09-18-2020, 02:30 PM
I have a Mars that is relatively new to me. As each layer prints, it is offset toward the rear of the machine on each layer. I believe this is related to the drive screw being tilted relative to the base. I've loosened the two small hex-head bolts and attempted to realign screw but it seems to shift back once re-tightened. The first picture shows two parts printed: the one closest to the granite block is after "realignment" while the other was printed prior to thinking this was a problem. They are essentially the same.
I have pictures of a right angle along the drive screw which is a bit exaggerated since the right angle needs to be pressed down at the lower corner since it tilts into the recess. The second one uses the right angle with the ruler to bridge the vat recess. It will rock if held against the drive screw versus the base. I've used my height gage to estimate how much the difference is about 6.5-7.0 inches out from the screw. The display is in inches so if the right angle is held against the screw it raises about 0.009 inches out at the 6.5-7.0 inch distance.
It is difficult to measure the total amount of displacement but it appears to shift 0.9 mm in 138 layers or 0.0065 mm/layer. This is a very small amount so I'm not sure how successfully I can align the system to remove it. If somebody has a method they've used, I'd be interested in learning it.
Additionally there is a thickness difference of about 0.5 mm from the thin edge to the thick edge on these samples. In the past I printed a similar block slightly shorter but the same width and it didn't seem to show the same amount of drift or thickness difference. The stl file was from a different program and the FEP film was replaced. I reset the zero before every print, so I don't think it is a misalignment between the print platten and base.
Is there a known issue in Chitubox that can introduce such a step in each print layer?
I've run an exposure test and the defaults for the Elegoo seem fine for their resin (grey).
I plan to make some structures that are taller to get some more accurate measurements but won't be able to print them for a couple of days. I should mention that the test ROOKs seemed to print fine. Unfortunately the base of the Rook was slightly bowed after curing so it rocks on the granite flat and I can't really measure it to see if there is a vertical drift in it.
I have pictures of a right angle along the drive screw which is a bit exaggerated since the right angle needs to be pressed down at the lower corner since it tilts into the recess. The second one uses the right angle with the ruler to bridge the vat recess. It will rock if held against the drive screw versus the base. I've used my height gage to estimate how much the difference is about 6.5-7.0 inches out from the screw. The display is in inches so if the right angle is held against the screw it raises about 0.009 inches out at the 6.5-7.0 inch distance.
It is difficult to measure the total amount of displacement but it appears to shift 0.9 mm in 138 layers or 0.0065 mm/layer. This is a very small amount so I'm not sure how successfully I can align the system to remove it. If somebody has a method they've used, I'd be interested in learning it.
Additionally there is a thickness difference of about 0.5 mm from the thin edge to the thick edge on these samples. In the past I printed a similar block slightly shorter but the same width and it didn't seem to show the same amount of drift or thickness difference. The stl file was from a different program and the FEP film was replaced. I reset the zero before every print, so I don't think it is a misalignment between the print platten and base.
Is there a known issue in Chitubox that can introduce such a step in each print layer?
I've run an exposure test and the defaults for the Elegoo seem fine for their resin (grey).
I plan to make some structures that are taller to get some more accurate measurements but won't be able to print them for a couple of days. I should mention that the test ROOKs seemed to print fine. Unfortunately the base of the Rook was slightly bowed after curing so it rocks on the granite flat and I can't really measure it to see if there is a vertical drift in it.