|
|
|
Total Quality Management
|
|
Introduction to TQMQuality thinkingTQM is management and control activities
TQM - The "home-court advantage"
Diagramming the Home Court Advantage
W. Edwards Deming:
(1900-1993)
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
To achieve this level of performance requires more than a good philosophy - the organization must change its behavior and adopt new ways of doing business. This is what Dr. Deming preached to the Japanese in 1950, and in the 1980s and 90s until his death, in America. Deming's approach were amply summed up in his famous 14 Points. These exhort management to rational action instead of merely sloganizing quality and blaming workers for issues beyond the workers' control. We call this "walking the talk." Deming formulated this into his System of Profound Knowledge™ by which management could change itself only with a view from the outside; the system cannot understand itself. |
![]() "We have learned to live in a world of mistakes and defective products as if they were necessary to life. It is time to adopt a new philosophy in America." |
Deming based much of his work on earlier work done by Walter Shewhart on statistical quality control (SQC). Shewhart is considered the father of quality control. SQC uses control charts to identify and control sources of variation in manufacturing processes. In TQM, we apply the principles of controlling the quality of machine-based factory operations to controlling the quality of people-based management operations. The principles we will learn are:
Variation is inherent in all processes - mechanical and human.
The Plan-Do-Study-Act (PDSA) cycle developed by Dr. Walter Shewhart helps us manage the effects of variation. This is the scientific method applied to problem solving which has us plan and test our improvements, make adjustments, and then standardize them to prevent recurrence. PDSA or PDCA (check) is fundamental to TQM.
To do PDSA, we must collect data relevant to the process and understand what this data means.
Understanding this data helps prioritize and direct improvement.
Improvement increases stakeholder (shareholder, employee, customer, community) satisfaction both now and in the future.
|
![]() |
Malcolm Baldrige National Quality Award and State versions
Keep US industries competitive in a global economy.
Hold business accountable for the cost of poor quality by providing a measurement system that ties customer satisfaction with product performance to design quality and process quality performance.
Variation is a fact of life. It is random and miscellaneous. Thus, the same process can produce two things that are not alike. In the days of hand-crafted products, this could be accounted for by "fitting" things together. In modern industry where interchangeable parts are assembled into mass-produced final products, controlling variation is critical to customer satisfaction. This is one of the most important tasks a manager faces.
Dr. Walter Shewhart identified two kinds of variation, controlled and uncontrolled, and their characteristics.
Controlled variation:
Uncontrolled variation:
Management's job is to manage variation in order to produce predicable results, such as quality, cost, and production schedules. Since all data sets contain random variation or noise, the noise must be filtered out, otherwise two kinds of mistakes could arise.
To manage the variation in a process, historical data must be analyzed to identify which changes are noise and which changes are signals. To do this Dr. Shewhart created the control charts. In manufacturing, we use a variety of charts for Statistical Process Control (SPC).
Dr. Deming asks six willing workers to manufacture white beads by scooping them out of a box containing an 80:20 mixture of white to red beads. They are given a target of no more than 3 red beads per day. But the number of red beads produced was as follows:
Willing Worker Day 1 Day 2 Day 3 Day 4 Mike 8 11 6 7 Leon 14 10 8 11 Karen 7 10 11 5 Bob 11 10 6 10 Melvin 7 12 6 13 Paul 14 7 7 14 Totals 61 60 44 60
Eventually all the Willing Workers lost their jobs and the plant was closed. Why were they fired? Was it their fault?
Control charts show whether the results were inherent to the process, which the workers did not create and could not control, or whether the results were due to some assignable cause which the workers might have been able to correct themselves. The individuals chart shows the production of each willing worker for each shift. The moving range shows the change from worker to worker.
Based on past performance of the bead plant, the variation in the number of red beads remains consistent from worker to worker, shift to shift.
Individuals Chart
x-barMoving Range
mRFor management, we will look at constructing a chart that tracks individual values. Here are the steps.
Constructing the individuals control chart (X-bar mR Chart)
- Collect data. Always show the data with your charts.
- Calculate and plot the moving range (mR). The moving range is simply to distance between two successive data points. So if the data points are 5, 2, 7, 6, the range is 3 for the first two data points, 5 for the second and third points, and 1 for the third and fourth points, and so on. The moving range is 3, 5, 1, etc. Plot these on a chart and connect the data points with a line. This is the beginning of the mR chart.
- Calculate the average moving range (R-bar) by summing the moving range numbers and dividing by n-1. The average moving range in the above example is (3+5+1)/3 = 3. Draw and label R-bar on the mR chart.
- Calculate the Upper Control Limit (UCL) for mR by multiplying the average moving range by 3.27. Draw and label the mR UCL on the mR chart.
- Plot your original data points and connect with a line on a separate X chart. Calculate the average of X and draw in as the center line (CL).
- Calculate, draw, and label the Upper and Lower Natural Process Limits of X.
Upper Natural Process Limit = X-bar (average of X) + 2.66 x (R-bar)
Lower Natural Process Limit = X-bar (average of X) - 2.66 x (R-bar)- Show both charts together (X-bar mR Chart) to interpret the results. Individual points outside the control limits indicate assignable cause. If the process is stable, points will be inside control limits. There are additional evaluation tests for stability given in MJ2.
- Only a stable process can be improved with predictable results.
It is your third year as production supervisor of a local plant. You have been called to the plant manager's office to explain why your July level of in-process inventory of 28 units has exceeded your target of 19.7 units, and in fact is at an all time high.
This is 42% above target, and a further review of your performance this past year shows that you are 12% above last July and 9.6% above target for this year already.
To better understand the situation, you gather some historical data since you were hired (table below). First, construct one individuals control chart (X-bar and mR) per above steps based on the past two full calendar years. Then, in order to determine if the current year work-in-process is in control, continue plotting the current year's inventory levels on the same chart. Do the current year's inventory levels fall within the historical control limits of the first two years? Has something outside the process changed? What does this say about the process? What needs to be changed in order to see an improvement?
In-Process Inventory [Wheeler 1993] Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1 19 27 20 16 18 25 22 24 17 25 15 17 2 20 22 19 16 22 19 25 22 18 20 16 17 3 20 15 27 25 17 19 28 The purpose of this assignment is to have you make an X and mR chart and analyze the results so that you will be able to teach this to plant and labor workers. Please do this chart by hand, not in an SPC program or spreadsheet, using the constants given above.
Extra Credit (5 pts. max.): Pick a controversial issue, and use control charts to validate whether the current status represents a "signal" meaning that the system has changed, or the current status is within historical limits. Ex. A study of "foot & mouth disease" occurrence in England last year showed that the number of new cases reported each day, once false cases were subtracted, showed no significant increase in the number of reported cases for several decades. You might wish to validate such controversial issues as global warming, student test scores, stock market changes, etc.
Software:
Variation. Great program to demonstrate the problem of trying to control variation with an uncontrolled process. Two versions: vari.exe and tennis.exe
Funnel. In addition to the red bead experiment, Dr. Deming also showed the futility of trying to drop a round ball through a funnel and hit a target consistently.
Books:
Deming, W. Edwards. 1982, 1986. Out of the Crisis. MIT-CAES. ISBN 0-911379-01-0
Deming, W. Edwards. 1993. The New Economics: For Industry, Government, Education. MIT-CAES. ISBN 0-911379-05-3
Inamori, Kazuo. 1995. A Passion for Success: Practical, Inspirational, and Spiritual Insights from Japan's Leading A Passion for Success: Practical, Inspirational, and Spiritual Insights from Japan's Leading Entrepreneur. McGraw-Hill Inc. ISBN 0-07-031784-4
Juran, J.M. ed. 1995. A History of Managing for Quality. ASQ Press. ISBN 0-87389-341-7
Kohn, Alfie. 1993. Punished by Rewards: The Trouble with Gold Stars, Incentive Plans, A's, Praise, and Other Bribes. Houghton Mifflen Co. ISBN 0-395-71090-1
Wheeler, Donald J. 1993. Understanding Variation: The Key to Managing Chaos. SPC Press. ISBN 0-945320-35-3
Wheeler, Donald J. and David S. Chambers. 1992. Understanding Statistical Process Control. SPC Press. ISBN 0-945320-13-2
tqmintro.pptStudent: tqmintro.pdf
Faculty and Professional:
|
© 1993-2004 Glenn H. Mazur. Comments may be addressed to glenn@mazur.net
|