JP2007264682A - Production management method in steel plate manufacture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an excess material allocating rate, and to reduce the comprehensive yield ratio and the staying time of stock. <P>SOLUTION: For production management of steel plates to be order-produced, as to excess materials to be generated due to a restriction on manufacturing, a database including information about the standard, size and specifications is provided. The excess material size is adjusted longer than the shortest size thereof so as to improve an allocation frequency for received order, and also reduce the yield ratio in order allocation and the staying time of the stock of stock plates according to the frequency of an ordered size for each standard and specification and to a database of existing excess materials. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a production management method in steel plate manufacturing, and more particularly to a production management method in steel plate manufacturing suitable for inventory management of thick steel plates that are custom-made in small lots.

  Production management in the iron and steel industry, especially for steel plates with a build-to-order production method, instruct production orders according to their specifications, start production according to customer orders, and complete production by a predetermined delivery date The method is almost. In order to meet the specifications of each customer, the build-to-order production method is often small lot / multi-product production. On the other hand, in terms of manufacturing, production of large lots and small varieties is advantageous in terms of cost and is economical.

  For this reason, the process of combining the orders of small lots into the production lots of each process is an extremely important process because it affects not only the productivity including the yield but also the production plan itself.

  Conventionally, in this process, various optimization methods such as those disclosed in Patent Documents 1 and 2 are used by using a computer in order to aim at maximizing various productivity indexes including yield. In addition, order combinations, lot organization, and material allocation are performed.

  For example, in Patent Document 1, a production plan for obtaining an optimal combination and a planing operation are performed by generating a plurality of lots by combining the sizes of products to be produced, combining the lots, and obtaining a combination having the smallest total number of lots. When making a plan, the combination of lots with the best evaluation is obtained by integer programming using neighborhood search.

  Moreover, in patent document 2, the combination is rearranged using a genetic algorithm at the time of cutting.

  Moreover, in patent document 3, when manufacturing a steel plate product according to the order from a customer, while realizing the optimal allocation to an order raw material in a short time, managing surplus stock and a yield to an optimal state. Shows how to be able to.

  These are aimed at lowering the yield due to the combination loss and reducing the loss at the time of allocating surplus materials, and are aimed at improving the productivity including the yield. Such extra material allocation is a very effective means in terms of overall yield and inventory management for relatively large lot materials that can be allocated (for example, general-purpose standards).

  On the other hand, in Patent Document 4, when a slab material is designed for an ordered order regarding the manufacture of a thin plate such as a coil, the slab surplus amount is obtained by efficiently designing the slab in consideration of repeated orders. It is described that the minimization of the system is to be minimized. According to this method, considering the continuity of orders in anticipation of the future, by combining orders that do not generate surplus parts, even if various orders are given, the product unit weight is large and surplus Slab design with fewer parts is possible.

JP-A-9-174387 Japanese Patent Laid-Open No. 7-96311 Japanese Patent Laid-Open No. 6-149850 JP-A-10-214104

  However, in the techniques described in Patent Documents 1 to 3, an optimum combination cannot be obtained for a small lot material in consideration of yield and productivity, and it depends on the skill of a skilled worker. In addition, for small lot materials, the frequency of allocation is low. For example, if the remaining material dimensions do not match and cannot be allocated, the long-term residence inventory will increase, or the remaining materials will not be allocated. As a result, there was a possibility that surplus materials would be further increased.

  On the other hand, the technique described in Patent Document 4 is mainly to increase the unit weight of the product, and also actively add extra material within the equipment allowance. For products that cannot be expected to increase in product weight, only surplus materials will increase, and overall yield cannot be improved. In addition, because it is manufactured so as to generate surplus materials to be used for orders that will be ordered in the future without taking into account the existing inventory status, inventory management and the size and characteristics of the target material lot Some of them have problems such as inappropriate.

  The present invention has been made to solve the above-mentioned conventional problems, particularly for small-lot materials with a low allocation frequency, when surplus materials are generated due to equipment restrictions at the time of new production, the past order dimensions, characteristics, By predicting the allocation of future surplus materials by simulating inventory from the frequency, and adjusting the size of surplus material generated, the surplus material allocation rate is improved, and overall yield and inventory dwell time are reduced. This is the issue.

  The present invention provides a database having information on standards, dimensions, and specifications of surplus materials generated due to manufacturing restrictions in production management of steel plates to be produced in order. In order to improve the frequency of allocation to the order by adjusting the size of the surplus material longer than the shortest dimension so that the allocation frequency is improved at the slab design stage from the database of the existing surplus materials, and at the time of allocation of the inventory plate order The above-mentioned problems have been solved by reducing the yield and stock residence time.

  In particular, it is possible to optimize the inventory of surplus materials by adjusting the surplus material dimensions so as to fill the difference from the target stock of the existing surplus materials.

  According to the present invention, it is possible to improve the frequency of allocation of surplus materials to orders, and to reduce the yield and inventory retention time when allocating inventory plate orders.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a conceptual diagram showing a manufacturing process of a steel plate. Material request 10 is a process of consolidating into production lots such as lots of tapping steel 12 and lots of rolling 14, so that the system and skilled workers can maximize productivity, including yield, within equipment constraints. The order combination is determined through trial and error. In FIG. 1, 16 is a product cutting, 18 is various processes such as refining and painting, 20 is an inspection, and 22 is an allocation of surplus materials.

  For example, when an order combination loss shown in case 1 of FIG. 2 or a surplus length due to equipment constraints shown in case 2 occurs when requesting a material, conventionally, scraps and end plates are generated, and a certain size or more. Things were stocked as surplus materials. On the other hand, in the present invention, at the time of requesting materials, by changing the dimensions of the loss part and the surplus length part in advance based on the past orders received, the frequency of allocating surplus materials to the inventory board is increased, and comprehensive Improve the yield.

  Specifically, as shown in a system configuration example in FIG. 3, when a new order is manufactured, orders are combined in order to obtain a production lot such as a steel-out lot or a rolling lot. In the figure, 100 is a new order information database (DB) of customers, properties, standards, dimensions (thickness, width, length), specifications, etc. 110 is also inventory information DB, 120 is also past order information DB, 130 is a conventional order combination calculation device, 140 is a past order information analysis device according to the present invention, and 150 is a surplus length control device for performing surplus length, loss determination and surplus length control according to the present invention.

  Usually, the order combination uses various optimization methods in order to determine the combination so that various indices are maximized or minimized under constraint conditions such as equipment constraints. Here, the order combination calculation device 130 refers to a system capable of performing combination calculation using an optimal method. In addition, there are two types of manufacturing: a case of newly manufacturing and a method of allocating inventory. Here, a combination for new manufacturing is performed for an order that could not be allocated in inventory.

  At this time, if a loss occurs due to the combination or a surplus length occurs due to equipment constraints, the surplus length control device 150 groups the customer, standard, and specification, and dimensions (thickness, width, length) at the ordering timing. The surplus length is controlled by calculating the frequency of.

  In determining the extra length dimension, the past order information DB 140 is used. FIG. 4 shows a more detailed processing procedure.

  First, in step S <b> 1 executed in the order combination calculation device 130, the combination is determined within the equipment constraints so that the combination loss is minimum and the unit weight is maximum by the same method as the conventional method.

  Next, in step S2 executed in the surplus length control device 150, it is determined whether the size of the equipment constraint combination loss is, for example, a width of 1 m or a length of 2 m or more.

  If the determination result in step S2 is negative, the slab is designed so as to generate a loss as it is in step S6 without extending the surplus length.

  On the other hand, when the determination result in step S2 is positive, in step S3 executed in the past order information analysis apparatus 140, a dimension with a high order frequency is extracted from the same specification and the same steel type within a specified period. To do.

  Next, in step S4 executed in the surplus length control device 150, it is determined whether the yield including the surplus length after changing the size of the facility constraint and the combination loss to the above-mentioned size is equal to or more than a predetermined yield.

  If the determination result of step S4 is positive, the dimension of the extra length portion is enlarged in step S5, and the slab is designed in step S6.

  On the other hand, if the determination result of step S4 is negative, the process returns to step S1.

  In this way, grouping is performed with the same plate thickness, the same steel type, and the same specifications of the target material. Then, after determining the product size range from the order frequency based on past orders received so that the inventory level is within the management range, the surplus material dimensions are sequentially changed in descending order of order frequency, and the surplus material is applied. The surplus material size is changed to the size when the yield is highest when the above is assumed. However, if the remaining material size is less than the specified yield value, this process is not applied and the order combination is returned to the stage.

  When the surplus material portion is expanded, the information is recorded in the inventory DB 110, and when the new order is received, the inventory and the inventory scheduled material are searched and linked in the inventory DB 110.

  In this way, from the database that accumulates data such as manufacturing information of existing stock plates, past order information (product dimensions, ordering timing, presence / absence of repeats), and past order information, it can be grouped by group such as steel grade and standard. Since there is a method to calculate the width, length, and delivery frequency for each order plate thickness, and to request materials by combining the orders, if there are surplus materials due to equipment restrictions or combinations, the dimensions of the surplus materials By adjusting the above, it is possible to improve the rate of allocation of surplus materials (inventory) and reduce the overall yield and the residence time of inventory.

  FIG. 5 shows an embodiment in which the dimensions of the surplus portion are changed. Here, as a result of combining the products 1 and 2, since the manufacturable size is not reached, an example in which the surplus material portion is increased is shown. The conventional method does not consider the yield due to the allocation to the surplus material (stock board), but only gives the surplus material up to the manufacturable size so that the yield becomes the highest at this point.

  FIG. 6 shows an example in which the product length distribution and the cumulative frequency within the same order of manufacture for the same steel type and the past order receipt record within 6 months are analyzed. As described above, there are almost no orders received with a length of 5,000 (mm) or less, and in many cases, inventory processing is performed before allocation to the inventory. On the other hand, if the allocation frequency is increased to about 80% in order to increase the allocation frequency, there is a possibility that a yield loss may occur when the inventory is allocated. The level of allocation frequency is individually set according to the production environment, steel grade, etc., in consideration of the yield and inventory level.

  Here, the allocation frequency is set to 50%, and the product length is set to 10,000 (mm). Conventionally, the extra length of 5,000 (mm) is added, but in the present invention, the extra material (inventory) is collected with 10,000 (mm).

  As an effect at this time, FIG. 7 shows the change in the overall yield, and FIG. 8 shows the change in the inventory retention date. It can be seen that this series of processes reduces the yield when stock plate orders are allocated and the residence time of inventory.

  In addition, in the said embodiment, this invention is applied to manufacture management of a thick steel plate, and the application object of this invention is not limited to this, It is clear that it can apply to a steel plate generally similarly. In addition to extending the length, the width may be increased.

Schematic diagram showing a general steel plate manufacturing process Conceptual diagram showing losses due to order combinations in steel plate manufacturing and losses due to equipment constraints System configuration diagram in the present invention The flowchart which shows the example of the information processing in embodiment of this invention The figure which shows the Example which similarly performed the dimension change of the surplus material part by this invention The figure which shows the example which analyzed the order frequency from the past order results similarly by this invention The figure which shows the example of yield improvement by this invention The figure which shows the example of improvement of stock residence days

Explanation of symbols

100 ... New order information database (DB)
110 ... Inventory information DB
120 ... Past order information DB
130 ... Order combination calculation device 140 ... Past order information analysis device 150 ... Extra length control device

Claims (2)

When managing production of custom-made steel plates,
Establish a database with information on standards, dimensions, and specifications for surplus materials generated due to manufacturing restrictions.
Frequency of ordering dimensions for each standard, specification, and surplus material database Adjust the surplus material length longer than the shortest order size so that the allocation frequency will improve at the slab design stage, and the allocation frequency to the order A production management method in steel plate production, characterized in that the yield when stock plate orders are allocated and the dwell time of inventory are reduced.   The production management method in steel plate manufacturing according to claim 1, wherein the surplus material dimensions are adjusted so as to fill a difference from a target stock of the surplus materials.