Form1+ laser flare issues illustrated - pics and video

Hi All,

I’ve been running lots and lots of tests to try and characterise the effects of laser flare. Basically it’s as previously described by @Monger_Designs and @RocusHalbasch - in that I am seeing bad flaking and corrugated surfaces on parts - on the faces of parts matching brightest flare side.

It might be a little “tl;dw”, but I think this video illustrates it best - I’m not done yet, there’ll be at least one more video, probably two, but imo this is conclusive evidence of the issues that laser flare can cause.

I call it conclusive proof - because it shows before and after prints - of identical form1 files, with the same vat, same resin (I didn’t even refill the resin, although I did have to strain it) - nothing changed between the prints except that I rotated the laser 180 degs in it’s aluminium block (I am always careful to be wired to earth before touching the laser) .

After rotating the laser - the flaking and surface corrugation switches sides on the parts - ergo - the flaking and surface corrugation can only be caused by the laser flare.

Here’s a pic of the type surface corrugation that I’ve been seeing - NOTE this is not flaking! these parts are washed, the corrugated surface is exactly that - corrugated.

note the right hand side (hinge side) front surfaces. They should be flat. Now contrast with the rear view:

More pictures to come along with more videos - I’m currently running taller versions of the same parts in the new grey resin with a brand new vat - both resin and vat having arrived yesterday.

As @Ante_Vukorepa and @JoshK have already said I think it’s now very clear that the Form1+ laser needs an iris (given that it seems extremely unlikely they would shift to an entirely new laser module). I’m not sure what the solution is though - Josh forwarded me his design but I think it would be difficult to install correctly.

In an ideal world Formlabs would step up - and ship out replacement lasers with pre-installed iris’s (the laser modules are exceedingly easy to install/uninstall) - and if the machine needed any configuration to match a new laser module, it could be done via Preform following an update allowing a remote connection to our Form1+'s.

I’m not holding my breath though - in the meantime I’m working on my own iris design that I hope will be easy enough to install - but I’m certainly not 100% confident on that front.

Thoughts from the usual suspects? any unusual suspects? FL?


Impressive tests, Kevin! It really does prove that the issue is caused by the flare.

The formlabs supports is insisting that the flare at best is measured to have less than 1% of the power of the spot, therefore it shouldn’t cause any issues.

However, the evidence can’t be ignored.


So continuing on - with taller parts now and in grey to show the flaking - these two were printed with the brightest laser flare pointing to the front of the machine, and as you can see - the front facing surfaces are covered in lots of flakes. Most of these will wash off - but the hinge side part will be left with surface corrugations. The non-hinge side part will probably come out fine

contrast this with the rear view of the same parts and note the lack of flakes.

After these prints were completed, I rotated my laser - which I filmed and will provide a youtube link for - and started a new print of the exact same two parts, in the same vat with the same resin (after straining, and a top up) - mirrors as always have not been touched.

This is what my laser spot looks now - note the bright flare side is now pointing to the rear of the machine (oppositely oriented from when the parts above were printed) - this means the flaking on my parts currently printing will now be on the rear side faces instead of on the front.

Has it been like this since the shipped it or is this something that developed over time?

@EvanFoss since it shipped

@KevinHolmes Thank you. I was worried this was some new form of laser aging issue. Man you have all the luck.

@EvanFoss I suspect this is actually a very common issue with the new Form1+ laser - exactly how common will be hard to tell - because a lot of people may not notice the effect with the parts they print. FL however have confirmed that most of their lab lasers show the “rabbit ears” profile - so I expect it will be more “good” luck to have a perfect laser rather than bad luck to have one like mine.

I take it you have a Form1+ - have you looked at your laser spot - have you tried printing all over the platform? parts with near vertical faces?

Here’s a form file for the tall pieces shown above if you or anyone else is interested:

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Thank you for the file. I will give that a go when I can.

The printer was emitting a smell when it operated that me and a few office mates sick. It has sat unused after only a week or two of operation. We are waiting for a fume hood to be delivered. :frowning: During the time I was operating the printer I got a lot of failed prints and a few successes. Printing near the peel edge had some issues like what you are showing. You have me worried enough to do a spot test. (tomorrow)

The good news in my case is that if there really is a problem form labs is literally 10min ride on the green line (subway) from my office.

Good work Kevin. I’m working on a simple print that will show the problem clearly no matter the direction. I think I have figured out why the rooks do this. I am pretty sure that outlines are cured more strongly than fill. And I think since the outline of the stair portions of the layers has two lines perpendicular to the outside walls, when they cure these outlines the higher power flares are run length wise over the outside surface resulting in rough surface. I think I can simplify this into a sample print that is just a cylinder that is rough on the side corresponding to the flare.

Also as for how common this is even Formlabs won’t print the rook at less than 100um because it doesn’t come out well on their printers. These are the same printers they say print fine even with a flare.


Brilliant illustration/investigation. I have exactly the same problem. Since upgrade to F1+ i have not had one good print, mostly total failures. Been through all the mirror cleaning and exchanging the big mirror in contact with support. Still same problem and my printer is actually useless… Before upgrade my laser point was really a spot but now it has the same shape as you show. I think my failures are due to the broad laser creates a lot of jelly flakes, increases over time the print goes on until the part failes. The jelly production after upgrade is huge compared to before when the laser had a good spot.

Do you have any idea what the technical difference is between the F1+ laser and the older one? Changes made to be able to measure the laser effect…?

Will keep up the communication with F1 support - soon to see what their next move will be. New laser…

Keep up your good work!

Kjell Nilsson
Östersund, SWEDEN

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There is another really simple test you can do to check how strong your laser flare is, it’ll take less than a minute and only one drop of resin.

Use a clear sheet of perspex, or perhaps just a clean tank - run the spot test - note where the spot is, and put a drop of resin there - preferably black. Then run the spot test again - perhaps twice - and then rinse off your perspex or tank with IPA.

Here’s what mine looks like - this is after two spot tests - the laser flare was very clear after one spot test - but I ran two.


I think that’s a gross oversimplification on their end.
Firstly, i wonder if they were referring to the “bunny ears” or the higher intensity “carrot”.

Second, while yes, it might be 1% of the power of the focal point, what they’re probably forgetting is the fact that while curing the perimeter (the outline of the object) the carrot will pass over the SAME area MULTIPLE times, because it’s much larger and more uniform than the gaussian profile at the focus.

So those 1% might easily become e.g. 10% after 10 passes around the perimeter + additional ones while scanning the infill.

While it may be interesting to experiment with your machine (and I totally understand tinkering, it is also my nature to tinker and explore), if you are under warranty, and you remove or rotate your laser without explicit permission from Formlabs support, you can void your warranty.

Formlabs does not support or permit users to handle any service or adjustment of their optical engine (galvos, small mirror, or laser).

well that was constructive … not “we’re aware of this issue and are working on it” - but not-so veiled threats instead…

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We are aware of the recent customer concerns with lasers and are working to address them. Please be patient and if you think that you are having any laser issues, get in touch with our support team.

My previous post was not a threat; it was simply meant to inform owners of printers that if they decide to operate on their machines to try to diagnose issues outside of official support channels, their warranty can be at risk. We have a great support team here who can walk you through official procedures to diagnose potential problems and can provide a solution.

Very glad that we have such passionate customers! :slight_smile:

Man this thread exploded. You guys should not bother wasting more resin testing this, I am very sure FormLabs knows more than they are saying. But they will not announce anything this bad in the middle of the 2015 CES show. And they are probably still working on how to break the bad news gently to the loyal Form1+ Upgrade buyers.

@KevinHolmes — the moment you posted your thread we began circulating it internally, and we certainly do appreciate all of the time you’ve put into these incredibly detailed, thorough diagnostics! We’re learning right along with you, and everything that you add is really useful.

Above all, our primary interest is in making a machine that is as reliable and effective as possible. The energy and passion that you put in help make that possible, and we really appreciate it.

I think @Aaron_Silidker’s point is one of caution, aimed at those who may be tempted to begin playing around with their machine—in general, not a good idea, and as he rightly notes, voids warranty (no surprise there). That said, this is an evolving issue, and for those who have machines that need replacement and repair, as always, we’ll make it happen.

A number of you have been through thick-and-thin with us, and know the ropes, here, and we appreciate your patience .

@JoshK — you know as well as anyone that the Form 1+ is a complicated machine. I think that @KevinHolmes has done a spectacular job zeroing in on some new issues that we’re seeing with particular laser profiles and particular prints. Any hesitation you may have detected is only from a sense of caution at avoiding spreading misinformation, and clarity in separating the problems seen here with earlier problems with the Form 1.

At any rate, what I would love, would be see this thread stay on track and focused on Kevin’s research. Ultimately, that’ll be better for everyone. Can we get on board with that?


@Aaron_Silidker the problem is support has repeatedly told users that flare is not the problem, when it pretty clearly is. They have also repeatedly failed to diagnose or rectify the problem through official procedures. This particular problem has been denied repeatedly and I appreciate Kevin taking the risk to his warranty. If he had not this could have dragged on significantly longer. There is a problem when the users have to go to great lengths and risk their warranty to prove the existence of issues, instead of the company taking their users seriously enough to investigate themselves.

I think there is a fine line between being completely open about problems like this and running a successful business. Obviously you can’t keep telling your users that there are no issues when the issues are obvious, but at the same time you can’t announce it to the world and hurt the business/sales.

I still think Formlabs cares and they will make things right, which is what’s important in the end.

Product development is hard.


@RocusHalbasch — ya’ll are on the bleeding edge!

We have found, in general, that in many cases where people have laser concern, it is often associated with dusty or dirty mirrors, poor part orientation, dirty resin tanks, etc. The issues caused by the artifacts here, while important, are not (in general) a widespread cause of complete print failures. I think that’s what contributing to the mixed messages you’re seeing from our support team, who are chiefly focused on making sure that everyone is successfully printing, and may be less able to address the complex issues that @KevinHolmes and others have raised. I would be surprised if anyone on our team has outright denied that what we’re seeing here might be an issue—I think they’ve only shared what we know, which, of course, is always less than we’d like.

I do know that our team has gone to great lengths to verify issues, attempt to repeat exact prints, etc. More difficult questions, like those here, are referred to R&D and engineering teams, who are continuing to take a look at the issue, but that does take time.

In short, as @Monger_Designs says, we care, we’re trying, and I for one, think we’ve been doing a good job of it. That doesn’t mean we’re perfect—far from it—but we’re planning on sticking around for the long haul, and the only way we know how to do that, is to make a great machine at a great price, so that’s what we’re going to keep on working on.