Failed prints...it's the software

[Maxer]

I've been using my Mars since Christmas and after dozens of successful prints I've entered the failed printing wasteland.  I've been trying for weeks to get my prints to adhere to the print bed with almost no luck, everything sticks to the FEP.  I've replaced it, double checked my leveling and tried several different STL files, none of it works.   I decided to see if it could print the Rook's that came with the USB drive, YES they print!  I also tried printing a model that I made back on the 28th of December and it also prints, however none of the files I've made since the beginning of February will.  That makes me think something changed in the software that might account for all these print failures.  I noticed a new version of the Chitubox software was released on January 16th and I'm thinking something changed in the default settings that may be causing this problem.   I'm just looking for a way to fix this problem so if anyone knows anything please let me know.

[Maxer]

I thought I'd give an update if anyone is interested, the software doesn't seem to be the problem.  After watching some video's on the FEP I realized I may have installed my incorrectly.  The video Elegoo made says you need to use a 5mm sponge when installing it, I used a plastic bottle cap which is probably 15mm.  If my FEP is too loose then I can see how it could pull the model off the build plate.  I've also read that the FEP should resonate at 235 Hz, I will try to test this when I replace it.  If anyone has any suggestions I'd welcome them.

[fromFDMtoSLA]

i am using this tool:
https://www.thingiverse.com/thing:3351933

printed on one of my FDM's in ABS and smoothed with Aceton, to get no scratches on the FEP

[Maxer]

I've decided to try one more test before I changed the FEP, I arranged 4 different models on the build plate to test different orientations and setups.  One was a new model I got off Thingiverse to which I added supports, another was a model I had successfully printed about a month ago and I placed it directly on the build plate.  The last two models were of the test Rook, I imported it from the STL file and placed one directly on the build plate and the other I reduced by 50% turned 45 degrees and added supports to.  The results are interesting and confusing, the models that were attached directly to the build plate with no supports printed, the models that had supports didn't print. 

To me this says that there's no problem with build plate leveling, the FEP or the resin, perhaps it's a problem with the exposure times?  I'm using the default settings for Elegoo black resin as well as the default configuration for the supports except I've reduced the density to 60%.  The question is what's different about the supports that's making them print on the FEP instead of the build plate??

[zemerick]

I've decided to try one more test before I changed the FEP, I arranged 4 different models on the build plate to test different orientations and setups.  One was a new model I got off Thingiverse to which I added supports, another was a model I had successfully printed about a month ago and I placed it directly on the build plate.  The last two models were of the test Rook, I imported it from the STL file and placed one directly on the build plate and the other I reduced by 50% turned 45 degrees and added supports to.  The results are interesting and confusing, the models that were attached directly to the build plate with no supports printed, the models that had supports didn't print. 

To me this says that there's no problem with build plate leveling, the FEP or the resin, perhaps it's a problem with the exposure times?  I'm using the default settings for Elegoo black resin as well as the default configuration for the supports except I've reduced the density to 60%.  The question is what's different about the supports that's making them print on the FEP instead of the build plate??

The default black print has an extremely short bottom layer exposure. It's 70s for some reason when bottom layer should be about 10-15x normal. This will greatly affect the stability and adhesion of the bottom layers. Additionally, black should not default to .05mm layer height. 0.04mm should be the max used for reliable good prints of black. In fact, for my dark grey that is 50/50 black and white, at 0.04mm, I still use 150s bottom layer exposure, and that's with only 12s normal layer.

[Maxer]

Thanks Zemerick you are right the default exposure times aren't correct, before I saw your post I increased bottom exposure to 90 and normal layer to 19 and it did make a difference.  It improved printing success to about a 50% but it had the nasty side effect of making the resin stick even more securely to the FEP when it failed.  It was stuck so well in places it made indentations in the FEP which I think is probably bad so I decided to change it.  I don't understand why Chitubox is using the obviously wrong settings, how did you figure that out ??  

One last detail, I noticed on the bottle of resin it had a date of 10/29/2019, I don't know if that's the date it was produced or the date it goes bad?

[fromFDMtoSLA]

did you change the FEP in the meantime?
for me it looks like your are "fighting" against different problems at the same time.

[Maxer]

did you change the FEP in the meantime?
for me it looks like your are "fighting" against different problems at the same time.

Yes I replaced it using the 5mm sponge method shown in the Elegoo video so I can eliminate that problem at least.

[fromFDMtoSLA]

and it sounds like a drum (235Hz)? ;-)

[Maxer]

and it sounds like a drum (235Hz)?  ;-)

Do you know how to read the expiration date on the resin bottle, does it indicate the date it goes bad or the date it was made?