Quality control system for manufacturing industrial products

• US 20060047454A1
• Filed: 07/01/2005
• Published: 03/02/2006
• Est. Priority Date: 08/27/2004
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nonaka, Youichi, Tamaki, Kenji
• Granted Patent: US 7,209,846 B2
• Time in Patent Office: Days
• US Class Current: 702/84
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling

Abstract

In a quality control system for manufacturing industrial products, the product quality history and the manufacturing process history are collected and collated to calculate the correlation magnitude between the two histories. The candidates for the cause of quality variation hidden in the manufacturing processes are listed, and the correlation magnitude between all combinations of the variates of the manufacturing process history are calculated. Further, by utilizing the manufacturing sequence history used for an input plan, a causation connecting structure model between the manufacturing processes of the manufacturing line is automatically generated and automatically analyzed thereby to automatically extract the fundamental cause of quality variation from the candidates for the cause of quality variation. By doing so, the cause of quality variation of industrial products manufactured through a complicated process can be traced in a complicated connecting structure in the manufacturing history data.

Claims

1. A product quality control system for controlling the quality of a product manufactured through a plurality of manufacturing processes and at least one inspection process, comprising:

a manufacturing sequence information management apparatus for storing and controlling the information on the order in which selected one of a material, a part and a product in progress used for manufacturing the product is input into each manufacturing process;

a manufacturing management apparatus for storing selected one of the product, the material, the part and the product in progress with corresponding unique individual identification information and giving an instruction to manufacture the product based on the individual identification information, the sequence information supplied from the manufacturing sequence information management apparatus and a product manufacturing plan; and

a causation analysis apparatus of quality variation for analyzing the cause of product quality variation based on the manufacturing history data collected by the manufacturing history data collection apparatus associated with each manufacturing process and corresponding to the individual identification information on the one hand and the product quality history data of the product corresponding to the individual identification information and measured at the inspection process on the other hand;

wherein the causation analysis apparatus of quality variation includes a correlation analysis module of quality variation for calculating by collation the statistical correlation magnitude between the quality history data and the manufacturing history data using the individual identification information and automatically extracting the candidates for at least one manufacturing process likely to cause the product quality variation based on the statistical correlation magnitude, and a causation analysis module of quality variation for calculating by collation the mutual statistical correlation magnitude between the manufacturing history data themselves using the individual identification information, and based on the statistical correlation magnitude and the sequence information thus obtained, determining the connecting structure information between the manufacturing processes thereby to automatically determine and extract the manufacturing process causing the product quality variation from the candidates for the product quality variation causing processes.

2. A product quality control system according to claim 1,

wherein the manufacturing history data concerns the processing and assembling in a manufacturing process, and includes selected one of the quality measurement values and the inspection values of selected one of a part and a product in progress processed in the manufacturing process.

3. A product quality control system according to claim 1,

wherein the manufacturing process has at least one manufacturing equipment for executing a manufacturing process, each manufacturing equipment corresponds to a unique machine number, and the manufacturing history data concerns the processing and assembling in the manufacturing process and includes the manufacturing execution equipment route information based on the machine number of the manufacturing equipment through which selected one of the part, the product in progress and the product is passed in each of the manufacturing processes.

4. A product quality control system according to claim 1,

wherein the manufacturing history data concerns the processing and assembling in a manufacturing process, and includes a designated set value of the operation specification of the manufacturing equipment used in the manufacturing process.

5. A product quality control system according to claim 1,

wherein the manufacturing history data concerns the processing and assembling in a manufacturing process, and includes the physical quantity measurement values of the operating condition of the manufacturing equipment used in the manufacturing process.

6. A product quality control system according to claim 1,

wherein the manufacturing history data concerns the processing and assembling in a manufacturing process, and includes a combination of selected one of the designated set value of the operating condition and the physical quantity measurement value of the operating condition of the manufacturing equipment used in the manufacturing process on the one hand and the manufacturing equipment route information based on the machine number of the manufacturing equipment through which selected one of the material, the part, the product in progress and the product is passed in the manufacturing process on the other hand.

7. A product quality control system according to claim 1,

wherein the manufacturing history data concerns the processing and assembling in a manufacturing process, and the manufacturing worker identification number for identifying the worker in charge of the processing or assembling in the manufacturing process is determined in advance, and

wherein the manufacturing history data includes the manufacturing worker route information based on the manufacturing worker identification number of the worker who has processed selected one of the material, the part, the product in progress and the product in the manufacturing process.

8. A product quality control system according to claim 3,

wherein the manufacturing equipment includes a plurality of element units, the manufacturing sequence information management apparatus has stored therein the operation sequence information of the element units, and the manufacturing history data collection apparatus collects the physical quantity measurement value of the operating condition of the element units in the manufacturing equipment, which physical quantity measurement value corresponds to the individual identification information and makes up the manufacturing history data, and

wherein the causation analysis apparatus of quality variation includes

a correlation analysis module of quality variation for calculating by collation the statistical correlation magnitude between the quality history data and the manufacturing history data using the individual identification information, and based on the statistical correlation magnitude, automatically extracting at least one candidate for the element unit likely to cause the quality variation, and

a causation analysis module of quality variation for calculating by collation the statistical correlation magnitude between the physical quantity measurement values of the operating condition of the element units using the individual identification information, and based on the statistical correlation magnitude and the operation sequence information. obtained from the manufacturing sequence information management apparatus, acquiring the connecting structure information between the element units and automatically determining and extracting the element unit causing the product quality variation from the candidates.

9. A product quality control system according to claim 1,

wherein the manufacturing process is a component element of a supply chain including selected one of a manufacturing factory and a manufacturing line for processing and assembling selected one of the material, the part and the product in progress and selected one of a transportation means and a transportation route for transporting selected one of the material, the part and the product in progress,

wherein the supply chain component element identification number is assigned to each supply chain component element in advance, the passage sequence information of the supply chain component element is stored beforehand in the manufacturing sequence information management apparatus, and the manufacturing history data includes the supply chain route information based on the identification number of the supply chain component element through which selected one of the material, the part, the product in progress and the product is passed, and

wherein the causation analysis apparatus of quality variation includes:

a correlation analysis module of quality variation-for calculating by collation the statistical correlation magnitude between the quality history data and the supply chain route information using the individual identification information, and automatically extracting the candidates for the supply chain component element causing the quality variation based on the statistical correlation magnitude, and

a causation analysis module of quality variation for calculating by collation the statistical correlation magnitude between the supply chain route information themselves using the individual identification information, acquiring the connecting structure information between the component elements of the supply chain based on the statistical correlation magnitude and the information on the order in which the supply chain component elements are passed through, and automatically determining and extracting the supply chain component element causing the product quality variation from the candidates.

10. A product quality control system according to claim 9,

wherein the manufacturing history includes the environmental information of the supply chain component elements collected by a measuring unit attached to selected one of the material, the part, the product in progress and the product, and

wherein the causation analysis apparatus of quality variation includes:

a correlation analysis module of quality variation for calculating by collation the statistical correlation magnitude between the quality history data and the environmental information of the supply chain component elements using the individual identification information, and automatically extracting the candidates for the supply chain component elements causing the quality variation based on the statistical correlation magnitude, and

a causation analysis module of quality variation for calculating by collation the statistical correlation magnitude between the component elements of the supply chain using the individual identification information and acquiring the connecting structure information between the supply chain component elements based on the statistical correlation magnitude and the order in which the supply chain component elements are passed through, thereby automatically extracting the supply chain component element causing the product quality variation from the candidates.

11. A product quality control system according to claim 1,

wherein the manufacturing sequence information management apparatus, the manufacturing management apparatus and the correlation analysis module of quality variation and the causation analysis module of quality variation making up the causation analysis apparatus of quality variation constituting the manufacturing quality control system have the functions described in claims 3, 8 and 9, and

wherein the product quality control system executes an arbitrary combination of the quality variation cause analysis of the supply chain component elements, the quality variation cause analysis of a plurality of processes of the manufacturing line, the quality variation cause analysis of a plurality of manufacturing equipments in the manufacturing process and the quality variation cause analysis of a plurality of parameters or a plurality of internal units of the manufacturing equipment.