Heated Bed Upgrade: New Bearings make 'crunching' noise

[fluxline 0]

Just working on installing the heated bed upgrade, well done kit so far.

I have just one issue. When aligning the bearings and sliding the platform up and down during the bolt tightening, I notice a crunching noise coming from both bearings when the bed is move down, not when moved up though. I was careful when putting on the rods so I don't think any of the balls in the bearings were damaged.

Has anybody else had the same or know what I might of missed?

Thanks

 

[jonnybischof 60]

It sounds like some misalignment between the shafts and the bearings (usually incorrect spacing, or something might be twisted).

I'm dealing with the same problem on my UM build, but I'm using four bearings which seems to make four times the trouble :(

 

[fluxline 0]

Thanks Jon.

pulled it apart again to check bearings and nothing seems wrong. i checked the rods with the original bearings and they were 'smoother', but that could just be wear.

put it all back and still the same. when letting the bed go, it does go back to the bottom on it's on (with some sticking points) so unless somebody else comes back with other info, I'm just going to call it inside ball bearing movement for now and see what happens.

thx again

 

[gr5 2,269]

it does go back to the bottom on it's on

 

*own

That's normal. I think I heard some crunch while printing sometimes also. It's a bit scary. No problems printing so far though.

 

[jonnybischof 60]

Maybe your Z-shafts are bent?

I've seen some Ultimaker shafts that were anything but straight...

That would explain the uneven friction across the z-length.

Btw, I've gotten smoother and quieter movement on my current buildm now that I've corrected the spacing. It's still rather loud, but doesn't hurt to listen to it anymore...

 

[fluxline 0]

shouldn't be bent, checked em when first installed with a micro-flat bench. with it completely installed though, it doesn't float down to the bottom when powered off. i think people have it both ways, some units, or people assembling them, are just a bit more square.

thx for the posts