Method and apparatusa for determining supply sequence of products ot be processed to production line

• US 5,506,783 A
• Filed: 06/29/1994
• Issued: 04/09/1996
• Est. Priority Date: 06/29/1993
• Status: Expired due to Fees

• Current Assignee: Hitachi Communication Systems Incorporated (Hitachi, Ltd.), Hitachi, Ltd.
• Original Assignee: Hitachi Communication Systems Incorporated (Hitachi, Ltd.), Hitachi, Ltd.
• Inventors: Ikebe, Junichi, Haga, Hidetoshi, Tanaka, Kiyofumi
• Primary Examiner(s): Mai, Tan V.
• Assistant Examiner(s): BROWN, THOMAS
• Application Number:
  US08/268,375
• Time in Patent Office: 650 Days
• Field of Search: 364/131, 364/138, 364/140, 364/468, 364/469, 364/401-403, 364/478, 364/148, 364/149
• US Class Current: 700/101
• CPC Class Codes: G06Q 10/04 Forecasting or optimisation specially adapted for administrative or management purposes, e.g. linear programming or "cutting stock problem" market predictions or forecasting for commercial activities G06Q30/0202

Abstract

A method of determining supply sequence of products to be processed to an N-step flow shop type production line, where N is an integer N greater than or equal to 2, is disclosed. To optimize the production time of all the products in the N-step flow shop type production line with high precision, the supply sequence of products to be processed to the N-step flow shop type production line is determined by virtually dividing the N steps to 2 virtual steps on the basis of a total number of necessary man-hour of products to be processed, sequencing the supply of the products to be processed in one of the virtual steps to a first step of the N steps in the order of smallness of the required man-hours for the product, storing the product to be processed in the other virtual step in a stack memory as products for which a new supply sequence is to be determined and repeating the supply sequence determining processing recurrently as long as N is greater than or equal to 2 and the stack memory contains stored virtual steps.

Claims

1. A method of determining a supply sequence of products to be processed to an N-step flow shop type production line, where N is an integer greater than or equal to 2, for a group of products to be assembled on a given day in an assembly line, wherein each of the products has pre-determined number of man-hours needed for each of respective flow shop steps, comprising:

dividing N-steps to 2 virtual steps on the basis of a total number of the pre-determined necessary man-hours for the products to be processed;

assigning a supply sequence of the products to be processed in one of the virtual divided steps to a first step in the order of smallness of the pre-determined man-hours of the product in the virtual step;

if the other virtual step contains a plurality of individual steps, storing the other virtual step in a stack memory as products for which a new supply sequence is to be determined;

if the stack memory contains stored virtual steps, redefining N as being the number of individual steps contained in a virtual step stored in the stack memory;

repeating the supply sequence determining processing recurrently as long as N is greater than or equal to 2; and

supplying the products to the N-step production line on the basis of the results of the supply sequence determination.

2. The method of claim 1, wherein the step of dividing N-steps to 2 virtual steps further comprises:

assigning an earliest processing start date and a latest scheduled finishing date to each of the products to be assembled on a given date;

assigning a day of determination to the given date; and

comparing the given date with the earliest processing start day and the latest scheduled finishing date for each of the products to be assembled on the given date to thereby determine the supply sequence of the products to be processed.

3. The method of claim 1, further comprising:

assigning a day of determination to a first given date;

identifying products which have a second given date wherein the second given date is less than the first given date and the identified products have not been completely assembled;

assigning the identified products to a step in the N-step flow shop type production line; and

thereafter dividing the N-steps to 2 virtual steps to determine the supply sequence.

4. The method of claim 1, further comprising:

identifying products that are to be assembled preferentially;

assigning a priority to each of the identified products;

arranging the identified products in the order of their assigned priorities; and

thereafter dividing the N-steps to 2 virtual steps to determine the supply sequence.

5. An apparatus for determining a supply sequence of products to be processed to an N-step flow shop type production line, where N is an integer greater than or equal to 2, for a group of products to be assembled on a given day in an assembly line, wherein each of the products has pre-determined number of man-hours needed for the respective flow shop steps, comprising:

an external memory device for preliminarily storing a product database which registers products to be assembled and the pre-determined man-hours necessary for assembly of each of the products;

a stack memory for storing products for which the supply sequence has not been determined;

input means for inputting to the product database in the external memory device the products to be assembled and the pre-determined man-hours required for assembly of each of the products;

means for dividing the N-steps to 2 virtual steps on the basis of a total number of the pre-determined man-hours of the products to be processed;

means for assigning a supply sequence of the products to a first step in the order of smallness of the pre-determined man-hours of products in one of the virtual steps;

means for storing the products in the second virtual step in a stack memory as products for which a new supply sequence is to be determined, when the second virtual step contains a plurality of individual steps;

means for redefining N as being the number of individual steps contained in a virtual step in the stack memory; and

means for providing a virtual step stored in the stack memory to the dividing means so as to repeat the supply sequence determining processing recurrently as long as N is greater than or equal to 2.

6. The apparatus of claim 5, wherein the external memory device further registers in the product database an earliest processing start date and a latest scheduled finishing date for each of the products in the data base and wherein the apparatus further comprises deriving means for deriving products whose supply sequence is to be determined by comparing a date of the determination of supply sequence with the earliest processing start day and the latest scheduled finishing date of the products in the product database whereby the supply sequence of the products to be processed is determined.

7. The apparatus of claim 5, further comprising:

means for assigning a day of determination to a first given date;

means for identifying products which have a second given date wherein the second given date is less than the first given date and the identified products have not been completely assembled; and

means for assigning the identified products to a step in the N-step flow shop type production line before dividing the N-steps to 2 virtual steps to determine the supply sequence.

8. The apparatus of claim 5, further comprising means for identifying products that are to be assembled preferentially, means for assigning a priority to each of the identified products, and means for arranging the identified products in the order of their priority before dividing the N-steps to 2 virtual steps to determine the supply sequence.

9. A method of determining a worker arrangement in the respective processing steps of products to be processed and supplied in an N-step flow shop type production line, where N is an integer greater than or equal to 2, for a group of products to be assembled on a given day in an assembly line, wherein each of the products has a pro-determined number of man-hours needed for assembly, comprising:

calculating a man-hour pile for each of the steps in the N-step flow shop type production line;

.

sequentially searching for a flow shop step whose man-hour pile is maximum among the flow shop steps;

assigning necessary workers to the flow shop step having the maximum man-hour pile; and

if the maximum man-hour pile of the flow shop step is smaller than that for one worker, assigning the one worker to the flow shop step together with at least one other flow shop step adjacent thereto;

wherein the man-hour pile in the respective steps is a sum of the man-hours of the products to be processed in the respective steps, and wherein the method further comprises a supply sequence determining process which includes the steps of;

dividing N-steps to 2 virtual steps on the basis of a total number of necessary man hours of products to be processed;

assigning a supply sequence of the products in a first of the virtual steps to a first step in the order of smallness of the pre-determined man-hours for each product;

if the second virtual step contains a plurality of individual steps, storing the second virtual step in a stack memory as products for which a new supply sequence is to be determined;

if the stack memory contains stored virtual steps, redefining N as being the number of individual steps contained in a virtual step stored in the stack memory; and

repeating the supply sequence determining process recurrently as long as N is greater than or equal to 2.

10. An apparatus for determining a worker arrangement in the respective processing steps of products to be processed and supplied in an N-step flew shop type production line, where N is an integer greater than 2, for a group of products to be assembled on a given day in an assembly line, wherein each of the products has a pre-determined number of man-hours needed for each of the respective flow shop steps, comprising:

an external memory device for preliminarily storing a product database which registers products to be assembled and the pre-determined man-hours necessary for assembly of each of the products;

input means for inputting to the product database in the external memory device the products to be assembled and the pre-determined man-hours required for assembly of each of the products;

means for determining the worker arrangement, including means for calculating man-hour piles for the respective steps in the production line, means for sequentially searching the man-hour piles to identify a step whose man-hour pile is maximum, and means for assigning necessary workers to the identified step having a maximum man-hour pile and for assigning at least a part of the steps adjacent to the step having a maximum man-hour pile to at least one of the workers assigned to the maximum man-hour pile step if the maximum man-hour pile is smaller than for one worker;

wherein the man-hour pile in the respective steps is a sum of the pre-determined man-hours of the products to be processed in the respective steps, and wherein the apparatus further comprises means for dividing N-steps to 2 virtual steps on the basis of a total number of pre-determined man-hours of products to be processed, means for assigning a supply sequence of the products to be processed to a first step in the order of smallness of the pre-determined man-hours of product in a first of the virtual steps, means for storing the second virtual step in a stack memory as products for which a new supply sequence is to be determined if the second virtual step contains a plurality of individual steps, means for redefining N as being the number of individual steps contained in a virtual step stored in the stack memory, and means for providing a virtual step in the stack memory to the dividing means to repeat the supply sequence determining processing recurrently as long as N is greater than or equal to 2.

11. The apparatus of claim 10, further comprising simulation and operation means for producing time charts of the respective steps by simulating progressions in the respective steps on the basis of a resultant worker arrangement in the respective steps, and display means for displaying a resultant supply sequence determination of products to be processed and the progression in the respective individual steps.

12. A method of determining a supply sequence of products to a production line having plural flow shop steps, wherein the number of steps is an integer greater than or equal to 2 and each of the products has a pre-determined number of man-hours needed for each of the respective flow shop steps, comprising:

calculating a total of the pre-determined necessary man-hours of the products per each flow shop step;

virtually dividing the plural flow shop steps to be processed into a first half and second half so that a sum of the total pre-determined necessary man-hours per each step involved in the first half is almost equal to a sum of the total pre-determined necessary man-hours per each step involved in the second half steps;

assigning a supply sequence of the products to be processed in order of smallness of total man-hours such that products from the first half should be processed first in the order of smallness of man-hour of a product and products from the second half should be processed late in the order of smallness of man-hour of a product;

testing whether either the first half or the second half contains more than 2 individual steps and if so, repeating the method from the virtual dividing step through the testing step until all virtual steps contain 2 or less individual steps; and

supplying the products to the production line having a plural flow shop steps on the basis of the supply sequence determination.

13. The method of claim 12 wherein the testing step further comprises the step of applying the repeating step to the second half before repeating to process the first half, if both the first and second half contain more than two individual steps.