JPH0233662A - Stock monitoring method - Google Patents

Abstract

PURPOSE:To attain the fine stock control by obtaining the stock correction value from the planned stock-in and stock-out values to perform the stock control based on said stock correction value and also to secure the margin time for monitor of the stock. CONSTITUTION:The dynamic stock correction value is calculated for each sample time point from the total value of the planned stock-in value obtained with every on-the-hour defined as a sample time point in case each product is supplied in a fixed cycle and the planned stock-out value set at a planned stock-out time point in case a certain number of products are stocked out at one time. Based on said stock correction value, the initial stock value and a fixed common difference are added for calculation of the proper stock value. This proper stock value is stored in a production/stock controller, etc. While the actual stock value is compared with the proper stock value to monitor the stock abnormality. Furthermore no stock abnormality is not finally decided in case the proper stock value is recovered within a fixed margin time even in case the temporary stock abnormality is detected. Thus no stock abnormality process is carried out. As a result, the confusion can be avoided on a production line.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for monitoring product inventory, and particularly to an inventory monitoring method suitable for application to a high-mix, low-volume production system.

(Prior Art) Conventionally, as a method for monitoring product inventory, there is a method that balances the number of products in stock and the number of products out, and keeps the number of products in stock within a tolerance range (for example, (Refer to JP-A-62-83906). Note that in recent years, computers have been used to save labor.

(Problem to be solved by the invention) However, in the production process and shipping process, it is possible to grasp the number of products in a relatively short period of time based on the production plan, etc.; It is not possible to make detailed judgments as to whether or not the product is appropriate, which can lead to an increase in unnecessary inventory, an increase in overhead costs, a decline in product quality over time, and the occurrence of stockouts and associated delivery delays. There was a delay.

In order to eliminate these inconveniences, methods such as shortening the cycle for grasping the inventory quantity and determining whether it is appropriate, and checking/examining tolerances have been used. This has caused problems such as increases in stock inventory and detection of unnecessary inventory abnormalities.

The present invention was proposed to solve the above problems, and
The purpose of this is to automatically detect inventory abnormalities and perform detailed inventory management by comparing the appropriate inventory quantity and the actual inventory quantity, which changes from moment to moment, at predetermined sample times, taking into account the computer load. To provide an inventory monitoring method that prevents the holding of unnecessary inventory and the occurrence of stockouts, reduces the detection of unnecessary inventory abnormalities, and reduces the burden on a manager.

(Means for Achieving the Object) In order to achieve the above object, the present invention calculates an inventory correction value at a predetermined sample time from the difference between the planned number of products in stock and the planned number of products out, which change over time. Inventory abnormalities are automatically detected by sequentially comparing the appropriate inventory quantity set based on this inventory correction value and the actual inventory quantity, and a certain margin is set from the point of comparison between the appropriate inventory quantity and the actual inventory quantity. The present invention is characterized in that when a time is set and the inventory hole is cleared within this margin time, the process that should be performed when the inventory is abnormal is not performed without determining that it is a final inventory abnormality.

(Function) According to the present invention, for example, when directly connected to a belt conveyor and products are received one by one at regular intervals, the cumulative value of the planned number of warehouses with every hour on the hour as the sample time and the number of products grouped together in the trunk are calculated. A dynamic inventory correction value for each sample time is calculated from the planned number of deliveries for the planned delivery time when the products are delivered at once. Then, an appropriate inventory quantity is calculated by taking into account the initial inventory quantity and a certain tolerance based on this inventory correction value, and the appropriate inventory quantity is stored in a production/inventory management device or the like.

On the other hand, the actual inventory quantity, which changes from moment to moment, is automatically managed, and the ratio between this actual inventory quantity and the above-mentioned appropriate inventory quantity is 1.
Monitor inventory abnormalities by checking.

Furthermore, even if there is a temporary inventory abnormality due to a change in shipping time, etc., if the inventory returns to the appropriate number within a certain margin time, it will not be judged as a final inventory abnormality, and the order of work-in-process instructions may be changed. It was decided that inventory abnormality processing would not be performed.

(Example) An embodiment of the present invention will be described below with reference to FIG.

First, FIG. 2 shows the entire production system to which the present invention is applied. This production system is for assembling, inspecting, etc., high-mix low-volume production products such as automobile engines. be.

In FIG. 2, 1 is a production management system consisting of a host computer, 2 is a production/inventory control device installed in a factory and is a mini computer system, etc., 3 is a data way such as a LAN using an optical cable, 41 to 45 is the production/inventory control device 2, assembly line 51 and inspection line 5
2, a data terminal for exchanging production instruction data, production performance data, inventory data, etc. with the product warehouse 6; 5, a production line consisting of an assembly line 51 and an inspection line 52; In addition, production management system J and production
Data is exchanged with the inventory management device 2 via a communication line 7 and a floppy disk (not shown).

In a production system configured as described above, if a product is directly connected to a belt conveyor and is stored one by one at regular intervals, the production line 5 is stored in the product warehouse at a sample time of a relatively short period, for example, every hour on the hour. It is assumed that the planned cumulative number of products to be stocked in 6 is as shown in Table 1 below.

Table 1: The planned cumulative number of units to be stocked is calculated based on the total planned number of units to be stocked per day of product A, the operating hours of the production line 5, the downtime, etc.

On the other hand, when a large number of products are delivered at once by truck, the planned number of products A to be delivered from the product warehouse 6 at the planned delivery time and the planned cumulative number of products are determined based on the delivery plan as shown in Table 2. Assume that it has been decided.

Table 2 Next, based on Tables 1 and 2, every hour on the hour and the planned departure time are taken as sample times, and the difference between the cumulative number of vehicles in stock and the planned number of vehicles to be delivered at this sample time is calculated as production/inventory. This is determined by the management device 2 and used as the inventory correction value (initial inventory fln o=O), and the following Table 3 is created.

The difference between the total number of vehicles in the third table and the planned number of vehicles to be delivered is determined, and this becomes the inventory correction value.

Next, based on the inventory correction values shown in the third table, the appropriate inventory quantity for each sample time is calculated to create a fourth table, and this fourth table is stored in the production/inventory control device 2. do. Here, the initial inventory quantity of product A is n. 20 units, tolerance 5
In this case, the appropriate inventory quantity is as follows.

In Table 4, that is, Table 3, there are no scheduled deliveries until 10:10, so the planned total number of vehicles entering the warehouse becomes the inventory correction value.
30 units) is larger than the total number of planned warehousing units (20 units) at the previous sample time (10:00), so 10 units are out of stock. Then, at 11:00, the cumulative number of vehicles scheduled to arrive at the warehouse is 30, so it becomes equal to the planned number of vehicles to be delivered at 10:10 (30 vehicles), the missing items are compensated for, and the inventory correction value becomes zero. Thereafter, in the same manner, the warehousing plan at each time is accumulated.In this table 4, for example, I
The appropriate number of units in stock from 0:00 to 10:10 is 35 units or more.
45 units, and the appropriate number of units in stock from 10:10 to 11:00 is 5 to 15 units.

According to each of the above tables, the total number of planned stockings, cumulative number of scheduled outgoings, and inventory correction value (n, = 0.
Figure 1 shows the relationship between (n0=20) and the appropriate inventory quantity.

Therefore, in the product warehouse 6, by successively comparing the appropriate inventory quantity shown in Table 4 with the actual inventory quantity, which changes from moment to moment, detected via the data terminal 45, the product A's current inventory is determined. I
Perform t%'ix observation. As a general rule, if the actual inventory quantity falls outside the range of the appropriate inventory quantity, it is determined that there is an inventory abnormality, and the production/inventory control device 2 performs inventory abnormality processing such as changing the work-in-process instruction order or outputting an alarm. .

Here, suppose that the shipping plan at 10:00 IO in Table 2 is shortened by 2 minutes, and 30 units of product A are shipped at 10:08, and the number of units in stock at that time is 5 units. As is clear from Figure 1, from 10:00 to 10:10
Since the appropriate number of units in stock up to 10:08 is 35 to 45, the stock is inherently abnormal at 10:08. However, at 10:10, two minutes later, the appropriate inventory range changes to 5 to 15 units, and at this point, the current inventory number (
5 units) is the appropriate number in stock and there is no problem.

Therefore, even when inventory monitoring is performed frequently in short cycles by comparing the appropriate inventory quantity and the actual inventory quantity, a slight margin time is set from each comparison point, and the original inventory abnormality is resolved within this margin time. In this case, it is possible to reduce the frequency of correction of work-in-process order planning, etc. by not ultimately determining that there is an inventory abnormality and not performing inventory abnormality processing.

In the above embodiment, a case has been described in which the inventory of a single type of product is monitored, but the present invention can of course be applied to a wide variety of products.

(Effects of the Invention) As described above, according to the present invention, an inventory correction value is obtained from the planned number of warehouses to be stocked and the planned number of warehouses to be shipped, and the appropriate inventory number is calculated based on this inventory correction value, and the actual inventory number is determined by the computer. Since it automatically and sequentially monitors the load in consideration, it has the effect of enabling detailed inventory management.

In addition, by using the inventory correction value, it is possible to detect the time in a day when the number of items in stock is the lowest, and by holding the minimum necessary amount of inventory so that the actual number of items in stock at this time is the minimum. Inventory management can be performed that does not generate any product and minimizes the burden of miscellaneous expenses. Furthermore, since it is possible to detect in advance the time when there is a risk of a stockout occurring, corrections to the work-in-process order plan, etc. can be made with plenty of time.

In addition, by providing a certain margin of time for inventory monitoring, frequent corrections of various plans are no longer necessary, and confusion on the production line can be prevented.

[Brief explanation of the drawing]

FIGS. 1 and 2 show an embodiment of the present invention, and FIG. 1 shows the planned cumulative number of warehousing vehicles over time. FIG. 2 is a diagram showing the relationship between the scheduled cumulative number of vehicles to be delivered, the inventory correction value, and the appropriate inventory amount, and is a configuration diagram of the production system. 2... Production/inventory management device 3... Data way 5... Production line 6... Product warehouse 45...
Data terminal patent applicant Toyota Motor Corporation representative

Claims (1)

[Claims] Calculate the inventory correction value at a predetermined sample time from the difference between the scheduled number of products in stock and the planned number of products out, which changes over time, and then calculate the appropriate inventory quantity set based on this inventory correction value and the actual inventory quantity one by one. In addition to automatically detecting stock abnormalities by comparison,
An inventory monitoring method characterized in that a certain margin time is provided from the time when the appropriate inventory number and the actual inventory number are compared, and when the inventory abnormality is resolved within this margin time, no inventory abnormality processing is performed.