Hello all!

We are molding HDPE lids with an electric press. The material recommended back pressure (and everywhere online) says 50-150 psi for back pressure. I was under the impression that this was a hydraulic pressure recommendation, so the plastic pressure would be 50-150 psi x IR.

If it were a hydraulic machine with an IR of 10:1, that would equate to a plastic back pressure range of 500-1000 psi.

An electric machine has an IR of 1:1, so what would the ideal back pressure be?