Hello !
I am about to try to use Preform textures for the first time, and on Elastic 50 .
Is there anything I should be aware of before trying ? Any tips / values you would recommend for this kind of material ?
It is for a kind of handle that we want to add some grip around.
I’ve only attempted it once in software, but your CAD model needs to have embedded color data, so not a typical 3MF or STL file if I remember correctly. I converted my models to an OBJ (?) but the scaling was completely off in preform. Your model faces need to have different colors for the software to recognize the different faces to apply the texturing. Maybe something I can dive into today.
No problem about that, my models are made in CATIA and I retrieve all the colors I put on faces on my software very well at the import, thanks to the new CAD importer.
I’m more worried of how the texture will feel on the material.
My tests with Elastic 50 have always been far from perfect for the moment ( prints were bigger by about 5%) which is why I’m worried on applying something like a texture on it.
But maybe I just need a bit more faith
Dimensionally larger by about 5%? If so, once again @leonhart88 has put together some great info on how to fix that. Tl;Dr version is you need to dehydrate the parts post print prior to cure. Effect of IPA on flexible resin print accuracy — Ember Prototypes | 3D Printing Vancouver, Rapid Prototyping, Engineering Design
100% dehydrating is needed 
I know, we had a great discution on it with him in my last topic and I read all of his articles and interventions. But they are getting out of the printer that way and even with more than 3 day of drying before curing it stay that way. I think it was more because of the size and shape ( a kind of cup with thin walls)
Got it. 3 days is more than sufficient (I usually do 4-6hrs at 110f and have been happy with the results). Cupping will 100% cause issues with the elastomerics, particularly with thin walls. If you really can’t reorient you may have to undersize the part slightly and work with that, but I’d try other orientations first. I’ve been able to get my touch points on Elastic50A reliably down to 0.35mm using 1.7-2.5mm support spacing and the manual brush which greatly improves surface finish if that is a concern for you.
I may need to do this kind of part again so I’ll try to change the orientation, but that would need a lot more support ( I was printing on the platform directly )
It was 3 day because I let it air dry during the weekend.
Surface finish was perfectly ok.
It’s hard to explain and I can’t share pictures because of my job but it was a kind of “sock” that you would put on an existing part to avoid to overmold this zone of the part. Effectively creating a seal between the part and the mold.
Dimensions needed to be fairly precise (around 0.1mm ideally) to have a nice even seal all around so having 5mm of gap on the initial print was a big nono.
To go back to the texture part my print is on the way, the first test was aborted by an error 292 after I left work. We will see tomorrow how it will look.
On the platform is solid. Can you add some bleed holes and then fill them? I’ve used Dental impression material for similar-ish uses in the past.
There is bleed holes than can stay open already, it is the shape of a cup but there is no cupping effect at all. Sorry if I was not clear
Three days of air drying certainly sounds like enough. Are you washing them in IPA for a normal amount of time?
Depending on what your part looks like, you might not be supporting it enough to get accurate results. Flexible resins can undergo hysteresis from peel forces and thin unsupported walls may print successfully but could be inaccurate.
Lots of things could be going on but hard to say without knowing what the part looks like.
If by “normal amount of time” you mean the 20 min asked by Formlabs then yes kinda.
I usually let them sit in TPM for about 15 minutes then rince them with water, then wait about an hour for them to dry and then do a 5 min wash in clean IPA. And then compressed air + days of air drying.
I’ll try adding more support next time to see if that helps a bit.
I understand that without looking at the part it is more difficult to diagnose, but my work IT dep forbid any upload of files from our computers.
That sounds totally reasonable.
When you are air drying them - are they exposed to ambient light and UV? Or are they left to air dry in a dark/protected environment?
Even a screenshot or link to a picture would help, but totally understand if your organization doesn’t allow sharing.
Completely in the dark : in a closed cartboard box in a closed cabinet.
The problem isn’t really sharing, it’s the IT making it impossible to upload on other clouds than ours. I’ll try to do it from home if possible.
I wonder if being in a closed box in a closed cabinet isn’t letting the parts dry properly…but I may be pulling on straws here. Post from home if you can and maybe we can give some additional thoughts.
I thought about that too, which is why I added some silica bags in the box, but I may be overthinking it.
Well the new elastic part I made with the texture ( a grip for a small handle) is spot on for the dimensions, it goes on an ejector perfectly not too tight but still as a suction effect when getting it off.
So the first part must have happened because of a lack of support.
About the textures on Elastic 50A it looks good, tho I think I would need to make them higher to increase grip, the texture being flexible, having it a 0.5 is a bit small. At least the contact point of the support add some grip too ^^
Glad it’s working! 