JP2002297215A - Production planning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production planning system for establishing a stable production plan. SOLUTION: This production planning system is constituted of input equipment for inputting standard inventory, standard inventory upper limit, standard inventory lower limit, and predicted demand, a storage device for storing information, and an arithmetic unit for deciding the number of production plans from the stored information. Thus, it is possible to provide a stable production plan.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a production planning system, and more particularly to a production planning system for making a prospective production.

[0002]

2. Description of the Related Art A standard stock quantity is set for each item number, an estimated stock is calculated from the current stock quantity, the latest forecast demand quantity, and a production plan currently in process, and the difference between the standard stock quantity and the estimated stock is calculated. The satisfiable quantity was regarded as the production plan number.

[0003]

In the above-mentioned conventional production planning method, since the standard stock quantity is calculated at one point, if there is a change between the latest forecast demand quantity and the previous forecast demand quantity, the production plan quantity is changed. Changes, equipment setup (change of equipment jigs and conditions according to the item number to be produced) and purchase of parts used for assembly are required. Since the setup change is performed with the production equipment stopped, as the number of setup changes increases, the equipment operation rate decreases and the production efficiency also decreases. Also,
When starting up production equipment, the incidence of defects also increases. In other words, fewer setup changes lead to higher production efficiency and less waste. However, the predicted demand number usually fluctuates with the passage of time, and as a result, the production plan number also fluctuates every time, and a large number of parts purchasing processes occur due to equipment changeover and plan change.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the present invention has reduced the number of times of equipment changeover and the load, and has responded to demand without reducing the equipment operation rate and production efficiency. An object of the present invention is to provide a production planning system capable of obtaining the number of production plans.

[0005]

In order to solve the above-mentioned problems, according to claim 1 of the present invention, when a new production plan is made, the previous production plan number, the current stock number, and the reference stock number of the item number are set. The production planning system retrieves the quantity, the reference stock upper limit, and the reference stock lower limit from the storage device, and calculates the estimated stock quantity when the same quantity as the production plan quantity in the plan period previously planned is produced. This makes it possible to manage the standard stock quantity by width. However, if there is a difference in the number of working days between the previous planning period and the current planning period, 1
The current production plan number is set so that the number of production per day is the same as the previous one.

In the present invention, it is determined whether the calculated estimated stock quantity is between the reference stock upper limit and the reference stock lower limit of the item number. If the estimated stock is between the base stock limit and base stock limit for that item number,
The current production plan number is the same as the previous production plan number. If the estimated stock exceeds the reference stock upper limit of the item number, the production plan number is reduced to an amount satisfying the reference stock quantity. If the estimated stock is below the reference stock lower limit of the item number, the production plan number is increased to an amount that satisfies the reference stock. As a result, there is no need to change the plan because the estimated stock has slightly decreased to the reference stock, and the number of setups and the load of changing the plan can be reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to make the contents of the present invention easier to understand, the present invention will be described below with reference to embodiments.

[0008]

FIG. 1 is a flowchart of the present invention, FIG. 2 is a configuration of the present invention, and FIG. 3 shows an image of calculating a production plan number according to the present invention. If the cycle of the production plan is one month and the target of the production plan is the following month, it will be as follows.

In advance, a reference stock number, a reference stock upper limit, and a reference stock lower limit are input to the reference stock management 42 of the storage device 40.
It is set by 0. The production plan of this month is searched from the production plan 44 of the storage device 40, and the number of production plans of the next month is provisionally determined by multiplying the ratio of the number of operation days of this month to the number of operation days of the next month.
The current number of warehouses is searched from the current warehouse 41 and the predicted demand number from the predicted demand 43 for each item number. From the information, the arithmetic unit 10 calculates the estimated stock at the end of the following month by the following equation (1). Estimated inventory at the end of next month = Current warehouse + Number of production plans after tomorrow of this month + Temporary production plan number of next month-Forecast demand until the end of next month ··· (1)

The reference stock upper limit and the reference stock lower limit that have been set in advance are searched from the reference stock management 42, and it is determined whether or not the estimated stock for the next month is within the stock management width. If it is within the inventory control range, the provisionally determined production plan is adopted. When the estimated stock exceeds the upper limit of the standard stock, the arithmetic unit 10 calculates the production plan number for the next month by the following equation (2). Number of production plans for the next month = Reference stock number-(Current warehouse + Number of production plans after tomorrow of this month) + Forecasted demand until the end of the next month ... Equation (2)

However, if the number of production plans in the following month becomes negative in the above equation, it is set to 0 (zero). If there is a production lot or the like, the production plan number for the next month is rounded by that value. When the estimated stock is below the lower limit of the reference stock, the calculation formula is exactly the same as when the estimated stock is above the upper limit.

In the above embodiment, when the estimated inventory exceeds the upper limit of the standard inventory and when the estimated inventory falls below the lower limit of the standard inventory, the planned production quantity of the next month is set so that the estimated inventory at the end of the next month becomes the standard inventory quantity. Although the calculation is performed, the following equation (3) may be used so that the upper limit and the lower limit of the reference stock are obtained. The number of production plans for the next month = the upper limit of the standard inventory (or the lower limit of the standard inventory)-(current stock + the number of production plans after tomorrow of this month) + forecast demand until the end of the next month ... Equation (3)

[0013]

As described above, according to the configuration of the present invention, as long as the estimated stock does not deviate from the upper limit of the reference stock and the lower limit of the reference stock even if the predicted demand number fluctuates with time,
The same item number as the previous one will be produced under the same conditions,
The yield can be stabilized, and the number of setup changes and the load can be reduced. In addition, the number of times the production plan is changed is reduced, and the production plan and the purchasing plan of parts are stabilized.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a procedure for determining a production plan number.

FIG. 2 is an apparatus configuration diagram for realizing a planning method according to the present invention.

FIG. 3 is an image diagram for determining a production plan number.

[Explanation of symbols]

10 arithmetic unit, 20 display unit, 30 input device, 4
0: storage device, 41: current warehouse information, 42: standard stock management information, 43: forecast demand information, 44: production plan information

Claims (2)

[Claims] 1. Input data such as a forecast demand number which is an expected sales quantity in a planning target period, a production plan number which is a quantity to be produced in a planning target period, a current stock quantity which is a current stock quantity, and reference stock management information. Input means, a display means for displaying the data, a storage means for storing the data, and an operation means for automatically calculating the number of production plans, a production planning system comprising: The standard stock quantity, which is the stock quantity necessary for normal operation, the standard stock upper limit, which is the maximum stock quantity due to space constraints, and the standard stock lower limit, which is the minimum stock quantity that does not cause product shortage A production planning system, comprising: a standard stock management width storage means for setting and storing the information. 2. When a new production plan is created, a previous production plan number, a current stock number, a standard stock number, a standard stock upper limit, and a standard stock lower limit are searched from the storage means. The quantity is used as a production plan number to be newly created, and the estimated stock, which is an estimate of the inventory quantity on the last day of the planned period, is automatically calculated by the calculation means based on the predicted demand number of the newly created plan period. Also, when the estimated stock is between the reference stock upper limit and the reference stock lower limit, the number of production plans of the newly created production plan is set to the same quantity as the previous production plan number, and the number exceeds the stock reference upper limit or the stock is exceeded. If it is below the lower limit, the number of production plans is calculated automatically,
2. The production planning system according to claim 1, further comprising means for changing the number of production plans to be stored.