Fraction defective estimating method, system for carrying out the same recording medium

• US 6,895,350 B2
• Filed: 02/13/2003
• Issued: 05/17/2005
• Est. Priority Date: 03/31/1997
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Asano, Masaaki, Miyakawa, Seii, Suzuki, Tatsuya, Kubota, Takashi, Ohashi, Toshijiro
• Primary Examiner(s): Shah, Kamini
• Assistant Examiner(s): Le, Toan M.
• Application Number:
  US10/365,433
• Publication Number:
  US 20040083019A1
• Time in Patent Office: 824 Days
• Field of Search: 702/81, 702/182, 700/117
• US Class Current: 702/81
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling

Abstract

A method and a system for estimating an assembling-related fraction defective coefficient of an article in the stage preceding to manufacturing, e.g. at a stage of design. Assembling operation, properties/conditions of parts to be assembled and conditions of an assembling shop having significant influence to the likelihood of occurrence of failure in assembling work are inputted as data. Estimated value of assembling-related fraction defective is arithmetically determined with high accuracy by executing an assembling-related fraction defective value estimating program on the basis of the data as inputted.

Claims

1. A fraction defective estimating method for estimating an assembling failure potential (fraction defective) upon manufacturing of a part constituting an article in precedence to manufacturing said part, said fraction defective estimating method comprising the steps of:

defining in advance a plurality of standard assembling operations by classifying assembling operations involved in a manufacturing process as attachment-destined parts and attachment-subjected parts;

setting for each of said standard assembling operations a fraction defective coefficient represented by a numerical value indicative of a probability at which the assembling operation cannot be carried out without fail;

representing apart under evaluation in terms of a combination of said standard assembling operations; and

estimating the fraction defective of said part under evaluation by adding together the fraction defective coefficients which said standard assembling operations have, respectively.

2. A fraction defective estimating method according to claim 1, further comprising the steps of:

determining arithmetically a supplementary factor for correcting said fraction defective coefficient for each of said standard assembling operations based on a combination information of said standard assembling operations; and

estimating the fraction defective by adding together the fraction defective coefficients acquired after having corrected said fraction detective coefficient for each of said standard assembling operations with said supplementary factor.

3. A fraction defective estimating method according to claim 1, further comprising the steps of:

determining arithmetically a supplementary factor for correcting said fraction defective coefficient for each of said standard assembling operations based on the number of said standard assembling operations; and

estimating the fraction defective by adding together the fraction defective coefficients acquired after having corrected said fraction defective coefficient for each of said standard assembling operations with said supplementary factor.

4. A fraction detective estimating method according to claim 1, further comprising the steps of:

determining arithmetically a supplementary factor for correcting said fraction defective coefficient for each of said standard assembling operations based on property of an attachment-destined part and that of an attachment-subjected part which are subjected to said assembling operations; and

estimating the fraction defective by adding together the fraction defective coefficients acquired after having corrected said fraction defective coefficient for each of said standard assembling operations with said supplementary factor.

5. A fraction detective estimating method according to claim 1, further comprising the steps of:

determining arithmetically a supplementary factor for correcting said fraction defective coefficient for each of said standard assembling operations based on environmental conditions of a shop where assembling work is performed; and

estimating the fraction defective by adding together the fraction defective coefficients acquired after having corrected said fraction defective coefficient for each of said standard assembling operations with said supplementary factor.

6. A fraction defective estimating method according to claim 1, further comprising the steps of:

determining arithmetically a supplementary factor for correcting said fraction defective coefficient for each of said standard assembling operations in dependence on presence or absence of a process for confirming whether or not an assembling work has been carded out without fall after completion of said assembling work; and

estimating the fraction defective by adding together the fraction defective coefficients acquired after having corrected said fraction defective coefficient for each of said standard assembling operations with said supplementary factor.

7. A fraction defective estimating method according to claim 1, further comprising the steps of:

dividing said standard assembling operations into positioning operations and post-positioning operations, operations succeeding to said positioning operation; and

determining arithmetically said fraction defective coefficient of said standard assembling operations based on combination of fraction defective coefficients relative to said positioning operations and fraction defective coefficients relative to said post-positionings.

8. A fraction defective estimating method according to claim 1, further comprising the steps of:

dividing said standard assembling operations into positioning operations and post-positioning operations, operations succeeding to said positioning operation,

wherein said fraction defective coefficients are set discretely in dependence on precision degrees of said positioning operations even when said positioning operations are of a same type.

9. A method of estimating an assembling failure potential (fraction defective) upon manufacturing an article which is constituted by a plurality of parts in precedence to manufacturing said article, the method comprising the step of,

estimating the fraction defective of said article based on results of fraction defective estimations performed for a plurality of parts constituting said article, wherein each fraction defective estimation performed according to said fraction defective estimating method set forth in claim 1.

10. A fraction defective estimating system for estimating an assembling failure potential (fraction defective) upon manufacturing of parts constituting an article in precedence to manufacturing said part, comprising:

input means for receiving as inputs thereto information concerning assembling operations of said parts and information concerning properties of attachment-destined parts and attachment-subjected parts, respectively, which are to undergo said assembling operations;

fraction defective coefficient storing means for setting and storing a fraction defective coefficient probability at which the assembling operation cannot be carried out without fail for each of plural standard assembling operations defined by classifying in advance the assembling operations involved in a manufacturing process;

supplementarily factor storing means for storing supplementary factors for correcting the fraction defective coefficients of said standard assembling operations, respectively, on the basis of properties of said attachment-destined parts undergoing said assembling operations and supplementary factors for correcting the fraction defective coefficients of said standard assembling operations, respectively, on the basis of properties of said attachment-subjected parts undergoing said assembling operations;

program storing means for storing a computation program; and

computing means for reading said computation program for execution thereof and reading out said fraction defective coefficients and said supplementary factors from said fraction defective coefficient storing means and said supplementary factor storing means, respectively, based on information input through said input means for correcting said fraction defective coefficients with said supplementary factors, to thereby compute the fraction defectives of said parts by adding together said fraction defective coefficients after the correction thereof.

11. A fraction defective estimating system according to claim 10, wherein said computing means is so arranged as to estimate the fraction defective of an article constituted by a plurality of parts based on a result of the fraction defective estimation performed for said plurality of parts constituting said article.

12. A computer program product for an information terminal having input means, output means and computing means, said information terminal including a device for a readable medium, wherein a program code read out from said medium and executed by said computing means comprises the steps of:

classifying in advance assembling operations of parts in a manufacturing process to register said classified assembling operations as standard assembling operations;

setting for each of said standard assembling operations a fraction defective coefficient represented by a numerical value indicative of a probability at which the assembling operation cannot be carried out without fail;

representing a plurality of parts constituting an article under evaluation by in terms of combinations of said standard attaching operations; and

estimating assembling-related fraction defectives upon manufacturing said plurality of parts constituting said article.

13. A computer program product according to claim 12, further comprising the steps of:

estimating an assembling-related fraction defective upon manufacturing said article based on the assembling-related fraction defectives of said plurality of parts.