PPM Calculation in Automotive Harnesses
This topic contains 3 replies, has 1 voice, and was last updated by Oguz Ozbek 9 months, 3 weeks ago.
- February 15, 2018 at 4:17 am #55940
I am in a bit of a challenge at the moment:
I moved to a new automotive company that produces harnesses (KSK’s); in this company the PPM is calculated as following (example):
2000 harnesses produced monthly & 2 failures monthly = 1000 PPM monthly
In the company I previously worked for 12 years the PPM was calculated at module level (each harness was built of 15 sub-modules) so the PPM was calculated as following:
30.000 modules (2000 harnesses) produced monthly & 2 failures = 66 PPM monthly
How could I motivate the second type of PPM calculation in order to apply it also at the new company so that the customer agrees it?February 17, 2018 at 6:28 pm #202276
PPM is parts per million so I assume you mean DPM (defectives per million). I don’t see a good basis for the formula used by your previous employer. It doesn’t match the percentage of defective harnesses. It treats all of the 15 sub-modules the same so it doesn’t help to identify in which sub-modules defects most often occur, something you really want to know.February 19, 2018 at 1:58 pm #202282
What does your customer care about – Harnesses or Modules? That should guide you on how to report the DPMO (defects per million opportunities) rather than you trying to persuade the customer to change to your numbers.February 20, 2018 at 4:47 am #202287
Product-level DPMO shows product quality, module-level DPMO shows process quality. For the customer (and for you as an end-result) product quality must be more important. But be careful, in that case, your defects must be identified as defects which make the product defective. What does the customer define as defective in the end-product? However, to improve product quality you must know the module-level DPMO, in order to prioritize your efforts.
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