1st filling ( Injection phase )

[Maheshkumar Hiremath]

During 1st filling ( Injection phase ) , is it right practice to turn off both holding pressure and holding time ?

[pjhall]

When first setting up the filling phase I do trun off the pack/hold pressures and leave the times there so the maching cycle time is consistant. I also start with the initial injection pressure set very high so the process will not be pressure limited. On some critical jobs I record the weight and take a picture of the part with the holding pressures turned off (95% filled). I don't do viscosity studies that often. When I have the fill phase set I set the injection pressure a couple of hundred psi (machine pressure) above what is used to fill at the speeds I have indicated. Then add the holding pressures after doing a gate freeze. I mostly do the gate freeze graphs for larger parts.

[rickbatey]

I leave a time in the press, normally using a similar part's numbers for hold time, until I finish. Then I do the gate freeze. Nowperfrom the viscosity study since it has been saving me lots of time and scrap, first; then the gate freeze. I also try to run my hold pressure at about 60% of peak injection; another one of those time and scrap savers.

[NATHAN]

Set the minimum value of the second stage pressure. [ some machine the minimum value was available ]
Set the holding time with the consideration of gate size, melt and mold temperature by right.

To minimize the screw bounce back at the transfer position time.

[1Aahz]

The answer to the original question is yes. Turn off hold time and pressure. Some machine slope/ramp 1st stage hold pressure so if there is any time on the clock it will use that time to ramp down from pressure at transfer to 0.

GBYA
Aahz

[Suhas]

Correct Aahz, One must study the controller to understand this.
Suhas