Corrugation in foamed PS profiles
Corrugation in foamed PS profiles
(OP)
When trying to produce fairly large profiles in low-density XPS foam we are continually faced with corrugation. We thought memory effect interfered with the foaming when exiting the die but (greatly) increasing the land length of our die has had no effect at all. A tip, anyone?





RE: Corrugation in foamed PS profiles
Regards
Pat
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RE: Corrugation in foamed PS profiles
We use pure CO2 as a blowing agent.
RE: Corrugation in foamed PS profiles
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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for site rules
RE: Corrugation in foamed PS profiles
I always look for the pressure ceiling when testing so I know increasing melt pressure does not have a positive effect on the corrugation.
Increasing the temperature is only possible when I decrease the amount of blowing agent, otherwise the pressure is insufficient to keep the CO2 dissolved in the melt.
Could replacing a small amount of the CO2 with an endothermic blowing agent be helpful? So as to decrease the foaming rate after exiting the die?
RE: Corrugation in foamed PS profiles
Could you spray them with cold water to keep the surface frozen.
I am shooting in the dark a bit here as I have minimal experience with EPS foam. What little I do have used I think isopentane as the blowing agent. My experience is with chemical blowing agents and density reductions in the order of 10 to 30% only. Corrugations then usually mean under packed and over blown usually has a blow out not a corrugation.
There is less than zero profit in reject parts so while 110kg per cubic meter makes for low profit, it seems 80kg per meter makes less than no profit at this stage.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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RE: Corrugation in foamed PS profiles
I guess we'll have to make do with a more dense product. Thank you for your help in this matter.
RE: Corrugation in foamed PS profiles
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
http://eng-tips.com/market.cfm
for site rules