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5th May 2021, 08:03 PM
#1
Enhancing flow properties of resin
Hi, I am new in injection molding. I recently got a cable tie mold (cold runner) made from a domestic mold-maker. (32 cavities, 4*300 mm)
But I am having several problems with the mold:
1. When I try to fill the cavity with nylon 6 at high speed low pressure, the cavities doesn’t fills till the end.
2. When I increase the pressure, there is flash at the gate.
I think the clamping force is not a problem as It is being run on a 350 ton machine.
Is there any way to enhance the flowability of the resin so that it fills till the end without flashing as the melt freezes before it reaches the end of cavity?
Any other suggestion would be great?
Thanks and Regards
Abhishek
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12th May 2021, 10:55 PM
#2
Re: Enhancing flow properties of resin
Some ideas:
increasing mold temp will improve flow
Increase plastic melt temp will improve flow
fast injection speed is your friend
Open up gates
If you're pressure limited, Read up on a "pressure loss study" to determine exactly where your pressure restrictions are, starting from the nozzle, cold-sprue, various sections of cold runner, the gates, then throughout your part geometry
From this data you can look into opening up sprue, nozzle, runner or gates to assist
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13th May 2021, 12:23 AM
#3
Re: Enhancing flow properties of resin
Is a pressure loss study even necessary on newer machines (last 20 years) that can graph the injection pressure vs screw position?
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19th May 2021, 06:06 AM
#4
Re: Enhancing flow properties of resin
Thanks for the reply chris. I’ll try raising mold temperature and opening gates as I have tried other ideas. I’ll read more about “pressure loss study”. Thanks for the help.
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19th May 2021, 01:38 PM
#5
Re: Enhancing flow properties of resin
Is tool venting OK? Making some additional scratches may hellp you (0,05mm).
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