Inj mold - Melt flow effects on cycle time
Inj mold - Melt flow effects on cycle time
(OP)
Is there a rule of thumb for the effect of melt flow rate on cycle time in injection molding? For instance - assume I have a 20 melt flow PP polymer making a part in 25 seconds. If I change to a similar property 30 melt flow can I assume a certain amount of cycle time decrease?
Or are there two many other variables like packing and what not to make any generalizations?
Or are there two many other variables like packing and what not to make any generalizations?






RE: Inj mold - Melt flow effects on cycle time
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RE: Inj mold - Melt flow effects on cycle time
This might, but not necessarily mean you can fill the mould at a lower temperature and therefore reduce cycle time.
There are many variables that effect cycle time, but cooling time is normally the most significant, but for example, with long flow path thin PP parts, screw back time might exceed cooling time and therefore less cooling time is pointless.
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RE: Inj mold - Melt flow effects on cycle time
For a PP part what could help a lot more than MFI would be:
1. Adding a nucleating agent (Miliken had good ones)
2. Adding filler, such as CaCO3 to increase thermal conductivity and thus shortening cooling times
There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell
RE: Inj mold - Melt flow effects on cycle time
Their web site has some good info.
The product is Hyperform and this is a link
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RE: Inj mold - Melt flow effects on cycle time
If anyone has other advice, it would be welcomed!
Bill
RE: Inj mold - Melt flow effects on cycle time
There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell