Lapping
Process of removing material from two workpieces / From Wikipedia, the free encyclopedia
Dear Wikiwand AI, let's keep it short by simply answering these key questions:
Can you list the top facts and stats about Lapped?
Summarize this article for a 10 year old
Lapping is a machining process in which two surfaces are rubbed together with an abrasive between them, by hand movement or using a machine.
This article needs additional citations for verification. (August 2009) |
Lapping often follows other subtractive processes with more aggressive material removal as a first step, such as milling and/or grinding.
Lapping can take two forms. The first type of lapping (traditionally often called grinding), involves rubbing a brittle material such as glass against a surface such as iron or glass itself (also known as the "lap" or grinding tool) with an abrasive such as aluminum oxide, jeweller's rouge, optician's rouge, emery, silicon carbide, diamond, etc., between them. This produces microscopic conchoidal fractures as the abrasive rolls about between the two surfaces and removes material from both.
The other form of lapping involves a softer material such as pitch or a ceramic for the lap, which is "charged" with the abrasive. The lap is then used to cut a harder material—the workpiece. The abrasive embeds within the softer material, which holds it and permits it to score across and cut the harder material. Taken to a finer limit, this will produce a polished surface such as with a polishing cloth on an automobile, or a polishing cloth or polishing pitch upon glass or steel.
Taken to the ultimate limit, with the aid of accurate interferometry and specialized polishing machines or skilled hand polishing, lensmakers can produce surfaces that are flat to better than 30 nanometers. This is one twentieth of the wavelength of light from the commonly used 632.8 nm helium neon laser light source. Surfaces this flat can be molecularly bonded (optically contacted) by bringing them together under the right conditions. (This is not the same as the wringing effect of Johansson blocks, although it is similar).