Just got some horrific cracking along a part. Seems to me that the new Grey is just too brittle. This part was completely watertight so there was no need for the Geometry to crack. Also its a pretty big part so I don’t think wall thickness has too much to do with it.
Any ideas on the new Grey?
Your experience with Grey V3 doesn’t look to be typical and we’ll want to make sure there isn’t something functioning incorrectly with your printer. Under-supported geometry can sometimes cause cracks like this but they’re typically more linear. I’ve reached out to our support team and one of our members will be in touch over email to help troubleshoot.
I’ve seen cracks like this on a few parts (various "standard resins… white black gray), but very uncommon, and not reproducible). We’re talking like 3-4 out of +400 prints. I’ve rerun the same parts (same file) and it’s been fine. I’ve attributed it to, simply, just one of those things that happens, sometimes. I’d run it again.
Make sure your resin is mixed enough before printing, it’s important to use the scraper to stir the resin in the tray and shake the resin cartridge before printing again if you aren’t printing continually.
grey v3 smell worse all of original resin. I think clear smell best. Not everyone have room with good ventilation. I find it very stiff and not brittle at all. After 3 print for grey v3, so not all tested yet.
I only got my form 2 about a week and a half ago and i mostly brought grey V3 and have had problems with a number of parts being more brittle that i expected. They seem to have been fine of the first few days but then i noticed some of my parts breaking from light weight forces, I am wishing i had brought the clear at this stage because the sample i got in clear seems to be far stronger than what i have printed so far. One item which was in a small box must have been slid against the box wall in the car and had broken in half. This item had very little post curing and was painted soon after whilst the same print which had been cured for longer also broke after falling 0.4m of my coffee table. Both are light weight items so i was suprised. To test it further i deliberately dropped a light weight (7g) box like design which had been a little too flexible in the first 12 hrs from a hieght of 0.5m and it fractured one wall. Im not going to go around dropping things but i do need the parts i am producing to be stronger than this
I did have one issue with this ever, and it was with the Black resin. Basically on a miniature but it was after I left him curing too long it seems and from the top of his shoulder, to the bottom if the miniatures are, it just sheered right in half. A completely clean cut straight through as if you took an xcto knife and cut right through it. Very weird.
While Grey V3 has lower impact strength compared to other materials due to high stiffness, your parts seem to be breaking more easily than we might expect. Were all of the fragile parts painted by chance? It might be possible that an additive in the paint like Acetone weakened the resin causing it to break more easily.
Only a single item was painted and that was the one that broke in the box, The first item to break had actually fallen 0.5m on to carpet about a week after having been printed. These parts seem to have become particularly brittle about 5-7 days after printing.
What sorts of steps are you taking to wash and post-cure these? Prolonged exposure to IPA or excessive post-curing can cause parts to weaken and become more brittle. Half a meter could be an issue for some geometries but your parts still seem more brittle than we’d typically expect.
As discussed via Email, I had both cured and none cured parts that were just as brittle. But I had been using IPA for 10 to 20 minutes depending on the part and whether excess resin had been removed and then had post cured some parts outside in sunlight and some in a heated box with a uv lamp.
I can now say that it seemed to be a particular issue with this cartridge as the Grey V3 I have used since didnt seem anywhere near as brittle as the first cartridge. I do however find that the Clear V2 I have used has made for stronger less brittle parts and im about to start using Clear V4
