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scottracing - 10/8/2018 8:50:04 PM

Hi Matteo

I have been using 3d printed parts as tools for many years now, and its very difficult to get any of the plastics to polish up nicely enough to a gloss finish.
Luckily there is a few things you can try especially with ABS, firstly you can use an acetone bath or mist to smooth out the ABS print. Have a search online for ABD acetone smoothing and that will help.

The other option is to use something like this material XTC-3D, which is essentially a self levelling lacquer which gives you a gloss finish.

https://www.youtube.com/watch?v=GSKxycs3kPg

Or you can look at getting some tooltec, which is a self adhesive PTFE tape which you apply to the print and you can layup onto it without any other release coating. As the part you are making look is relatively simple the tooltec should conform ok to the geometry.

I look forward to seeing how you get on.

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Hanaldo - 10/9/2018 1:32:37 AM

XTC is probably the most suitable solution for your current plan, but it doesn't work quite as well as they claim, still needs a bit of sanding. When you're trying to make a matched compression mould, this gets tricky.

In all honesty, if you want a gloss finish then I dont think your approach is terribly well suited to anything more than a one off that you then clear coat. You need the exact finish on the mould that you want on the part because that is the surface the resin is replicating. You cant expect resin to come out glossy when you're moulding off a dull surface.

Why dont you 3D print a male version of what you want to make, sand it to 1200 grit, and then make a fibreglass mould of it? You can then polish up the fibreglass mould to a really high standard and bang out parts with a consistently great finish?

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Hanaldo - 10/10/2018 12:11:45 AM

The glossy image of primer is just after it has been sprayed while the primer is still wet. This gloss backs off and it dries to a satin finish, not unlike what you already have. You can get good pattern coatings where you can prime it and then apply a gloss coating, or mix the two together to get an in between result. This is an option for you, but wont work with ABS - ABS is quite a vulnerable plastic, and also difficult to bond to. It's also this reason that makes me doubt S120 would work.

Yes, you would need to polish the fibreglass mould, but fiberglass moulds generally take polishing very well if you use the right materials.

Dont get me wrong, I have great respect for additive manufacturing. But for me it is still more of a prototyping solution, I'm yet to be convinced that it is great for direct printing of tooling, at least not in the traditional sense anyway. 3D printing mandrels and dissolvable cores, fine; there isnt currently a much better solution for that. But for the part you are making, in the way that you are making it - 3D printing the mould isnt the way to go about it for me.

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Steve Broad - 10/10/2018 12:33:17 AM

I agree with Hanaldo.

If I tried this method, I would CNC the moulds in aluminium. It is easy to machine, hard wearing and polishes to a glossy finish easily. They look pretty straightforward so a basic 2.5D mill would make this very accurately with no problem.