Lapping Hydraulic Pump - Case Study

Test Requirements: Lap seal face
Component: Danfoss hydraulic pump
Machine Type: Kemet 15” diamond lapping/polishing machine
Lap Plate: Kemet Iron
Abrasive Type/Grade: 14 micron Type K Standard Diamond Slurries

Process Breakdown
Stage Plate/cloth type Abrasive type/grade
Lapping Kemet Iron 14µ Type K Standard Concentration

Process for Lapping Hydraulic Pump

Due to the shape of the part, the staging on the machine had to be removed. Once removed, the part was placed onto the plate allowing the bottom half of the part to hang off (See photo below). Once we had ensured the whole land area was seated on the plate, the part was held in place manually by hand whilst lapping. A suitable fixture will need to be made to automate the process. The part was cleaned with CO42 cleaning fluid then inspected; the drag finish on the part is a result of being in a fixed position and not being able to rotate. Due to the drag finish, we were unable to read an accurate result using the monochromatic light & optical flat. Surface finish (Ra value) after lapping: 0.0270 µm

Before Lapping Hydraulic Pump

Before lapping Hydraulic Pump

After Lapping Hydraulic Pump

After lapping Hydraulic Pump

Positioning of Hydraulic Pump on lapping machine

Positioning of Hydraulic Pump on lapping machine