Control, Quality 2

Quality Management
for Organizational Excellence
Lecture/Presentation Notes

By:

Dr. David L. Goetsch and Stanley Davis

Based on the book

Quality Management for Organizational Excellence (Seventh Edition)

Quality Management, Seventh Edition Dr. David L. Goetsch

© 2013, 2008 by Pearson Education, Inc. Upper Saddle River, NJ 07458. All Rights Reserved.

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Eighteen:
Optimizing and Controlling Processes through Statistical Process Control (SPC)

MAJOR TOPICS

• Statistical Process Control Defined
• Rationale for SPC
• Control Chart Development
• Management’s Role in SPC
• Role of the Total Quality Tools
• Authority over Processes and Production
• Implementation and Deployment of SPC
• Inhibitors of SPC

Quality Management, Seventh Edition Dr. David L. Goetsch

© 2013, 2008 by Pearson Education, Inc. Upper Saddle River, NJ 07458. All Rights Reserved.

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Eighteen:
Optimizing and Controlling Processes through Statistical Process Control (SPC)
(Continued)

• Definition: SPC is a statistical method of separating special-cause variation from natural variation to eliminate the special causes and establish and maintain consistency in the process, enabling process improvement .
• The origin of SPC was in the work of Dr. Walter Shewhart at Bell Laboratories 1931. Although SPC was ignored in the West after World War II, Japan adopted and subsequently developed it into total quality.
• The rationale for SPC includes the following:
• Enables the control of process variation.
• Makes possible continual improvement of the process.
• Results in predictability of processes.
• Results in elimination of waste.
• Makes less expensive inspection modes possible.
• SPC is essential today to elevate the quality of products and services while lowering costs in order to compete successfully in world markets.

Quality Management, Seventh Edition Dr. David L. Goetsch

© 2013, 2008 by Pearson Education, Inc. Upper Saddle River, NJ 07458. All Rights Reserved.

*

Eighteen:
Optimizing and Controlling Processes through Statistical Process Control (SPC)
(Continued)

• Control Chart Development:
• There are several types of control charts, the choice of which being determined by the kind of process under consideration. Further, some control charts are designed for variables data (something measured), others are concerned with attributes data (something that can be counted). Different procedures are used for developing these two types of control. Both require Upper Control Limits (UCL) and Lower Control Limits (LCL) and a Process Average.
• Upper and Lower Control Limits and Process Average calculations for constructing the control chart are made from the actual process data, which must be of sufficient quantity, and taken over a relatively short period.
• After drawing the blank control chart with UCL, LCL and process average, the data from which the calculations were made are plotted on the chart. No data points can penetrate UCL or LCL, and there must be no long runs of data on one side of the process average. That will only be true if the process is free of special causes of variation. If that is the case, the chart is ready for use.

Quality Management, Seventh Edition Dr. David L. Goetsch

© 2013, 2008 by Pearson Education, Inc. Upper Saddle River, NJ 07458. All Rights Reserved.

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Eighteen:
Optimizing and Controlling Processes through Statistical Process Control (SPC)
(Continued)

• Continual improvement of processes requires that special causes be eliminated first. Process improvement narrows the shape of the process’s bell curve, resulting in less variation.
• Continual improvement is a key element of SPC and total quality. SPC enhances the predictability of processes and whole plants. Elimination of waste is another key element of SPC. SPC can help improve product quality while reducing product cost.

Quality Management, Seventh Edition Dr. David L. Goetsch

© 2013, 2008 by Pearson Education, Inc. Upper Saddle River, NJ 07458. All Rights Reserved.

*

Eighteen:
Optimizing and Controlling Processes through Statistical Process Control (SPC)
(Continued)

• SPC makes sampling inspection more reliable. SPC supports process auditing as a substitute for more expensive inspection. SPC requires a capability in statistics, either in-house or through a consultant. Process operators should be key players in any SPC program. Understanding the process is a prerequisite to SPC implementation. All employees involved in SPC must be trained for their involvement. Measurement repeatability and reproducibility is essential for SPC.

Quality Management, Seventh Edition Dr. David L. Goetsch

© 2013, 2008 by Pearson Education, Inc. Upper Saddle River, NJ 07458. All Rights Reserved.

*

Eighteen:
Optimizing and Controlling Processes through Statistical Process Control (SPC)
(Continued)

• Management’s role in SPC is similar to its role in total quality overall: commitment, providing training, and involvement. The seven tools, augmented by flowcharting, five-s, FMEA and DOE are required for SPC. SPC and the operator must have process-stop authority, SPC implementation must be carried out in an orderly, well thought-out sequence.
• SPC requires collaborative team activity.