Engineering plastic linear bearings?

I've read a number of criticisms of the various linear bearings used for 3D printers and am wondering if engineering plastics may not be a better alternative.

As the rails the bearings travel over are (or should be) very smooth, wear should be very low. These plastics don't need lubrication and have long life.

I appreciate these links are both from a single manufacturer but they certainly make a case for plastic bearings:
[www.youtube.com]
[www.igus.com]

Has this been tried? I've searched for references to it in these forums and other places but haven't seen anything definitive.

Richard

Lulzbot taz printers use them.

They've been tried. Search the forum for igus or drylin. Sometimes they are referred to as being bushings instead of bearings as well.

It comes down to cost. A standard LM8UU bearing is 1/10th the price of a Igus Drylin bearing.

Thanks, both.

I'll search for that.

Richard

Don't forget (or underestimate) printed bearings!

I've been printing some for testing. I currently run them on my X and Z axis on my Prusa i3.

I attempted to use them on the Y but it is very difficult to print them to such high tolerance that they fit the rod without having play. Because the arrangement of my bed has 3 slots for bearings, and the arrangement of the belt down the middle, you end up with a problem where the "triangle" of bearings attempts to rotate amongst the invisible axis that the centered belt creates.




My analysis may be incorrect, but based on observation, if the three bearings have play in them, the bed will wobble.

You can print bearings using Nylon or Delrin if you can find Delrin filament. Ultimately, I had to sort through my 2 dozen steal LM8UU bearings I have to find the best fitting three for the bed.

Quote
cdru
They've been tried. Search the forum for igus or drylin. Sometimes they are referred to as being bushings instead of bearings as well.

It comes down to cost. A standard LM8UU bearing is 1/10th the price of a Igus Drylin bearing.

I think an order of magnitude is overstating it a bit, but there's no question that the igus bearings are more expensive. They are much more expensive than cheap Chinese bearings, but they are manufactured to much higher tolerances. One of the main problems with the igus bearings is that there outer dimensions are slightly larger than lm8uus, requiring a change to the standard carriage parts. If anybody's interested, I've got a set of prusa i3 designs of modified to take the igus bearings I can post to thingiverse (I'll probably do this anyway, but if there's any interest it'll motivate me to get off my lazy butt and do it sooner).

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