Study On The Forming Of Pressure Bulging Composite Metal Mold Of IMD Film

With the requirement of surface decoration technology improved, the traditional technology of surface decoration has been unable to meet market demand. In mold decoration technology (In-Mold-Decoration) is a surface decoration technology of forming a set of functional and decorative in one, and the product on the pattern of the text in the mold of injection time. But the forming of IMD diaphragm are limited by the traditional processing method of forming shallow depth, surface mold marks, diaphragm thickness uneven distribution and so on. On the basis of the traditional machining, the compound forming ideas was proposed, and the characteristics and the regularity of deformation of composite forming material were studied. The specific work is as follows:(1) The simulation model was established. After selected material model, according to the need of solving material parameters, tensile test group four at the temperature of 25℃,50 ℃,70℃and 90℃, through the PET membrane of the experimentally obtained stress-strain curve, fitting parameters of material. A detailed description is applicable to diaphragm pressure bulging and metal mold simulation model establishment method.(2) The PET diaphragm metal mold and pressure bulging was simulated, obtained the influence law of the temperature, blank holder force, friction coefficient on the distribution of film thickness and the magnitude of the stress. Research result indicated that the minimum temperature of the PET diaphragm flow stress was at 70℃, and has good plastic. The maximum thinningrate of the metal mold diaphragm was 5.3%, and the 70℃ was optimum forming temperature. When the diaphragms free bulging, the center part was thinnest, forming was limited by die, and the thinnest is located at bottom corner of die. The friction of dies and diaphragm is benefits the thickening to punch bottom material. The blank holder force diaphragm pressure bulging is greater than the required metal mold.(3) The pressure bulging compound metal mold forming method and the metal mold compound pressure bulge forming method are proposed to study the forming characteristics and deformation law. The research result shows that the maximum thinningrate of the metal mould composite pressure bulging is 4.7%. The composite molding method can improve the uniformity of the diaphragm thickness distribution and reduce the forming of the pressure required to reduce the demand for equipment.(4) Author design a set of mold of suitable for metal mould composite pressure bulge forming method. According to the technical scheme, the scheme of the diaphragm positioning, blank holder device, lubrication and heating device were determined, and the entire process were described.