I was wondering if anyone had experience with 3D printed resin moulds for injection moulding and knew any vendors with this capability. Specifically, I’d be interesting in hearing more about using this technique for medical devices (biocomp materials, sterilisable materials, etc.) and transitioning from a resin mould to a steel mould. We often work with medical startups and we are looking for solutions that allow for flexible volumes and quick ramp-ups with low cost.
I saw some articles on Formlab’s site talking on the topic.
In terms of corporate medical, I don’t see a use outside running a limited batch for preliminary testing. I can’t imagine that tool being able to get through any PPAP. And the testing run on those parts probably couldn’t be used for finished good as FDA or an notified body probably wouldn’t consider molding on a printed tool equivalent to a “real” tool. I certain could be wrong on that last point, but there is risk involved. A startup may accept that risk. Even making parts for biocomp testing may not be considered equivalent.
Also, the $18K and 30 days in savings is not enough for finished good from a corporate sense. Maybe a startup, but even in that case, again, for finished good, I just don’t see it at a startup level.
I know acrylic molds are used for low volume IM applications. They are just as good, just have more wear so you can’t go beyond say 5,000 products.
The people at Fictiv will probably be eager to help you, they know injection molding and the medical industry: https://www.fictiv.com/medical
I would not recommend SLA resin for commercial-use products because of surface finish, plus the mold may distort and wear faster over time.
I’m surprised to hear of acrylic molds, certainly new to me, as the glass transition temperature of cast acrylic is so low - 100-115°C (212-239°F).
I don’t know of any plastics that mold below that temp.
I think you are right Dan, and the people in manufacturing just throw around the term ‘acrylic’ because it is a transparent material.
It is probably not technically acrylic, perhaps some kind of epoxy or composite.
DSM does rapid tooling and recommend SLA as well.
For surface finishing they use a high-speed CNC.
In my experience, the length of time to build and cure the SLA mold, then machine it to fit it to a mold frame, then run a high RPM, low-speed CNC finish pass (then polishing), and the time to accurately zero the parts for machining - it will be faster to go straight to machining an aluminum tool. You also benefit by being able to run more parts.
If you can mold without all of the machining and finishing then it may make sense.
