Standard Black resin is rubbery and wont seem to harden

I did a couple of prints in the last couple hours with a new tank of Black standard Form 2 resin and both prints are rubbery. Hard but rubber like. The supports are almost impossible to remove because of this. It reminded me of the not so hot Tough Resin. Typically my prints have a nice rigid feel post cure. I even let them cure hours longer than normal and they stayed rubber like but did get a little harder. I had noticed similar issues with another batch of Black I printed previously. Is the Black resin just kinda crappy? So far the best preforming resin has been the standard grey. Do the pigments in the resin effect the effectiveness of the laser cure? I know Formlabs isnt keen on saying yes the Black preforms poorly compared tot he Grey but since I got my printer the only resin that really impresses me is the standard grey.

I have the exact same experience as you, I chose a few months back to not use Black anymore because I was getting very inconsistent or straight poor results with it. The important sedimentation meant I’d spend a lot of time stirring/homogenizing the tank before printing while wondering what kind of mess is in the Cartridge which I can only shake for so long before putting in in the printer. I had rubbery parts, bad surface finish/rashing, bending, important accuracy issues, …

Some people are having a great time with Black and I did too a years back or so, for a few amazing consumer-facing prototypes I printed at max resolution and it was so smooth I couldn’t tell it was 3D printed. Never could reproduce these results. Grey is working great as to other resins (Tough, Durable, Grey Pro).

Yes aside from the rubbery properties I’m also getting some weird dimensional issues and bad surface finish in other areas. Perhaps since we are using UV cured resin the black pigment effects the way it cures. I noticed Clear resin cures very hard and quite well, although very brittle. Call me crazy but I know light reacts with different colors differently so why wouldn’t the same sort of physics be applied here?

Yes the pigment do mess with the laser, but Formlabs should be able to account for that, and they did at one time. I think they have important sedimentation issues with this resin and maybe some production/stability issues ? This is merely conjecture though as @Formlabs has been pretty silent about this.

When a batch of resin begins to fail or fails they are always very quick to send a new one out. I would guess quality control with the resins is very hit or miss and forever ongoing. The printer seems pretty sensitive to variations in the chemical make up and consistency of the resin.

That is also my gut feeling, although I have absolutely no authority in the matter so it’s worth what it’s worth (=nothing)

As for putting a new version out shortly after a failure is detected, it has been true for the V3-V4 resins but they seem to be happy with black V4, and some other consumers too, so I guess it’s really a QC issue rather than a formulation issue.

I have had similar issues with black and white resin and another person on the forum has the same issues. Because we all have similar problems around the same time I’m starting to think this is a software related issue or something?

See the thread of jbrown:

And my thread:

Maybe Formlabs can respond to this??

I have had issues since mid December 2017

Start time Finish time Elapsed print time (ms) Layers Layer thickness (um) Volume (ml) Material Z offset (mm) Open mode?
2018-01-23T17:26:35.848439Z 2018-01-24T00:32:24.843858Z 25549832 982 50 51.63 Black V4 0 FALSE
2018-01-22T17:12:00.259824Z 2018-01-22T22:35:55.870364Z 19436431 1151 100 34.49 Black V4 0 FALSE
2018-01-17T12:27:46.173968Z 2018-01-18T08:34:37.651550Z 72415608 3055 50 131.45 Black V4 0 FALSE
2018-01-16T15:23:47.096703Z 2018-01-17T10:34:20.852282Z 69035314 1710 100 315.91 Black V4 0 FALSE
2017-12-22T12:28:05.084733Z 2017-12-22T13:58:07.576106Z 5402758 246 50 2.97 Black V3 -0.1 FALSE
2017-12-21T11:10:44.257860Z 2017-12-21T12:23:23.525952Z 4359331 266 50 0.59 Black V3 -0.1 FALSE
2017-12-20T17:08:26.670336Z 2017-12-21T07:31:05.527106Z 51761324 996 100 152.36 Black V3 -0.1 FALSE
2017-12-18T17:10:15.631754Z 2017-12-19T06:19:51.183242Z 47375962 758 100 150.91 Black V3 0 FALSE
2017-12-18T07:13:11.977068Z 35634565 829 100 149.61 Black V3 0 FALSE
2017-12-15T16:48:18.475329Z 224187227 829 100 149.61 Black V3 0 FALSE
2017-12-01T15:17:15.288902Z 2017-12-01T16:50:11.980366Z 5576831 176 100 2.11 Black V3 0 FALSE
2017-11-10T15:45:32.372425Z 2017-11-12T14:22:00.114664Z 167803838 6753 25 199.59 Black V3 0 FALSE
2017-11-09T16:50:01.568385Z 2017-11-10T01:03:54.471403Z 29633567 2190 25 9.02 Black V3 0 FALSE
2017-11-09T14:22:48.281042Z 2017-11-09T16:48:41.242313Z 8753626 479 25 0.9 Black V3 0 FALSE
2017-11-03T16:02:10.694794Z 2017-11-04T08:06:27.562221Z 57864568 2997 50 74.22 Black V3 0 FALSE
2017-11-02T16:29:30.920160Z 2017-11-03T12:21:32.365882Z 71530383 3880 25 56.5 Black V3 0 FALSE
2017-11-02T12:16:51.384713Z 2017-11-02T16:22:26.315465Z 14735392 737 50 11.97 Black V3 0 FALSE
2017-11-02T07:56:07.305245Z 2017-11-02T11:15:10.908874Z 11944038 424 100 17.24 Black V3 0 FALSE
2017-11-01T10:25:32.568310Z 2017-11-02T06:28:27.387970Z 72184123 3825 25 60.04 Black V3 0 FALSE
2017-10-30T09:25:46.798892Z 2017-10-31T02:33:25.281766Z 61663952 2796 50 83.46 Black V3 0 FALSE
2017-10-27T12:52:00.416944Z 2017-10-28T06:56:52.113742Z 69794419 2796 50 103.18 Black V3 0 FALSE
2017-10-27T10:14:56.364244Z 2017-10-27T12:52:00.444914Z 5803 2796 50 103.18 Black V3 0 FALSE
2017-09-22T15:38:55.369791Z 2017-09-23T14:15:19.232927Z 81391597 3147 50 194.26 Black V2 0 FALSE
2017-08-15T13:24:20.235339Z 179162 816 25 9.84 Black V2 0 FALSE
2017-08-14T14:10:08.031209Z 2017-08-14T16:07:12.181722Z 7024537 264 100 10.39 Black V2 0 FALSE
2017-08-14T08:49:41.601558Z 2017-08-14T11:20:20.918980Z 9039924 533 50 4.13 Black V2 0 FALSE
2017-06-29T14:23:33.424075Z 2017-06-30T08:07:32.062339Z 63845773 4047 25 50.87 Black V2 0 FALSE
2017-06-28T16:46:34.461345Z 2017-06-29T10:31:01.603056Z 63872836 4047 25 50.87 Black V2 0 FALSE
2017-06-13T08:58:34.250004Z 2017-06-13T16:06:02.067935Z 25648803 1546 100 27.03 Black V2 0 FALSE
2017-05-31T14:14:47.291336Z 2017-06-01T12:33:14.533663Z 80309720 3334 50 183.73 Black V2 0 FALSE

All prints since the 15th of Dec. showed defects of various types including rashing, deformation, soft prints. Most of these prints have since been done in Grey Std and went flawlessly. We’ve also been printing in Tough a lot without issues. As you can see V3 and V4 were used in the failed prints, and we checkes/changed tanks when necessary or when we hope it would make things better.

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glad someone brought this up because in my opinion black v4 is garbage unless you only print small low surface area parts. i print constantly with almost all resins and i always try to talk customers out of black. I’ve gone through 10 black v4s using multiple form2s with both standard and lt resin tanks. It is awful at surviving even average peel forces. Ever notice how black v4 100um requires .8mm support tips but 50 and 25 are the typical standard resin .6mm? Definitely an indication of some sort of inconsistency. To me, black v2 was it - never had a problem and loved the gloss appearance. once they went matte in v3 and v4, things changed. i haven’t tried color resin yet but am wondering if just making my own black with the pigment kit will be better


Plus one on the soft parts. Really not impressed with Black v4. I did just buy a new cartridge of the stuff, but am dreading every morning going to check the latest build; another failure last night when some parts fell off their supports, and in removing the remains from the platform, it was like chewing gum… Strikes me as the laser is grossly under exposing. I’d rather have a longer build time and a successful print, than a super efficient, right on the cutting edge of possibility, macho super build, that actually fails after 2 hours…

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So I opened a support ticket with customer support. Now my optics are to blame and not the under preforming resin. Here are some snippets from what they had to say.

“I took a look at your laser power logs and saw that they have started to drop. Black resin takes more laser power to cure due to the dark pigment in the resin, so issues with laser power might appear there first and not in other resins. To solve this I’d like to try cleaning your galvo mirrors, the small motorized mirrors in your printer that direct the laser’s path. I’d be happy to send you a galvo cleaning kit. Please confirm the address we have on file:”

"The printer is designed to protect the optical system from dust and debris, but sometimes it still gets in and causes slight defects in the optical system. Sometimes the lubricant for the motors in the galvo mirrors can cause some debris to form on the mirrors as well.

I cannot send you your system logs, sorry! We use very specialized software to read printer logs and we cannot share it with our users. What I can tell you is that your printer’s laser power is at about 85% right now, which would cause issues with Black resin but not other resins. You will likely see issues with all resins when it’s at around 70%, so I’d like to see if your laser power improves after a galvo cleaning. It is possible that your laser is having issues, so it’s important we take this step."

Mind you my machine was just purchased in March. I wasn’t having issues with the my last cartridge of black or any other resins for that matter. I think my last cartridge was V3. Perhaps it was the combination of a software update and this new V4 resin. I’m not sure but I’m a little annoyed right now because this stuff isn’t cheap.


yep, I am having the same issues with the v4 resin. Multiple failed prints where the supports snap off at the base and the rubberiness leaves much to be desired. Never had issues like this with the v2 or v3.

It seems you have a no-brainer here. You have a printer with a defective laser that is still in warranty. If you don’t send it back to Formlabs your problems are going to continue while you want to use a resin that requires near maximum laser power.

Thanks for the eye opening insight. Mind you this is the 2nd Form 2 they have sent me since I purchased back in February. The first printer had similar but worse optics issues. I doubt they want to send me another free printer.

A warranty is a warranty. You are entitled to as many replacement printers until you get one that works as advertised.

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If only it was that easy. They sent me some cleaning kit that will probably void my warranty so they dont have to send me a 3rd printer for free.

Hey everyone,

Thanks so much for taking the time to contribute to this thread. Firstly, I want to apologize for the frustration you’ve experienced so far with your printers. That’s certainly not the experience we want our users to have. As has been mentioned already by other users here, there are no restrictions within that warranty period. We will stick with folks until they have a machine that’s working at 100%. You purchased a printer, you need a working printer, simple as that.

Additionally we will never send a procedure or instructions to someone via support that will void their warranty. Typically we’ll send free optical cleaning kits if we think there’s a decent chance we can get things going without a full repair because this saves everyone time. If the cleaning kit doesn’t do what you need it to, we’ll take whatever steps are necessary to get you a working Form 2.

All that being said, I’m sorry again your experience thus far has been less than ideal, and we genuinely do appreciate the feedback so we can help users more efficiently, and with less effort and frustration on their part in the future.

Thanks for hopping in ! Glad to see you guys are keeping an eye on the forums as I’m sure you’re all quite busy.
Any comment regarding the experience with Black in general ? Would you say it is possible that the heavy sedimentation could cause printing issues or should we immediately contact support to diagnose an issue with laser power ?

That’s a great question. I think it was posted above, but I’m happy to dig into things a little deeper.

Because of the pigment particles in Black resin, it requires more energy to cure completely. For this reason any optical issues, whether they’re the laser diode itself, or a contaminated optical surface(optical window/tank/mirrors etc) will manifest first with Black. That’s why it can appear the Black is the problem, when it’s really just an early symptom of a different problem.

So if you are seeing issues with black, the first thing would be to just check the easy stuff, the bottom of the resin tank and the optical window below that to look for streaking or other dirtiness. If both those surfaces look clean that’s when I’d encourage folks to reach out to support and we can dig into the root cause of the issue a little more easily on a person by person basis. Standard ticket submission form can be found below!

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Looks like I’ll be looking at a galvo mirror clean then… Another crash last night! Everything else i can see is spotless.

One question. Is there no internal laser power check, then? I spent 12 years running a 3D Systems SLA 250, and that device shone the laser spot on a couple of sensors which measured the laser output power, amongst other things, and adjusted the speed of the laser over the surface of the resin to compensate. The machine would work perfectly well from first install until the laser pretty much died.