first layer artifacts
Hi everyone,
I'm getting some trouble with the first layer. I tried z axis calibration, even fine tuning in the setting, I still get strange artifacts on the first layer.
I can understand that the extruder is a bit too low on the right side, but I can't understand what the hell are those lines running in the middle of the layer.
As you can see from the second picture after a couple of layers the defect tend to disappear, but it's still visible.
Any help will be GREATLY appreciated, thanks a lot.
Tommaso
Re: first layer artifacts
Z looks a bit low and might be causing the ugly texture near the perimeters. Low Z also makes the tracks wider than they should be, and leads to more of the next problem.
The middle lines are when the slicer decides to work around holes and other "obstacles" in the print area. It'll print one direction for a while, then work around the hole, leaving an unprinted area. It later comes back and fills in the area. The delay allows the existing track to cool so it doesn't weld as well, leaving a thicker artifact. Slowing the print speed may help because it allows the nozzle time to reheat the adjacent track. You can raise the bed temp, too, and that will also help adhesion of large parts when they begin to warp.
Another possible aspect of the thick lines is if the belts are on the loose side and the slack isn't taken up - and you get thin and thick spots depending on nozzle direction. This would show up as other artifacts in the print, too.
Re: first layer artifacts
Thank you very much, I understand now why I had those strange lines.
By the way after posting my request I find out in the forum that the I'm not the only one to have a high bed on the right/front side. The problem is that if I raise the z-axis more than this on the left side I have poor adhesion and it seems it's not possible to correct this even with the fine tuning in the settings.
Anyway thanks a lot for your help!
T.
Re: first layer artifacts
I also have a non-flat bed with high front right - but in my case I refer to it as low back right (the bed power cable weighs that corner down). I managed to adjust it with a 0.016" washer in that corner, and a couple 0.004" washers and filing down one spacer. Then trim everything with manual bed level correction entries. It's not perfect, but got me close enough. Then I read about a user generated firmware that fixes the calibration issue.
I've begun using that firmware: it has a 7x7 point auto-bed-level function. This function measures and adjusts to a full 7x7 point array, which better fits the contours of the spring steel sheet. It does so much better than the factory 3x3 method that uses an odd interpolation algorithm to fill in a 7x7 table.
I'm hoping Prusa adopts the N7 cal procedure in one of their next releases: it is a major improvement over the current method. Until they do, I'll probably stick with what I am using.
ps: in another thread Joan pointed out if the pulley set screws loosen up, the pulleys can wobble and can cause a bit of dither, too.