Hourly Cost of Machinery
Introduction
Machining is a manufacturing process that includes a set of part-shaping operations by removing material, either by chip removal or abrasion. Also in some areas of South America the term machined is used, although, due to the double meaning that this term can have (plotting or plotting something), it would be better to use the first one.
It is made from semi-finished products such as ingots, billets or other pieces previously formed by other processes such as molding or forging. The products obtained can be final or semi-finished that require subsequent operations. The most used machine and tool in this manufacturing process is the lathe. [1].
Machining without chip removal
All metal parts, except cast ones, have at some point in their manufacture been subjected to at least one metal forming operation, and several different operations are often required. Thus, the steel used in the manufacture of tubes for the construction of chairs is forged, hot rolled several times, cold rolled into sheet metal, cut into strips, cold formed into a tubular shape, welded, weld machined and sometimes also cold drawn. This, apart from all subsidiary treatments. The theory of metal forming can help determine how to use machines as efficiently as possible, as well as improve productivity. The machining includes a highly resistant final piece.
Abrasion machining
Abrasion is the removal of material by wearing down the piece in small quantities, releasing particles of material, in many cases, incandescent. This process is carried out by the action of a characteristic tool, the grinding wheel. In this case, the tool (grinding wheel) is made up of particles of very hard abrasive material joined by a binder (a binder can be described as an additive capable of agglomerating a material and that can produce resistance between its bonds). This way of removing material by scratching the surface of the piece requires less force to remove material by pressing the tool against the piece, which allows for much thinner passes to be made. The precision that can be obtained by abrasion and the surface finish can be very good but the productive times are very long.