Internal PPM's in a medium sized metal stamping plant



I have a question regarding Internal PPM's. I have search the forum and could not believe that there were few post's on this.
Our internal PPM average for the 2016 year is 1273.
I have been told this is too high. We are a medium sized metal stamping plant & we run around 500 part numbers and I do not see this as being high.
Is 1273 a high number. What is a normal Internal PPM. On the treads I did see all the answers were its hard to say. There has to be an industry standard.
Any feedback would be appreciated.


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Re: Internal PPM's

Too many factors to say. Depends a lot on what you are doing. Who said it was too high? The number itself isn't that useful. But the trend towards 0 is. I'd focus on cutting in in half, then in half again, etc.


Re: Internal PPM's

For example in the month of July we ran 1,629,859 parts and scraped a total of 1455 pcs. which gives me a Internal PPM of 892. For running a million and a half parts I believe this is a low number. We have 15 Presses and 30+ welders. All it takes is one die to screw up and then we are scrapping parts. To set a number without knowing what the outcome for the month is you would always be doing corrective actions for internal PPM's.


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I have worked in metal stamping and you have a low PPM. I agree with Golfman25, in that scrap reduction is a goal, but the reality is you will never reach zero. I have seen shops where getting a scrap rate on a complex, poorly bid job saw (a deep draw which should have used prog dies but was bid for "one die" on one press - and the product was an aluminum alloy) scrap rates on that specific piece exceeded 40%.

I would look at and trend your PPM on each part number. PPM across a range of parts is OK to look at but not very useful.


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Internal PPMs depend heavily on the type of product and the process. Some processes generate defects that are independent of each other while some like stamping can generate slugs of consecutive defective parts. The latter type of process will typically generate higher PPM levels.

Another consideration is how you count. Do you include/exclude setup scrap into the calculation?


I exclude the setup scrap. I can trace the scrap back to certain trouble jobs that are never going to change.

Bev D

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To address your other question - there really is no industry standard. first what is good today is too high tomorrow. each company has their own mix of products and technologies and pricing structures. so each standard would only apply to a very small number of companies in any industry. It isn't like airline crash rates or 'on-time' flights or medical infections while in hospital. These metrics must be reported and these industries are highly standardized to begin with. most industries do not have to report their metrics regarding defect rates and very few actually do this.
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