for each item status as an inventory amount and an in-process amount. By using this result, the user can analyze which status stock of products, intermediate products, parts, etc. is stagnant or in progress. For example, if the inventory amount is high and the inventory amount does not decrease even when the time progresses, it is possible to infer various things such as (1) a large divergence between the procurement plan and the shipping forecast plan (2) there is a stock in storage. .

  FIG. 14 is a summary of the inventory balance and the in-process amount as a graph for each item status. As a result, the user can intuitively grasp the inventory balance transition.

  FIG. 15 summarizes the shipping forecast plan on a monetary basis. The horizontal axis represents the bucket, the vertical axis represents the base date, and the shipping forecast plan obtained by multiplying the shipping forecast plan at each time point with the payout unit price is calculated on a monetary basis. A similar table is also created in the procurement plan.

  FIG. 16 is a graph summarizing the shipping forecast plan on a monetary basis. The horizontal axis is the reference date, and the vertical axis is the amount. The bar graph represents the planned shipment amount for each month, and the line graph represents the cumulative estimated shipping amount. As a result, the user can intuitively grasp the plan transition at each point of time, and can also be used to investigate the cause of the increase in the remaining amount of shelf in FIG. A similar graph is created in the procurement plan.

FIG. 1 is an example of a hardware system configuration that can be used in an inventory balance calculation simulation system. FIG. 2 is an overall system flow of a system related to the inventory balance simulation system. FIG. 3 is an overall system configuration diagram of the inventory balance simulation system. FIG. 4 shows a file format of the base date definition. FIG. 5 shows a file format of the procurement plan file. FIG. 6 shows the file format of the shipping forecast plan file. FIG. 7 shows the file format of the initial inventory file. FIG. 8 shows the file format of the scheduled storage amount file. FIG. 9 shows the file format of the loading / unloading / stock quantity file. FIG. 10 is a system configuration diagram for calculating the remaining amount of shelf. FIG. 11 shows a file format of the payout unit price file. FIG. 12 shows the file format of the shelf remaining amount forecast file. FIG. 13 summarizes the inventory balance simulation system results for each item status as an inventory amount and an in-process amount. FIG. 14 is a summary of the inventory balance and the in-process amount as a graph for each item status. FIG. 15 summarizes the shipping forecast plan on a monetary basis. FIG. 16 is a graph summarizing the shipping forecast plan on a monetary basis.

Explanation of symbols

1001 ... Input device 1002 ... Calculation device 1003 ... External storage device
1004 ... Output device, 1005 ... Central processing unit (CPU), 1006 ... Read only memory (ROM), 1007 ... Random access memory (RAM),
1008 ... Display, 1009 ... Keyboard, 1010 ... Mouse,
2001-2006 ... Execution step of inventory balance simulation system,
3001 ... Base date definition file, 3002 ... N time point procurement plan files,
3003 ... Scheduled receipt file, 3004 ... SCM master DB, 3005 ... Initial inventory file, 3006 ... Shipment forecast plan file for N points, 3007 ... Inventory balance simulation system, 3008 ... Receipt forecast for N points,
3009 ... Outgoing outlook for time N, 3010 ... Inventory outlook for time N,
3011 ... Base date change processing function, 3012 ... Procurement plan n point function, 3013 ... Receipt planned quantity function, 3014 ... SCM master function, 3015 ... Initial inventory function,
3016 ... Shipment forecast planning function, 3017 ... MRP calculation for parts procurement, 3018 ... New order quantity function, 3019 ... MRP calculation for production / shipment, 3020 ... End-of-stock quantity function, 3021 ... Inventory forecast function, 3022 ... Shipment forecast function, 3023 ... Receipt forecast, 3024 ... Receipt / inventory / inventory forecast file

Claims (1)

In response to fluctuations in parts procurement plans and product sales forecast plans that are expected to change in the future, a method of simulating the inventory balance of the preceding period using a plurality of plans on a computer,
When the computer advances the time point that becomes the base point of MRP calculation to the future, the step of simultaneously changing the time point of the parts procurement plan and product sales prospect plan;
Calculating the inventory of parts at any time from a new plan at each point of advance to the future, and calculating the future inventory quantity;
Prepare multiple parts procurement plans and product sales forecast plans that reflect planned changes that are expected to change in the future, and use those plans to calculate inventory balances that take into account plan deviations caused by future plan changes. Steps,
A simulation method for calculating an inventory balance, comprising:

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