Hello everyone

I am working on a full suspension bike frame and my design requires some inserts that will be placed inside the tooling that need to be dissolved or mechanically removed after curing, due to negative draft angles.
The insert needs to resist to at least 80°C and 3 bar of pressure during the cure cycle. surface requirements are not critical for this project. Ideally it would be something that can be cast in a 3D printed mould, machining is an option too.

The best would probably be just to use aquacore, but with the minium ordering quantities I am inclined to figure out a MacGyver solution instead.

Does anybody already have a secret recipe, or an idea what could work? I tested a couple things and have some routes, but i figured id ask here as well.

In any case i will share my findings at a later stage.

Ciao!

Why not directly print the soluble mould ? I would do it from HIPS filament, with proper part design (perimeter thickness & infill shape) it should comfortably resist 3bars@80C and can be easily dissolved with limonene afterwards - it shouldn't damage the cured epoxy matrix and is comparatively benign and safe compared to most other chemicals used when working with composites (even acetone, which would be another option together with ABS filament).

Well, it's almost ten degrees better then 80C softening point of ABS but I understand it would be close call - I would still try it, printing small test piece (but with similar cross section as real thing), bag it and test the deformation after 80C/3bar cure cycle -whether it survives it without deformations.

I agree it's worth trying, HIPS has a glass transition temp of 100°, so it should still be pretty stable at 80°. The HDT isn't as critical - it may mean you get a higher degree of fibre print, but it shouldn't be worse than that.

This is an idea I have tested on AL prepreg mould.

I ordered some hips and will report back. currious to see how that goes.

@Rosta Spicl
Thanks for your input. I considered this as well for one area, but one of the inserts would be a major pain with this method still.