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Sanjay Bhatikar

#13666

Equipment Selection - Cp, Cpk | 27 October, 1998

sirs,

which equipment manufacturers provide Cp and Cpk values for automatic stencil printing equipment?

what would be a good experiment for specifying these process indices?

Cheers - have a nice day - Sanjay

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Stefan W.

#13667

Re: Equipment Selection - Cp, Cpk | 28 October, 1998

The only method I would trust measuring the cp or cpk is with an optical coordinate measuring machine used in metrology labs. The machine should have at least ten times better accuracy than the machine to be measured. For a print area of 18"X18" you are asking for a measuring machine of $ 200.000 to $ 500.000. Most likely on a single image looking at one print you can determine X and Y coordinates and with multiple images you can calculate the theta offset. Suppose you would do it with every machine delivered ( Siemens does it with their P&P machines ), what proof do you have that the machine is still the same when it is installed in your plant? Do you have your own measuring machine? My own experience, out of thousend customers one wants to evaluate the cpk in his plant and 999 customers pay for it.

| sirs, | | which equipment manufacturers provide Cp and Cpk values for automatic stencil printing equipment? | | what would be a good experiment for specifying these process indices? | | Cheers - have a nice day - Sanjay |

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