Chapter 9 Quality Management – Focus on 6 Sigma

1Slides used in class may be different from slides in student pack

Chapter 9

Quality Management – Focus on 6 Sigma

Total Quality Management Defined Malcolm Baldrige National Quality Award Components of Quality Costs of Quality Continuous Improvement Six Sigma Quality Tools Benchmarking Fail-safe Design ISO 9000


Total Quality Management (TQM)Defined

Total quality management: managing the

entire organization so that it excels on all

dimensions of products and services that are

important to the customer.


Leadership Strategic Planning Customer and Market Focus Information and Analysis Human Resource Focus Process Management Business Results

Malcolm Baldrige National Quality AwardEstablished 1987, Revised in 1999


Categories for the Baldrige Award Manufacturing companies or subsidiaries that

–

–

Service companies or subsidiaries that sell service Small businesses Health care organizations Educational institutions


Components of Quality Design quality: Inherent value of the

product in the marketplace

–

Conformance quality: Degree to which the product or service design specifications are met


Costs of Quality

Costs ofQuality


Continuous Improvement (CI) Management's view of performance

standards of the organization–

The way management views the contribution and role of its workforce–


CI Methodology: PDCA Cycle (Deming Wheel)


Six Sigma Quality A philosophy and set

of methods companies use to eliminate defects in their products and processes

Seeks to reduce variation in the processes that lead to product defects

The name, “six sigma” refers to the variation that exists within plus or minus six standard deviations of the process outputs


Six Sigma Quality (Continued) Six Sigma allows managers to readily

describe process performance using a common metric: Defects Per Million Opportunities (DPMO)

1,000,000 x

units of No. x

unit per error for

iesopportunit ofNumber

defects ofNumber

DPMO 1,000,000 x

units of No. x

unit per error for

iesopportunit ofNumber

defects ofNumber

DPMO


Six Sigma Quality (Continued)Example of Defects Per Million

Opportunities (DPMO) calculation. Suppose we observe 200 letters delivered incorrectly to the wrong addresses in a small city during a single day when a total of 200,000 letters were delivered. What is the DPMO in this situation if 2 opportunities for error exist for each letter?

Example of Defects Per Million Opportunities (DPMO) calculation. Suppose we observe 200 letters delivered incorrectly to the wrong addresses in a small city during a single day when a total of 200,000 letters were delivered. What is the DPMO in this situation if 2 opportunities for error exist for each letter?


Six Sigma Quality: DMAIC Cycle

Define, Measure, Analyze, Improve, and Control (DMAIC)

Developed by General Electric as a means of focusing effort on quality using a methodological approach

Overall focus of the methodology is to understand and achieve what the customer wants

DMAIC consists of five steps….


Six Sigma Quality: DMAIC Cycle (Cont.)

1. Define (D)

2. Measure (M)

3. Analyze (A)

4. Improve (I)

5. Control (C)


Example to illustrate the DMAIC process…

Suppose we are a manufacturer of breakfast cereals. Consumer Reports has just published an article that shows that we frequently have less than 16 ounces of cereal in a box.

What should we do?


Step 1 - Define Customers –

Project – our boxes of cereal are reported to contain less than 16 ounces of cereal. Determine how large the problem is and what should be done about it.

Critical-to-quality characteristic:


2 - Measure

How and what should would we measure to evaluate the extent of the problem?

What are acceptable limits on this measure?


2 – Measure (continued)

Let’s assume that the government says that we must be within ± 5 percent of the weight advertised on the box.

Upper Tolerance Limit =

Lower Tolerance Limit =


2 – Measure (continued)

We go out and buy 1,000 boxes of cereal and find that they weigh an average of 15.875 ounces with a standard deviation of 0.529 ounces.

What percentage of boxes are outside the tolerance limits?


Upper ToleranceLimit = 16.8 oz.

Lower ToleranceLimit = 15.2 oz.

ProcessMean = 15.875 oz.

Std. Dev. = 0.529 oz.

What percentage of boxes are defective (i.e. less than 15.2 oz)?

Mean - LTL

Z


Upper Tolerance = 16.8 oz.

Lower Tolerance = 15.2 oz.

ProcessMean = 15.875 oz.

Std. Dev. = 0.529 oz.


Step 3 – Analyze - How can we improve the capability of our cereal box filling process?

Decrease Variation–

Center Process–

Increase Specifications–


Step 4 – Improve: How good is good enough?

Six sigma philosophy: minimum of 6 from process center to nearest spec

1 23 1 02 3

12

6

LS US


Six Sigma Impact Implies 2 parts/billion “bad” with no process shift

1 23 1 02 3

6

LS US

With 1.5 shift in either direction from center (process will move), 3.4 parts/million “bad”.

6


Step 5 – Control

Statistical Process Control (SPC)– Use data from the actual process– Estimate distributions– Look at capability - is good quality

possible?– Statistically monitor the process over

time


Six Sigma Roles and Responsibilities

1. Executive leaders must champion the process of improvement

2. Corporation-wide training in Six Sigma concepts and tools

• • •

3. Setting stretch objectives for improvement

4. Continuous reinforcement and rewards


APPLICATIONS FOR PROBLEM SOLVING TOOLS/TECHNIQUES Brassard, Michael. The Memory Jogger, Goal/QPC: Methuen MA, 1988

PROBLEM IDENTIFICATION PROBLEM ANALYSIS

CHECK SHEETS HISTOGRAMS

PARETO CHARTFLOW CHARTS SCATTER DIAGRAMS

CAUSE & EFFECT

CONTROL CHARTS


Example: Process Flow Chart

No, Continue…

Material Received

from Supplier

Inspect Material for

Defects Defects found?

Return to Supplier for

Credit

Yes

Can be used to find quality problems.

Can be used to find quality problems.


CHECK SHEETS (or tally sheets)

Simple tool to record frequency of an event: Use it to gather data to begin to detect patterns. Often this is the first step in most problem solving cycles.

HINTS FOR USE:


A Check Sheet

Problem Month

1 2 3 Total

A

B

C

Total

Number of Customer Complaints.


PARETO CHARTS

A vertical bar graph that helps us prioritize problems

Portrays attribute data (frequency of each type of defect or problem) gathered from check sheets.


Problem(most recent6 months)

Number ofCustomer

Complaints

CumumulativePercent

Print Quality 23 37.7%

ExcessFlash

13 59.02%

Type Error 6 68.85%

LateShipment

6 78.69%

MisplacePrint

4 85.25%

Bad Count 4 91.80%

Rough Edge 3 96.72%

Missing Ring 2 100%

Total 61


Pareto Chart

0.00%

5.00%

10.00%

15.00%

20.00%

25.00%

30.00%

35.00%

40.00%

Problems

0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

120.00%

Percentage

Cumulative Percentage


Example: Cause & Effect Diagram

ManMachine

MaterialMethod

Environment

Possible causes:Possible causes:

Effect

The results or effect.

The results or effect.


Example: Control Charts

970

980

990

1000

1010

1020

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

LCL

UCL

Can be used to detect unusual variations in ongoing production process quality and quality conformance to stated standards of quality.

Can be used to detect unusual variations in ongoing production process quality and quality conformance to stated standards of quality.

CL


Example: HistogramN

um

be

r o

f Lo

ts

Data Ranges, i.e., temperature

Defects in lot

0 1 2 3 4


SCATTER DIAGRAMS:

These charts portray the relationship between two variables. Use them to explore hypotheses you generate about causes and effects. If a relationship shows some correlation check it out mathematically.

Scatter Graph, Platen Pressure vs Defects/Batch

0123456789

0 10 20 30 40 50 60 70

Platen Pressure

Def

ects

/Bat

ch

Here it looks like platen pressure and defects/batch show a high degree ofcorrelation. Hmm …


Other Six Sigma Tools Failure Mode and Effect Analysis

(DMEA) is a structured approach to identify, estimate, prioritize, and evaluate risk of possible failures at each stage in the process

Design of Experiments (DOE) a statistical test to determine cause-and-effect relationships between process variables and output


Benchmarking

1.

2.

3.

4.


The Shingo System: Fail-Safe Design

Shingo’s argument:– – –

Poka-Yoke includes:– –


ISO 9000

Series of standards agreed upon by the International Organization for Standardization (ISO)

Adopted in 1987

More than 100 countries

A prerequisite for global competition?

ISO 9000 directs you to "document what you do and then do as you documented."

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Chapter 9 Quality Management – Focus on 6 Sigma

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