Hi all,

I just finished reading the Optimization of the Injection Phase - Rheology Study and found myself confused

The procedure is to establish a 95-98% filled shot at close to the machines maximum. Record the data and reduce the injection velocity by 10% until producing parts at the slowest injection velocity possible.


I completed my study and found that the viscosity stays fairly constant at about 50% of the machines maximum velocity.

Now here is where I get confused...The procedure doesn't exactly spell out what I am to do next...unless I overlooked it in the text.

I set the machine to around 60% of the machines maximum to ensure that the process will stay consistent with slight viscosity variations. At 60% of the injection velocity, the parts appear to be 70% filled.

I was inclined to adjust the transfer position such that the parts were filled 95-98% at this speed. But then questioned myself because for process development activities, I was asked to get a High and Low value for injection speeds to see the effect injection speed has on part dimensions. If I were to choose 60-70% injection velocity for the test, would I have to adjust the transfer position for both during the study?