All prints fail after a certain time/height

Hi All,

I have searched these forums at length for people with similar issues as I am having to little avail. I did find one thread from several years ago which I tried to revive but I think it was perhaps too out of date.

Before I explain the problem…

  • I am running a Form 1+ for about 18 months or so - all latest firmware and Preform software
  • I am pretty familiar with the common problems this machine has
  • To this end I have cleaned the galvo mirrors several times along with the small mirror - all as the FL guidelines dictate
  • My large mirror was streaky and stained from a resin spill so I replaced it
  • I keep the machine as dust/dirt free as I possible can
  • Every print is conducted with new resin - the previous resin is filtered
  • I am using new resin tanks

With all of the above in mind most small prints work reasonably well, albeit a little flakey. I wouldn’t say they’re great, but they’re useable.

The problem…

When I attempt a larger print with a z height of over around 60mm things never work.

At around the exact same time/height they fail spectacularly. What really bothers me is that these fails occur in line with an area that was printing perfectly on previous layers i.e. the laser is working in exactly the same path, not encountering a new area of mirror or tank.

I am home at the moment so I don’t have photos to post just yet but I will later on. I really hope someone might be able to help with this as I am beginning to tear my hair out. I am ploughing through resin/money with failed large print after failed large print.

Please, help!!


I am impressed that you have had a machine last that long. I have not had a Form 1 or 1+ last a year. I think the longest lived machine was ~10 months. Most of mine didn’t last 4 months.

From experience, Formlabs will probably tell you that the new lasers in the 1+ can’t possibly go bad. I beg to differ, something can happen that introduces flare and causes failed prints. Not every print quality problem is mirror related, though I will concede that many problems are resolved with perfectly clean or new mirrors. Have you done a laser spot test? If yes, can you post up pictures. The flakes with new everything including as clean as possible mirrors is what is pointing me to something with the laser. Again, FL will probably tell you that it can’t possibly be the laser related.

Here is what I would do:
Run (if you haven’t run it yet) the laser spot test. Take lots of pics. Somewhere around here is the pdf of the paper you can print out. You don’t really need it. Just a piece of paper over where the tray goes would be fine. Cut it to shape so you can run the tests with the cover closed. I would also take a pic or two of what the laser dot looks like as it shines on the top of the cover. The dot may be very slightly out of focus when seen on the cover but you will get an idea of what it looks like.

I would next, run your print with out the vat and build platform. Yes, this is a huge waste of time but so is going through resin like it is going out of style as you said you are. While printing, see if the leading and trailing “ghost” edges of the laser path changes over time. Especially where the failure layers occur.

Once the print has completed, I would do the laser spot test again. Right after it finishes. Don’t wait more then a few minutes. If it is failing over time, ie, when your prints go to pot, you should be able to see a difference in the laser spot. The flare shape should change, the laser will be dimmer, something.

Another test (FL never asked me to do this but I remember reading it on here somewhere as a test FL wanted them to do) is to run the Z axis arm to the area of the failures. If you feel any resistance or strange movements, your problem may be Z axis related. If the light lubrication that was put there a year and a half ago has finally dried out and crusted away, it might be time to lightly lubricate the screw and linear bearing (I believe that is what it is called). I do not know if FL recommends this so do it at your own risk. Maybe someone from FL can chime in on my suggestion.

As with the above tests, look at the Z axis while it is doing the ghost print… Around the height of the failures, you may see the Z axis binding up.

As with anything I suggest, use at your own risk. Be sure to take all precautions with your safety. I assume no responsibility with voided warrantees, injury, etc.


Hi @DavidRosenfeld

Thank you so much for your detailed reply - it is hugely appreciated.

You have highlighted a few things which I suppose I have been hoping aren’t the problem I.e. the laser and/or an issue with z axis travel.

I will conduct the laser test tomorrow when I’m back in the office and revert with some photos. Also the ghost print seems to be a good idea. Again I will come back with some further info once these are complete.

With regard to it being a rarity that my machine has lasted so long I guess I underplayed my dissatisfaction with it in my initial post. Our yield rate, despite very careful maintenance and cleaning, is extremely poor. It is coming to the point where it is costing us more than it is worth.

Anyway fingers crossed your help will get us somewhere.

Thanks again,


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