Lapping & Polishing of case hardened part

Test Requirements: To mirror polish 2 x sectioned components.
Component/Material: Case hardened part
Machine Type: Kemet 24 lapping machine

The parts were supplied with a cut finish and flatness that meant before polishing, the surface must first be lapped to generate a flat and uniform finish.

The parts were put inside a work-holder, placed inside a conditioning ring on the Kemet Iron lapping plate and lapped with 25µ oil based diamond slurry until all the cut marks were removed and the face was perfectly flat. Due to the shape of the parts, there was no additional pressure applied, but if a machine was purchased, we would recommend that additional pressure is applied through a fixture of some sort.

The lapping process took 1 hour. After lapping the parts were placed inside a work holder on an ASFL polishing pad, and the parts were polished until the surface had a mirror like finish. This process took 15 minutes on 1 sample and 30 minutes on the second sample, but again, the polishing time would be significantly reduced by applying additional pressure.

work holding for lapping

This picture shows the component inside a work holder, inside a plastic faced conditioning ring on the polishing pad.

After the polishing, each component had a mirror finish on the originally cut face, one component in particular showing the hardened surface depth clearly down the shaft.

Lapping Process breakdown
Stage Plate/cloth type Abrasive type/grade Process time
1 Lap Kemet Iron 25µ Type O diamond slurry 1 hour*
2 Polish ASFL polishing pad 3µ Type O diamond slurry 15-30 minutes

Case hardened part as supplied

Case hardened part

Case hardened part after lapping

Case hardened part lapped

Case hardened part after polishing

Case hardened part polished