Mix

In the first production step, the powdered raw materials are mixed in the desired composition. Powders of pure metals as well as powders of alloys are used as the base powder. Solid lubricants can be mixed into the metal powder.

Press

In the second stage, the parts are pressed in purposely manufactured tools. The space filling or porosity can be varied by selecting the pressing pressure, which is mainly in the range of 200-600 N/m2 (2-6 t/cm2).

Sintering

The pressed parts are given the necessary strength in a subsequent sintering process – a heat treatment under protective gas controlled by temperature and time. This is carried out slightly below the melting temperature of the main alloy component. The metallic structure of the material is created through diffusion and recrystallization processes, without changing the shape of the part.

Calibrate

After sintering, the bearings are calibrated in a second pressing process to achieve the required dimensional accuracy and surface quality. In the case of spherical bearings, calibration also serves to create the final shape of the spherical bearing.

Lubricant impregnation

After calibration, the bearings are carefully cleaned and then impregnated with lubricant under vacuum.

Structure

The microstructure of a sintered plain bearing shows a metallic framework in which the original powder particles are no longer visible. The pore space (black) is used to absorb the lubricant.