Tin is one of the oldest metals used by human beings. The metal is known for its fluidity and low melting point. Owing to the softness and formability of the metal, it is easy to use tin to make alloys with other metals. Tin has a high boiling point and is solderable and non-toxic. Another desirable character of tin that makes it suitable for die casting is that the difference of temperature between melting and boiling points is much greater than many other metals.
Different types of casting methods are used to cast tin alloys, such as pressure die casting, centrifugal casting, and gravity die casting. The advantage of tin alloy die casting is that there is little or no shrinkage on solidification, making the components sound and dimensionally perfect.
In case of tin alloy, casting the molds should be designed in a way that sufficient quantity of metal is fed to the inside corners of cavity. As tin has low melting points when compared to the other metals, rubber or carbon steel molds can be used for the process.
Even though tin is a bit expensive, many die casters consider tin to be the perfect metal for casting and prefer tin die casting over brass die casting. As the melting temperature of the metal is low, simple molds made from special rubber can be used in casting. Unlike lead and its alloys, tin is a non-toxic metal, which is shiny and does not tarnish easily.
Benefits of Die Casting Tin Based Alloys
- Tin is the first material to be die cast.
- Leaves little to no wear on the molds.
- As tin alloys have very low melting point and have great fluidity, they can be cast inexpensively.
- Easy casting techniques like centrifugal or gravity die cast can be used.
- Less to no shrinkage.
- Tolerances in the range of 0.0005 in./in. and wall thickness can go down to about 1/32 of an inch.
Apart from making parts and components using die casting, tin alloys are also used in low temperature solders, foundry patterns, seals for glass, and other materials that are heat sensitive and to make molds for low volume production of plastic items. Tin and tin alloy powder is also used to make powder-metallurgy parts, in tinning and solder pastes, and in spray metallization of surfaces.