Method of creating production plan of demand variation input type and method of creating production plan minimizing risk of demand variations

• US 20050222888A1
• Filed: 03/30/2005
• Published: 10/06/2005
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Igarashi, Ken, Kaneko, Yuichi, Hosoda, Junko
• Granted Patent: US 7,660,730 B2
• Time in Patent Office: Days
• US Class Current: 705/8
• CPC Class Codes: G06Q 10/06315 Needs-based resource requirements planning or analysis
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: G06Q 30/0202 Market predictions or forecasting for commercial activities

Abstract

A production plan is created so as to minimize risk of demand variations. Forecasted values of amounts of requests are entered for each different item of products, markets, dates, past accuracy of demand forecasts, and order achievements at the time when the plan is created. Scenario information is created in which assumable amounts of request for each different item of the products, markets, and dates and probabilities at which the amounts of requests agree with actual amounts of requests are defined. Management indexes are found from the amount of stockout and amount of stock calculated in each different scenario, based on the scenario information, target values of the management indexes, and information on strongpoints. An amount of production that maximizes the achievement ratios of the management ratios to their targets within the ranges of supplied materials and within the range of the production capacity is calculated by an optimization algorithm.

Claims

1. A method of creating a production plan of a demand variation input type, comprising the steps of:

calculating amounts of request for each different item of products, markets, and dates that can be assumed and probabilities of occurrence at which the amounts of request agree with actual amounts of request, based on forecasted values of the amounts of request for each different item of the products, markets, and dates, on past accuracy of demand forecasts, and on achievements of orders at the time when the plan is created;

creating scenario information in which combinations of the calculated amounts of request and probabilities of occurrence are defined;

finding values of management indexes from amounts of stockout and amounts of stock calculated in the individual scenarios, based on the scenario information, on strongpoint information, and on target values of the management indexes, the strongpoint information including characteristics of manufacturing plants and parts vendors and supply routes for materials and manufactured products, the management indexes being capable of quantitatively evaluating the production plan such as a stockout rate and a stock turnover rate; and

calculating an amount of production that maximizes achievement ratios of the values of the management indexes to their targets within ranges of amounts of supplied materials and range of production capacity.

2. A method of creating a production plan of a demand variation input type as set forth in claim 1, wherein said scenario information consists of plural sets of scenario information among which said probabilities of occurrence are different, and wherein said scenario information is created such that the sum of said probabilities of occurrence is 100% for each different item of the products, markets, and dates.

3. A method of creating a production plan of a demand variation input type as set forth in claim 2,

wherein an amount of stockout and an amount of stock are calculated in each different scenario for each different item of the products, markets, and dates,

wherein the amount of stockout and the amount of stock in each different scenario are multiplied by said probabilities of occurrence and the resulting products are summed up for all the scenarios to calculate an amount of stockout and an amount of stock for the production plan, and

wherein said values of the management indexes are calculated, using the calculated amount of stockout and amount of stock for the production plan.

4. A method of creating a production plan of a demand variation input type as set forth in claim 3, wherein said plural sets of scenario information created for each different item of the products, markets, and dates are created to include a scenario in which a stockout occurs and another scenario in which a stock occurs, and wherein a tradeoff relation between stockout and stock can be evaluated using the calculated amount of stockout and amount of stock for the production plan.

5. A method of creating a production plan of a demand variation input type as set forth in claim 3, wherein amounts of orders to the parts vendors and an order in which products are introduced to production lines are determined based on the amount of product that maximizes achievement ratios of said values of the management indexes to their targets, and wherein even if demand variations take place, no adjustment is made to cope with excess or shortage of materials in the introduced plan nor the production capacity is adjusted.

6. A method of creating a production plan of a demand variation input type as set forth in claim 3, wherein said forecasted values of the amounts of request for each different item of the products, markets, and dates are calculated by referring to at least past sales achievements.

7. A method of creating a production plan of a demand variation input type as set forth in claim 3, wherein at least one of said amount of stockout, amount of stock in each of said scenarios, said values of the management indexes, and the amount of production that maximizes the achievement ratios of said management index values to their targets is displayed.

8. A method of creating a production plan of a demand variation input type as set forth in claim 3, wherein said scenario information includes scenario numbers, said amounts of request that can be assumed for each different item of the products, markets, and dates, probabilities of occurrence at which the amounts of request agree with actual amounts of request, and group IDs providing units at which the risk of demand variations is minimized.

9. A method of creating a production plan of a demand variation input type, comprising the steps of:

calculating forecasted values of amounts of request for each different item of products, markets, and dates by referring to at least past sales achievements;

calculating amounts of request for each different item of products, markets, and dates that can be assumed and probabilities of occurrence at which the amounts of request agree with actual amounts of request, based on forecasted values of the amounts of request for each different item of the products, markets, and dates, on past accuracy of demand forecasts, and on achievements of orders at the time when the plan is created;

making a setup such that the sum of the probabilities of occurrence at the calculated amounts of request is 100% for each different item of the products, markets, and dates;

creating scenario information in which combinations of the calculated amounts of request and probabilities of occurrence are defined;

calculating an amount of stockout and an amount of stock in each different scenario for each different item of the products, markets, and dates;

multiplying the amount of stockout and the amount of stock in each different scenario by said probabilities of occurrence and summing up the resulting products for all the scenarios to calculate an amount of stockout and an amount of stock for the production plan;

calculating values of management indexes, using the calculated amount of stockout and amount of stock for the production plan;

calculating an amount of production that maximizes achievement ratios of the values of the management indexes to their targets, within ranges of amounts of supplied materials and range of production capacity, based on the calculated values of the management indexes, on strongpoint information, and on target values of the management indexes capable of quantitatively evaluating the production plan such as a stockout rate and a stock turnover rate, said strongpoint information including characteristics of manufacturing plants and parts vendors and supply routes for materials and manufactured products;

determining amounts of orders to the parts vendors based on the amount of production that maximizes the achievement ratios of the values of the management indexes to their targets; and

determining an order in which the products are introduced to production lines based on the amount of production that maximizes the achievement ratios of the values of the management indexes to their targets.

10. A method of creating a production plan in such a way as to minimize risk of demand variations, comprising the steps of:

accepting time-sequence forecasted amounts of sale for individual products and individual markets, information about algorithms of calculating amounts of production set for ranges of a tilt of the forecasted amounts of sale, sales achievements, and a period during which the tilt of the sales achievements is found, said tilt of the forecasted amounts of sale being an amount of variation of each forecasted amount of sale per unit time for the specified period;

calculating the tilt of the sales achievements from the actual amount of sale during the period in which the tilt of the sales achievement is found;

identifying a range of the tilt of the forecasted amount of sale that contains the calculated tilt of sales achievements; and

calculating an amount of production in accordance with a production amount-calculating algorithm set for the identified range.

11. A method of creating a production plan so as to minimize demand variations as set forth in claim 10, further including the steps of:

causing the production amount-calculating algorithm set for said identified range to calculate assumable plural amounts of request for each different item of products, markets, and dates and probabilities of occurrence at which the amounts of request agree with actual amounts of request, based on forecasted values of amounts of request for each different item of the products, markets, and dates, on past accuracy of demand forecasts, and on orders achievements at the time when the plan is created, and to create scenario information in which combinations of the calculated amounts of request and probabilities of occurrence are defined; and

finding values of management indexes from an amount of stockout and an amount of stock calculated in each scenario, based on the scenario information, on strongpoint information including characteristics of manufacturing plants and parts vendors and supply routes for materials and manufactured products, and on target values of the management indexes capable of quantitatively evaluating the production plan such as a stockout rate and a stock turnover rate, and calculating an amount of production that maximizes achievement ratios of the values of the management indexes to their targets; and

wherein the amount of production is calculated using the target values of the management indexes set for said identified range.

12. A method of creating a production plan in such a way as to minimize demand variations as set forth in claim 10, wherein ranges of the tilt of said forecasted amounts of sale are partitioned at locations where the tilt varies greatly.

13. A method of creating a production plan in such a way as to minimize demand variations as set forth in claim 12, wherein in ranges where the tilt of said forecasted amounts of sale is steep, information about the production amount-calculating algorithm used in said method of creating a production plan of the demand variation input type is set, and wherein in ranges where the tilt of said forecasted amounts of sale is mild, information about the production amount-calculating algorithm used in said method of creating a production plan of the safety stock addition type is set.