Buildup after Acetal Moulding 2

[cpretty]

Hi all,

We mould a number of parts in acetal and get white buildup to certain degrees on the moulds as expected with this material. On most of our moulds it can be polished straight off.

One part we mould has a sparked finish so cannot be polished, and due to moulding complexity has a large amount of buildup occurring.

Does anyone have a quick and easy method for removal of the buildup?

I have seen that Slide market a product called Resin Remover, but think that maybe someone out there has a 'tricks of the trade' style solution.

Thanks for your help.

Craig

 

[patprimmer]

I am looking for data, but from dim dark memories from 40 years ago, methylene chloride helps. It is quite a nasty chemical. Polyplastics in Japan used to sell a pressure pack can of mould deposit remover, but once again that was 40 years ago. Maybe Ticona does it today.

To minimise mould deposit you can do several things like:-

Make sure the mould is very well vented.

Dry the material. Yes I know they say it is not necessary, but it does reduce mould deposit by driving out volatiles like free formaldehyde and oligomers.

Run the material at a reasonable melt temperature even if it means a higher mould temperature is required.

Run the mould hot. Never below about 40 deg C and up to 90 deg C helps.

Choose a well respected brand and opt for their low mould deposit grade if they offer it. A lot depends on how well the polymer manufacturer washed it before compounding as water removes formaldehyde and oligomers.

Regards
Pat
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[cpretty]

Thanks Pat,

We are following all the recommendations to try and minimise the deposits, and it has just built up slowly.

I don't know where the idea came from (thin air I think), but one of the guys here rubbed it off with tinfoil. It would appear to like sticking to aluminium, and the tinfoil doesn't damage the finish.

Cheers,
Craig

 

[Pud]

We use a brass suede shoe brush to get crud off tools.

Cheap and effective - will not damage steel tools.

H

http://www.tynevalleyplastics.co.uk