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Carbide saws are machine tools for cutting. The saw teeth are made of cemented carbide, so that hard materials can be cut. == The history of carbide == In 1926, Krupp, a German company, developed carbide, a very hard mixture of sintered carbides of various heavy metals, especially tungsten carbide, used for cutting edges and dies. This new material revolutionized metal-removal or “chip-cutting” in manufacturing. In the 1950s, carbide was used in all machining processes except for sawing. In 1942, German scientists further developed carbide into cermet. After World War II, American universities developed this material further and began to market it as a cutting material for machine tools under the brand name Cermet. Sawing non-ferrous material, such as aluminum, brass, plastic and wood with carbide tipped circular saw blades began in the 1930s. However, attempts to cut ferrous material with carbide tips failed because the existing saws lacked the speed, rigidity, and innovation required to transfer high force with low vibration. These attributes are all necessary for carbide sawing. Also, the existing tooth geometry with positive cutting angles caused cracking of the carbide tips which were harder and consequently, more brittle than the high-speed steel (HSS) circular blades. The name carbide saw came from the tool, a circular saw blade, with silver soldered carbide tips. It competed with and just about replaced, solid or segmental HSS blades, because carbide is much harder than HSS. Before HSS saws were developed, abrasive, friction or hot saws were used and are still manufactured for certain applications. These processes create heat and are therefore called hot saws. However, HSS blades use coolant and the cut surfaces don’t get hot, thus called cold saws. With the unique geometry of the teeth of carbide circular saws, the heat, developed by the cutting process is transferred into the chips and carried away with the chips. The cut surfaces stay cool. Therefore, carbide saws were also called cold saws. Other names include cold cut saws, cold circular saws, cold cut off saws or circular cold saws. In 1963, the American Company, Ingersoll Milling Machine Co. in Rockford, Illinois, developed the first carbide plate saw that was used to cut steel plates with carbide tipped circular saw blades. The positive cutting angle of the teeth minimized the life of the tool. Between 1963 and 1969, professor Pahlitzsch and engineers Arno Willemeit and Horst Doepcke at the University of Braunschweig, developed new carbide tip geometry with a negative cutting angle and a pair of teeth which split the chip into three parts. With this development in tip geometry it became economical to saw alloy steel billets. In 1969, Advanced Machine & Engineering Co. (AME) of Rockford, Illinois developed the first Billet Saw which used carbide tipped saw blades incorporating the "Braunschweig geometry". AME began to build these machines for the company Metalcut Inc., another Rockford based company.〔(AMSAW pioneers in carbide sawing )〕 The machine was sold on the global market under the name Metalcut 12 and was exhibited at trade shows in Milan, Italy and Chicago. Its cutting efficiency was eight times faster than band saws and four times faster than HSS circular cold saws and revolutionized the production sawing market. From 1972 to 1976 for his dissertation, Horst Doepcke, a scientific assistant at the Institute for Machine Tools and Manufacturing Engineering at the University of Braunschweig, developed a specific carbide cutting geometry for tubes which had every tooth splitting each chip into two. In 1984, Speedcut Inc. of Rockford, Illinois developed another type of carbide tooth geometry by the name of, "Notch Grind". This was used for steel billets and it would split the chip with one staggered groove per tooth. With the incorporation of this “Notch Grind” technology, saws became significantly faster than with the Braunschweig geometry.〔((US Patent Aug. 7, 1984, Number 4,463,645) )〕 For several years after, various companies have been developing carbide saw blades with exchangeable carbide tips. These saw blades, so far, have not been proven economical for cutting steel. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Carbide saw」の詳細全文を読む スポンサード リンク
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