Grooves in bottom x axis bar
I am taking apart my x axis tonight in anticipation of the new bearings coming tomorrow to hopefully fix the horrible squealing I was getting from my first few prints. I have only printed 3 small things so far. Taking it apart I felt something rough on the bar and looking closer it appears the four rows of bearings on the bottom bar have scored my rod pretty nicely. Not sure if the bearings seized up and gouged it or what but before I assembled it it was fine.
I have some of the drylin bearings coming tomorrow so I guess I need a suggestion of a place to get a new rod fairly quickly since I doubt I can use these new bearings on a damaged rod.
Any idea what would cause this to happen?
Re: Grooves in bottom x axis bar
Mine are scratched too. Maybe we had to oil them a bit. Check that the rods are well fit into the holes and LOOSEN the 2 hex screws on the right of the right X carriage part - if you have a digital multimeter, use the continuity test between the hex driver and the rod, and stop tightening as soon as you hear the beep. This is particularly important when you'll use igus bearings, they'll bind like hell if you overtighten those screws.
It's not really a big problem to use drylin bearings on a scratched rod, but you can replace them with igus AWMP-08 aluminium ones. DON'T use those with ball bearings.
Re: Grooves in bottom x axis bar
Ideally, the anti-rusting oil coating applied on the bearings by the manufacturer should be removed before use.
Whether you then re-apply a lubricant before assembly is down to the environment in which you print - if it is quite dusty (as mine is) then lubricating the bearings works for a while and then becomes very destructive.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Grooves in bottom x axis bar
Loosen those two screws on the end of the xaxis part? The ones that look like they push against the rods? Can you explain why that would effect the bearings? I assumed that was just to put tension on the rods so they don't slip back and forth.
PJR, how can you remove the oil coatings on the stock bearings? I still have the 4 in the Z axis that sound fine and move smoothly that I'm leaving in. While I have it disassembled again I can work on them to prevent them from doing the same.
Re: Grooves in bottom x axis bar
Soak the bearings in IPA.
The screws at the right side of the X axis; it too tight they will cause the X and Z axes to twist.
I believe they are there simply to relieve the pressure on the printed X bearing holder and so must be set to only just do that.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Grooves in bottom x axis bar
Loosen those two screws on the end of the xaxis part? The ones that look like they push against the rods? Can you explain why that would effect the bearings? I assumed that was just to put tension on the rods so they don't slip back and forth.
They may cause the rods to twist/bend a little. I was surprised to discover how easy is to reproduce a X carriage bind by just overtightening one of those screws a bit when using IGUS bearings (which have less tolerance than stock bearings). My idea is that doing the same with metal ball bearings would cause scratches on the rods. At least, mine were overtightened (my fault), and i have scratched rods. Once the damage is done, you may slightly rotate the rods.