Distortion of printed shape

[Zogster]

So I've had my Mars Pro for a few days now, and I'm impressed with the quality it's capable of though it does seem to need care and attention in preparing files, settings etc. Had a couple of issues with adhesion/release but more attention to supports is definitely helping there, though I think i am also going to try a dry PTFE spray on the film to help with release.

I'm having a problem with distortion in some prints, however. Pics below - as you can see, some edges and corners that should be sharp are rounded off, and there's one area that has failed to print, like something has taken a bite out of one edge. I've also included a screen grab of the .ctb file to give an idea of orientation, supports etc.

Can anyone suggest how to tune settings to improve this print? I have a feeling that maybe more supports is again the answer

btw, I'm using Elegoo's own white ABS-like resin, and have adjusted exposure time to 5.5 seconds (after trying a calibration print that suggested 7s was over-exposing the resin)

[cliffyk]

5.5 s is far too short an exposure. try the settings recommended in the Chitubox configuration for the Mars (8 seconds):



I have not yet found any of these presets that do not work, they may not be optimal they work...

[Zogster]

5.5 s is far too short an exposure. try the settings recommended in the Chitubox configuration for the Mars (8 seconds):




I have not yet found any of these presets that do not work, they may not be optimal they work...

Thanks, I'll try longer exposure again, but I note that a) I had similar distortion using the original default settings which had 7s exposure, and b) the calibration print I tried (a Photonsters 'validation matrix' suggested by this video https://www.youtube.com/watch?v=r9GwPEJ8Lq8&t=10s) strongly indicated that the 7s exposure was too long. 

I may look for some other test/calibration models. Is it possible that different models suit benefit from different exposure settings with the same resin? That seems wrong, but the validation matrix text showed clear 'growth' of shapes that should have been smaller and sharper