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Reflow Oven Cp & CpK Test at customer place

Views: 1916

Charls

#47468

Reflow Oven Cp & CpK Test at customer place | 10 February, 2007

Hi Friends,

We would like to know what is the procedure to test Cp & Cpk on Reflow oven at customer place .

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#47470

Reflow Oven Cp & CpK Test at customer place | 10 February, 2007

Choices are: * Run a Cp, Cpk capable profiler through the oven. * Review the results of your supplier's process qualification that would include Cp, Cpk on their oven.

Handspring contract [REV. 6 - 7/1/99] with Flextronics says: [snip] 4. Process Capability Index Cp and Cpk: a. Supplier will perform process capability index for critical electrical and mechanical parameters that are being measured in production. This should be performed on early production units. Generally any Cpk of less than 1.33 will be flagged as a potential problem and corrective action will be expected before release of the product. [snip]

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CK the Flip Guy

#47562

Reflow Oven Cp & CpK Test at customer place | 12 February, 2007

DaveF,

Please define a "Cp/Cpk capable profiler." Do you mean one that has software that automatically calculates this for you?

I do this at my company, and we track 2 critical variables - Time Above Liquidous and Peak Temps. and this is done on all ovens on a monthly basis. The data is then plugged into an Excel spreadsheet that has the Cpk formulas built in. Most SPC, quality manuals, and "Six Sigma" books will tell you a Cpk of greater than 1.33 is standard, which is probably what your supplier recommends.

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#47565

Reflow Oven Cp & CpK Test at customer place | 12 February, 2007

CK the Flip Guy

You're correct. Some profiler suppliers include a Cp, Cpk calculatoromiter with their very nice units.

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#47574

Reflow Oven Cp & CpK Test at customer place | 12 February, 2007

Would their calculatoromiters set off my BS detector? It's quite sensitive with things like Cp,Cpk and use of statistics. Or are they actually genuinely usefull?

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#47585

Reflow Oven Cp & CpK Test at customer place | 12 February, 2007

stepheniii

Unsure how they determine that the process is stable and in control, a prerequisite to calculating Cp, Cpk. A trained chimp smoking a cigar could calculate Cp, Cpk.

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