Bubbles, pores, inclusions, and mucous membranes are all related to improper use of die-casting release agents

Nonferrous metal die-casting release agent is a functional substance between the mold and the product, which is a type of processing aid that prevents metal molded products from sticking to the mold and makes them easy to detach from the mold. During the entire metal die-casting process, the role of release agents mainly includes the following three aspects:

Before the metal hydraulic injection, it is evenly distributed on the surface of the mold cavity to form a layer of isolation film between the mold and the molten metal liquid, which prevents the mold cavity from being directly washed away by the molten metal liquid; During the die-casting process, it helps the liquid metal to enter the mold cavity and ensure that the filling is complete; After the casting is formed, it can be easily demolded.

Many defects in die-casting parts, such as bubbles, pores, inclusions, and mucous membranes, are directly or indirectly related to improper selection and use of release agents. Table 1 presents some defects in castings during the die-casting process and the contribution of the selection and use of release agents to these defects.

When choosing a release agent, it is usually necessary to consider the temperature and spraying of the mold, as well as the quality requirements of the die-casting parts. So it is necessary to understand the efficacy of each component in the release agent in order to correctly select a release agent that meets the requirements of die-casting technology.

The composition of traditional water-based die-casting release agents is water and other active ingredients. The other active ingredients mainly include oil wax, surfactants, and other trace additives such as antibacterial and defoaming agents, usually in the form of concentrated solutions. In die-casting production, it is necessary to continuously adjust various factors such as dilution ratio of release agent, spraying pressure, spraying amount, and spraying time according to the type of die-casting product to achieve a near ideal state.