Help me improve the definition for internal PPM

[mihaelacs]

Please help me improve the definition for internal/ external PPM for my company in the field of quality control services. For this activity our customers give us their parts only for quality control and some reworks.
For external PPM it is clear we consider the defective parts found at customer side after our activity (like rejected part that we passed as accepted) , after our process.
For internal PPM it is not very clear for me what to consider, we usually considered only that parts damaged after the reworks but I am thinking if I should also consider parts accepted by the inspectors but found internally as not conform (during the daily audits, product audits, supervisor inspection). but I am a little bit confused because we supply a service over a customer product and also usually the activity is performed in one stage such as visual inspection.
I appreciate your help.

 

[Bev D]

Internal ppm is the accounting of all defects found internally to your facility. Defects can be found by operators, inspectors and automatic test equipment. Some organizations like. To differentiate between defects in supplied parts and defects created by their organization. There is some utility in this distinction but don’t let it be a game. Remember that if a defect that comes from your supplier makes it through your organization to your Customer it is still bad. Your Customer won’t care who created it, only that you let it get to them.

 

[Yaron]

I have read the above discussion and other materials available on the internet but it is still not clear for me what to count as internal PPM, is there any standard for that?
My opinion is that I need to count as internal PPM only that failures that passed through my manufacturing process (including automatic and manual test stations) and yet, were caught by the quality inspection or ESS process. will appreciate any answer.

 

[Jim Wynne]

I have read the above discussion and other materials available on the internet but it is still not clear for me what to count as internal PPM, is there any standard for that?
My opinion is that I need to count as internal PPM only that failures that passed through my manufacturing process (including automatic and manual test stations) and yet, were caught by the quality inspection or ESS process. will appreciate any answer.

PPM is a mostly-useless metric. There is no standard method for identifying things to be counted. Do what works for you.