Microfinishing Yesterday-Today and Tomorrow from Micron to Nano and Ångström

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The Double Wheel Lapping Technique

In the middle of the 20th century, when the double wheel lapping technique
had its first success and Hahn & Kolb already used bound grit wheels, the
research for low wear tools and working wheels began.

Inserting diamond honing strips into the grooves of cast iron wheels gave the first positive results. The reinforced double wheel machines in C-execution (DLM 750/1985) and the cooperation with diamond wheel manufacturers (Diametal) brought the first big successes.

Soon, other manufacturers started as well to build this type of machine and the proper breakthrough was realized when working wheels made from synthetic material, ceramic-bound diamond and CBN were used in order to have a wheel perfectly adapted to the corresponding work piece material.

The double sided flathoning of ceramic control discs used in mixing faucets is exemplary. The obtained stock removal of up to 0.8 mm in less than 30
seconds for loads of 200 pcs, Ø 35 x 5mm, was revolutionary to everyone.
Furthermore, the results of tolerance in thickness, flatness and roughness were so excellent, that only little polishing time was needed to obtain the required final quality (picture 4).

Picture 4
Flathoned ceramic discs
Sealing surface polished to Ra 001, flatness <2 light bands 0.6 Micron