Form1+ laser flare issues illustrated - pics and video

That’s really interesting @SachaGloor - they look great. Thankyou very much for posting your results.

One note of caution however, those test pieces are probably only going to show issues for people who’s laser flare is oriented closely to one of the four points of the compass - if your laser flare is at 45 degress to X or Y dimensions instead - then I’m not sure if those test pieces are good indicators. I haven’t tried my laser in that orientation.

If you could provide a picture indicating your laser spot orientation like mine or @KjellNilsson’s or @Steve_Johnstone that would be a great help.

If you have trouble getting a clear photo of your laser spot - you could run the simple test I’ve shown above in post 12. Use a clear sheet of perspex, or perhaps just a clean tank, or even a transparency sheet in 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 the uncured resin with IPA. You will then have a cured blob of resin in the shape of your laser spot.

I’m really keen to see your laser spot orientation - because those pieces looks so good - and it would very interesting to know for sure that the Form1+ laser quality is that variable.

Hi Kevin

Will try it this weekend. How do i run a laserspot test ? Is it a special .form file ?



Here it is:

On post #1 explain all for Mac

On post #73 there is a capture from Windows

In fact it did used to be a special form file, but now when you start Preform with the command line option “-diagnostic” it gives you an extra menu called “diagnostic” and the one entry there is “laser spot test”.

If you’re on windows and have preform in your shortcut bar you can just edit the shortcut properties to look like this:

edit: alternatively see @Jose_Ignacio_Vicente’s link above :slight_smile:

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at the same time… :smile:

@KevinHolmes, I’ve just reread the Cluster or Bubbles of Cured Resin and @KenCitron comment ready struck a cord -

What is it’s this jello caused by the lenses flare that’s causing the problems on my parts?

There is more surface area being cures in these areas and a greater chance on the jello causing problems.

I had a think about what you said reference trapped air bubbles. I’m pretty sure that the print surface of the print remains submerged during the whole print process so cant see how air could be introduce unless the resin level was too low. I may be wrong but will pay a bit more attention with my next print.

I’m going to print a solid version of Test Exhaust v2 to see what happens.

@SachaGloor, +1 on @KevinHolmes comment.

I would love to see what your laser spot test looks like.

@KevinHolmes - Awesome tip!

Having to type the whole command line into the cmd window, exactly as shown in the FormLabs instructions is a PITA.

Your way is so much easier. Even better is having the diagnostic tab available when ever I start up preform from now on :smile:

This is my laser today… ( I’m having trouble in printing ) I am awaiting the response of support

Well you know what they say about a picture painting a thousand words …

The results from @KevinHolmes tall_thin_calibration_30mm_cross test.

Printed in FormLabs v1 clear resin @ 0.5mm Layer Height.

As @KevinHolmes predicted from my laser spot test the worst surfaces affected were those facing the rear of the printer.

Although I haven’t cleaned the parts the right hand part ( 1st pic) shows the exact same defects as the previous parts I showed. I very much doubt the defects are caused by trapped air.

@Jose_Ignacio_Vicente it’s hard to be sure with that photo. I mean it looks terrible - and maybe it is exactly that; a terrible broken spot - but I know it’s very difficult to get a good shot of the laser spot. There are so many factors that can make the photo messy and hard to pick out the important features of your laser spot profile.

Paper thickness for one thing - I suspect thinner paper is probably better than thicker- I got my best shots using the tissue paper backing that comes with a transparency sheet. Also the Form1 cover seems to be very good at blocking a good view.

I think we need to try and standardise a method for taking pictures of the spot. @EvanFoss’s approach is interesting - but I suspect perhaps @Steve_Johnstone’s method might be more broadly applicable. Steve how did you take your spot shots?

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@KevinHolmes I will do a video today of how I do my laser spot tests. Hopefully it will give others the confidence to do it and share their results.

@KevinHolmes If you or a couple other people want photography paper I can mail out a few sheets. It isn’t like the lab will be using it any time soon. (I was actually told to throw all that junk out 3 years ago) I am very nervous about people becoming encouraged to operate their machines lasers with the cover open. My lab is in the Mass. Eye and Ear Infirmary and I see some scary stuff in passing.

We need photos of the test done with printers that work well and we need to make the testing we are doing quantitative instead of just qualitative.

Hi Steve

That would be nice.


Watching this thread very closely… Ive had the same issues for over a month now. “I’m about to jump”

Thank you @KevinHolmes

No one says it has to be a perfect circle.
No one expects it to be. Laser beams need to be conditioned to achieve a clean profile.

Use an aperture. It’s the simplest spatial low-pass filter there is and is a normal part of about every laser optical path out there. Relying on the fact scans are fast and intensity of the flare is low is misleading - you keep curing over the same area in the vat with the flare. At some point it’s bound to solidify, and, even worse, resin with chunks of semi-solid resin will flow UNDER the printed object when you do a peel.


Or better yet, switch to DLP projection, Formlabs. Lasers are clearly full of problems.

Build volume would be VERY small.
Not a problem for jewelry, but it would gouge a huge chunk out of Formlabs’ user base.

@Ante_Vukorepa pretty sure that was heavy irony … not something I’ve seen from @Monger_Designs on the forums before, but I suspect he’s a little peeved at the long dialogue with FL support he’s had over this …