Linear Bearing Development with Chris

From 3D Printed Linear Bushing

Thu May 4, 2020

1

Chris,

Can you print linear bearings in POM? I'll buy them from you for production printers if you can produce them with documentation on how they are produced but they would have to be lower cost than the current China sources. I'm seeing it's possible to do 10 pieces/hr. I'm aiming for the high T chamber here by the end of the month, and looking into 4-head printing so that we can set up high quality part production.

Marcin

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Hey Marcin!!

Yes I don't see why not! I have not tried to print this material before, but it looks interesting - ordered a spool to come in and I'll let you know how it goes!

For the linear bearings you are thinking this same size that we used before? Or for all sizes 8mm - 3in?

For the D3D, they will need to be low friction but also stiff, I was having issues for some of the axes. Y axis linear bearings worked fine, but the Z axis did not great as they had too much give.

I'm sure we could get price down under import cost - 4grams even with this more expensive material, something like 10 cents each raw material cost. So sale price of $0.50 makes 80% margin, and 6 minutes would make 10/hour, or $4 profit per printer hour -- which is right in the sweet spot!

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Great. I am thinking more like these - https://www.thingiverse.com/search?q=igus&type=things&sort=relevant - since these are more proven. If you can test our open source design and it works for stronger force, that would be good, too.

Ideally, we have one that is your spiral for low force, and one super solid for higher force. So a customizer in OpenSCAD would be a good deal.

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To Joshua Pearce at MTU

Joshua, Maybe this would be interesting to you for a paper: studying practical open source 3D printing of acetal, using a high temp, insulated heated bed and no enclosure?  Problem statement: printers can't do it well. Thermal gradients across a bed are an issue, high T is an issue. Solution: high T, insulated heated bed to minimize gradients. Makes 3D printing of this high performance plastic practical - with a low cost insulated heatbed. The OSE insulated heated bed is the only insulated bed we know of - 2" of rock wool. Do you know any others? Our bed is prime for this experiment, as it's rated for 167C with its PEI from McMaster. Because it's insulated, it addresses the gradient issue. Best I found so far om Acetal - https://wiki.opensourceecology.org/wiki/How_to_Print_With_Acetal

The practical connection here is that the acetal can yield an equivalent to Igus bearings, which are $1 each from China. If we 3d print them, material cost is more like 10 cents using off-the-shelf plastic. So this could be turned to localized production. Implications are high quality linear bearings for 3D printers and larger machines - so we are pursuing this. Collab would be good, such as thermal imagining of the insulated vs un-insulated surface. Marcin