| With the rapid development of the plastic industry, the tendency of product plasticization and lightness got enhanced. The plastic has the advantage of low cost, lightness and higher strength, which are widely used in instrumentation, automotive, electrical and electronic, medical equipment and other fields. With "plastic" generation "steel" will become a new trend of industrial development in the future, injection molding technology is the most important way in plastics processing, accounted for more than 80%.This demands the higher requirements for quality of plastic products and production cycle, apparently, the traditional mold design method based on experience has been unable to meet short-period, less test/repair mold, high-quality development of new requirements of the mold. However, the application of CAE technology in injection molding is a good solution to solve the shortcomings of the traditional mold design method.This paper took the medical ultrasound probe shell as the research object, with "design+simulation" method, using Pro/E and Moldflow software as design and simulation platform, completed the injection mold design and CAE numerical simulation. The main research of this paper is as follows. Using Pro/E to design the mold formed parts and structural components, including:internal model set parts (punch and male die), filling and cooling systems, side type bodies (angle pin and slide rand slanting rejecting mechanism), exhaust system, ejection mechanism and standard mould. Using typical Moldflow analysis software to simulate the filling, flow and cooling process, found deficiencies in the original design of gating and cooling system. In order to get the optimal gating and cooling system, optimization of the design was done. Finally, the numerical simulation of plastic injection molding process was analyzed by the orthogonal test method. Paper has made the following achievements:(1) The product structure processing of the prototype ultrasonic probe shell that I participated in the design previously was analyzed. And found some deficiencies in the structure, for example:pattern draft is negative; existing holes on the inner surface; stiffeners and boss did not fillet). A reasonable structure of probe shell was got by Pro/E, which laid the foundation for Moldflow simulation through building accurate physical model and obtaining more realistic results.(2) The good liquidity filling system and better cooling system was got through the simulation of filling, flow and cooling process with Moldflow. The results showed that the use of "s" type balanced runner (diameters of primary and secondary runner is respectively 6 and 5 millimeter) and submarine gate (the bevel, the diameter of gate and length is respectively 45 degree,2.5 and 12 millimeter) can get better fluidity in the initial design of gating system filling. The cooling effect is very good with 6 cooling path(diameter of runner is 8 millimeter), the difference in temperature of water inlet and outlet cooling circuits medium is respectively 0.5 ℃ and 2.5 ℃. The results showed that it can greatly shorten the cycle of injection mold design, die design quality, reduce total cost of mould development with combination of CAE technology.(3) The warpage of the probe shell in injection molding processes was predicted by orthogonal experiments and found out the main factor affected the warpage is injection time ti, and the sequence is injection time t1> mould temperature T1> melt temperature T2> cooling time t3> packing time t2> packing pressure P, and got a set of minimum warpage of molding process parameter combinations. Parameters is T1=247.5℃, t,=3s, P=75%, t2=7.5s, t3=25s, the warpage is only 0.1974mm that is mainly caused by uneven cooling. That provides a solid and reliable theory for the future selection of process parameters in the actual production process. |
PDF Full Text Request