It is well known that plastics score over metals in terms of weight and technical properties, depending on the area of application. However, there are also a big differences in the processing of the materials, which speaks in favour of plastics. This is because the production of plastics facilitates or eliminates some additional work steps, which saves processing costs and energy costs.
This starts with a fundamental work step, namely corrosion protection. While many plastics are resistant to liquids and chemicals simply by virtue of their chemical composition, metals require a protective coating to be applied in an additional work step after production. The production of coloured finished parts also requires an additional painting step for metals. With plastics, on the other hand, the color is already mixed with the raw material, which means that no further coloring is required after injection molding.
After injection molding no further material finishing is required. There may be exceptions (depending on the plant and the finished part) with regard to the post-processing of finished plastic parts, but these can be carried out without great effort and are relatively simple. With metals, on the other hand, burrs have to be removed and holes re-milled.
Plastics also offer some advantages in the production of components with threads. On the one hand, threads can be formed by injection molding alone, or if heavy-duty threads are required, they can be integrated into the material as inserts during the injection molding process. For the production of metal parts with threads, an additional work step is necessary in which the threads are drilled into the metal.
The surface of the finished parts can already be produced with the desired surface structure during the injection molding process. This is done in one process with the molding. To create a surface structure on metal parts, more complex measures are necessary, such as sandblasting.