Introduction Of Bumper Mold And Introduction Of Common Runner Types

The Bumper Mould's bumper is one of the important parts of the car. It is a decorative automotive exterior part. It not only has a decorative effect, but also has the functions of absorbing and alleviating external impacts, protecting the front and rear bodies, and pedestrian safety. In the past, the front and rear bumpers of automobiles were stamped from steel plates into channel steel, which were welded or riveted with the frame rails. There is a big gap with the body, and the appearance is not beautiful. With the development of the automobile industry and the application of engineering plastics in the automobile industry, the automobile bumper, as an important safety device, has also been innovated.

No runner or hot runner for bumper mold

When the plastic melt is thermally stable, the use of runnerless molds eliminates the need to regrind the runners. One common type is a hot runner mold. In this bumper mold, the plastic is injected into an insulated runner plate that is kept slightly above the melt temperature by a set of individual torch heaters, then through the runner channels and insulated nozzles into each cavity. This is a runnerless operation because there is no runner regrind. The air gap thermally insulates the hot runner plate.

Hot runner bumper molds have many advantages due to the removal of runners and gates. There is no material loss or contamination from regrind, and there is no additional cost for automotive companies to mix regrind with virgin resin. Polymer properties are not changed by regrinding, especially optical and electrical properties. Neither melting nor cooling the regrind wastes any energy. The injection volume is effectively increased, and the mold opening stroke is shortened. With cold runners, this can happen during ejection and is eliminated with hot runners. Bumper molds fill faster and balance flow to the cavity is easier.