During a recent webinar, I received this great question…
Do you recommend running at different pressures when performing gate seal studies?
You should first determine the optimum pressure using a relatively large 2nd stage time. This allows you to determine the actual amount of pressure that is required to pack and hold the part. Afterwards, determine the optimal 2nd stage time – once the pressure is established.
Many people overlook the relationship between 2nd stage time and 2nd stage pressure (pack and hold combined). 2nd stage pressure is used to pack out the part and prevent back flow until the gate seals. In comparison, 2nd stage time should only be used to allow enough time for the gate to freeze.