What are the black spots in the products produced by aluminum die-casting molds

After aluminum die-casting parts are produced by aluminum die-casting molds, the products sometimes show black spots, so how should this situation be avoided? Let’s take a look at the specific reasons.

It may be the formation of die-casting molds to make silica, or alumina. The solution is simple, use fresh aluminum ingots.

Secondly, it may come from the release agent. It may be that too much mold release agent has been sprayed on aluminum die castings, or it may be that the organic content of the mold release agent is too high.

At the temperature of hot-melting aluminum, some of these organic substances are reduced to carbon elements, and some become organic macromolecular polymers. The mixture of these carbon molecules and polymers is included on the surface when aluminum castings are formed by aluminum die-casting processing in China, and become black spots that we see.