Lapping Aluminium - Case Study

Test Requirements: 1. To lap flat and mirror polish 4 of components: 2 x aluminium and 2 x hardened steel

3. Process breakdown

Parts were run one at a time because of size differences. They were fixtured using a non-slip backed 15” handweight weighing 8 kg. The Total run time for each part is 20 minutes, 10 minutes on each side

4. Results data

Aluminium part : Ra: 0.0.161 µm
Hardened Steel: Ra: 0.0049 µm

After Lapping Aluminium

after Lapping aluminium

After Polishing Aluminium

After polishing aluminium

Customers Criteria: Free from all contamination
Material: Aluminium
Component: Vacuum specimen holder
Contamination prior to cleaning: Aluminum oxide lapping residue

Machines used for lapping Plate Abrasive Time
Kemet 24 Cast-Iron Kemox 0-800s 2 minutes
Machines used for cleaning Cleaning Fluid Temperature(s) Concentration
Kemet 12 Decospray TM 70°C 3%
Kemet 12 De-ionised water 50°C 100%
Versa 120 Dryer N/A 70°C N/A

Process for Lapping & Cleaning Aluminium

Lapping: The parts were placed evenly around the ID of a 24inch conditioning ring. A 24inch weight was then faced using dycem, a non slip membrane used as a temporary fixture. The parts were then lapped for 2 minutes, removed and inspected. Full coverage of kemox on the required face indicates the parts have fully cleaned up and can now be cleaned.

Cleaning: The parts were placed face down in the basket, then submerged in the tank and set for a cycle time of 10 minutes. The parts were then rinsed in deionised water, and manually dunked before being left to settle for 2 minutes. Finally the parts were dried in the hot air dryer for 10 minutes.

Comments: When cleaning, the parts are placed faced down so the soundwaves are directed at the small holes to optimize the efficiency, however the finish created from the lapping is marked by the vibrations. A fixture can be easily made to suit and resolve this. The holes were then inspected under a microscope to check for any lapping residue, no visible signs of contamination.

Before Cleaning Aluminium

before lapping aluminium

After Cleaning & Lapping Aluminium

after lapping aluminium