I'm using an Elegoo Mars 3 printer. For some reason, all of my prints are now getting these deep ridges. each layer I can hear it peel away from the vat before it lowers again for the next layer.

I've tried various exposure times as well as different approaches to supports.

Resin 3D printed model with deep ridges

  • $\begingroup$ that'S really hard to see, but I guess you mean the ripple pattern in the horizontal? how old is the resin un the vat? As in: has it been opened a long time? I have a gut feeling that possibly there is something wrong with the model bending in some way when returning to position, and that might be either a printer or a resin having degraded. $\endgroup$
    – Trish
    Mar 4 at 10:59

1 Answer 1


Open Resins degrade

If photopolymer resin is sitting open a long time, its curing behavior can degrade. One of the effects of degrading resin is, that it might not harden to the same point in the same time, requiring either longer exposure or not curing to hardness at all.

This can lead to the prints staying somewhat flexible when they get peeled off the sheet, and when they get pushed back into the print position, that can lead to the print having a misalignment in one direction. As the next layer is added, peeled and repositioned, this might very well result in the "banding" pattern in layers all orthogonal to Z.

That this is a systemical error that happens everywhere in the vat you can notice at the support structure: it shows the same banding.


You might want to toss that resin, or at least add some virgin resin to it, so it can get refreshened.

As a general rule of thumb, it is not advisable to leave resin and vats out in the light for any prolonged time and if you don't print for several days, it is best practice to drain the Vats and store the resin in light-tight bottles.


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