1. Control Charts - SPC Types of Control Charts:
SPC – Statistical Process Control
X – Chart & R Chart Quantitative Data – Control Mean and
Variation for a Process
P – Chart Qualitative Data – Control Percent Defective
C – Chart Blemish Rate – Control the Number of
Non-Fatal Flaws per Item

2. Product Meets Specifications
3 – Sigma Control Limits
.9973 obs
µ - 3σ
µ + 3σ
LCL = µ - 3σ UCL = µ + 3σ
Six – Sigma – Design the Process so Product can vary by 6 Sigma
Product Meets Specifications
µ - 6σ
µ + 6σ
obs

3. X – Chart and R – Chart
Take m Samples of Size n Each.

4. Control Chart: Bearing Diameter
Ex 18.1: m = n = 6 X = R = .136
Sigma level: 3 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Bearing Diameter
UCL =
Average =
LCL =
Control Chart: Bearing Diameter
Mean

5. Control Chart: Bearing Diameter
Sigma level: 3 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Range .4 .3 .2 .1
0.0
Bearing Diameter
UCL = .2725
Average = .1360
LCL = .0000

6. Remove Data Sets: 3, 5, 11, 16, X = R = .12

7. P – Chart X j = Number of Defects in j th Sample out of n
p j = X j / n Sample Proportion
Ex 18.3: m = n = ∑X j = 53

8. C – Chart c j - # Flaws in the j th Sample
Poisson Distribution – Std Dev = Square Root of the Mean
Ex 18.4: m = ∑c j = 50

9. Interpreting Control Charts: Points above UCL and/or below LCL
Centerline

10. Interpreting Control Charts: 8 Consecutive Points on One Side of the Centerline
UCL
LCL
Centerline

11. Interpreting Control Charts: 7 Consecutive Increasing Points
UCL
LCL
Centerline

12. 2 out of 3 Consecutive Points in Outer 1/3
UCL
LCL
Centerline
4 out of 5 Consecutive Points in Outer 2/3
UCL
LCL
Centerline