Modern bumpers are made of various materials. The first element is a shock-absorbing spring device, usually an inflatable cylinder, which mounts the front bumper on the chassis. This allows the bumper system to absorb less impact without causing any damage.
The next part is a steel or aluminum support structure, which is a beam.
Most importantly, the honeycomb or egg box-shaped plastic parts made of HDPE define the final external shape of the bumper and support the shape of the bumper cover. At the rear, these can be connected to other bodies or components of the car. In more serious accidents, this part of the bumper structure is usually the damaged but invisible part.
Finally, put the urethane or other flexible polyethylene plastic bumper cover outside the car to give the car a complete appearance. These can be charcoal or pure black, or they can be painted to match car paint. They are designed to be impact resistant and can withstand little or no damage.
In fact, bumpers in cars are designed to absorb low-speed shocks or impacts, such as accidentally hitting when reversing.
Now it is necessary to choose the material used to make the bumper, the material should have the ability to absorb impact (ie eliminate the impact of impact or reduce the impact of impact).
Let's think of metal as a bumper. Metal transfers the load applied from one end to the other with little loss, so metal is not the best material for bumpers. Let's think of plastics as bumpers. They have a tendency to absorb loads and reduce the impact of impact, and rubber also has a tendency to absorb this effect and make the effect almost disappear.
From the perspective of design and processing, the size of the bumper is large, so it can be processed by injection molding, blow molding and rotomolding. Considering the above processing technology, plastic is a suitable choice of materials.
Considering the above treatment methods, the most common is ABS, PC / ABS is injection molded, and blown ABS is used in Hyundai, Ford and other cars. When processed by rotomolding, crushed HDPE is easy to process and can be used to make bumpers.
Cars used steel and aluminum decades ago, and used springs or hydraulics to provide protection and cushioning, allowing the bumper to absorb impact and maintain relatively good damage. In terms of style and practicality, many manufacturers use rubber to absorb impact and protect chrome bumpers. I prefer this material to foam and aluminum covered with modern plastic. The new car was slightly scratched, cracked and chipped when it was parked.