I’m having a problem where, across all filaments and print settings tried, the nozzle is rubbing against the build plate when printing the first layer. It causes ridges in the first layer, and horrible grinding noises when printing the next few layers. It also causes excessive elephant’s foot, and excessively strong bed adhesion with PETG, and continual false “nozzle covered with filament” errors. It coincides with having to generally raise nozzle temperatures 5-10°. All these symptoms started after I disassembled and reassembled the toolhead (without replacing or changing any parts), which seems like a strong hint that the problem is mechanical in nature.
With this information, is there any chance of pinpointing the problem? Like, is there a toolhead reassembly error that would cause the bed levelling to consistently detect too low at every point?
- Printer model used
A1 with 0.4mm stainless nozzle, textured PEI plate for PLA or PETG, blue tape plate for TPU
- Slicer settings used
Many (slicer settings have almost no effect)
- Type of filament used
Bambu PLA Basic, Elegoo PLA Plus, Bambu PETG HF, Elegoo TPU 95A, Siraya Tech TPU 85A
- Photos that clearly show the problem
Typical appearance of 1st layer (Bambu PLA Basic shown)
I am having the same issue. Thanks for bringing it up.
I have a theory, though I can’t prove it: The nozzle has a slight amount of vertical play, and it may get pushed higher in its holder during bed leveling, and then pushed down by extruder pressure early in the bottom layer (maybe at the first deretract?)
I read in another thread here that you can manually slide a piece of paper under the nozzle during bed leveling as a workaround. I wouldn’t consider that a solution, but it’s good enough that I can continue my design work.
I also learned that you’re supposed to periodically take the nozzle off and clean the heating element behind it. My heating element was corroding, which is probably why I’ve had to turn the temps up. I scratched off the corrosion with steel tweezers, which we’ll see whether or not was smart. (At least I know I can replace the whole toolhead if worst comes to worst.)
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The heating element and thermistor are located behind the hotend which is in one plastic unit held on by 3 screws. Behind that are some smaller screws. This is a common fault with the A1. You can try tighten the smaller screws as this sometimes resolves the bad first layer issue. I’ve had to replace that whole unit on 2 of my A1’s
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Sounds reasonable. I will investigate.
I have not done much PM on this A1 but it looks like I really need to. It has been such a dependable beast that I thought it may go on forever. You know the story, if it ain’t broke, don’t fix it.
Thanks GuyH77 for the advice.
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Totally. Shows how far we’ve come when it’s not every day you have to tinker with a printer
When I had this issue it was due to the nozzle not being properly seated, so the downward pressure of extrusion pushed the nozzle down.
did this work i am having the same issue currently
Thanks for the explanation, GuyH77. On my unit I overtorqued one of those screws and stripped the plastic, and that’s probably the root cause if I had to guess. Machine screws driven into plastic are set up to fail and require extreme care.
Reverse_Oreo, the piece of paper technique is working well for me. It provides a repeatable offset of .1 mm with printer paper, or .05 mm with tracing paper. I just had to figure out what paper to use for each type of bill plate, and now I’m getting print results as good as when the printer was new.
I feel you pain on the stripped screw holes in plastic. The parts are not very expensive so I replaced those that were defective. The nozzle no longer drags on the plate.
Why not changing the z-Offset in the starting G-Code to 0.05mm or 0,01mm? You will find a command for the PEI builtplate a -0.02mm. Just as a first aid solution…
i’ve already said this before in another thread but make sure your heating assembly (the remove-y nozzle-y portion with the heatsink) is installed correctly and re-run the calibration if you do find you latched it on incorrectly.
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Loose screws anywhere on that head assembly will cause issues. But, be careful, you don’t over tighten them, or they will strip out. When the printer checks for bed leveling and something is even a tiny bit loose, the z axis comes down closer to the bed than if everything was snug and did not move. When the printer comes around to print, it uses that reference when it checked at bed leveling and drags the nozzle. When you install the nozzle, make sure the whole area is clean, especially where the nozzle mates with the heater. Before you fold the clamp over the nozzle, push the nozzle toward the heater and slide it up to be sure it is seated and snugged against the stops, then pull the clamp over the nozzle.
I finally found the problem: The four screws on the back of the heater assembly were loose. I couldn’t find this until one of them fell out during a print. I tightened all four and the problem went away.
Thank God (literally) that this screw gave away the problem! I had already removed and reinstalled the heater multiple times without spotting the issue.
I ruined a plate with this issue. With the A1, if you can’t close the clasps with zero effort, the nozzle is not seated properly. It has to pushed UP and IN and it should have no vertical play. The clasps should close effortlessly.
Your theory was absolutely correct — the slight nozzle movement during leveling checks was indeed the root cause of my problem. While troubleshooting, I also tried the suggestion of putting a piece of paper under the nozzle during leveling, which worked great and helped avoid those nasty first layers. Thank you for sharing that tip — it saved me a lot of frustration.
At first, I checked my hotend and everything seemed tight, but I decided to buy a new one just to be sure. While installing it, I noticed that the two screws marked as 3 and 4 in the image (attached) would not tighten properly. Even after replacing the entire extruder unit, these screws still wouldn’t tighten up, and the issue persisted.
Eventually, I replaced these two screws with slightly larger screws, which then tightened up perfectly. After this change, my printer is now running flawlessly and producing first layers like new.
I would strongly recommend everyone to check these screws regularly (perhaps once a month) as part of routine maintenance — it can prevent many headaches and ensure consistent print quality.
Thanks again for helping me (and surely many others) identify and resolve this issue!
As an additional tool, you can also manually level the bed:
This -really- shouldn’t be done unless you’ve replaced the heat bed.
I have to replace the one on my A1 mini (person i was letting use it kept putting a soaking-wet build plate onto it that also had 99% iso sprayed on it and so over time the steam and alcohol trapped under it ended up peeling away the upper surface) so I’ll be going through this very soon but unless your bed is damaged you really
𝙧𝙚𝙖𝙡𝙡𝙮
shouldn’t be messing with that. the average person can actually make problems worse if they’re not careful.
I would agree, however, if all else fails and you’re going to destroy a nozzle and/or build plate because of scraping then desperate means. Probably more for an experienced user unless directed to by support.
