DIRECT FORMING
Direct forming (DF)
The compression-molding technology, also known as Direct Forming (DF), is analogous to injection molding a process for the large-scale production of technical components made of plastics which do not allow thermoplastic processing due to their rheological properties.
In compression molding technology, a plastic powder is generally cold-pressed and then sintered in a thermal process. Similar processes are known from the powder metallurgy.
The tools for the compression-molding technology are significantly cheaper than injection molding tools, since they are more simply in design and do not have to be heated. Due to the process method, however, only components with relatively simple geometry can be technically produced.
Similar to the injection molding technology, there are also several restrictions that must be considered in the component design.
When designing it should be ensured that directly formed components have a wall thickness of at least one and not more than 50 millimeters. The component size is limited to a surface area of approx. 2500 mm2 for production reasons, round parts can only be manufactured up to a maximum diameter of 300 mm.
Undercuts are fundamentally not possible, and sharp edges must be rounded for better demoldability. Angles up to 30° starting from the press plane are possible, but larger bevels and chamfers must be flattened 0.1 to 0.3 mm.
In addition, other factors dependent on the component geometry must be taken into account, but should be checked on a case-by-case basis. Here again it becomes clear that during the design process, the special features of the processing technology must be taken into account.
Learn more about the special features of the processing methods injection molding technology and machining technology!