Resin sticking on tray


I have a brand new Form 1+, I have been trying to print this part for the 3rd time.

Here is a link in case you want to see it in 3D

It is for a lamp I’m designing and the part will be solid in reality. I need the print to be solid to simulate how the light will behave on the final PMMA part.

First try: Was running quite OK, but the printer was 1 degree inclined (I found this our afterwards) and made it run out of resin towards the back of the print, creating this:

As obvious as it sounds now… nowhere I saw a warning to check the level of the printer on installation, and after checking… it was just 1 degree tilt. The resin level didn’t yet reach the bottom line on the front of the tank and the auto pause to refill didn’t reach the calculated layer yet. (I do not trust the auto pause since then).

I have to say that the surface quality is not nice even before the problem with the resin level. The layers are quite visible and not exactly aligned. Here are some pics from another part I did in white that illustrates the steps on the prints:

Second try: I extensively cleaned the tank. Used the scraper as described by FL and a fine comb to find any traces of cured resin. (I couldn’t find any though). I inspected the tank on the bottom and saw no ghosting or anything strange.

After several hours, Part of the print stuck to the tank… I sopped the print and trashed it.

This time, there were support ghosting marks on the bottom of the tray, so I decided to change it (even thought I used less than 1 liter of resin on it).

Third try: I used a NEW tank and NEW resin.

I also verified there were no dirt on the mirror. I used Zeiss cleaning spray and a photography lens soft brush.

In person looks better than on this picture though…

After several hours printing, I noticed that one of the supports (that should continue) is ending on the air. I cancelled the print and again found a patch of resin sticking on the tray.

One more time I removed a patch of cured resin strongly sticking on the tray and noticed that the new vat had been ruined again with localized ghosting.

I have been super careful with the printer, read all the advice from Formlabs before I got it, I close the cover as fast as possible to avoid dust from getting in, etc.

In general I’m a picky and careful person when it comes to tools. At this point I feel very very frustrated… this thing is supposed to work and it doesn’t. it is making me lose a lot of time and money, I feel I can’t rely on it for client work and I’m not feeling happy with the purchase.

Any advice to troubleshoot what is wrong is highly appreciated.

p.s. I noticed one of the trays is cracked on a corner. It sure came that way but don’t think it is part of my problem.

You need to hollow out that part! I’m very surprised that you got as much to print as you did.

Solid cross-sections make it very difficult for the peel process to work correctly, and often will lead to failed prints.

(A large surface area is being pulled by the peel, while the thin supports try to keep it connected to the build platform.)

I’ll bet if you hollow it out (wall thickness 2mm or > ) you will get better results.

The point to have a solid part is to test how it reacts with the light. If I hollow it, is not how it will be on the final product and there is no point to prototype it.


According to your screenshot you are doing a 20 hour print. That’s too long, the resin can only stay mixed about 10 hours. At that point surface finish goes downhill. After about 18 hours small features become explosive failures.
Try 0.1 resolution. Also, consider printing it in two halves then gluing them together to reduce surface area during printing. I am curious if that picture of your mirror is a before or after? The mirror needs to be perfect.

When I upgraded my Form 1 to the Form 1+ I also got that new orange resin tray. Mine also ended up cracking in the same corner over the weekend and looks like yours. I’ll post up a pic later when I get home from work. It must be a design flaw in the new resin trays.

This is a very interesting piece of information that nowhere I read before of after purchasing the printer :frowning:

I’m already in contact with FL support, they sent me instructions to clean all the mirrors. I had to order Pec Pads, it will take around a week until I get them and I can try anything new.

So for now I still have a couple of questions:

  1. Is there anything I can do about the ghosting on those tanks? It was new and used it only for that failed print.

FL states they should be replaced every 2 liters of resin and suggest to move your prints around… but still… this was not even 1 complete print and the fist tank didn’t even handle 1 liter! This is looking very disappointing.

  1. Are these marks normal on the top side edges of the cover? They seem like internal cracks from stress in the material.

The 10 and 18 hour markers are my observations. @Justin_Shumaker has observed the phenomenon too. Here’s Justin’s quote:
“Five: Use 100 micron resolution on large parts. The longer your part takes the print, the greater the chance of failure. Save 50 micron and 25 micron for small figurines.”

High five to Justin!

I wish FormLabs would state it too. Customers always insist on 0.025 resolution with no understanding that it will be worse that 0.05 resolution on large prints.

I think the 10 and 18 hour markers would only apply with pigmented resins. There is nothing to settle out in the clear resin so time should not be a factor at all. I do agree that anything over an inch tall, and some things under that, should be run at the .1 setting though.

Also, the small cracks on the cover are due to the manufacturing process. Liquid gets trapped in the acrylic when it is being formed and as it dries out, the cover will get those little cracks. My printer has them as well.

Actually the clear contains UV blockers and other ingredients that settle too. The resins are like house paint, gravity separates some ingredients.

I suggest trying a slightly different process.

  1. Hollow the part, with a wall thickness of 2.5mm-3mm.
  2. Make a mold, that is compatible with acrylic, or whatever translucent material you want to study for the illumination effects. If you are careful, then you can attempt using a range of materials and colors for a low quantity of parts. I am estimating that you will need to polish the surfaces after they are removed from the mold. We look forward to reading and seeing your results.

Very interesting regarding the 10 hour mix limit, that would definitely be a useful bit of info to put on the resin packaging and appropriate sections of the website (if not already there). If you need a solid object, I suggest printing hollow as others have suggested and then making a mold and casting from the mold.

Hi Nicolas
I would suggest to print it hollow. You have to add two holes. A small one and a larger one. After the print close the smaller one and fill the body with “Polyestergießharz” ( This 2K Polyester is thin like water has two hours of pot life or even longer. So most air bubbles will disappear. You can sand this material and polish it and it is cheaper.


the polyester resin will probably warp the model as it gets too hot. Better use polyurethane and a slow curing version. “Kaupo” offers nice pouring resins that fit your needs. One question: do you always clean your mirrors with a Zeiss cloth? It might be possible to get so called ablations on the first surface mirror with the wrong stuff. Even Kim Wipes are not suggestable! Check your big mirror for small unreleasable spots that appear to be dust. Maybe your mirror is damaged. I had this problem by using kimwipes recently.

1 Like

Stupid question, but…

If you really need a completely solid (huge) object printed, why not print it hollow a hole at the bottom (or the top, depending on orientation).

Then, after it’s printed, pour a few mm of resin inside, and cure it in the sun or under a UV lamp. Then pour a few more, then cure. Repeat until completely solid.

(The reason i’m suggesting doing this a few mm at a time is because the resin is not very UV transmissive - it mustn’t be, or you’d get horrible overshoots on top layers. Also, large amounts of resin can change their volume during a cure significantly and this prevents cracking.)

A couple comments I’d like to make:

Firstly, with regards to the resin separating, it is true resin will separate over time, hence why we recommend shaking your bottles before pouring resin in. However,I run the print farm here at Formlabs, and I have not experienced resin separation after just 10 hours, especially during a print. I’ll keep a closer eye on my prints lasting 10+ hours to see if there is indeed a correlation but, in my experience, most failures can be attributed to problems with orientation and support and/or selecting a resolution that may not be ideal for the type of print. Also I would imagine the constant movement of the peel cycle would help agitate the resin enough to keep components from separating out.

Secondly, the issue of ghosting. When printing large, solid objects, the tank will inevitably ghost faster. This will be compounded by using 50um or 25um resolution as you are exposing the tank to the laser 2x or 4x respectively. A little ghosting does not mean your tank is dead though. I have had tanks on the farm that have significant ghosting and still manage to print just fine. Usually, the ghosting will eventually ware down the PDMS to the point where it gouges or delaminates from the tank, at which point I switch to a new tank. Ghosting can and does lead to failures but it usually needs to be pretty opaque to be responsible for failures.

1 Like