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SPC

Former Member
0 Kudos

Hi

I have an issue with Display Statistical value in SPC control chart screen (QGC2)

I have recorded 12 results but still I am getting message "'There is insufficiant data available""

Message no. QE720

Inspection plan -SPC task list characteristic selected

inspection char -- Sampling procedure and SPC selected, single result

Inspection Point - free inspecton point

Sampling procedure -

fixed sample, sample size -1

Mean value within tolerence

free inspection point,

Control chart # Shewart chart for x-bar/ sample/USA

I can able to see, generate, the control chart

When I want to check Statistical values in the chart, insufficant data

even i have tested with 20 results... not able to see Cp and Cpk

Can you pls throw some lights on this issue

what went wrong & how to see the Cp & Cpk in control chart window

thanks

Accepted Solutions (1)

Accepted Solutions (1)

Former Member
0 Kudos

The way system is behaving is correct The reason behind this is you are using range charts and your sample size is = 1.You can get the cp,cpk values if subgroup size is greater than 1. Change sample size in sample procedure (>1) , record the results - you will be able to see cp,cpk.

In the industry, if the sample size =1 - std practice is using moving range charts than the range charts.

Thanks,

Ram

Former Member
0 Kudos

Hi Ram

thanks for the quick response

I thought, inspection point it will work... but it is not working.

MOVING range chart will work for both inspection points and normal inspection (multiple lots)

We can get Cp anf CpK values..

thanks

Former Member
0 Kudos

Could you able to get your cp,cpk after changing sample size with range charts as per my reply?

Answers (1)

Answers (1)

Former Member
0 Kudos

thanks