Lap plates are widely used in the ceramics, optics, semiconductor and automotive industries to polish and finish surfaces. In this machining process, also known as lapping, the two surfaces are rubbed together, sometimes with an abrasive material between them. The polishing is done using a machine, though this is sometimes done by hand.
The right polishing machine for the job
Materials and methods used for polishing vary according to the material that is to be polished. Polishing machines can have different surfaces depending on the materials to be polished. For ceramic machining or for finishing projects that call for edge-to-edge flatness, diamond lapping is the best suited method.
Surface flatness is known as accuracy and is measured in units of Helium Light Bands or HLB. One HLB is about 0.000011 inches (280 nm), lapping machines typically achieve accuracies of 1 to 3 HLB. Diamond lapping can achieve surface flatness and accuracy results up to sublight band, which is 11 millionths of an inch and, under specific conditions, up to 1/20 wavelength.
Diamond lapping is not only more precise but also more effective and cost-efficient for some materials. For an alumina wafer, using diamond lapping reduced cycle time by 30 minutes and eliminated the need for hand polishing. It also provided a saving of $14.87 per hour in slurry and waste disposal costs. Since no abrasive was used, cleaning time and use of cleaning solutions were also reduced.
Lapping machines also vary in size according to the job they are needed for, and sizes range from table top units to lap plates that are up to 72? in diameter.
Polishing machines produce a fine edge
Lap plates are the basic component of industrial lapping, polishing and micro grinding machinery. They are used to polish surfaces to the precision levels required by certain industries.
The purpose of lapping is usually to produce a flat surface, though sometimes concave and cover surfaces are needed by opticians. Using interferometry, lensmakers can achieve surfaces that are flat to better than 30 nanometers or 1/20the of the wavelength of light from the 632.8 nm helium neon laser light source.