Machining sintered bushing

[freddyolen]

We are using a sintered bushing as a bearing. (1 bushing at each sides of the application)
Bushings are not impregnated with oil but oil is fed through the axle and the hydrodynamic film is built-up.

But the bushing need to be machined to reach the press-fit.
Now we have problems with the bearing capacities.

Is it wise to use sintered bushing for this application?
What happens when you machine a sintered bushing , do you fill the porosities with debrie so oil can't get in anymore

Does anyone know some literature about the use of these sintered materials as a bushing and the pro and cons?

 

[unclesyd]

I assume you are asking about a bronze material.
Machining a bronze material is no problem if you use sharp tools.
We machine both the impregnated and non-impregnated materials all time. Some will say not to use a reamer though we have never had any problems when reaming with a sharp reamer. We also broach some bearings, especially the smaller sizes. We have also burnished and ballized some bearings with no problems.

As you are using forced lubrication the closing of surface porosity is not that much concern. In fact one might look at the use of solid bushing.

To get an idea of the clearances and tolerances check out the following.

http://www.beemerprecision.com

http://www.buntingbearings.com/home.htm

 

[plasgears]

Sintered bushings are routinely precision ID sized at the mfr. Machining porous bushings is OK for prototype only. It also defeats the principle of "sintered and ready to use."

Oil feed thru a porous bearing is enhanced by holes and grooves. Without these measures you have a porous bearing acting as a filter, which will fill up with fine debris.