How Much to Fill the Mold…

I received a few questions from a blog reader the other day, this is one of them…

Regarding the Cavity Balance Test – which is preferable, 50% or 90% full.

note: this test uses different injection speeds to determine which provides the most balanced fill during a 1st stage short shot.

My Response
It is preferable to use a 1st stage fill which provides a ~90% filled part. This provides a good representation of how the part will perform during production.
Additional Thoughts
If you have a product which require a profiled 1st stage injection, it may be a useful exercise to perform such a test at each stage in the profile. This will help you ensure the final fill balance is optimal.
For more blog entries on cavity imbalance, please feel free to review the following:

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