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Mould Making – Release Agent

This topic contains 5 replies, has 6 voices, and was last updated by  Mark Bachrach 1 year ago.

Joe Giddings gang-o-six

Mould Making – Release Agent

25/01/2017 at 14:27


I’ve built an injection machine at Underbroen in Copenhagen. I’m testing aluminium moulds, and I need some kind of release-agent/de-moulding-agent, that will help with removing the plastic after moulding! At the moment it is very difficult.

I’m going to test silicone spray and teflon spray, but I have doubts about their capacity to handle heat. I’m experimenting with injection moulding very thin pieces, so I’m pre-heating the moulds before injection.

Any advice on correctly designing moulds is welcome!

All the best,

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01/02/2017 at 23:09

I was recommended vaseline by an retired toolmaker, it works very well but it might clog air-vents and it moves around and soften sharp corners. I’ve also had a hot-vaseline explosion due to too high heat, gas and pressure, so be careful, it’s quite liquid when hot.

16/05/2019 at 19:22

I am not sure if you solved the problem, but if anybody comes to this post due the Title, Dave mentioned this in another post:

I’m not sure which technique or type of plastic you use.

However the plastic that mainly sticks is HDPE, you could try to use another type like PP (quite similar). Also if you inject or press hot plastic in a cold mold it doesn’t stick to it. Most of the times it happens when you heat up the plastic together with the mold (compression machine) potentially you could see if there is another way to get your plastic into the mold or switching techniques


17/05/2019 at 16:12

i personnally do my compression out of the oven;
process is following :
-turn oven
-put plastic un teflon coated dish and wait for it to melt
– take dish out of oven
– put molten plastic in mould
– compress

/!\ unmoulding is VERY easy and requires no additive
/!\ a lot of time & energy gained, because if compression is in oven, then in order to unmould you need to wait for the oven to cool down etc… and turn back on for next product.
hope it helps !

(i tried butter, virgin coco oil, vaseline, release agent, unmoulding wax… but never felt as easy as the process i just explained)

09/09/2019 at 20:34

I use silicone spray in compression oven.  It works reasonable well, or at least it works better than anything else I have tried.  Silicone has a super high heat resistance by the way!

09/09/2019 at 23:05

Silicon oil from a can is the best i’ve used so far

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