Builds getting *Stuck* on the resin tray?

I just received my printer last week and have run a total of eight prints on it and now with the last two build attempts I am running into an issue where partway into the printjob the model gets stuck onto the resin bed causing the tray to have to pull for a second or two on each layer before the model comes free with a very audible “Pop” as if it had to defeat some kind of suction.

I know that this can’t be good for the printer and have canceled the prints each time it has started happening  but I need to know how to fix this.

Any ideas?

If its just a little pop with each peel I’m pretty sure its normal.  It happens almost every print for me to some degree.  Its just the cured resin separating from the silicon layer at the bottom of the tray.  Usually the taller in Z the part, the louder the pops get as it grows bigger.

It’s not just a little “pop” more of a more of one to two seconds of the motor pulling and then " Bang" as it releases. Yesterday the force was great enough to literally tear a solid, half inch thick model in half.

How about some photos of what your prints look like afterwards?

The force of the separation is so great as to have literally ripped apart a 1/2" thick section of resin during the build process.

Other builds have suffered similar results however I have been cancelling those once it has become obvious that the model has been broken.

Yeah, the tilt mechanism needs to be adjusted/slowed down for sure. A friend of mine has an envisiontec printer that has a similar tilt peel mechanism, but it’s so much slower and smoother.

You should also check the coating of your resin tank to see if it’s clouded or damaged, because that can cause sticking, etc.

The coating is still very clear. However I am concerned that this problem is going to damage the silicone on the bottom of the tank.

I have also tried moving the print job to different sections of the platform but all have resulted in similar results.

I am also noticing that the problem seems worst between layers 70-130 on a 100 nanometer build.

And it has broken tree more attempts on the same model so far today.

Different orientations, placement on the platform and support changes all result in the exact same trouble releasing and model breakage.

@DS so your model is solid - does it have to be? if it was hollow I’m betting it’d peel easier …

I would prefer that it be solid.

I might attempt to hollow out the base however I am concerned that the same problem will still occur once the print hits the surface of the base (which would have to remain a single solid surface of a minimum of 1.5 mm thickness.

However, I am currently attempting the same print at 50 nanometers as opposed to 100 and right now the print job is at the same relative height (7-9mm) and is NOT having the same issue.

There is a slight bit of adhesion between the print and the tank however the result this time is a fairly quiet, gentle release versus the much more violent (and loud) release with the 100 nanometer print.

I suspect that the added layer thickness and the intensity from the laser in curing the thicker layers is what is responsible for the difference.

I also suspect that the printer should be able to be re-calibrated to account for this issue by simply initiating a slower pull/release between layers when the build is set for 100 nanometers and the build surface is greater than say one inch square.

@DS scaling the peel tilt speed to the surface area of the current layer sounds like a great idea to me - you should post it in the suggestions.

Glad to hear it’s not sticking so much at 50 - something I’ll remember for when my machine finally arrives. The things I want to print will be at larger end of the build envelope so sticking is going to be an issue …

re: your concern about experiencing the same issue printing a shelled part when it hits the surface of the base - surely you could just tilt the model on supports to get around that?

And apparently my optimism regarding the print at 50 nanometers was misguided.

Even at that resolution the printer managed to break the model in a similar manner.

I am coming to the conclusion that there must be something defective about this specific printer unit because a simple 2" square block shouldn’t be beyond the capability of a stereo-lithographic printer.

Well out of sheer frustration I went ahead and took the printer apart and found a tiny 1" long, 1 - 1.5mm wide smudge on the middle of one edge of the first surface mirror under the build tank.

I now suspect that the smudge may have been obscuring the laser just enough to weaken a thin line of the print which allowed the larger models to deform and break under the stress of the tray retraction. All of my previous, successful prints have been of smaller items where the laser probably shot around the smudge and I am guessing is why I never noticed the problem before I started attempting the larger prints.

I went ahead and cleaned the mirror with the lens cleaning supplies from my camera kit, removed the smudge (and a lot of dust as well) from the mirror and now I am attempting the print again at 50 nanometers.

(Fingers Crossed)

@Dungeon Stone, did cleaning the mirror help?