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Clinching also referred as "Press-Joining" is a bulk-sheet metal-forming process aimed at joining thin metal sheet without additional components, using special tools to plastically form an interlock between two or more sheets. The process is generally performed at room temperature but in some special cases the sheets can be pre-heated to improve the material ductility. Clinching is characterized by a series of advantages over competitive technologies: * Reduced joining time (the joining time is less than a second); * Reduced cost and weigh: the process does not involves additional elements such as screws of rivets or adhesives * Reduced cost of the machine; * No pre-holes are required; * Can be adopted to join different materials including metals, polymers, composite and wood; * Can be easily automated and does not require qualified workers; * Eco-friendly: it does not require pre-treatments (solvents, acids, etc) * the mechanical behavior of the metal material near the joint is generally improved since the work-hardening; * Cleaness: the process does not produce flashes of fumes; * Repeatibility; * Flexibility: the same tools can be employed for a wide series of materials * Reduced Joining Forces == Tools == Because of the process involves relatively low forces (ranging from 5 to 50 kN depending on the material to join, type of tools and sheet thicknesses), clinching generally involves reduced size (often portable) machines. The tools consist typically of a punch and a die. Different tools have been developed so far, which can be classified in round and rectangular tools. Round clinching tools include: fixed grooved dies, split dies (with 2-4 movable sectors) and flat dies. Such tools produce round joints which show almost identical mechanical behaviors in all plane directions. when round tools are adopted, the integrity of the sheet in the joint must be guaranteed in order to preserve good mechanical behavior of the joints. On the there hand, rectangular clinched joints exhibit behaviors which depend on the loading direction and both sheets are intentionally sheared along the "long direction" in order to produce the interlock. The choice of the tools is highly influenced by: * Material ductility * Loading direction * Thickness of the sheets In addition, the choice of the clinching tools highly affect the joining strength and absorbed energy of a clinched connection other than the joining force e.g. rectangular tools require lower joining force than round tools since the material shearing, while among the round clinching tools split dies require the minimum joining force and the largest interlock. One benefit of clinching is the capability to join prepainted sheet metal commonly used in the appliance industry without damaging the painted surface. Clinching is an important means of fastening aluminum panels, such as hoods and decklids, in the automotive industry, due to the difficulty of spot welding aluminum. 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「Clinching (metalworking)」の詳細全文を読む スポンサード リンク
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