What quantity of scrap parts are traditionally accepted during startup?
I have heard anything up to 50 parts is an acceptable level of scrap during startup. My experience has been 10 to 15 parts are an acceptable level but others dispute this as a quantity that is too low. Any thoughts?
1. Optimize your process first, then modify the mold to get it into spec.
2. NEVER, send the 'crown jewels'. Send what will be typical for future production.
3. Once you have an optimized process, don't be silly enough to speed it up. Good parts are better than scrap parts made quickly.
Process stability determines dimensional stability of the parts, more importantly whether ii is single or multicavity based on these criteria it takes more time to get acceptable parts, and agree with earlier comments on complexity of the parts takes more time on fine tuning the process window, atleast average 30 minutes required to get good parts irrespective of number of cavitation