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Clear Resin and Holes... and premature screen failures?

Hi to all!

At the beginning of 2019, I received a bean 3D printer and had some great success printing some cups out of clear resin… A few months later I started printing again to run into an assortment of issues I can not seem to go around. My cups would develop holes and vertical stripes or cracks during the print process… I thought it was old resin, so I switched in between different bottles… not much change. I then ended up identifying that there were dark spots in the light quality during the print that resulted in absent details on the cup walls. I purchased a new screen and had some success… but after 20 hours of run time and 2 cups printed, I started experiencing similar dead zones seen with the last screen. Has anyone else experienced vertical voids propagating the whole length of an object?

My cups are fairly cylindrical…
I added relief holes to mitigate the suction that would blast holes in the walls. I also increased the wall thickness of the cups to avoid frail collapses of the walls.

How long are the screens supposed to last?

-Kyle

Is there anything ‘special’ about the cups in that specific area?
(Probably not, just asking)

Are the holes in the exact same spot as you had on the old ‘screen’?

Are you talking about the LCD screen, or the Teflon film, because the LCD should last significantly longer. Even the Teflon film sohuld last longer than that.

I uploaded here some photos of my results. This is of course with the newly installed screens! In the photo with the two cups were the first sucsessful prints with the new screen. Shortly after the two successful prints… resumed to garbage qualities as seen with the previous LCD screen.

What does this look like to you? I can’t possibly imagine the LCD screens dying out so rapidly. Is this what fatigued resin does?

IMG_3307|666x500

Ok… just checked the screen for dark spots without the film and tray. The black spots are back!

Before removing the tray, I checked for clumps/scraps in the bath with the rubber spatula. I found a couple thin sheets about .5" x .5" laying around and removed them carefully…

What in the world causes this smudgy black spotting in the screen?

-Kyle


New development! I peeled the protective screen off of the LCD slowly while my big block test pattern ran. Interestingly enough the black spots migrated along the line of the peel like black oil being squeegeed from one side of the glass to the other. I confirmed that the black liquid was apart of the LCD and not the interface between the protective glass or the glass itself. By peeling it up and laying it back down, I could refresh the black points to be more distributed or migrate the general amount of blackness to one corner… but I am not able to entirely eliminate the effect all-together. I can imagine that high pressure points from rogue clumps will cause the formation of this LCD like failure.

Perhaps the clear resin has a higher probability of sticking to the teflon than other materials…

For quite some time, I assumed that the blackness forming in the LCD was a matter of heat buildup… but this may indicate something else…

Thoughts?

Something screwy is going on, yes.
Does your resin vat have the rubber seal, or is it sealed with silicone sealant?
(The rubber gasketgoes under the metal ring with the screws, but the sealant is under the lip around the opening, so if there’s sealant it should be visible)
If it’s with rubber seal, please check that the screws are NOT poking down below the bottom of the vat.
(This can happen, at least with vats that was sold without the rubber seal originally. All KS printers were without rubber seal)
It probably doesn’t matter… but it can lift the Teflon film up above the LCD so the prints aren’t correctly exposed.

One issue you have with your prints is that the glasses are entirely vertical. That means as you print the bottom you will end up with a masive amount of holding force to overcome every time it lifts the print. Tilting the glasses a bit, or eve nlaying them on their side will get rid of that problem, though.
(Remember, the vat drops down after the print releases from the teflon film. It shouldn’t be violent enough to damage the LCD, but…

Hi Gadgetman,

The resin vat is the original silicone sealed design. It was the Kickstarter model. I had one vat fail/leak previously with this design already so I purchased a metal vat to reduce this problem but I have not implemented it yet.

The black screen blotchy liquid in the LCD, what is that a symptom of? Is it possible that my Home position was applying too much pressure to the screen? Do flakes in the resin cause point load damage that results in the black LCD stains?

Here is another picture showing the latest attempts now that I re-seated the protective glass… (I was able to move the dark spots off to the edge, but now the entire screen has subtle variations in cloudy darkness)

I suppose folks who use the DLP projector style resin printers never have this problem :slight_smile:

From your description of the problem it sounds like your suspicion that there were chips or something putting pressure on the LCD was right.

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