We were doing our second print with our new Form 3. Everything looks perfect except… there was a line across the model for some reason. Anyone know what could be the problem?
Hey there @westcoastmill!
This is an issue you’ll definitely want to reach out to our support team about and they’d be more than happy to investigate the potential cause a little more closely. 
How does the plane of the line compare with the orientation of the model relative to the build plate? Is the bottom surface (that is, the surface the model is sitting on in the picture) where the build plate was?
If the line is horizontal (that is, it is coplanar with the back-and-forth movement of the LPU), then look for a dirty spot on top of the LPU glass.
The model was flat on the platform. There were supports with a raft below the model. The line is perpendicular to the base of the model.
Right. If it goes left-to-right (when looking at the front of the printer), then, again, I’d look for a splotch or something on the top of the LPU glass.
Take out the cartridge, build platform and tank. Go into the maintenance menu and start the “LPU replacement” procedure. That will move the LPU out to the center where you can see it. Look for a dirty spot on the glass that matches up with where the line was. If you find anything, VERY CAREFULLY clean it off with a PEC pad. If you need a solvent, I found success with photographic lens cleaner, but I don’t believe Form recommends anything except IPA. For my part, I found IPA didn’t come clean enough without following up with lens cleaner, but YMMV.
If that doesn’t fix it, then the smudge might be on the inside. If that’s true, and this is a new printer, then you probably are better off asking support to send you a new roller/glass assembly under warranty.
Of course, all of this advice is wrong if the defect isn’t oriented parallel to the motion of the LPU.
The glass seems pretty clean. I did notice the rollers are pretty dirty and I had to wipe it off with the PEC pad. Also, I did notice there were quite a few lines under, ontop or inbetween the tank. I couldn’t wipe it off from the top or bottom surfaces so I assume its inbetween? This is our second print so I am surprised there were that many lines in the tank. Not sure where its from.
If the defect is in the tank, then the best you can do is move the model out of the way.
Note that if you have a new printer, everything under the tank should be scrupulously clean. I’d have to wonder where any contamination came from if you needed to clean the rollers.
But I may be getting in over my head here. I’d contact support.
Haha, I appreciate all the help. We’re gonna try another print today. Will update here on how it goes. I wiped the underside of the tank as clean as a toilet seat. So… hopefully it’ll be ok. It could be dust from our office since we do alot of zirconia milling. If that’s the case, we’d probably have to check it everytime before we do a print. Thanks again.
Hum, zirconia dust doesn’t sound like it will prolong the lifetime of all the mechanical parts of the printer…
I had a similar problem. There was a bit of dust inside the LPU. Had to RMA my machine under warranty and the line went away.
Did you find out there was dust in the LPU? or was it when you returned the machine they found out it was dust?
I could see dust in the LPU myself when I looked at it.
Ok. I’ll take a closer inspection. Thanks.
Update: So support seems to believe it is an optics issue. We printed 3 more jobs and it seems to be in the same line across the platform.
You might need to replace the unit like I did. I also saw it across different models always in the same area.
1 Like
Can anyone explain what is the LPU?
westcoastmill: was it the optics? or did changing the resin tank to a new one fix it?
The LPU is the “Light Processing Unit”. In the Form 3 it’s the big aluminum case inside the printer, which holds the laser, galvo, and mirrors. This thread: Swapping an LPU may be intersting too.
1 Like
Thanks, I didn’t realise this was in the Form 3 section