QUALITY PLANNING
Who is customer?
What do they need?
QUALITY CONTROL
Evaluate, compare, act
QUALITY
IMPROVEMENT
Establish infrastructure
Who is customer?
What Level of Quality do they need?
Are they purchasing to Some Quality Specification?
Any Safety Considerations?
Future Litigation?
Ethical Issues?

QUALITY PLANNING
Who is customer?
What do they need?
QUALITY CONTROL
Evaluate, compare, act
QUALITY
IMPROVEMENT
Establish infrastructure
QUALITY CONTROL
Inspection

Destructive

Non-destructive

Sampling
Process Control

Monitoring Process (relates to inspection)

Feedback Control

Statistical Process Control (knowing when the process is out of control)
Correction

Knowing what to correct when process is out of control

Cost of Quality Before & After
Improvement
80
70
60
50
40
30
20
10
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Time
Series
1

Tools for Quality
Control
Check Sheets
Pareto Charts
Why-Why Diagrams
Cause & Effect Diagrams
Flowcharts
Histograms
Scatter Diagram
Control Charts

Problem
Solving
Steps
Plan
Do
Study
Act
Link these
Two in
Quality
Circle

CHECK SHEETS
Used to keep a record of the number and type of discontinuities over a specified period of time or within a certain batch of product.
PARETO CHART
A graphical representation ranking discontinuities from the most to least significant. Used to help brainstorm what discontinuities, if worked upon first, would be the most likely to produce the greatest improvement in quality.
Class Example
Our manufacturing procedure is composed of several steps. Several of these procedures have lead to discontinuities noticed upon inspection. The steps causing defectives are as follows:

Caulking

Fitting

Connections

Torque

Gapping
198 defectives
25 defectives
103 defectives
18 defectives
72 defective
A Pareto Diagram will be developed.

WHY-WHY DIAGRAMS
A systematic representation of causes of why some occurrence happens. Used to guide brainstorming sessions.

FLOW CHARTS
Flow charts are graphical representations of the steps involved in a process. Constructing a flow chart helps give a better understanding of the systems involved.
Process
Data Decision
Y es
Process
No
Process
Control transfer
Terminator

CAUSE AND EFFECT DIAGRAMS
(Fishbone Diagram)
Used in brainstorming session to help identify the causes of quality losses. This diagram is particularly useful after the flow chart and the Pareto diagrams have been developed.
QUALITY
(Effect)
Step 1:Decide on the quality characteristic {e.g. Reduction of wobble during machine rotation}
Step 2:Set up the fish bone backbone
Step 3:Identify main factors causing effect {e.g. Workers,
Materials, Inspection, Tools}
Step 4: Add Cause to each branch







Benefits of Cause and Effect Diagram

Making diagram is educational in itself
Outline relationship
Note what samples need to be taken
Guide for discussion
Causes are actively sought and results written on diagram
Appropriate data collected - no time wasted
Shows level of technology

Problem
Solving
Steps
Plan
Do
Study
Act
Link these
Two in
Quality
Circle

CONTROL CHARTS

Used to test if the process is in control

Used to see if significant changes have occurred in the process over time
“Indiscreet” or
“Continuous Data
Chart” or “X-R Chart”
Measurement at time intervals
Measurements compared control over time.
Examples:
“Discrete Data Charts” or
“pn-p charts”
Inspection on lot or batch
Note # good/defective
# of parts inspected in the lot = n
Fraction of defective in lot = p
Number of defectives = pn
Length (mm) Volume (cc)
Weight (gm) Power (kwh)
Time (sec) Pressure (psi)
Voltage (v)

X
- R CHART CONSTRUCTION
Class Example
In the manufacturing process for this example parts are being machined with a nominal diameter of 13 mm. Samples are taken at the following times of day: 6:00, 10:00, 14:00, 18:00 and 22:00, for 25 consecutive days. The diameter measurements from these samples are presented on the table in the next slide.

Step 1: Collect Data
Step 2: Sort data into subgroups (i.e. lots, order #, days, etc.) n = size of the subgroup {in this example 5 times per day) k = number of subgroups {in this example 25 days}
Step 3: Find the mean for each subgroup ( X )
X =
X
1

X
2

X
3

.....
n
X n
Step 4: Find Range for each subgroup ( R )
R = X largest value
- X smallest value

Step 5: Find Overall Mean ( X )
X =
X
1

X
2

X
3

...
X k k
Step 6: Find average value of range ( R ) R =
R
1

R
2

R
3

...
R k k
Step 7: Complete control limits using attached table
For X Control Chart
Central Line - CL =
Upper Control Limit - UCL = +A
2
R
Lower Control Limit - LCR = - A
2
R
For R Control Chart
Central Line - CL = R
Upper Control Limit - UCL = D
4
R
Lower Control Limit - LCR = D
3
R

Step 8:Plot Chart

P CONTROL CHART CONSTRUCTION
Class Example
An inspector at the end of the manufacturing line for the production of car wheel rims, at the end of each shift, inspects the lot of wheel rims made during that shift. On good days when the welder is running properly, over 400 wheels are made per batch. On poor days, as low as 50 to 60 wheels are made per batch. The inspector marks on his/her
“check sheet” for each batch the total number of wheels inspected and the number of defects returned for rework in each lot.

Step 1: Collect Data
Step 2: Divide data into subgroups (usually days or lot). Subgroup size should be greater than 50 units. n = number in each subgroup pn = number of defects in each subgroup
Step 3: Compute fraction of defectives (for %, multiply by 100) p = pn/n
Step 4: Find the Average Fraction of Defectives ( ) p =
(
(
=

 pn n
Step 5: Compute the Control Limits for each Lot
Central Line CL =
Upper Control Limit UCL = + 3
- 3 p ( 1
 p ) n p ( 1
 p ) n

Step 6:Draw P Control Chart

PN CONTROL CHART CONSTRUCTION
Class Example
On an assembly line of windshield wiper motors, the inspector selects randomly 100 motors per hour to examine. The inspector notes on the
“check sheet” the number of defective motors in each 100 selected.

Step 1: Collect Data (lot size set constant)
Step 2: Calculate Values p =

 pn n n n + 3 pn ( 1
 p ) n - 3 pn ( 1
 p )
Step 3: Plot Chart

QUALITY PLANNING
Who is customer?
What do they need?
ISO
9000
QUALITY CONTROL
Evaluate, compare, act
QUALITY
IMPROVEMENT
Establish infrastructure