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Research on relationships between fluid pressure and technological parameters, shape of cylindrical part in hydro static forming

This article deals with determination of relationship between forming pressure, blank holder pressure and radius of bottom die using experiments. The results of this study are the basis for further validating the quality and accuracy of product, as well as optimizing hydrostatic forming technology. | Journal of Science & Technology 127 (2018) 001-005 Research on Relationships Between Fluid Pressure and Technological Parameters, Shape of Cylindrical Part in Hydro Static Forming Nguyen Thi Thu*, Nguyen Dac Trung Hanoi University of Science and Technology, No. 1, Dai Co Viet, Hai Ba Trung, Hanoi, Viet Nam Received: September 13, 2017; Accepted: May 25, 2018 Abstract In sheet hydrostatic forming, accuracy of products depends on many technological parameters and shape of die, especially working fluid pressure plays very important role. Determination of this pressure is usually difficult, because it depends on the other parameters, such as blank holder pressure, workpiece material, geometrical shape and tightness of die, so on. This article deals with determination of relationship between forming pressure, blank holder pressure and radius of bottom die using experiments. The results of this study are the basis for further validating the quality and accuracy of product, as well as optimizing hydrostatic forming technology. Keywords: forming pressure, blank holder pressure, sheet hydro static forming. 1. Introduction* such as: enhance surface quality (avoid scratch on surface), decrease elastic deformation, especially suitable for forming complex profiled products[3] [4]. However, this technology has some disadvantages, for example local strong thinning, so that the product thickness it not equal [5]. Therefore, this technology is appropriately applied to manufacture body shells of car [6]. Many developed countries like USA, Germany, Japan, Korea, China are using this technology in the industrial fields such as defense, transportation, aerospace, home appliances . In hydrostatic forming, high pressure fluid works as punch (in conventional stamping hard die and punch) and has direct impact on surface of workpiece to deform it following to the die cavity [1]. Hence, the shape of die and working fluid pressures will play an important role for filling of material .