This section contains detailed description of all the major casting processes specially designed for the benefit of the buyers who are looking for buying casting products for applications across the industries. Metal casting processes are used to design and manufacture a variety of components and finished products. Almost everything ranging from simple nails and fasteners to large machine parts and engine blocks can be casted using these casting processes. Most popular and commonly used metal casting processes are sand casting, investment casting, centrifugal casting, die casting, lost foam casting, permanent mold casting etc.

Usually, large machine parts and other components of iron, bronze, brass and aluminum are produced through sand casting process. Natural or synthetic sand is used to make moulds from sand casting process. Casting is done by pouring molten metal into the mould cavity, which is designed out of sand. Sand casting components come with surface impurities and surface variations and a rough surface.



The die used for die casting is usually made of a high-strength metal or graphite material. These dies are very expensive to produce. Die casting process is most suited to repetitive and high-value casting components. Sand casting is the most common technique and very popular among the casting manufacturers around the world. The process combines good casting quality with flexibility in metal type and casting size. Sand casting process is most suited to foundries, which produce a wide variety of large casting products. Permanent patterns, used in this process, are typically made of wood and less expensive than die moulds. Molten metal is poured into the mould that collapses automatically once the solidification of metal.

The purpose of developing shell casting process was to achieve high levels of throughput for repetitive casting operations. One of the advantages of shell casting is that it greatly reduces the sand:metal. At the same time the dimensional accuracy of the castings is typically higher than for sand moulding. It minimizes the work involved in cleaning and machining the product.

Temporary patterns are made from wax or foam In investment casting and lost foam casting. These patterns are generally made manually using traditional carving tools and carved mechanically using automated tooling.

These processes cost more and can't be applied to all type of casting size, but it can achieve the highest casting quality. In case of complex parts where machining is almost impossible, investment casting can be very cost effective. High dimensional accuracy can also be achieved by Lost foam casting process. It also has many environmental and operational benefits over traditional sand casting process.

You can't define a casting process as 'the best' as it completely depends on the specific need of the application. Hence, you should be careful while selecting the most appropriate technique or techniques that suit the type of castings produced and the operational constraints. We have discussed the major casting methods and their more common variants in the following sections.

	Sand Casting	Die Casting	Sand Shell	Investment Casting
Tool costs	Low	High	Average	Average
Unit costs	Average	Low	Average	High
Maximum casting weight	Over 1 tonne	30 Kg	100 Kg	45 Kg
Thinnest section castable(mm)	2.5	0.8	2.5	1.6
Typical dimensional tolerance(mm)	0.3	0.25	0.25	0.25
Relative surface finish	Fair to good	Best	Good	Very good
Relative mechanical properties	Good	Very good	Good	Fair
Relative ease of casting complex design	Fair to good	Good	Good	Best
Relative ease of changing design in production	Best	Poorest	Fair	Fair
Metal options	Best	Poorest	Fair	Fair
Comparison of Several Casting Methods