Hi everyone,
Thanks for letting me be part of your forum.
I could use some help. The Ender 3 V2 I got from 3DPC keeps intermittently homing 0.5mm higher or lower than it should. I’ve been printing for a couple of years and have a few printers, so I know how to level a bed - but it always seems to start the print too high, then I level again, trying to get it to start at the “new normal” and it goes back and grinds across the buildplate. Then, I level again and goes back the other way. I use the z-offset to fix it every single time and it’s driving me nuts.
I don’t think the z-rod isn’t slipping because it’s really tight. Although, when it kicks in sometimes there is a distinct “chonk” where the gantry releases some tension somewhere.
Thoughts? 3D printing is actually an income source for my family and having one printer down becomes a problem during busy times. (I have an Ender 3 Pro and Ender 5 Pro and they work amazingly well)
Your Z axis rod might be to tight and hanging up, the Clunk noise could be it dropping free and catching up to the position the steeper was tying to move it to. Also check the z axis limit switch and make sure it is fastened tight in place, if it is loose then it can move around and affect your z offset.
HI, @Als3DPrinter Welcome to the forum, Truly glad you found us.
I have seen this on a couple of machines and I have found a couple of different solutions. I will go through them in order of commonality.
Loose Brass nut on the Z-axis leadscrew, In shipping these screws often come loose so just give them a double check to ensure they are snug.
Z motor out of alignment with the above-mentioned Brass nut, after completing step 1 loosen the 2 screws slightly that mount the motor, give it a little shake to ensure it’s loose but is not going to fall out on you. Move the Z-axis to its Maxima, (top) and then home the printer so the gantry comes all the way to the bottom. Carefully tighten up the 2 screws that mount the motor without changing its position. Now you should be able to move the Z-axis up and down without any fear of binding.
Bedsprings, I personally try to keep my bed as close as I can to the Y-axis frame, I tighten all the 4 knobs down as far as they will go then home the printer, You will be left with a fairly large gap between the nozzle tip and the bed, Let’s say for example this distance is 10 mm just for explanation sake. The next step is to move the Z-axis limit switch down about 6 or 7mm. and home the printer again, Keep adjusting the location of the LImit switch until the nozzle stops about 2-3 mm above the build surface. Once you are able to do this repeatability then unscrew the bed knobs to bring it up to the nozzle using the “paper Leveling” process for your printer. This way the springs are always under the max amount of tension and are able to keep height more accurately.
If you are not able to get your printer to stop 2-3mm above the bed a couple of times in a row without changing anything else it may be the limit switch itself is bad, That is a warrantable item and will be covered.
I know this one is going to sound weird but I have seen it… Check your hotbed and gantry cable routing. make sure they are routed outside the frame of the printer and that every time the bed moves to the back the cable itself is not unscrewing the bed knob. And yes I kid you not this has happened, on more than 1 printer. If one of our customers reads this that it happened to believe me you are not the only one.
Let us know if this gets you straightened out. One of these solutions should get it fixed up.