Hey all, I was hoping to see if anyone else noticed a substantial difference in the tough v2 vs the tough v3?
I’ve been printing with the v3 for a few days now and it seems SIGNIFICANTLY more brittle and way stronger than the v2. This makes it realllllly hard to print flat on the platform, since it just wants to snap when we try to remove it.
Any suggestions or other validation of this?
Yes, big difference!
I really like V3 over V2. I need much smaller supports(they even allow 0.2mm for V3!) and deformation of parts is much lower as well. Much easier to print and snap features seem to work better. No complaints here.
This makes it realllllly hard to print flat on the platform, since it just wants to snap when we try to remove it.
You don’t want to print “flat” on the build platform. That orientation is important for FDM if you want a “true” part, but it can cause the opposite problem with SLA. Let PreForm orient the part. If there’s something about the orientation you don’t like (like the front face of the print is down towards the supports) just tell PreForm to orient it again until you do.
The biggest issue for me isn’t the orientation in 90% of the parts we print. I print flat on the bed to reduce time cleaning supports, reduce time printing, and to reduce part removal difficulty…or at least that’s what I was doing with v2. V3 won’t let me, since it’s just way too brittle. I would place chamfers on the faces of the parts contacting the platform to aid removal, and it used to be super fast.
Admittedly the v3 parts have less deflection than v2, but this just seemingly places v3 closer to the standard resins than the durable.
You really can’t judge the material properties in the portion of the print that’s on the plate. This zone is intentionally over cured and compressed. The raft and first part of the supports are intended to take up this space.
The supports and extra time are well worth eliminating failed or non-functional prints. Features in this initial zone are not accurate.
While that is 100% correct and well stated, I’m simply pointing out that the v2 did not have the issue where the first layer was significantly overcured and nearly impossible to remove from the platform. There’s a good chance that my build platform is damaged or my tank is funky, so I’m just now changing tanks.
I do like the optical properties and increased strength of the v3, it’s just currently harder to print with. Hopefully my changes fix it, since everyone else seems to find v3 to be a much better revision.
If you printed with a base and supports, you might still have trouble getting the base off the build platform. I do. But the part itself is almost always fine, even when I have to remove it from the base first, and then chip the base off the build plate.
The initial layers of the print are executed with the build plate in contact with the bottom of the resin tray. How many layers get printed this way varies, and depends on the tolerance stackup of each particular machine (and it probably changes a little each time you remove the build platform and/or replace the resin tank). But as a result, some number of the first layers are always overcompressed. This means if you print without a base, the Z dimension of your printed object will also always be compressed.
If you’re not printing a base, I do not think the printer over-cures (meaning makes multiple passes per layer). The multiple-passes the printer makes to further cure the resin are, I suspect, unique to the base and support printing process and separate from the object printing process.
It’s worth noting here that I had to increase my printer’s Z offset by 0.3mm in order to minimize the problem I was having removing prints from the build platform, and that the problem was significantly worse with V2 than it now is with V3. You could try the same Z-axis fine tuning with your printer and I bet it will help both in getting parts off the platform and also with the Z-axis accuracy of the print. But I’ll still say the right answer is to use a base and not print the object directly on to the build plate.
Thank you for the long response and suggestions! I just printed some relatively small parts and they seem to have been perfectly removable off of my new tank and second platform. I have a feeling the whole issue may just be related to the build platform. I can’t believe the resolution on V3! It’s literally unbelievable how fine it is! I’m going to restrain from fine z-axis tuning until I have another issue, since all 3 of the .305" parts I printed came out to be .309" height.
I can confirm, something was wrong with my tank or platform. The v3 is now very easy to remove. Thank you all for the feedback, it helped me realize there was a problem on my end.
You build platform is probably scratched. I had issues with removing parts as well. The solution couldn’t be found in tuning the Z-height. I had to do a rough polish of the build platform and everything was working like before again.
What grit did you use to do the sand/polish?
I used 1200 grit paper after sanding it flat as the build platform didn’t seem to be flat either.
Great, thank you for the information! I used 800 to eliminate the scratches, going in every direction evenly and I think that grit size made it impossible to remove. I’ll try out the 1200.
1200 is finer than 800… So make sure you only see 800 grit scratches and then switch to 1200. If 800 is not enough, go for 600 or 300 first.
I only posted about this topic last week and now look, there’s a v4 out in the release notes of the latest preform…was there an announcement I missed? I thought v3 was released only a few months ago! Talk about rapid development! 
We switched suppliers for one of the components in Tough Resin which is the reason for the re-formulation. Mechanical properties are nearly identical for both versions and the primary difference is a more blue color. You can find the announcement post here.
It sure looks like a pretty blue! Thanks!