Parts for End Use


#1

We have a Form3 and Form 3L . Both great machines. So much so I would like to use them for production parts if necessary. We have a few FMDs as well. I am concerned about suggesting use of these parts for bridge production prior to injection molding. So I am looking for some real world example or experiences in which parts where used for production part replacement. I realize so many variables; but some examples would as a minimum exclude certain areas. There is no long term data and our printers are fairly new, so I don’t know if the part just get brittle over time when exposed to light; so they stabilize. Can I expect 1 good year. Any feedback is appreciated.


#2

Most SLA parts I’ve used (which goes back to about 1992) required a primer coat to stop the UV aging that makes them brittle sooner than later, easily seen as the part turns from clear to amber or from light amber to dark amber. Many of the resins in the 1990s and 2000s were brittle right off the printer so I urged customers to prime them quickly (I still do this for my in-house parts).

It’s “logical” (to me) that uncoated parts would age since the resin is initially UV cured and there’s nothing to stop that process completely once printed if exposed to UV, even if not the same wavelength used to print the part. Shop lights and sunlight thru shop windows seem to be primary sources for UV in my modeling world, which is why I tell customers to spritz parts with a rattle can auto primer to stop aging.

I recently started testing GreyPro and am very happy with results so far. I don’t know if those will be less succeptible to continued UV aging since they are tinted grey. I would “assume” yes but only time and asking folks at Formlabs will tell me for sure.

I use my Form3 for production parts and rubber mold patterns. GreyPro will likely become the production resin and Clear will be used for mold patterns since those are captive to me and Clear has the best tiny-detail replication.


#3

Thanks for the great response. Yes UV can be a nasty monster for all plastics really. Mostly we have been using Tough 2000, Draft, 10K, and Grey. I think these will all need to be painted or Primed quickly after curing so that the UV polymerization can be stopped or slowed. I think outdoor use is out of the question unless some others can suggest otherwise. My gut is telling me possibly parts with minimum stress, cover and enclosures. Not certain internal parts not exposed to direct light. I am making some barbs right now. The specific size is an issue or I would buy them. 2021-04-23_15-27-11
Simple. I print them FDM, but would like to suggest 10K but cannot back up with long term data. Worried they will just snap later. If others could post or suggest similar end use applications I would feel I could consider it.


#4

It really depends on part geometry and resin. Stiffer ones like 4K and 10K will be much more stable than something like Tough 1500, 2000 or Durable.

In my experience, thin walled parts in Tough 2000 will warp over time regardless of UV exposure. Agree with the above post about coating any resins to prevent degradation from UV.

If you are printing a simple barbed fitting like that, I imagine you won’t see issues of warping over time because of the geometry.

I would be extremely hesitant to print that in any of the more rigid resins though. The barbs will be prone to snapping off (speaking from experience), especially if they are cycled.

I’ve printed barbed fittings in Tough 1500 and Tough 2000, and they seem to be holding up fine a year or more later (not exposed to UV). One thing to keep in mind is that these materials are fairly soft compared to their injection molded counterparts, so the threads might not withstand repeated cycling as well as molded parts.


#5

Actually I am completely surprised by the strength of the 10K. You can’t break this with your fingers but I imagine it is brittle so that any impact will be an issue. I know just don’t hit it right?
Most of the time barbs similar to this are PP or Nylon. So the tough maybe great. I will print some and test.
It is just the long term that frightens me. Would you still give a light UV dusting or leave it if it is indoors. Does the long term UV exposure make even the Tough resin brittle?


#6

Yeah, it’s strong, but brittle. Tough 2000 and Tough 1500 are much more similar to thermoplastics used for real barbed fittings like you suggested.

Long term UV will make all photopolymers degrade, even true for some thermoplastics (eg. ABS).

What is “long term” to you? I think if it’s a barbed fitting that’s being used in a lab setting, it might survive fine. You would have to qualify this somehow :slightly_smiling_face: