Super stiff axis - where to start on diagnosis

[vectorzero 0]

Hi

I've just received my new UM2 and after a couple of hours it started to make a screeching noise.

Moving the head by hand reveals that the head binds on one axis around the mid point.

 

Can an expert out there tell me if this is just a question of a pulley adjustment or is it something else like a bent rod?

I've very lightly lubricated all the axes, but the issue did not go away.

Thanks

Neil

[Labern 724]

I would think it's the shaft of the linear bearing.

You could loosen the 4 thumb screws the holds the hot end assembly together and push the bearing on its own to see if that's the issue. Or alternatively you could loosen the grubscrews on the pulleys for that axis, move it and test then try then tighten 1 at a time is its moving freely till you find the problem pulley.

Make sure none of the shafts has moved sideways and is rubbing on the side of the machine.

[gr5 1,108]

I had a similar sound and feel and it turned out that the belt had hopped one "gear step" on one side but not the other such that the two rods were not perpendicular anymore. I fixed it by loosening 2 of the pulleys on one belt and pushing the head to one side until both blocks hit the end then recentering and then retightening the pulleys. Tighten the hell out of those pulleys! The allen wrench should twist slightly.

Also add a drop of oil to each of those rods plus the other rods in the outer walls. Any ordinary petroleum based light oil is fine but not wd40 which has lots of cleaning additives. Sewing machine oil, 3-in-1 oil, just ordinary oil. Not vegetable oil.

[IRobertI 434]

Also take a look at the left side of the printer. You should see the cutout which the pulley of the left stepper motor sticks into. Does it look like it's in contact with the wall? If that's the case you need to remove the stepper, loosen the set screw of the pulley and move it in towards the motor ever so slightly. You want it really close, but not touching.

[vectorzero 0]

Just to close off this thread, the issue in the end was simply that the printer was out of alignment. I got excellent (and patient) support from the Ultimaker team.

I got a local firm to print off a pair of these.

I realigned the axes by slackening off the appropriate pulleys, and then retightening.

Its been working perfectly since.