Lapping Machines Process

Lapping Machines are a type of precision finishing machine. Lapping is a loose abrasive machining process that differs from honing or grinding because the abrasive action comes not from a solid abrasive (like a grinding wheel) but from a slurry--abrasive particles mixed with oil or water. The slurry forms an abrasive film between the underlying lapping plate and the parts to be lapped. The part stock is gradually removed through the rolling and sliding action of the abrasive grains between the lapping wheel and the workpiece. The slurry, along with the removed stock, drains away from the table.

Lapping machines create truly flat surfaces--normally up to 0.001mm, with surface finishes of better than Ra.01. Overall, lapping produces extreme dimensional accuracy, corrects minor imperfections of shape, refines surface finish, and produces close fit between mating surfaces.

Lapping machines may be beneficial whenever absolute flatness, parallelism, or surface finish is essential. Since it is a loose abrasive process, irregularly-shaped or non-magnetic parts can be easily accommodated. Lapping removes stock quickly, with no clamping or heat distortion, no expensive tooling required, and virtually no maintenance. Inspection and production costs are also lower, since the machine can be run by semi-skilled operators. Parts can be run as easily in small batches as in production processes.

How does it work?

Flat Lapping Machines consist of 5 parts: the rotating table (called a lapping plate), several conditioning rings, the topweight, the slurry, and the machine itself.

The machine houses the controls, engine, coolant, filter, and other subsidiary components for proper operation of the mechanism.

The lapping plate is the only thing that is turned by the motor--the conditioning rings turn automatically as the plate itself turns. The plate is usually made of high-quality soft cast iron, though copper and other soft metals may also be used. It may be anywhere from 12 to 144 inches in diameter and feature spirals, cross-hatches, rings, or other shapes.