OFD in Mechanical assembly

[gscotland]

Like most manufacturing companies we analyse performance using DPMO ,defect per million opportunities and where defining opportunities is reasonably straight forward in Circuit card assemblies (and defined by IPC) I am finding it difficult to find a similar definition for mechanical assemblies. Is there a universal standard or has anyone created their own?

 

[BML]

I would suggest that opportunities in a mechanical assembly could be viewed similarly to those in an electrical assembly. Is the part present or not; is it the right part; is the part in the correct location? However, I would advise against using this as an overall measure of quality, and simply use it as a tool to identify and reduce variation. After all, it doesn't matter to the customer how low the DPMO is if the final part doesn't work.

 

[PSE]

I would agree with BML especially on functional testing. Additionally depending upon the sophistication or total quantity of the product, you may need to shift from DPMO to a more relevant (tailored) scale.

 

[gscotland]

Hi Guys
Thanks for your input ,however our application of DPMO is not to replace fault detection stages eg Inspection, ICT Test, Functional test but in some cases to re-inforce and justify detection stages. DPMO is a simple meausre which is used to identify processes that are not performing to an acceptable level or products poorly designed for process compatability.