Optimization And Application Research On Hot Runner Sequential Control Of Injection Molded Car Front Bumper

Traditional bumper injection molding was injected by using hot runner and more gates to achieve, because it was injected by more gates at the same time, the products were easily appear bubbles, shrink mark, more defects such as weld lines which have great influence on apparent quality and the strength of bumper and the consequent painted effects. Uses the hot runner gates sequence control injection molding technology, the time sequence controllers were concatenated in the injection molding machine control system. According to the trigger signal by the injection process, opened or closed each needle valves’ time of sequence controller, which make melted material flow sequently through each gate into the cavity from middle to both ends, balanced continuous feeding, break through the traditional defects such as imbalance injection filling pressure, air bubble, sink mark and more weld lines etc. It made the injection molding process to adjust more easily. Effectively ensure the quality of car bumper production.Reasonably select the gating system points and position of front bumper mold by Moldflow injection molding simulation analysis and optimization, analysis filling, cooling and warp etc,solve the balance and optimization of the large car front bumper mold gating system, forecast the reasonable solution of good appearance quality.Using hot runner sequence control technology, made process design and quality control easily, shorten the molding cycle, produce effectively, save cost. Traditional bumper plastic scrap rate was roughly around 5%, and use hot runner shunt technology after the bumper production of qualified rate was as high as 99%, only or so 1% discarded; Traditional car bumper production cycle was roughly in the 75 s or so, and after using the technology the bumper production cycle was around 48 s or so.Using sequence control valves on the front bumper mold, realize the melted filling material flow orderly, solve the large area injecting, molding difficultly, a series of problems such as more weld lines, and guarantee the appearance quality of bumper.In the mold design, use the type of inner parting line to replace the type of outside parting line, the products after painting were more beautiful.These studies for the design and production of bumper provided an efficient way to avoid the problems that exist in the reality, namely by Moldflow aided design and optimization, mold design and optimization, manufacturing, test validation and process adjustable, through these three steps to achieve injection molding optimization, control product defects, to achieve the requirement of painting which was no burr, lack of material, air bubble, no obvious shrink mark, more welding lines, deformation defects etc.