Comment on PETG damaged plate
dual_sport_dork@lemmy.world 4 days ago
Are you sure you didn’t scrape your nozzle against the plate the whole way? I’m looking at those long diagonal lines there that appear to be travel moves.
You will have to adjust your Z offset every time you print at a different build plate temperature or appreciably different nozzle temperature, because thermal expansion will cause the plate and nozzle to grow in size slightly the hotter they get and that will take up some or in extreme cases all of the gap.
I have a different set of Z offset presets for every material I print with, because the temperatures are all different.
user_6282638282@sopuli.xyz 4 days ago
It’s possible that it was scraping… my printer is in a detached shop and because it was a repeat print, I though it was all good and walked away.
I had some trouble with the printer auto bed-leveling before which would leave the Z-offset too high and I had multiple failed prints due to poor/no adhesion. So I’ve made a habit of doing auto-leveling and then reducing the Z-offset .06mm to .08mm. I last did this with PLA since that’s what I use most. It did not occur to me to do that when changing materials, since I don’t recall it being a problem before… but it’s possible I never did this exact sequence before.
Thanks for confirming.
dual_sport_dork@lemmy.world 4 days ago
I think it’s a sound theory then, that your nozzle scraped the surface off of your build plate. Both the plate and nozzle are now probably roached. On the bright size, nozzles are cheap. The plate, less so.
I have learned not to allow my printer to auto-level with every single print. It’s just as likely as not to get it wrong, and unless you have major league mechanical issues the relationship between your plate and nozzle should not be changing from print to print except when you change temperatures. You should be able to generate one Z offset preset per temperature combination and use it repeatedly until you make some other mechanical change to the printer such as replacing the nozzle or replacing the build plate.
Also watch out for having debris trapped underneath the steel build plate and its magnetic base, which will cause nozzle crash issues. Scraps of black filament are the classic way this happens, since they’re functionally invisible in poor light against the black magnetic surface.
user_6282638282@sopuli.xyz 4 days ago
This is good advice, thank you. The printer did include another nozzle, although I don’t know what size it is. Or even the process for changing it. The plate is double-sided so I have something to work with until a replacement arrives.
I’ll do an auto-level, write down the Z-offset, and then print the leveling test in each material, resetting Z-offset in between, and noting the relative adjustment.
dual_sport_dork@lemmy.world 3 days ago
Note that while people conflate the two and use the terms interchangeably, leveling and setting your Z offset are not necessarily the same thing.
Leveling the bed is a process to ensure that it is square (“trammed,” in many peoples’ parlance) and flat relative to the travel of the print head, preferably at all points on its surface. This may or may not also entail setting your printer’s Z offset as part of the process depending on how its inbuilt process works, or whether or not you so it manually.
Z offset adjustment is ensuring that the starting position for your printer’s nozzle is the correct distance from the build plate on its first layer. It doesn’t necessarily have anything to do with ensuring that this value is the same everywhere across the build plate.
You should make sure your build plate is level relative to the nozzle first, then mess around with Z offset heights. Theoretically you should only have to level the plate once, unless something works itself loose or some other mechanical issue presents itself. Your Z offset, however, should be adjusted between prints every time you switch from materials that require one temperature versus another either on the plate or the nozzle itself.
On my machine, a Qidi X-Max 3 running Klipper, I can directly twiddle the Z offset from the printer’s touch screen while printing, or at any time in the console via the Mainsale interface which is accessible via web browser over the network. I have a test print that’s just a 0.2mm thick rectangle I use to assess the correct-ish Z offset, since I can observe it while it prints and diddle with the Z offset setting as it goes until it looks right to me. Since it’s only 0.2mm tall, the generated print will automatically be only one layer thick. I then use that value going forward for whatever that temperature/material is. My printer has a built in routine that allegedly assists you in setting the Z offset but I’ve found that it’s functionally worthless and also much more of a hassle.
Because I’m lazy, I then created a bunch of Klipper macros that do nothing but set the Z offset to one of my figured out values, one each for each material and also for either side of my plate (textured on one side, smooth on the other). To switch offset values I just hit one of those macros from the list in the Mainsail console and it’s done. That way I don’t have to keep a Post-It note or something around with each temperature/material’s Z offset value, nor remember them.
If you’re switching between a flat and textured plate, or the flat and textured sides of your plate, you’ll also have to make a Z offset adjustment. Your nozzle has to be closer to the plate on the textured side to ensure the extruded material makes it all the way down into the valleys in the textured surface. If your printer has a bed probe it will only sense the very top of the textured surface, which probably has a depth of 0.15mm or more all by itself which is nearly the entire thickness of a print layer to begin with.