A supplier of mine is using the cold press moulding process, and I wonder if anyone here has tried this, as the cycle time seems very low (5 min?), and it uses simple resin tooling? Guess a cheap chinese press would probably do, and looks like it might be ideal for making things like small cosmetic bike parts say?
Cold press molding? Not sure how that would make things go fast, unless using REALLY quick curing resin.
or mixing the epoxy and catalyst while infusing the closed mold?
tooling costs are obviously higher.
2 Part resin tools are used, so obviously more costly than 1 part tool, but as there is no need for consumables used in something like vac infusion process, works out cheaper if you are making anything more than a smallish number of parts.
A supplier of mine is using this process, and he has 6-8mm thick GRP tooling, and uses single venturi pump to vacuum infuse resin into the sealed 2 part tooling.
some of the best carbon parts I have seen made were from a press using machined aluminium and prepreg carbon for the parts. you can make amazing complex parts this way, but very expensive
we use compression moulding with prepregs for really quick cycle times at 160deg C cure, but also do a few bits using infusion in this way. Its almost like rtm light. The problem is the split tools need to be very accurate in allowing for the thickness of the component and we only do small parts like this as we havnt found a viable interlaminar flow media yet!! 
I guess if you had a heated compression set in a press using vinylester you could get the time down a lot to demould
5 minute demold time? or maybe i read that wrong. Too many exhaust fumes lol i’ve been working on the bike this evening.
Hojo, i’m guessing those parts had to be baked in an oven under pressure?
the molds them selfs are heated
What is a good way to heat an FRP mold that is approximately 3/16" thick? a heated wire somehow attached to the backside of the mold? Or a heat lamp? or? I know there will be days when it’s 50F outside where i work, i can heat up the resin with warm water, but just needing to know a good way to evenly heat up the mold to around 95F or so.
I have seen coils laminated in to molds before, also plumbing for hot water. but for your case probally just a heat lamp for the temp you are looking for. you can all so get a small space heater, and tent off a smaller space. when I had a shitty shop in the winter back in the day I used a 115,000 btu portable heater, bought for $300 new, heated my shop which was 60’x 30’ x 14’ high with shitty insolation, heated it in 10 minutes, but as soon as I shut it off it got cold quick
Was speaking to a supplier of mine yesterday, and he told me that he had visited a factory producing GRP parts for trucks. Process time was 30 seconds per moulding, using aluminuim tooling.
Well, when dealing with injection molded plastic parts yeah, 30 seconds. I think the flow of the thread is composite laminated parts.
The problem with heated molds is the time it takes to heat up the mold, and cool it down enough to cure properly (along with avoiding CTE issues of the parts.)
2 part molding I would think would only be worth the cost, if you need a tooling surface finish on both sides. That’s the only way to go.
But also, i guess if you need a certain thickness, and fiber volume ratio, 2 part is the way to go as well.
On a commercial basis making mouldings using 2 part resin tooling, seems very cost effective in terms of faster process times, and low consumable costs.
Takes a little more effort to set up than one piece tools, using vacuum, and would be interested to hear if anyone has tried this to make small run of parts?
Well, yeah, commercially. But people are always scared to make a large investment in something they don’t know much about anyways.
RTM lite or even reuseable bagging systems are great for production. prepregging is the way to go as well.
Making a simple 2 part resin tool isnt really that costly, and this process seems it certainly might be worth a look for anyone looking at low volume production.
Is there a void issue? How are gases that get trapped in the press and laminate dealt with?
The guy I know who uses this process, simply has resin intake and vacuum line on one half of the resin tooling he has.
Dont think there is really any need for costly aluminium tooling, if you are wanting to make small runs of cosmetic motorcycle parts say, but obviously most large run industrial production would be done with heated metal tools.
they didnt have void issues, infact there parts had a beautiful finish with some very small complex shapes. it was durham boat company that uses this process, I have been to there shop a couple times before. there was also a factory in china that I worked at that made paddles with a press too
I guess the fact that using a press with 2 piece tooling, means far more uniform pressure on the parts that are being formed, and few if any problems with voids?
yea, aslong as the tools are machined correctly.