Messy build lines on print

Does anybody know the most likely cause of these errors?

not sure about the bottom of this part but it could be that there is a vacuum being created that makes the peeling process harder on the materials. might help if you could show more angles of the part.

Here’s another print, done at a different angle. This time with a fresh tank of resin after formlabs support suggested the problem might be caused by tiny bits of cured resin


Looks like a good optics, resin tank and resin (fresh or filtered) clean. I do this pretty regular now and definitely before an important print as a precaution.

Is the part solid and if not how thick are the walls? Are your mirrors clean?

It’s hollow with 3mm walls

waiting on delivery of pec pads to clean mirrors but I can only see a couple of specks on the big mirror.

Try reducing the thickness of your walls to something between 1.5mm and 2mm. I’m guessing you will get better results. If you try it please post the results.

Mmm, I’m having some new issues. Can you post pics of your main mirror?

Also do you have a drain hole on the area of the part closest to the platform. You need one to regulate pressure.

I did a laser spot test. The result shows the dreaded square pattern that others have seen.

The latest print has the open neck facing the build platform so pressure shouldn’t be an issue. I have also printed it solid and get the same result.

Here’s a photo of the newly cleaned mirror. It appears to have one speck that is firmly stuck but the rest is spotless.

The pictures you have look like they were done with the neck sealed. If so, can we see a picture of the print with an open neck?

Here is one open at the neck

Here’s a close up of artefacts found at the early layers.

Here’s another one open at the neck

I had a last ditch attempt. In order to rule out anything other than laser failure, I cleaned all the mirrors again, installed a new tank and added fresh resin. Unfortunately the problem persists so I think it may need to be returned. It would be good if formlabs would just send out a replacement laser. Is there a real reason why a user cannot unplug one laser and plug in a new one?

I had similar marks/holes on a model. It happend as I got abletions on my main mirror:

It sounds like your mirrors are all good, David, and your resin is fresh… so the last idea would be if there is a finger-print on the bottom of the tank and the print is being done in the same spot each time?
Otherwise you are probably right, early stages of laser spreading. My laser has been getting worse for a while, but it was still printing my parts okay when it tested like yours. But now it’s screwed.
You are right, there is no reason we couldn’t replace the laser ourselves. But lasers are probably a bit spendy and FormLabs doesn’t want everyone crying laser every time a print fails. Also, with the huge history of the Form1 laser failures, keeping Form1+ laser failures under wraps would be good business. When I pointed my laser directly at a sheet of paper at the correct distance, they agreed my printer needed to come in for “inspection and repair”. But would not comment on the test results.

Ablations as in your main mirror was starting to peel?

The problem occurs wherever I place the object. I have tried all positions and orientations. They’re still insisting it’s an optics issue and are sending me a new main mirror. I can’t see how a speck in one area of the main mirror can effect prints in all areas of the build platform.