Process window 98% full temperature

[DeanG]

On this website it states to set the temperature to the lower settings and make a part that is 95-98% full. If I then go to my mid range temperature, you have already packed the part out without having to add hold time or pressure. Why would you not set your decoupled process in the mid range of the temperatures to start instead of at the low end of the temp range?

[Suhas]

Dean,
You are right. You must always adjust the transfer (cut off) position such that you are always 95-98% full so that you have a decoupled process. This is true when you change the melt or mold temp or for that matter even the injection speed or any parameter that affects fill.
Yes, you can start off at any temperature you like. But for a process Window studies you must choose the widest ranges possible and so you start typically at the low end.
Hope this helps, if not we are here to help more!
Suhas

[rickbatey]

I too always start at the low end of the process parameters sheet. The reason for this, is it is easy to add heat. Removing heat from an injection unit involves plasticizing plastic or fans to force cool the outside of the barrel. That way I can step up through the ranges.
Remember-We are all selling machine time. Less heat in equates to less heat to remove, or shorter cooling times.
Rick.