1. Control Charts Using Minitab Control charts display the process average (center) and process variability (spread). Process Average is the “expectation” and Process Variability indicates “risk” associated with the expectation.

2. 2 Frequently Used Control Charts Attribute: Go/no-go Information, sample size of 50 to 100 p-chart ( Proportion Defectives) c-chart (# Defects) u-chart (Defects/Unit) Variable: Continuous data, usually measured by the mean and standard deviation, sample size of 2 to 10 –X-bar and R-charts –X-bar and s-charts –X-charts for individuals

3. 3 Attribute Charts in Minitab Stat / Control charts / Attribute Charts

4. 4 p-Chart HourSampSize Non- conforming 17517 27518 37518 47516 57520 67522 77524 87519 97515 107522 117519 127524 137512 147522 157520 167520 P charts are used to study the proportion of defectives in each sample. A “defective” is an attribute that makes something useless. Data on non-conforming (defective) chips produced at a facility

5. 5 c-Chart UnitSqFtBlemishes 1662 2 2 3 0 4 0 5 1 6 4 7 0 8 0 9 2 10663 C charts are used to display the number of defects in each sample. A defect is a flaw that is undesirable but does not make the product useless. Data are number of blemishes in 66sqft of painted area

6. 6 U-Chart UnitSqFtBlemishesRate 17350.0685 27040.0571 36010.0167 45710.0175 55800.0000 65730.0526 75910.0169 85240.0769 95510.0182 105920.0339 116700.0000 125520.0364 135410.0185 U charts are used to display the number of defects per unit of measurement. Useful when samples are of different sizes. Data are number of blemishes in different areas

7. 7 Variable Charts in Minitab Stat / Control charts / Variable Charts for Subgroups or Individuals

8. 8 XBar-R Charts SampleObs1Obs2Obs3Obs4Obs5 111.99112.00112.17612.00412.030 212.06512.01812.22311.95511.959 311.94611.98012.08912.12512.111 412.01112.06912.06512.15512.197 511.78312.14012.00812.07612.044 611.96212.13212.14911.99112.128 712.16311.96111.93212.11511.870 812.053 11.88911.97512.037 912.10811.94212.10211.96712.056 X-Bar charts are used to plot subgroup means. R charts are used to plot the range for each subgroup. Data represents actual contents in 12 oz soda cans

9. 9 XBar-S Charts SampleObs1Obs2Obs3Obs4Obs5 111.99112.00112.17612.00412.030 212.06512.01812.22311.95511.959 311.94611.98012.08912.12512.111 412.01112.06912.06512.15512.197 511.78312.14012.00812.07612.044 611.96212.13212.14911.99112.128 712.16311.96111.93212.11511.870 812.053 11.88911.97512.037 912.10811.94212.10211.96712.056 X-Bar charts are used to plot subgroup means. S charts are used to plot the standard deviation of each subgroup.

10. 10 Is the Process in Control? XBar-S ChartX (individual) Chart

11. 11 Process Capability Process capability refers to the ability of a process to produce a defect-free product or service in a controlled manner of production or service environment