Trouble Shooting – Part cured resin (jello) after every print

As some of you are aware I’ve been having print quality issues with my Form1+. I’ve posted on the @kevinHolmes thread “Form1+ laser flare issues illustrated – pic and video” – LINK some typical examples.

Although there are similarities with print quality, I feel there are more factors at play them just the laser flare.

FormLabs support has been great, and I truly believe they are taking the laser flare issue seriously. One thing they have asked me to do is revisit the ambient temperature of the room the printer is located in. The room, a conservatory, is only heated when it’s been used and in winter the temperature can get right down. That been said, I only print when the room temperature has stabilized at 16 to 18 degrees C for at least 2 hours.

Last night I brought the printer into the living room to run some prints to see if this is a factor…… yes I have a very understanding wife. The ambient room temperature is normally between 18 to 21 degrees C. I will reprint some of the test pieces and report back here.

I’ve also posted a video showing how I’m straining the resin between prints which gives a good indication of the amount of part cured resin I’m removing between prints. As I say and demonstrate in the video, the quantity of part cured resin increases with each print cycle.

Is that a halogen desk lamp on the desk?

If so, that’s a very bad choice for working with resin, as halogen bulbs emit a fair amount of near UV and UV light. Unless the bulb has a UV shield (usually a pane of glass in front), i’d rethink the workspace lighting if i were in your shoes.

Thanks for the heads up @Ante_Vukorepa, I’ve just checked and there is a uv filter on it.

A quick update on trouble shooting our Form1+.

Operating our Form1+ in a room that maintains a constant ambient temperature between 16c -20c has worked wonders. I’m still getting a lot of part cured resin but when printed a 0.1mm layer heights, getting usable parts.

All the surface holes and major of defects are gone. At 0.1mm LH, the part cured resin on the surfaces washes off. At lower layer heights the part cured resin effects the surfaces in a similar ways as documented in @KevinHolmes thread.

BEFORE (Ambient temp. 8c to 20c, room warmed to 18c for 2 hour before printing )

Layer height 0.05mm, Clear v1 resin

AFTER (Ambient temp. 16c to 20c)

Layer height 0.1mm, Clear v1 resin
The part cured resin shown, washed off with no noticeable effect on the the print surface

My interpretation of laser flare on my printer

Thoughts & observations

  • Operating the Form1+ in a room that holds a constant ambient temperature above 16c is a must. Both the printer & the resin need to stabilize with the ambient room temperature.

  • Cold resin exacerbates lasers flare issues.

  • The part cured resin still forms on the print faces perpendicular with the laser flare.

  • I have to strain the resin through a paint filter after every 5 – 8 prints. This is the only way to remove the build-up of part cured resin.

  • The part cured resin is of a jelly consistency and not the result of a failed print. It’s also not the same consistency as that shown on the FormLabs support page for Cleaning the Resin Tank after a Failed Print.

Moving forward

  • Although not ideal, its great been able to print usable parts - even if it’s just at 1mm layer height.

  • Even at 0.1mm LH, the prints are awesome! We can’t get anywhere the same quality with our FFF printer at 0.1mm LH.

  • I fully trust the FormLabs support team and believe that until they have a solution for this issue, there is very little to be gained by returning the printer for a 3rd time.

  • I’m confident that when they have a solution they will repair the printer.

FormLabs support experience

My personal experience of FormLabs has been very good. They’ve been very professional , timely and most of all honest with me. The FormLabs support team and support policy is the COMPLETE OPPOSITE of the market leader in consumer FFF printing, MakerBot. Trust me; compared to MakerBot’s one star support, FormLabs have given me the 5 star treatment.

I will continue to update this thread as things develop.


nice work @Steve_Johnstone - I will add one point that I differ on however. I always thought your print holes/bubbles/hollows were unconnected to laser flare - so I don’t agree with this statement:

Personally I think cold resin will likely cause issues like your bubbled prints for every printer - even if they have next to no flare issues.

Also - I think you are confused about layer heights - before the latest Preform update, 0.1mm was the thickest layer height - and will minimise flare issues with prints. So rather than “even at 0.1mm” you should be looking for “even at 0.05mm”, or even at “0.025mm” - and was this a typo? or not?

In any case - it’s great to see another reason for bubbled prints nailed down. From your experience it was obvious there had to be another cause beyond walled in air pockets in the part orientation.

You are right @KevinHolmes it should have been 0.05mm - I’ve edited the post.

@KevinHolmes the reason I’ve come to this conclusion is that with the cold resin prints, the poor defective surfaces, only occur on the faces perpendicular to the laser flare (rearward faces). The hinge and peal sides of the print have always come out fine at all layer heights. This behavior has been the same on every print I’ve done since first receiving the printer.

@Steve_Johnstone what I meant was that you’re possibly conflating two separate issues - cold resin causing bubbling/hollows, and flare causing bad surfacing and flaking.

I don’t see that you can conclude cold resin makes flare issues worse is my point. My contention is that cold resin is likely sufficient to cause bubbling/hollows on its own - even in a machine that had a perfect spot without any flare at all.

@KevinHolmes I fully understand where you are coming from, but that doesn’t explain why the major faults never once appeared on the hinge or peal sides surfaces of any print I’ve done to date. For your argument to be true I would have at some point seen bubbling / hollows throughout the prints, not just concentrated on the back surfaces, facing the hinge.

@Steve_Johnstone but how can bubbling/hollows have a “side” or “surface”? - those parts are only 2mm thick - the bubbles must be in the middle of the part.

If your point is that the bubbles appeared only in the y-axis (or x? not clear from your pics above) oriented slab-features and not the in the x-axis oriented slabs, then that’s an interesting point - which I hadn’t picked up on before…

But I would argue that it’s still not connected to flare, and is most likely caused by the direction of the peel - and that if the F1 peeled in the y-axis instead, the bubbles would switch axis - independantly of your flare orientation.

I guess I could experiment - since I’ve seen that kind of bubbling in the past and didn’t understand why. At some point though I switched to keeping the lab heated, so given your results I strongly suspect that my bubbling was also due to cold resin. I could turn off the lab heating again - see if I got bubbles, then print again with flare oriented in the Y axis instead - and see if the bubbling changed. Lots to do at the moment though - not sure if I’ll have time.

@Steve_Johnstone Can you please post pictures of those same prints after washing.

For clarification. The prints I did of the same file on our now defunct thread were done at 20.9C. The fume hood I run the printer in and that room have good temp control because of the other stuff done in that space.

The solid parts e.g. the rook have the major bubble flaws on the rear facing surface. The last print I tried before bringing the printer in doors was a solid version of the cockpit canopy that failed at about 50%. Again the the major bubble defects were on the rearward face.

Solid Canopy, 0.1mm LH, clear v1 resin

Rear / Hinge Side

Rear Face

Front Face

@EvanFoss, I have now printed the test cross at the other two layer heights 0.05mm & 0.025mm. It’s my opinion that the rear facing surfaces get progressively worse the as the layer height is reduced. To me this make perfect sense as at 0.05mm the laser flare covers the same patch of resin twice a many time as it does at 0.1mm. At 0.025mm, this increase too 4 time… I hope that makes sense :smile:

I agree with reported comments from Formlabs support that orientating the print at 45 degrees will improve the surface quality as the laser flare path won’t cover the same patch of resin as many time. But from my experience with other parts printed since, you are still get part cured resin in your tank that can only be filtered out. The test piece however, was design and orientated to purposely to test @KevinHolmes theory, which I think it does very well.

Grey resin is probably a better colour for these tests as its quite hard to photograph clear parts.

Test Prints

Printed at 0.1mm Layer height, clear v1 resin

Printed at 0.05mm Layer height, clear v1 resin

Printed at 0.025mm Layer height, clear v1 resin

@Steve_Johnstone ok - that rook bubbling is interesting. So what’s the theory; that flaking on the flare side can act as traps for air bubbles?

I think it’s obvious now why cold resin can cause bubbles/hollow parts - cold resin is more viscous, and once past printing the base and into printing the part proper when we have fast peel cycles - if the resin is viscous enough (eg when cold) then air will be sucked under the part during the peel cycle creating bubbles than can get trapped under the in-progress part - preventing any resin cure at those points.

The open question for me is whether flare and cold resin interact to cause a greater problem - and going by your rook print, perhaps it does. I’m going to run some experiments myself now.

Note - I suspect the resin level in the tank can also contribute to bubbling/hollow problems - ie a half full vat will be more likely to generate bubbles than a full one.

Well I couldn’t reproduce the bubbled parts problem by reducing the temp - although I did only try a couple of times. I turned off the heating left the window open over night. It was 12degC in the morning - which produced one complete failure. Then after shutting window and warming to 14deg - I managed to get a complete print - but no bubbles in the parts.

I still believe that cold resin causes bubbling though. I did see a lot of it in the past when I wasn’t heating the lab. Also presumably it’s made worse by bad flare - as shown in @Steve_Johnstone’s rook print above, but I don’t have time to look into it further.

I did notice however that air bubbles were being created during the peel - and also that my bases were flaky - showing layers of uncured resin in the base.

So it seems cold resin is the cause there too - not the platform height as I thought previously - which makes sense. Because the resin was so viscous I could hear and see the “thunk” of separation when peeling the base layers - and it seems that suctions forces are so great on the peel cycle with cold viscous resin, that base layers can be partially separated.

@Steve_Johnstone, @KevinHolmes,

Unfortunately i have encountered similar problems with my latest prints and I don’t have a solution for it either. Hopefully we’ll be able to fix this together because it’s affecting my prints in a bad way as well.

Like Steve’s print. I have rough surfaces at the front and back side of the print. Hinge and other side are perfect.

As far as I can conclude it has nothing to do with the laser as this is my laser:

I have printed the same part over and over again, using the same angle and spot to print with no good results as of now.

My printer operates in a 21 degrees Celcius room, and my cabin with all the resins in it is actually placed against the heating so the cabin is a few degrees warmer. Therefore, temperature does not seem to be the issue. A cold environment might make the print worse, but it’s not the cause.

I’ve tried printing the print with 0.2mm layers and 0.1mm layers with no difference in finish. Both were rough.
Cleaned the mirror with IPA and pec pads and printed again. No difference.
Strained the resin and printed again. No difference.

I have no idea what I can do next to find out why the print has such a rough finish.

Thing I noticed is when washing the part with warm/hot water between the 2 IPA baths, the rough spots seem to be highlighted in white… No idea how that helps. Hopefully we’ll find a solution :frowning:

@Alex_Vermeer if you have rough surfaces on one side of your parts near the hinge side - then that sounds very much like laser flare. I don’t think that laser spot photo is really any evidence that your laser spot is fine.

It is very difficult to take photos of the spot through the cover - and there are so many factors that can mean you miss detail; the camera exposure, the thickness of the paper, etc, etc,…

Moreoever - for there to be a completely separate issue that causes those same specific symptoms; ie rough surfaces on one side that are worse near the hinge, seems unlikely to me - that is, if you really do have exactly those symptoms.

Do you have a lot of flaking on the rough surface side as well?

Have you tried my test cross pieces? Form1+ laser flare issues illustrated - pics and video they illustrate the symptoms really well.

@Alex_Vermeer, I agree.

To get a good picture of your laser spot I put together a paper template and some video instructions you may want to try -LINK

I would defiantly print @KevinHolmes cross test pieces as well. The lower the layer heights are, the more evident the problem should be. If possible take some photos of the printed parts still on the build plate, before washing, then after once they have dried etc.

@Steve_Johnstone, Thanks for the PDF. I’ve taken another photo without the cover and it seems you are both right (unfortunately)…

@KevinHolmes, I do have small flakes on the rough surface sides of the part. I shall print your cross pieces in .1mm to see how they come out.

Thanks for the help and I will get back to you soon!

@Alex_Vermeer a better test is 50 micron - the smaller the layer height the more obvious the symptoms.

Also if you can, don’t use clear - since it’s hard to see which side defects on are on.

Glad you replied so quickly! I canceled my clear print and will print in Grey with .05mm