New Form 2 - Optical Window issue

Hello all. Having recently purchased a Form 2 for our R&D department only 3-4 weeks ago we are having significant problems with printing. Upon delivery of the printer I noticed a fog or condensation INSIDE the optical window. At the time I thought it was nothing to be concerned about, simply caused by the change in temperature from the delivery van to the working environment - where the printer is now.

It was during a larger print taking up much more of the build platform that I noticed the problem; anything placed on the left side of the build platform will completely fail (basically no adhesion to build platform, terrible build quality etc.). I have verified this by building an identical PreForm file on the right side of the build platform. Please see attached images to see the optical window & builds.

In my few years experience with the Form 2 I haven’t personally witnessed this problem before. I believe I may have to carefully remove and clean the optical window in order to resolve this issue. Is there a particular protocol to be followed for this? And is the warranty still valid after doing this under Formlabs supervision?

Thanks for all of the troubleshooting you’ve done so far. This will help us to more quickly identify the issue and get things fixed for you. Our support team is going to be best suited to look into this further and advise next repair steps. One of our members will be in touch with you over email to help troubleshoot.

Thanks Frew. How long does it usually take to hear back from the support team via email?

Hey there, we have had the exactly same issue. Some fog or condensation INSIDE the optical window. It´s also on the left side so naturally prints on this side tend to fail more often.

Here´s the story so far:

After about one month using the brand new Form2 very successfully and with impressive prints the prints gradually got worse.
I opened a support ticket and they made me film the optical window with my flashlight on. And that´s how I found out about the fog. (it´s only visible at a certain angle) Since It is really difficult to take a picture of it Formlabs didn´t belief me at first and had me run the usual troubleshooting. (cleaning window again, resetting, lower build plattform etc.) Only after nothing of that brought a solution they sent me a new optical window and an instruction on how to change the window. I found out that the sealant of the old optical window was not glued probably and had a huge gap on the left side. So I thought that´s were the fog came in.
However prints got not better significantly. So I had to sent the Form2 in for reparis. After 3 weeks it came back and the prints were perfect again. Unfortunatly they wouldn´t tell me what had been repaired. Bcause here´s the thing after one month of perfect prints it starts to get worse again.

Guess what? The fog is back.

I would really like to hear back from Formlabs what this issue is. The whole process so far cost me and my company about 2 month in which we were only troubleshooting, loosing a lot of time, resin and tanks. Not the best experience.
I am opening a ticket right now but I hope that we might find a permanent solution together and that we can speed up the whole process on your side.

I found another one with this issue:


you were replying in this topic also. Do you know how this story got solved?


I have the same problem as you described. The glass window is blurred from the inside and I do not know how to clean it. Right now the printer is still working as long as I stay clear from that area so I just let it be but I really think Formlabs should at least show us how clean or replace the glass window.


Formlabs did sent me a PDF with instructions how to take the window out and insert a new one or clean it. I already did this in the past and it´s not very complicated. You need a 2mm hexagon socket screw key. Be careful with the screws and don´t scratch the window accidently, maybe put a pecpad on it. However if you´re still in warranty I would recommend to contact support directly and have them send the PDF. Just to be on the safe side.

This isn’t an error we see often so often our support team will often attempt other troubleshooting steps first to get things back up and running as soon as possible. Thanks for opening a ticket and here’s to hoping we’re able to get things corrected for you quickly!

Our manufacturing team is actively look into instances of window fogging to get a sense for its prevalence and gauge the effect on print reliability. Currently, there are a few ways our support team will try and correct this. Replacing the window assembly is one solution though oftentimes opening the machine and wiping the underside of the optical window with a PEC will also work. Our team will be best suited to figure out what’s ideal for you.

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