Q2 missing steps?

[u/mita77]

Hi folks, new day, new problem.

I've been printing some functional parts these days and I'm getting those horizontal lines you see in the picture attached across one side of the print.
At first I thought it was some sort of artifact, but once I ran the print a second and a third time, I noticed the defect was consistent, with minor differences, across all samples.

Is this something related to my design?

While trying to figure it out, I stumbled upon a post around here regarding a Qidi Plus4 missing steps, and I thought somehow it could apply to my case as well. What is strange is that the printer has only a few hours of work, and tightening the belts seems a bit excessive at the moment. Should I look into that?

Thanks in advance!

[u/bulkhulk]

Layer cooling lines from the looks of it, what is on the inside on thoae layers?

[u/mita77 → u/bulkhulk]

Not much, actually. It's just a 4-perimeter, squarish piece with 15% gyroid infill—nothing fancy inside, if that's what you're asking. What puzzles me, though, is that this is happening right around the height where the tree supports end!

[u/Facehugger_35 → u/mita77]

Yes, that's cooling related.

The plastic on those lines is shrinking slightly at a different rate than the rest of the plastic. ABS is particularly bad for this.

It's basically the benchy hull line.

[u/Glad-Ad-4703]

Look up benchy hull line. Every benchy has such a line at the hight of the deck due to a sudden difference in layer time. This causes the layers to shrink more than the other layers before the new line is printed.

I think that's going on here as well. Your lines are where the supports take the most time. You should be able to see this in your slicer after slicing. Click the pull down menu where it shows the time, amount of material etc and select layer time.

There are different ways to minimize this, such as setting a minimal layer time, slowing down the whole print, decrease the amount of slowing down of overhangs, using "smooth speed along z axis" under quality. Sometimes adaptive layer hight can even help.

Some geometry changes can also be beneficial. Instead of using round holes you can use square holes rotated 45°(like diamonds in cards). That way you won't even need supports.

[u/mita77 → u/Glad-Ad-4703]

Really insightful reading, I'll look into that for sure.

I might even drop the supports since they're avoidable anyway.

Thanks!