Hi, I want to start making parts using Carbon and Kevlar. Initial requirement is for a duct. I am contemplating a 3D printed investment mould using ABS or PLA. I have seen it is possible but cannot find any videos showing the process.

The parts will not be massive, perhaps 500mm cube. I would like to be able to start on a relatively low budget so anyone with existing facilities who would be able to help out in the locality I would appreciate it.

Charlie

Hi Charlie and welcome. Surface finish and getting a good release can be issues with 3D printed moulds. The costs are also high (at the moment) compared to conventional moulding systems. Are you looking for help with the 3D printing or making the composite parts. I approached a local university for the 3D printing and ran it is a joint project. Universities often have the latest tech so could be worth a try. 3D laser printing with aluminum is an area that is interesting me at the moment, but again additional work is still required to achieve a good surface finish and its expensive.

Warren

Carbon Copies Ltd

Warren, thanks for the reply, I have the 3D printing technology already. In terms of the surface finish this can be achieved by using acetone vapour to merge the banding you get with the printing process. I have researched PLA and found that it is possible too but cannot remember the name of the chemical process, enough to say it is possible on a semi DIY basis.

Other than that I have found that sanding the part down can achieve the results required. Yes it will take longer but for the small production runs and prototyping I don't see this as an issue.

What I am asking about is if anyone has used the investment mould process, either with wax PLA or ABS. Some complex 3D printed structures with overhangs use a PLA support structure with one nozzle and the actual part will be ABS. Once printed the part is placed in a dissolving agent to remove the PLA leaving the ABS part. And so if the mould were made of PLA and we wrap it in carbon we should be able to dissolve the PLA in the same manor. The alternative would be similar except rather than dissolve the PLA it would burn off in an autoclave at curing time.

Trouble is I do not have access to an autoclave.

One must also remember that multiple 3D printed parts may be bonded together successfully to create a much more complex part.

why do you think you need an autoclave?

well look I am new to this, I watched a video promoting Stratsys 3D printer and during the presentation they held up the part and said, "so this is a 3D printed part wrap it in carbon fibre and during the curing process in an autoclave the plastic melts away"

Is it that autoclave doesn't come into carbon fibre work at all?

I think Chris was simply trying to point out that there are pre-pregs that don't require an autoclave, but if you would rather watch videos than listen to experience that's up to you.

Carbon Copies Ltd

Yes, I was a little rushed earlier to expand on my original post. You shouldn't need an autoclave, if you want to melt away the sacrificial former then you just need an oven.