1. First, the front and rear bumpers. Bumpers are all plastic (not to mention the unpopular ones). All plastic parts on the car body are not resistant to collision, easy to damage and inconvenient to maintain, so they are usually replaced. Car owners often ask, this kind of plastic will break once it is hit, so why not use iron? As far as I know, the front and rear bumpers are made of plastic, or even more easily damaged materials, because those materials do less harm to human body. (Some models will also consider the body weight, such as carbon fiber for sports cars. ...
2. What do these parts problems mean? For example, the door won't open, the door glass won't rise, the skylight won't close, the hood won't hold up, and so on. It looks very simple. Actually, it's really simple. Understand the structure of the car, the working principle of each component, find the root of the problem, and then try to solve it. Of course, it will be a little troublesome to operate. After all, you have to take the time to understand these things. For example, the door won't open. ...
3. Finally, to sum up, this answer is to explain automotive sheet metal from an introductory perspective. ...