Fix nozzle scraping

In August 2023, I get this problem occasionally on infill where the nozzle scrapes the top of the supports. This can lead to print failures when the supports get damaged.

On Reddit, user Several-Ice-6605 said in September 2022:

Just a side note as I have noticed tons of posts on the internet regarding nozzle dragging on infill, or more appropriately only on infill.

If you calibrate your flow rate, check your e-steps and adjust accordingly, and are certain your bed is as level as you can get it, then you need to look at your systems build, i.e. your gantry is square, your rollers are adjusted right, your belts are aligned, and that your hot end on the X axis is secure and has no movement on its Z axis tilting forward or back, or on the x axis no counter or clockwise rotation it should be rock solid.

IF you have checked all of the above, then it's your slicer settings 100%. You have something set to comb. You turning on Z hop for an issue that should NOT exist if the above is true, does not "fix" the issue, its just a workaround.

My suggestion if you cannot figure it out, is to use a default profile to make sure you are running on bare slicer settings, then go though them and only change the following variables: Temp, bed temp for the filament, your print speed appropriate to your printer, retraction settings, flow rate.

Then do a test print that normally causes your nozzle to run across infill and cause the printer to vibrate and make noise (note this is only if does it on infill only). The reason I bring this up is if it's a hardware problem with something out of alignment physically, it will indiscriminately scrape across everything the entire print.

If it's just infill then most likely only one of a handful of slicer settings causing it, and the most likely setting is combing is turned on, and some other setting that works along side of combing is contributing to the issues. So reset your profile to default, set only your specific variables and do a test print with combing off. If you go and play with infill settings like reducing infill flow but nothing else, then you should think about what you are doing. If flow is fine for walls and floors and roofs then why would it be off for infill only? I see so many posts like this and I never see anyone suggesting not to use combing.

Personally I had a printer that had some stuff that was loose, I checked it, swapped out a roller that actually was bad, fixed an x axis gantry issue with both lead screws being misaligned, and after all that. The problem persisted. There was no physical reason to keep doing it, I went back to the software, and found combing was still on….. Doing what its supposed to do though but not at speed and not full time. =)

So if you account for the above, check the settings its in there =) do not adjust stuff that may reduce the issue or "skip" it thinking its solved as it introduces other issues. Like extending print times to move the head up and down etc.