The Symptoms Of Machine Dependant Documentation

In a recent discussion with a brand new customer, when discussing common defects he posed this query…
Steve K.
Although we don’t really have one or two defects we get all the time, but we get a lot of different defects all the time. We run a lot of different molds, machines, and materials… and we change a lot of molds. Do you think that might have anything to do with it?
My Response
After a few pointed questions, Steve explained that his employees only documented the machine settings during start-up. Although this is very common in the injeciton molding industry, the process settings of one machine provide virtually no guidance when the mold is hung in a different machine. Even using the same barrel temperatures can result in melt tempertaure differences in excess of 50ºF! 
We went on to discuss the importance of machine independent documentation that includes part specific data such as part weight, fill time, coolant and melt tempertaures as well as the actual pressures applied to the polymer. We also strategized methods to get Steve’s employees to adjust their behaviors over the long term.
Additional Thoughts
Even though Steve had some good employee working for him, every time they put a mold into a machine, they put the data into the machine. When the part does not magically come out right… the have to process without a set of machine independant targets to aim for.
If the mold ran great in machine #4 last week you need to know specific details such as: Fill Time = 3.2 seconds, Melt Temperature = 427ºF, Final Part Weight = 23.5 grams. This information is invaluable when you put the mold in machine #3 next week.
If you or anyone you work with would like to learn more about process documentation… we have some FREE multimedia webinars on scientific molding which can be viewed at

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