Impossible to print Clear V4 straight onto bed!

tl;dr although Formlabs say they did not change the print settings for Clear V4, this clearly is not true as it is impossible to print parts with Clear V4 @ 0.05mm layers (failure rate >90%) but when pouring V4 into an older V2 cartridge everything comes out fine. Bug in PreForm?! tl;dr


My name is Mikus and I am engineer at a startup. We are developing a device which we produce in low volumes using Form 2. The main body of the device is a 2.5mm thin shell from two parts and is 174mm in height - this meant that to optimize the Form 2 print time and efficiency we need to print the parts straight onto bed vertically. This way we can fit 2 cases at the same time cutting down time from ~36h to 25h. Since there are overhangs supports are needed, but since there is no room for PreForm generated supports (since they require raft) we had no other choice as to incorporate our own custom supports which we dialed in trough trial and error but they came out perfect. We printed from Clear resin (V2 at the time) at 0.05mm layer height. We have printed around 10 sets of these parts but then we ran out of Clear V2 and had to order Clear V4.

As Formlabs has stated, the formulation for V2 and V4 is basically identical so we did not expect any issues. At the same time new firmware and Preform 2.14 was released. As soon as we received V4 and started printing, it was obvious that something was not working as it is supposed to… After first few layers, parts and some supports just broke loose and were delaminating, resulting in a ruined part at best and ruined resin/tank at worst without a part in one piece. You can see a small timeline of how the parts look like and how the V4 performed on the same identical parts in this Google Photos gallery. The results speak for themselves. You can see each parts print settings and resin captioned.

At first I thought that there were some issues with new firmware/PreForm and upon checking out forums it seemed like I wasn’t the only one having quality issues with the new firmware/Preform. So I downgraded back to the older firmware and Preform 2.13.1 but that did not help as the issue remained. We also tried to lower the Z platform for the first layer by -0.2mm with no luck - first few layers come out perfectly fine - remaining ones barely holding on or delaminated entirely.

We have had Support ticket open for 2 weeks with literally no suggestions just blaming our custom supports or “broken” STL’s. So I tried to take the investigation to myself to understand what the f*ck is going on here, since our production has been halted for literally 2 weeks with no solutions in sight.


To diagnose what is the potential issue here, I cut a small piece off our large part to have a part that actually represents our use case as well as a small rook, similar to what Formlabs prints for example parts to make sure that the issue is not in our part not having appropriate contact surface with build plate.

So I printed the two parts at 0.05mm (since this the the resolution we need) in different materials and print settings since changing PreForm/Firmware did not change anything visible. This way I wanted to narrow issue to either 1) material 2)print settings or 3)model issues (although we previously had no issues, it could be a factor).

These are the two parts:


Gray V3 printed out perfectly fine - no issues here so I did not even bother to put a picture up.

Things however get interesting when we come to Clear V2 printed with V2 settings and Clear V4 printed with V4 settings. V2 came out perfect and V4 failed. So I printed one more set with Clear V4 but poured in an empty V2 cartridge and using V2 settings - and guess what, part came out exactly the same as Clear V2 parts. See for yourself:

(parts are updside down)

I did not test V2 with V4 settings since we are really behind our deadlines in our production… But considering these results it is pretty obvious that there are STILL issues with V4 print settings and they ARE NOT identical to V2 despite what @Frew said here and here.

I also read there was a bug with V4 resin settings that is supposedly fixed in Preform 2.14 but that is irrelevant since this was the same exact issue that also occoured when I used Preform 2.14.

On top of that there was a new thread created on the same issue here which states that guy is having issues printing V4 at 0.05mm even with supports. This correlates with my issue.

As for technical information: Preform 2.13.1 / Formware rc-1.14.21-154 / .FORM file

For now we will just pour V4 in our remaining single V2 cartridge since we just threw out remaining ones just a week ago but this is not acceptable for a long term solution! Hopefully this will be fixed soon :persevere:.

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First Black v3, now Clear v4.
Wash with no gaskets, with badly fitting side-doors and freely evaporating IPA all over the place, Cure with no sleep function…

What’s been going on this past year at Formlabs?
This isn’t exactly instilling confidence.

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Thank you for showing us your studies on the issues you are having with the program setup. I have also noticed a poor quality of pressure on the gray resin after these update.

Thanks for all of the documentation you’ve done here, this will be a big help in working towards correcting this. Clear v2 and Clear v4 are identical chemically and the print settings did start out identical. Print settings for Clear v2 and v4 have since diverged and it looks like that could be causing issue here.

Clear v2 and v4 do differ in the settings for the early layers and it looks like that’s causing the bulk of the problems here. One temporary workaround while we work towards correcting this might be to create a raft for the parts to build off of rather than printing them direct on the platform. We certainly hope to improve reliability and performance with each update so we’ll work towards correcting this behavior.

Could you please elaborate more on the raft part or give an example? The part size is an issue here, since it is already 174mm in height. We would be willing to try and make a raft but without knowing what kind of behavior was changed, it’s hard to make any guesses what kind of design would help to avoid this issue…

Also, is there any other way of using the Clear V2 print settings other than using an old cartridge? If not, do you know the exact volume after which the cartridge is “worn out”? We have 6 Liters of V4 that needs to be turned into parts asap and so far the print settings looks like the only sane way of printing it at the moment but we only have one V2 cartridge left.

EDIT: Wait… you said the V2 and V4 settings did start out identical… Could you pinpoint to the latest firmware/Preform where they are still the same? This way we could make a workaround without needing to use V2 cartridge.

The first 5mm or so of a print are treated differently as to improve part adhesion. This does affect part quality and dimensional accuracy somewhat, so the raft tends to be an important way of ensuring proper adhesion and part quality. We’ve optimized the rafts that are created with the automatic support generation algorithm for adhesion and part quality so those should serve as a good reference if you’re looking to design your own.

I believe the ‘worn out’ message gets thrown after 3L, though we recommend against refilling cartridges as it can lead to the bite valve failing and encourage risky behavior like re-filling cartridges with 3rd party resins.

If possible, I’d try to get rafts working with the current updates as downgrading can remove feature improvements and cause compatibility issues. PreForm 2.12.2 introduced the Clear v4 profile.

So at the moment we are so behind deadlines that we don’t have any time to mess with the rafts, that’s something I might explore later, especially when we have only 1mm to work with until we hit height limit.

Good news (atleast for us at the moment) - using V2 cartridge the parts printed perfectly fine (PF 2.13.1). Not even a slightest hint of failing/delamination/not sticking to platform. Only thing I noticed that V4 seems to be a bit heavier than V2 as support mentioned - some of the very thin supports on the very top where looking a bit shady but still held up. Easy fixable by making the posts a bit thicker. Awesome! Here’s some pictures:

Successful Print

Thin line on top of towers is from a paused print due to running out of resin in cartridge. Some of the supports removed to show that they print out perfectly fine and cause no issues to the problem explained in the thread…

Bad news - Judging by dashboard we have only 1897ml left (could be less, since during last print, the printer went offline for no reason and did not report to dashboard) to put through our only V2 cartridge until it is “Worn out”.

I also tried out if the print settings (that are supposedly identical to V2) would work from the older PreForm 2.12.2 and Preform 2.12.3 but with no success. Test part @0.05mm on 2.12.2 failed miserably and @0.1mm on 2.12.3 came out as a half-part (missing literally 50% of the part). This means that our current and only solution is to print using V2 cartridge and my gut is saying that print setting fix for this issue is not coming anytime soon from Formlabs.

We have the resources to figure out how to reset cartridges and hack stuff up for us to be able to print the parts with the new resin but like… wtf guys. I really thought that this would not come this far but it actually seems like our most realistic way out… :expressionless:

@Frew You even mentioned at the launch of V4 that it was mostly a UX question to make a new version rather to instruct users to use older print settings. If they are so identical then why would you prohibit using Clear V4 cartridge with V2 settings… Why…? A simple exception on the firmware would make a workaround for those who need this feature…


We bought Form 2 for one sole purpose - to print these parts. Yes, it was pushing limits of the printer but we took the risk, developed a part that actually printed and we were golden. Now with an supposedly identical resin they say that it is no longer possible to print such parts although I proved the opposite. Yes, a 3k$ hobby printer should not be taken for granted for pushing such boundaries but clearly this is within it’s possibilities and we are getting locked out of them by none other than Formlabs themselves…

I strongly believe that 2k FDM can be as 95% good as 30k FDM and that 3k SLA can be as 95% good as 80k SLA but only when they allow users to have more control of the process instead of locking them out…

Current solution:

  • Use PreForm 2.14 with V4 settings for preform generated supports and it will work out fine. We use some 0.6 posts for most stable results.
  • Use PreForm 2.13.1 with V2 cartridge to print directly on surface just as with Clear V2 and it comes out just fine. Note that Clear V4 is indeed a bit heavier so use some thicker features than you were used with V2.

We tried a lot if different combinations with settings, preform versions etc. and the settings above where the ones we will use until a pernament fix is deployed. We talked with the support and they said that this is a real issue that Formlabs team is currently working on as we speak. Until then, we’ll just have to scramble for V2 cartridges until we run out but atleast we know there is a potential fix being worked on…

DO NOT USE PreForm 2.12.2/2.12.3 for printing with V4 settings however - those are completely broken and result in failed prints in all cases (atlest for us, even trying to print normal parts with preform supports).

Which PreForm are you using right now? I am currently using 2.12.2, V4 resin is currently no problem

For normal prints using PreForm generated supports and bases we use PreForm 2.14 now. Bear in mind we only print at 0.05mm resolution and at that resolution we could not print a single model using 2.12.2 or 2.12.3.

If it’s working for you, just keep using it but if there’s some quality issues or delamination/resin contamination, you should try te latest version. Keep in mind that if you update your firmware, you won’t be able to print with older PreForm versions however.

Thanks for your reply, I will try again with layer 2.14 at layer 0.05, but still hope the next firmware and PreForm will improve the success rate of clear resin

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