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Liquid Impact Forming is a metalworking process in which the combined use of a stamping press and a liquid medium forms the desired shape on the workpiece. This technique is a synthesis of two metalworking processes; stamping (metalworking) and hydroforming. It is especially suited for the cold forming of tubular structural parts in automotive, railroad and aerospace industries. The process is based on a patent by Stanley Ash from the Greenville Tool & Die Company in Greenville, Michigan. ==Process== Liquid impact forming uses the principles of hydroforming process with conventional stamping equipment. Even though hydroforming offers great advantages over conventional tube stamping through the reduction of manufacturing steps and the reduction of variation in workpieces, it still requires expensive mechanical equipment such as dies to withstand extreme pressures and pressurizing equipment such as pumps and intensifiers. As an alternative to this, the liquid impact forming utilizes the increase in the internal pressure of the liquid inside of a tube during the stamping process, eliminating the need for the use of above mentioned equipment. The process includes the following stages: 1. A metal tube is filled with a liquid, preferably water and placed between lower and upper die sections of stamping dies. 2. The ends of the liquid-filled tube are sealed to confine the liquid within the tube at approximately atmospheric pressure. 3. The liquid-filled sealed tube is stamped in a conventional die to form the tube into a desired configuration, such as a box-shaped structural member. The compressive forces produced as the die closes to form stamped tube also compress the liquid within the interior of the sealed tube as it changes shape. Thus, the pressure of the liquid increases as the die closes. As the liquid resists compression, it forces the tube walls outwardly toward the interior surface of the die cavity. Once die sections are fully closed around the sealed tube, the tube walls take the shape of the die cavity. 4. The remaining liquid is drained from the formed tube. 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「Liquid Impact Forming」の詳細全文を読む スポンサード リンク
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