- Set pack and hold timers to zero.
- Set pack and hold pressures to zero.
- Set shot size and injection high pressure to ensure a short shot.
- Set mold temperatures to a nominal value.
- Set injection rate to the desired value.
- Start a single cycle.
- Increase shot size to barely fill the part.
- Set cushion to approximately 0.25 inches. Add same to shot size. Set cutoff point to just before cushion. Note injection fill time.
- Increase injection pressure in 250 psi increments. Note where fill time starts to plateau. You have to have an injection maximum 200-300 psi over the minimum fill pressure or the injection velocity will not be met. I.E. the fill pressure is a process limit. As the controller reads pressures approaching the pressure limit it will begin to slow the ram forward speed to ensure the pressure is not exceeded.
- Adjust cut off point to achieve 95% fill. Note the injection pressure needed.
- Perform injection time optimization if required.
Part Pack Out and Gate Freeze Off:
- Set packing pressure to 1/2 to 2/3 of injection pressure.
- Set packing time to time required to pack out the part.
- Set hold time long enough to freeze gates.
- Cooling time has to be long enough to allow screw recovery.
- Check ejected parts by hand. If cold, cooling can be reduced. If very hot or parts are deforming to tearing in the mold, increase the cool time.