Manufacturing project forming method and device

• US 5,737,228 A
• Filed: 02/06/1996
• Issued: 04/07/1998
• Est. Priority Date: 02/09/1995
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ishizuka, Hiroaki, Matsumoto, Shigeru
• Primary Examiner(s): Trammell, James P.
• Application Number:
  US08/597,257
• Time in Patent Office: 791 Days
• Field of Search: 364/468.05-468.1
• US Class Current: 700/102
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G05B 2219/31407 Machining, work, process finish time estimation, calculation
• CPC Class Codes: G05B 2219/32304 Minimize flow time, tact, shortest processing, machining time
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A variable F (a, n) defined by Equation (1) (wherein k (a, n) is a constant set on a step P (a, n) which is the nth step of a product a, Tave (a, n) is an average wait time for the same step as the step P (a, n) which is obtained from the past processing results, Tw1 (a, n) is a processing wait time which is a time difference between a processing end time for a step P (a, n--1) and a processing start time for the step P (a, n), N (a) is a final step for the product a, Te (a, N(a)) is a end time for a final step P (a, N(a)), Tout (a) is a target delivery date for The product a, and E (a) is the number of steps in which the product a is not yet processed) is set on all manufacturing steps of a product which is put in a manufacturing line. The processing start and end times for each step are determined in such a manner that the absolute value of the variable F (a, n) is smaller than a preset constant Fmax which is equal to or greater than 0 so that an initial manufacturing project is formed. The initial manufacturing project is corrected so as not to violate preset constraint conditions. Equation (1) equals: ##EQU1##

Claims

1. A method of forming a manufacturing project for a product which is put in a manufacturing line comprising;

an initial manufacturing project forming step of setting, on all manufacturing steps, a variable F (a, n) defined by Equation (1);

##EQU11## wherein k (a, n) is a constant set on a step P (a, n) which is the nth step of a product a, Tave (a, n) is an average wait time for the same step as the step P (a, n) which is obtained from the past processing results, Tw1 (a, n) is a processing wait time which is a time difference between a processing end time for a step P (a, n-1) and a processing start time for the step P (a, n), N (a) is a final step for the product a, Te (a, N(a)) is a finish time for a final step P (a, N(a)), Tout (a) is a target delivery date for the product a, and E (a) is the number of steps in which the product a is not yet processed, and then determining the processing start and end times for each step in such a manner that the absolute value of the variable F (a, n) is smaller than a preset constant Fmax which is equal to or greater than 0 so that an initial manufacturing project is formed, and

a constraint condition canceling step for correcting the initial manufacturing project formed in the initial manufacturing project forming step in such a manner that the initial manufacturing project does not violate preset constraint conditions.

2. A method of forming a manufacturing project for a product which is put in a manufacturing line comprising;

an initial manufacturing project forming step of setting, on all manufacturing steps, a variable F (a, n) defined by Equation (2);

##EQU12## wherein A is the number of products, N (i) is the number of steps for a product i, G (a, n), h (a, n) and m (a, n) are constants which are common in steps having the same contents of the processing as those of the step P (a, n) which is the nth step of a product a, Tw2 (P (a, n), P (i, j)) is a time difference between a processing start time for the step P (a, n) and the processing start time for a step P (i, j) if a manufacturing apparatus for executing the processing of the step P (a, n) can perform the batch processing, Tw2 (P (a, n), P (i, j)) is a time difference between a processing end time for the step P (a, n) and the processing start time for the step P (i, j) if the manufacturing apparatus for executing the processing of the step P (a, n) cannot perform the batch processing and the processing start time for the step P (a, n) is earlier than the processing start time for the step P (i, j), or Tw2 (P (a, n), P (i, j)) is a time difference between the processing start time for the step P (a, n) and the processing end time for the step P (i, j) if the manufacturing apparatus for executing the processing of the step P (a, n) cannot perform the batch processing and the processing start time for the step P (a, n) is later than the processing start time for the step P (i, j), δ

(P (a, n), P (i, j)) has a value of 1 if the processing conditions for the step P (a, n) are the same as those for the step P (i, j), and has a value of 0 if the processing conditions for the step P (a, n) are different from those for the step P (i, j), f (a, n) is a constant or a function which increases as the number of steps having the same processing conditions as those for the step P (a, n) increases, and then determining the processing start and end times for each step in such a manner that the absolute value of the variable F (a, n) is smaller than a preset constant Fmax which is equal to or greater than 0 so that an initial manufacturing project is formed, and

a constraint condition canceling step for correcting the initial manufacturing project formed in the initial manufacturing project forming step in such a manner that the initial manufacturing project does not violate preset constraint conditions.

3. A method of forming a manufacturing project for a product which is put in a manufacturing line comprising;

an initial manufacturing project forming step of setting, on all manufacturing steps, a variable F (a, n) defined by Equation (3);

##EQU13## wherein k (a, n) is a constant set on a step P (a, n) which ts the nth step of a product a, Tave (a, n) is an average wait time for the same seep as the step P (a, n) which is obtained from the past processing results, Tw1 (a, n) is a processing wait time which is a time difference between a processing end time for a step P (a, n-1) and a processing start time for the step P (a, n), A is the number of products, N (i) is the number of steps for a product i, G (a, n), h (a, n) and m (a, n) are constants which are common in steps having the same contents of the processing as those of the step P (a, n), Tw2 (P (a, n), P (i, j)) is a time difference between the processing start time for the step P (a, n) and the processing start time for a step P (i, j) if a manufacturing apparatus for executing the processing of the step P (a, n) can perform the batch processing, Tw2 (P (a, n), P (i, j)) is a time difference between the processing end time for the step P (a, n) and the processing start time for the step P (i, j) if the manufacturing apparatus for executing the processing of the step P (a, n) cannot perform the batch processing and the processing start time for the step P (a, n) is earlier than the processing start time for the step P (i, j), or Tw2 (P (a, n), P (i, j)) is a time difference between the processing start time for the step P (a, n) and the processing end time for the step P (i, j) if the manufacturing apparatus for executing the processing of the step P (a, n) cannot perform the batch processing and the processing start time for the step P (a, n) is later than the processing start time for the step P (i, j), δ

(P (a, n), P (i, j)) has a value of 1 if the processing conditions For the step P (a, n) are the same as those for the step P (i, j), and has a value of 0 if the processing conditions for the step P (a, n) are different from those for the step P (i, j), f (a, n) is a constant or a function which increases as the number of steps having the same processing conditions as those for the step P (a, n) increases, Te (a, N(a)) is a finish time for a final step P (a, N(a)), Tout (a) is a target delivery date for the product a, and E (a) is the number of steps in which the product a is not yet processed, and then determining the processing start and end times for each step in such a manner that the absolute value of the variable F (a, n) is smaller than a preset constant Fmax which is equal to or greater than 0 so that an initial manufacturing project is formed, and

a constraint condition canceling step for correcting the initial manufacturing project formed in the initial manufacturing project forming step in such a manner that the initial manufacturing project does not violate preset constraint conditions.

4. A device for forming a manufacturing project comprising;

line information fetching means for fetching line information such as the operation information about a manufacturing apparatus on a manufacturing line, the beginning information about a product and the like,

step allocating means for calculating processing start and end times Ts (a, n) and Te (a, n) for the unprocessed steps out of the step P (a, n) as the nth step of a product a based on the line information fetched by the line information fetching means with Equation (4);

##EQU14## wherein Tave (a, n) is an average wait time for the same step as the step P (a, n) which is obtained from the past processing results, N (a) is a final step for the product a, Te (a, N(a)) is a finish time for a final step P (a, N(a)), Tout (a) is a target delivery date for the product a, E (a) is the number of steps in which the product a is not yet processed, and T (a, n) is a processing time for the nth step of the product a,

variable calculating means for calculating each variable F (a, n) of the unprocessed steps by Equation (5);

##EQU15## wherein k (a, n) is a constant set on the step P (a, n), Tave (a, n) is an average wait time for the same step as the step P (a, n) which is obtained from the past processing results, Tw1 (a, n) is a processing wait time which is a time difference between the processing end time for a step P (a, n-1) and the processing start time for the step P (a, n), A is the number of products, N (i) is the number of steps for a product i, G (a, n), h (a, n) and m (a, n) are constants which are common in steps having the same contents of the processing as those of the step P (a, n), Tw2 (P (a, n), P (i, j)) is a time difference between the processing start time for the step P (a, n) and the processing start time for a step P (i, j) if a manufacturing apparatus for executing the processing of the step P (a, n) can perform the batch processing, Tw2 (P (a, n), P (i, j)) is a time difference between the processing end time for the step P (a, n) and the processing start time for the step P (i, j) if the manufacturing apparatus for executing the processing of the step P (a, n) cannot perform the batch processing and the processing start time for the step P (a, n) is earlier than the processing start time for the step P (i, j), or Tw2 (P (a, n), P (i, j)) is a time difference between the processing start time for the step P (a, n) and the processing end time for the step P (i, j) if the manufacturing apparatus for executing the processing of the step P (a, n) cannot perform the batch processing and the processing start time for the step P (a, n) is later than the processing start time for the step P (i, j), δ

(P (a, n), P (i, j)) has a value of 1 if the processing conditions for the step P (a, n) are the same as those for the step P (i, j), and has a value of 0 if the processing conditions For the step P (a, n) are different from those for the step P (i, j), f (a, n) is a constant or a function which increases as the number of steps having the same processing conditions as those for the step P (a, n) increases, Te (a, N(a)) is a finish time for a final step P (a, N(a)), Tout (a) is a target delivery date for the product a, and E (a) is the number of steps in which the product a is not yet processed,

step moving means for changing the processing start and end times Ts (a, n) and Te (a, n) in such a manner that the processing of each step is started at the time when the variable F (a, n) is equal to or smaller than a preset constant Fmax sequentially from a step having the greatest absolute value of the variable F (a, n) obtained by the variable calculating means so that an initial manufacturing project is created, and

constraint condition canceling means for correcting the initial manufacturing project created by the step moving means in such a manner that the initial manufacturing project does not violate preset constraint conditions so that the manufacturing project is formed.

5. The device according to claim 4, further comprising forward moving means for moving forward the processing start and end times Ts (a, n) and Te (a, n) for each manufacturing step of the manufacturing project formed by the constraint condition canceling means within the range in which the manufacturing project does not violate the constraint conditions.

6. The device according to claim 4, further comprising initial manufacturing project forming time checking means for deciding whether the variable F (a, n) should be calculated again by the variable calculating means or not after the step allocating means finds the variable F (a, n), causing the variable calculating means to calculate the variable F (a, n) again, then causing the step moving means to change again the processing start and finish times Ts (a, n) and Te (a, n) so as to start the processing at the time when the variable F (a, n) calculated again is equal to or smaller than a preset constant Fmax so that the initial manufacturing project is created if the initial manufacturing project forming time checking means decides that the variable F (a, n) should be calculated again, and causing the constraint condition canceling means to correct the initial manufacturing project created by the step allocating means in such a manner that the initial manufacturing project does not violate preset constraint conditions so that the manufacturing project is formed if the initial manufacturing project forming time checking means decides that the variable F (a, n) should not be calculated again.

7. The device according to claim 4, further comprising means for moving the nth step of a product a before or after the down period of a processor for executing the processing of the nth step of the product a if the processor is in the down state for a processing period defined by the processing start and end times Ts (a, n and Te (a, n) obtained by the step allocating means.

8. The device according to claim 4, further comprising;

constant setting means having initializing means for setting constants k (a, n), m (a, n) and h (a, n) in Equation (5) to optional initial-values, constant selecting means for selecting other values which are different from the initial-values, and constant changing means for changing the constants k (a, n), m (a, n) and h (a, n) from the initial-values to the other values so as to set the changed values,

manufacturing project evaluating means for evaluating the validity of the manufacturing project formed by the constraint condition canceling means, and

constant setting time checking means for deciding whether a time for the processing executed by the constant setting means is within the range of a preset constant setting time, causing the constant setting means to continue the processing if the time for the processing is shorter than the constant setting time, and causing the constant setting means to complete the processing if the time for the processing is equal to or longer than the constant setting time,

wherein the variable calculating means has the function of calculating the variable F (a, n) with Equation (5) based on the initial value set by the initializing means and the changed value set by the constant changing means.

9. The device according to claim 4, further comprising processor selecting means for selecting a processor which is the most suitable for the processing of each step if there are a plurality of processors used for the processing of each step.

10. A device for forming a manufacturing project comprising;

line information fetching means for fetching line information such as the operation information about a manufacturing apparatus on a manufacturing line, the beginning information about a product and the like,

line update information fetching means for fetching the updated line information if any,

step allocating means for calculating processing start and end times Ts (a, n) and Te (a, n) for the unprocessed steps out of the step P (a, n) as the nth step of a product a based on the line information fetched by the line information fetching means with Equation (6);

##EQU16## wherein Tave (a, n) is an average wait time for the same step as the step P (a, n) which is obtained from the past processing results, N (a) is a final step for the product a, Te (a, N(a)) is a finish time for a final step P (a, N(a)), Tout (a) is a target delivery date for the product a, E (a) is the number of steps in which the product a is not yet processed, and T (a, n) is a processing time for the nth step of the product a,

variable calculating means for calculating each variable F (a, n) of the unprocessed manufacturing steps by Equation (7);

##EQU17## wherein k (a, n) is a constant set on the step P (a, n), Tw1 (a, n) is a processing wait time which is a time difference between the processing end time for a step P (a, n-1) and the processing start time for the step P (a, n), A is the number of products, N (i) is the number of steps for a product i, G (a, n), h (a, n) and m (a, n) are constants which are common in steps having the same contents of the processing as those of the step P (a, n), Tw2 (P (a, n), F (i, j)) is a time difference between the processing start time for the step P (a, n) and the processing start time for a step P (i, j) if a manufacturing apparatus for executing the processing of the step P (a, n) can perform the batch processing, Tw2 (P (a, n)), P (i, j)) is a time difference between the processing end time for the step P (a, n) and the processing start time for the step P (i, j) if the manufacturing apparatus for executing the processing of the step P (a, n) cannot perform the batch processing and the processing start time for the step P (a, n) is earlier than the processing start time for the step P (i, j), or Tw2 (P (a, n), P (i, j)) is a time difference between the processing start time for the step P (a, n) and the processing end time for the step P (i, j) if the manufacturing apparatus for executing the processing of the step P (a, n) cannot perform the batch processing and the processing start time for the step P (a, n) is later than the processing start time for the step P (i, j), δ

(P (a, n), P (i, j)) has a value 1 if the processing conditions for the step P (a, n) are the same as those for the step P (i, j), and has a value of 0 if the processing conditions for the step P (a, n) are different from those for the step P (i, j), and f (a, n) is a constant or a function which increases as the number of steps having the same processing conditions as those for the step P (a, n) increases,

step moving means for changing the processing start and end times Ts (a, n) and Te (a, n) in such a manner that the processing of each step is started at the time when the variable F (a, n) is equal to or smaller than a preset constant Fmax sequentially from a step having the greatest absolute value of the variable F (a, n) obtained by the variable calculating means so that an initial manufacturing project is created,

initial manufacturing project duplicating means for duplicating the initial manufacturing project created by the step moving means to create two initial manufacturing projects, and

constraint condition canceling means for correcting one of the initial manufacturing projects created by the initial manufacturing project duplicating means in such a manner that the initial manufacturing project does not violate preset constraint conditions so that a manufacturing project is formed,

wherein the step allocating means has the function of calculating the processing start and end times Ts (a, n) and Te (a, n) for the manufacturing step which should be updated, with Equation (6), based on the updated line information fetched by the line update information fetching means and the other initial manufacturing project created by the initial manufacturing project duplicating means, and

wherein the variable calculating means has the function of calculating, with Equation (7), the variable F (a, n) of the manufacturing step which should be updated.

11. The device according to claim 10, further comprising forward moving means for moving forward the processing start and end times Ts (a, n) and Te (a, n) for each manufacturing step of the manufacturing project formed by the constraint condition canceling means within the range in which the manufacturing project does not violate the constraint conditions.

12. The device according to claim 10, further comprising initial manufacturing project forming time checking means for deciding whether the variable F (a, n) should be calculated again by the variable calculating means or not after the step allocating means finds the variable F (a, n), causing the variable calculating means to calculate the variable F (a, n) again, then causing the step moving means to change the processing start and end times Ts (a, n) and Te (a, n) again so as to start the processing at the time when the variable F (a, n) calculated again is equal to or smaller than a preset constant Fmax so that the initial manufacturing project is created if the initial manufacturing project forming time checking means decides that the variable F (a, n) should be calculated again, and causing the constraint condition canceling means to correct the initial manufacturing project created by the step allocating means in such a manner that the initial manufacturing project does not violate preset constraint conditions so that the manufacturing project is formed if the initial manufacturing project forming time checking means decides that the variable F (a, n) should not be calculated again.

13. The device according to claim 10, further comprising means for moving the nth step of a product a before or after the down period of a processor for executing the processing of the nth step of the product a if the processor is in the down state for a processing period defined by the processing start and end times Ts (a, n) and Te (a, n) obtained by the step allocating means.

14. The device according to claim 10, further comprising processor selecting means for selecting a processor which is the most suitable for the processing of each step if there are a plurality of processors used for the processing of each step.

15. The device according to claim 10, further comprising:

constant setting means having initializing means for setting constants k (a, n), m (a, n) and h (a, n) in Equation (7) to optional initial-values, constant selecting means for selecting other values which are different from the initial-values, and constant changing means for changing the constants k (a, n), m (a, n) and h (a, n) from the initial-values to the other values so as to set the changed values,

manufacturing project evaluating means for evaluating the validity of the manufacturing project formed by the constraint condition canceling means, and

constant setting time checking means for deciding whether a time for the processing executed by the constant setting means is within the range of a preset constant setting time, causing the constant setting means to continue the processing if the time for the processing is shorter than the constant setting time, and causing the constant setting means to complete the processing if the time for the processing is equal to or longer than the constant setting time,

wherein the variable calculating means has the function of calculating the variable F (a, n) with Equation (7) based on the initial value set by the initializing means and the changed value set by the constant changing means.