Im working with a customer who intends to print/sell small electronics housings to real-world customers until the project can earn enough to justify injection tools. We opted to pick up some TOUGH resin as we need the parts to be strong and functional, not brittle like most SLA.
In my experience, SLA parts always seem to get brittle over long periods of time, probably due to UV exposure and possibly just drying out. Has anyone noticed this with TOUGH? Would TOUGH still be really tough after a year or two in an average household or would it get brittle slowly over time like older resins?
If yes, would it help to apply a paint coating to help stop it from over-curing?
Just trying to prevent any regret with our early-adapter customers
Painting with something that blocks UV will certainly help.
I have printed some enclosures for electronics using Tough. What size and wall thickness are you looking at? My observations are:
It takes substantial thickness (more than 0.125") to prevent warping during the recommended post-cure (especially at elevated temperature - maybe not as much of a problem if curing with UV light only). I had an enclosure design with a relatively flat base that warped. The mating part had the enclosure sides and had only minor warping.
It will take manual finish work - maybe more than you are expecting
You might want to paint it regardless as the texture of Tough picks up dirt and grime pretty readily.
You might want to consider Durable resin for the increased impact resistance, but whether or not it will work will depend on your enclosure size and wall thickness (it might be too flexible for your needs).
No, it becomes brittle. No matter what.
Painting the part completely inside-out help in controlling oxidization.
Also, your post-curing cycle will influence part flexibility a lot.
A more intense post-curing will render the part more brittle.
Green Tough is quite flexible indeed…
I haven’t used the service, but you might also consider electroplating from someone like Repliform. Some on the forum here have been happy with the results. While it would almost certainly improve the lifetime of the enclosure, it might not be desirable because it would be highly conductive (depends on your application - it might be a benefit).
I think if you are running decent-sized batches the plating ends up being pretty reasonable.
If you are selling the parts as product- then you might want to skip printing the enclosures and instead print a low run injection mold tool.
Formlabs just recently posted a white paper on making low run injection tooling…
That would do much better.
Or- alternatively- you could make print a split master for producing a silicone mold you could use for casting the enclosures in a compounded resin like Urethanes.
Compounded urethanes can be found in just about any rigidity or elasotomeric calss you might need… and tho they will not last as long as thermoformed plastics, they will last linger than most printed resins.
Also- you might try Rigid resin- which might has a greater stability and lower warpage in thin walled prints.