Did some mechanicals today since my printer is down for repairs. I have had wonky readings when I do my bed leveling and the back left corner is always lower then the other 3 corners. Upon inspection I see that the entire bed is being supported by plastic/nylon spacers, and in the back left corner that plastic spacer is on top of a plastic wire support for the bed heater wires. Ugh plastic on plastic, terrible for a cnc machine.
I have read read reports of people finding the bed screws have come loose, or you can tighten one screw tighter then the others since the plastic has give. Now I understand these are budget machines so let’s clean things up shall we.
First things first, tear it all to pieces, the entire bed plate system, down to the bare plates, screws and nuts. Next up I took the plate and hit it both sides with my orbital sander with some 180 to break any sharp edges and look for high spots. Then I checked it with a machinist straight edge and surprising it was on the straight and level. Next up I had some aluminum spacers made to the specs of the factory spacers. I did not take into account the plastic wire holder so I had to find an additional spacer of about .075.
I drilled a hole to relocated the plastic wire support to get it out from under the bed spacers and got everything all together. In addition, to prevent the screws from possible backing out and coming loose I used both a nut and wave washer on the bottom side of the hold down screw to prevent it from loosening.
Now once I get the printer back up and running I will be able to run a fresh z offset and auto bed level routine and adjust as needed from there. Yes I know its auto bed level but if I know its compensating because the bed is wonky its just going to grind on me so might as well nip it in the bud now and get it as level as possible.
