Page 49 - Injection Molding Advanced Troubleshooting Guide

32 3 Decoupled or Scientific Molding
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Whenever possible a process should be kept as simple as possible. If first-stage fill
does not need to be profiled why use six steps of profiling? Every extra level of
complexity in the process leads to more opportunities for a mistake to happen. It is
much easier to validate that the fill only weight and fill match the documented
process than to try to determine if every step of a complex profile matches what
it should. As Albert Einstein put it, “everything should be made as simple as
possible, but not simpler.”
To be successful with these molding principles it is absolutely critical to not pro-
cess around material, mold, or machine problems. The 4M method of molding
troubleshooting (see Chapter 1) helps to focus on eliminating problems. Instead of
blaming the process because fast fill rates lead to burns, it is much better to correct
the venting on the mold than use the process method as an excuse. Scientific/
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Decoupled molding is very effective but molders cannot expect success if they are
trying to process around other issues.
Another key to successful implementation of scientific/Decoupled molding meth-
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ods is that all processors in the molding plant must understand the tools used to
develop processes and be confident that they work. If a process is developed in a
typical Decoupled II methodology with a fill only weight at 98% full and someone
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decides to fill the part farther it is likely that the mold will flash. Blaming this flash
on the method is foolish; instead the processor must understand the tools that the
process is built with. Training is foundational to successful molding, as without
adequate training the personnel will feel like the processes are being “tossed over
the wall” into manufacturing and may not provide the support required to supply
quality parts. Incorporate thorough training for all of the process engineers, tech-
nicians, die setters, and material handlers to help eliminate learning from the
“school of hard knocks”.

References

[1] Paulson Training Programs Inc., 3 Inspiration Lane, Chester CT, 06412; Tel. (860)526-3099; https://
www.paulsontraining.com/
[2] Injection Molding Solutions, 1019 Balfour St., Midland MI, 48640; Tel. (989)832-2424; http://www.
scientificmolding.com
[3] RJG Inc, 3111 Park Dr., Traverse City MI, 49686; Tel. (231)947-3111; https://rjginc.com/
[4] Groleau, Rod, “The Fundamentals of Decoupled Molding”, Plastics Today, May 2005
[5] Bozzelli, John, “Why and How to Do Gate Seal Experiments”, Plastics Technology, Oct 2010