Does preheating/drying material have big effect on flow pattern during mold filling?
Hi! Holiday greetings to all. Just a quick question, what happen if we increase the drying temperature higher than the spec given by material suppliers? For instance, 90 degree C instead of 70 degree C? Does that affect the flow pattern during mold filling? If let say, product released from mold does have a weld line at edge when using standard temperature, will increasing the temperature help reduce/ relocate the weld line? Thank you for sharing.
The best way to solve your problem is minimize packing pressure and dwell time.
Now if you want to move a knit line; fill rate, mold and melt temps are the only methods, providing you don't have a valve gated tool. There is one other trick, a melt flow helper. This is just a localized thickening of the wall stock, done to the non-visible side of a part, to assist the melt front in getting into an area and pushing the knit line into a more acceptable place. These do not always work, due to part cosmetics or tool design. But they can help you keep a customer.
Hope this helps, Rick.
Air vent can be provided near joint line to release gases/air.
I agreed 100% with Kumar.
Pre drying PP will not improve welding lines or increase the melt flow index, especially PP.
The injection gate is very important, do not forget to make a lot of radius on the sprue and like the colleague said, good venting gases are crucial. If you want a better flow, you will need to choose another grade of PP with a better melt index!
Best Regards,
Gaspar
If I have problem with flashes, after for example 4 hours of production, can it be a reason of "wet" polyamide?
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