Tasty looking molten metal. Found here.
We won't spend too much time on the melting step because of it's variability. Many metals can be used in sand casting, and different metals have different properties like melting point. This is so that it doesn't begin solidifying immediately so there is enough time to pour the metal. For sand casting, the metal must be heated to a point a above it's melting point.
This website is a good resource for anyone interested in melting their own metal, and really for sand casting in general.
Pouring metal seems pretty simple, just dump some molten metal into the hole right? Well, yes, but no. When pouring, the temperature of the metal must be higher than the freezing temperature. Also, the pouring rate must not be too slow or too fast, pouring too quickly can cause turbulent flow, which reduces the part quality and can mess up the mold. If the metal flows too slowly, then the metal will freeze before the mold cavity is filled. Large parts, and parts with intricate geometry can be more difficult to pour; in these cases mathematical engineering analysis may be required to figure out the best way to pour the metal. Pouring can be automated for increased precision and accuracy.
This website is a good resource for anyone interested in melting their own metal, and really for sand casting in general.
Pouring metal seems pretty simple, just dump some molten metal into the hole right? Well, yes, but no. When pouring, the temperature of the metal must be higher than the freezing temperature. Also, the pouring rate must not be too slow or too fast, pouring too quickly can cause turbulent flow, which reduces the part quality and can mess up the mold. If the metal flows too slowly, then the metal will freeze before the mold cavity is filled. Large parts, and parts with intricate geometry can be more difficult to pour; in these cases mathematical engineering analysis may be required to figure out the best way to pour the metal. Pouring can be automated for increased precision and accuracy.
This training video discusses the proper safety precautions when working with molten metal, as well as demonstrating an example of the melting and pouring operations.