Adjust Z at different layers
I have only been printing for a few weeks now and learning a lot. My printer is the MK3s.
Some designs I am experimenting with require 3-5mm of solid layers at the base of the model. Printing with PETG, I can barely make it to 1mm then the nozzle starts to push into the previous layer. It seems the PETG material is expanding in the Z axis as each layer is put down. Possible since each is a solid layer, the material flows on the Z axis as there is no room to push out on the X/Y axis'? Note I set the flow to 112% with infill perimeter overlap at 5%.
An idea I am currently look at, is to adjust the Z at each, or every other, layer. I am printing at a layer height of 0.05 with the first layer at 0.2. After the fourth layer I want to adjust the live Z by +0.02 at each new layer. So print as though the layer is 0.05, but move the Z axis by +0.07.
If I add a G92 Z-0.02 command in to each Before_Layer_Change section in the Gcode, would this accomplish what I am looking for? What I do not know is, does the G92 Z command reference the live Z when printing or does it reference the absolute Z from the axis calibration?
RE: Adjust Z at different layers
Why are you pushing flow up to 112 percent?
that would lead to over extrusion, which seems to be what you are complaining about?
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RE: Adjust Z at different layers
@joantabb
Yes, that is the plan. Pushing extra to push out air and fill gaps. Still playing with flow percentage. Issue is the excess cannot go out the X/Y direction very far, so it it building up. I need a way to dynamically adjust Z as the layers build. No issue if I stay under 0.7mm build height and keep walls that build on the base less than 1mm thick.
RE: Adjust Z at different layers
[...] that is the plan. Pushing extra to push out air and fill gaps. Still playing with flow percentage. Issue is the excess cannot go out the X/Y direction very far, so it it building up.
If there is excess, you are printing at more than 100% infill. The more you exceed 100% infill, the more it will build up.
I need a way to dynamically adjust Z as the layers build. No issue if I stay under 0.7mm build height and keep walls that build on the base less than 1mm thick.
Do you mean adjust Z independent of the slicer's understanding of Z? Otherwise, the slicer is just going to calculate additional material to fill in the selected layer height.
You could try doing some funky adjustments under Printer Settings->Custom G-code->Before layer change G-code to bump Z up and reset the position at selected layers -- essentially lie to the slicer -- to do this, but I wouldn't expect happy results.
RE: Adjust Z at different layers
@bobstro
Learning process. Yes, I want to adjust Z outside of the slicer calculations. Not able to do it in the slicer as that applies the Before layer change and after layer change to every layer. I want to adjust the Z around layer 5-7 and adjust for a few layers after then no adjustment for another 10 layers. Once I can do this, I will play around with which layers the adjust applies too based on the material and flow.
Just now looking into usage of the IF statement in Gcode. If I can build statements that reference the current layer number (layer=5) then I could do it in the slicer. Will keep looking into this direction. Thanks for the insight.
RE: Adjust Z at different layers
You can use conditions in PrusaSlicer for either layer height (in mm) or layer number.
The M221 gcode command can be used to adjust flow on the fly.
I wouldn't get my hopes up too much, but it's an interesting experiment.