ControlChart

[Former Member]

Dear All,

Could you tell me about control chart?I have tried generating control chart and i got a graph also but there is no cp cpk values...

For this i have maintained

MIC Control Indicator i have set SPC and Sampling procedure

Sampling procedure with SPC Inspection as valuation mode

Attached MIC as well as sampling procedure in Inspection Plan with single results in the control indicator

But however in results entry am able to give only one value in the results entry for a MIC.How do i enter multiple valus for a MIC?

Secondly after maintaining the settings which i mentioned above am getting a chart but ther is no CP Cpk vales Have i missed out anything?

And also why control chart is used?

Could you give me inputs regarding this......it would be very helpful

[former_member186399 · Accepted solution]

Dear JR

The formula for standard deviation is as given in the link

Link: [http://www.gcseguide.co.uk/standard_deviation.htm]

Regards

Gajesh

[former_member186399]

dear JR,

CP is calculate by this method - ( Upper limit - lower limit ) / ( 6 * Standard deviation)

or simply Cp = tolerance / 6 * sigma

Cpk = ( upper limit - Mean value) / (3 * standard deviation ) or ( Mean value - lower limit) / ( 3 * standard deviation whichever is minimum

hope this solves

Regards

gajesh

[Former Member]

Dear Gajesh,

Thanks your answer is exactly what i wanted...

I tried w.r.t to your formula...with system calculated standard deviation value i tried and am getting the result

Could you tell how we get standard deviation..whatz the formula?

Just for my understanding....thanks for your immense co-operation

Regards

JR

[former_member186399]

Dear JR

Kindly input single recording for getting a control chart

This can be done by going to

1 ) QS23 , give the mic for which you want the control chart

2) Control indicator

3) select single recording.

4) Update the inspection plan by inputting mic again ( if MIC is incomplete or complete you need to refresh the mics in inspection plan again

Please test and let me know

Regards

gajesh

[Former Member]

Dear Gajesh,

Thanks for you input regarding control chart.

As i said one last doubt...

How does the cp and cpk values get calculated

[former_member186399]

Dear JR,

Find below my answers.

Control charts

Please follow the steps

1) Create MIC (QS21) with control indicator SPC sampling and Single recording

2) Create Sampling procedure ( QDV1) selection valuation mode as SPC valuation

3) Select any of the Bar charts

4) Assign the MIC and the sampling procedure in QP01

5) Create and do result recording

6) Make sure that you have single recording and you RR for 5 to 10 lots

7) Now got to QGC1

8) Put all the relevant fields

9) Maintain in the status of control chart as 1

10) Execute

11) Select the MIC and click on activate control chart

12) Click on call control chart

13) Next time you run the chart use the status of control chart as 3

2) for getting multiple sample values make sure that you selection single recording in control indicators in MIC

3) Control charts will not show Cp, CPK directly in the graph

4) control charts are SPC tools for understanding the stability of process and to check whether the process are running within the specified limits

5) You can get CP, CPk in information system MCXD also

6) Also there is another option for getting cp cpk please follow the steps below link

Link: []

please let me know your feedback

Regards

gajesh

[Former Member]

Dear Gajesh,

Thanks for your step by step details...

Actually i have done the same procedure except activating control chart but still i get a graph when i call control chart..

My doubt actually was...there are different MIc's shown and corresponding lots and control chart.So is control chart used to analyze only what values for a lot has been entered?

For example Carbon is a mic and i have 4control charts seen in qgc1 for 4 lots so when i selct all four and call control chart..the graph doesn show any data except a point which gives value of a lot not even averaged value

So i really dint understand the significance of the graph what i thought is i can analyze carbon mic value for four lots in the graph so that it gives me a study of variationsPlease correct me if am wrong

And secondly do i have to enter multiple results for a particular Mic in a lot for control chart??

Please provide me some ideas....

[Former Member]

Dear Gajesh,

Please provide some input......