TAZ Very loose Solid rod bearings?

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1013
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TAZ Very loose Solid rod bearings?

Post by 1013 » Mon Jun 10, 2013 8:37 am

I was just going over the TAZ we recently got, and noticed that the rod bearings were very loose on the rod. It seemed like I could slip a piece of paper in between the rod and bearing on one side. I specifically noticed this on the X-carriage. you could easilly wobble the carriage.

I know there has to be some room for sliding but this seemed excessive. Anyone else notice this? Perhaps a loose batch of bushings are out there?

It has been printing, but I doubt 0.1mm "print tolerance" accuracy is possible (like the specs call out for).

I'll see if I can measure the gap somehow.

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Orias
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Re: TAZ Very loose Solid rod bearings?

Post by Orias » Mon Jun 10, 2013 11:27 am

Here's an improved double bearing holder, with some modifications to help retain the bearings: http://devel.lulzbot.com/TAZ/test_parts ... er-2.0.stl. If you're unable to print the bearing holders send an email to support@LulzBot.com and we'll do what we can to help.

1013
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Re: TAZ Very loose Solid rod bearings?

Post by 1013 » Mon Jun 10, 2013 12:02 pm

The machine came with the double bearing holder.


It's not the holder that is loose....its the white plastic BEARING itself.

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Orias
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Re: TAZ Very loose Solid rod bearings?

Post by Orias » Mon Jun 10, 2013 12:50 pm

Is the gap between the smooth rod and the bearing or the bearing and the bearing holder? If it's between the bearing and the bearing holder the new linked model should help.

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Re: TAZ Very loose Solid rod bearings?

Post by 1013 » Mon Jun 10, 2013 1:30 pm

Bearing and smooth rod. They all seem to be loose.

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Orias
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Re: TAZ Very loose Solid rod bearings?

Post by Orias » Mon Jun 10, 2013 2:59 pm

I've asked one of the guys in the fleet if they've seen something similar, They've noticed a little bit of play but it hasn't affected the print quality. We'll keep an eye on it and see how it proceeds. How much of a gap have you noticed? Is it measurable?

1013
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Re: TAZ Very loose Solid rod bearings?

Post by 1013 » Tue Jun 11, 2013 6:26 am

I just measured 0.3mm of "slop" on one of the bearings in the X-carriage....but if all of them are like this, that will quickly add up.
Attachments
0611130826c.jpg
I am pulling the carriage slightly "forward" (away from the smooth rod) with my thumb.
0611130826a.jpg
Here it is zeroed.

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Orias
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Re: TAZ Very loose Solid rod bearings?

Post by Orias » Tue Jun 11, 2013 10:19 am

We've looked into the tolerances on the bearings, they are listed as: 0,032-0,075mm. We've worked with tighter IGUS bearings in the past and found that they've led to binding from too much friction. We haven't seen a reduction in print quality in the 8 TAZ we are running in the fleet in comparison to the prints ran on the AO-101. It's something we're keeping an eye on in the meantime.

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Re: TAZ Very loose Solid rod bearings?

Post by 1013 » Tue Jun 11, 2013 10:40 am

These bearings are clearly 3 times the tolerance specs you mention.
Can I get replacement bearings under warranty? Who do I call?

I can check the other bearings, but they also have a noticeable gap.

FYI, The rod measures 9.98mm

Are there higher precision ball bearings available?

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Orias
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Re: TAZ Very loose Solid rod bearings?

Post by Orias » Tue Jun 11, 2013 11:19 am

If you don't mind you can open a ticket by emailing Support@LulzBot.com, It'll be the easiest way to get in touch with us.

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