3D printing PEEK Bearing Cages

[AM3D]

Hi,

I am just looking for some information to see if anyone has any experience in using 3D printed PEEK Bearing Cages. we have just had a client that asked us to Print some off so i am wondering if anyone has any experience with this.

 

[tbuelna]

PEEK is a good choice for rolling element bearing retainers in certain applications, due to its strength and temperature capabilities. PEEK retainers are usually precision injection molded. What most people don't realize is that rolling element bearing retainers require fairly tight tolerance control of features like pocket faces, retention tabs, land surfaces, etc. For most applications I don't think a 3D printing process would provide the accuracy necessary "as printed". But you could 3D print a retainer preform and then finish machine any critical surfaces such as pocket faces, which would save some cost for small quantities.

 

[AM3D]

thanks for the advice. Do you have any idea about the tolerances that would be needed? i think our printers get a accuracy of XY 11 μm / Z 2 μm.

 

[AidanMc]

The tolerances would obviously be dependent on the application of the retainer. I'd guess size tolerances in the single thousandth of an inch range. Probably on the low end of that.

When you say that your printers have an accuracy of "XY 11 μm / Z 2 μm" is that the positional accuracy or the actual capability of a printed part? If that is what you can actually hold on a part, then you shouldn't have any real problems with the dimensional tolerances of a retainer.

Aidan McAllister
Metallurgical Engineer

 

[AM3D]

The "XY 11 μm / Z 2 μm" does relates to the positional accuracy of the machine. I think that the accuracy of the parts would be around 30μm.

 

[tbuelna]

AM3D-

You did not mention the type or size of your bearing(s), or the application they will be used for. But here is an example of tolerances used for the critical features of a good quality (ABEC 5) commercial cylindrical roller bearing retainer:
- bearing size (mm): 100 x 140 x 20
- roller size (mm): 12 x 12
- roller qty: 24
- retainer pocket axial clearance (in.): .0076 to .0136
- retainer pocket circumferential clearance (in.): .0046 to .0106
- retainer pocket positional tolerance (in.): .010 @ MMC
- surface roughness of retainer pocket faces and land surfaces: 32 microinch Ra
- retainer land surface diameter tolerance (in.): +/- .004

Below is a picture of a couple different injection molded polymer retainers. You can clearly see the precision features and excellent surface quality. You can also see some very fine features like the retention tabs that might be hard to produce with a 3D printing process.

Hope that helps.