Manufacturing Part Quality (MPQ) is the risk of a delivered product form a supplier, in case of for instance a machine builder, not functioning during final assembly until first year of use at the customer caused by the manufacturing of the product. Risk are coming from vendor parts which are not correct functioning and cause a failure in the future or the used processes used during manufacturing and assembly of the product.
There are three types of parts identified with their different failure modes.
- Vendor parts have a failure rate based on the manufacturing processes used and the applied test. Most of the time theses are small contributions due to the large quantities produced.
- Manufactured products are parts starting with a material and transformed into a part based on a technical product description either from a drawing or electronical file(s). Again with the processes used to make a manufactured part a failure can occur, which when not tested properly, wind up as a failure in the manufactured part.
- Assembled products are parts which consist of more than one part. The failure rate comes from the sum of the failures from all parts and processes used to make the assembled product. Not all part and process failures lead to a failure in the final product.
The method followed to determine the product failure rate is based on a Value Stream Map. As starting point a BoM (Bill of Material) is used. Out of the BoM a mflow (manufacturing flow or process flow) is created automatically. This can be done with the first published BoM during design until the final volume BoM. The most effective way to work is to start during the design phase where the identified failure rates can be improved or tested. Out of the mFlow a Value Stream Map (VSM) is created by adding the failure rates, test and rework information to the part and processes. Next step is to calculate based on the failure rate, test slip and rework activities a product failure rate. This results in a realistic number of products which will fail in the future and the amount of scrap. To know where to start mitigating the largest contributors are visualized.
Note: for manufactured parts tooling is available which calculate the manufacturing time and cost based on a PMI/Step file.