Calculation of Cp & Cpk in case of SPC

[Former Member]

Hi Gurus,

In an inspection plan for material i have maintained 4 Mics. All these Mics are maintained as SPC Characteristics.when i am using transaction MCXD, inspection result analysis i am not getting the values of Cp & Cpk for material.Instead i am getting *** in the columns for Cp & Cpk.What might be the reason.

Regards

Amit

[former_member617635]

I do refersh this post and have question about Cp Cpk values in MCXD.

I do have the same issue like in the original post quote "Instead i am getting *** in the columns for Cp & Cpk."

I understand that there are different levels in MCDX, but Iam  doing drill down, clicking there to different levels an I am always getting ***. How to get right level there to get CP CPK calculated?

My configuration and RR looks correct, I can see for example SPC chart in QE51N for that MIC, I can see also Cp CPK there but can not see this in MCXD.

Thank You.

[Former Member]

Hi Gajesh,

Thanks for your help.

Regards

Amit

[former_member186399]

Dear Amith

in the charts which you will get there lot many options of different charts. I dont know about frequency polygon. please explain for my knowledge

regards

gajesh

[former_member186399]

Dear Amith

one input for CP CPK you need to have single recording for the MIC. it requires some single values to be get registered before giving the Cp, CPK

1) QS28

select the MIC for which you need to get the Cp CPK > execute > select the Mic again and click on result history > a pop will appear > execute selection ( selection of vendor, bacth is available there ) select the all the lot > pop will appear with inspection lots > select all the lots below you can see various option > click on histogram and in the click on Statistics value

this works if you MIC attached to one material only

2) if you are using incomplete copy model time you can get the same

go to QA32 > put the material , plant ( combination you want) > select the lot with usage decision > execute > select any of the lot > go to results> select the mic which you need to see the values> click on result history > you will ge tthe pop for execution and will then get the lot list

there are other charts also. you can get the details in the sampling plan (QDV2) in chart type . there is a separate process for the same

give me ur feedback

Regards

gajesh

[Former Member]

Hi gajesh,

Thanks for your reply.I have two materials say hcl & zinc bath.Material master for these is not available.In current scenario results for these materials are recorded on sheets daily on shift basis.Now for mapping it in SAP i will create MM without accounting views.In inspection plan header i will assign inspection points.Now my client wants Frequency polygon for results recorded weekly and monthly.Is there any transaction where i will get frequency polygon for results recorde.

Regards

Amit

[Former Member]

Hello Amit

Check if you have tolerance limits established for the inep. characteristics. Theese needs to be in place in order to have Cp anc Cpk values displayed.

Regards

Jan Erik

[Former Member]

Hi Jan,

Tolerance limits have already been derived for characteristic.After that also i am unable to get the values for Cp & Cpk.

Regards

Amit

[former_member186399]

Dear Amith

One material have different MICs attached to it and every mic will have different tolerance limit and specification . So you will not get the CP , CPk material wise. Instead in MCXD click on Switch Drilldown button and choose Inspection characteristic. You will be able to see the CP, Cpk.

You will get Cp, CpK analysis in QS28 also with histogram, run chart and statistical values

Please give your feedback

Regards

Gajesh

[Former Member]

Hi Gajesh,

Thanks for your reply.As per u r suggestion i tried using drilldown and choosing inspection characteristic, still i am not able to get cp & cpk values.

I also tried transaction QS28.Can u throw some light on how we can get Cp, Cpk values, run chart and histogram from transaction QS28.

Also i wanted to know which type of graphs(i.e. bar , pie chart etc) can be extracted from SAP system.Whether x bar chart and r bar chart can be derived from SAP and how they can be seen.What are the requirements for getting x bar chatr and r bar chart.In which transaction i can get normal distri bution curve.

Regards

Amit