High pressure diecasting provides the shortest route from molten metal to completed component, by injecting molten metal into a hardened steel mould and allowing it to solidify under pressure before ejection.
The Dimensions in Die Casting
The process allows fast, precise, cost effective production of aluminum or zinc die castings, meeting the needs of hi-tech industries where product appearance and dimensional tolerances are critical. Manufacturers have high pressure die casting machines with locking forces of between 220 and 530 tons. All feature computerized real-time shot control, automatic ladling, die-spray, automatic casting extraction and cooling. Many pressure die casting foundries only offer their services for high volume orders, claiming that lengthy set-ups make the process prohibitive to small quantities of zinc or aluminum die castings. Manufacturers have optimized their tooling preparation and set-up operations to make the process more accessible to customers who require only small quantities, but whose applications would benefit from the excellent dimensional and cosmetic properties of pressure die casting. So, manufacturers can provide the complete service, whether you require a batch of 10 or 10,000.
The diecasting process involves the use of a furnace, metal, die casting machine, and die. The metal, typically a non-ferrous alloy such as aluminum or zinc, is melted in the furnace and then injected into the dies in the die casting machine. There are two main types of die casting machines – hot chamber machines (used for alloys with low melting temperatures, such as zinc) and cold chamber machines (used for alloys with high melting temperatures, such as aluminum). The differences between these machines will be detailed in the sections on equipment and tooling. However, in both machines, after the molten metal is injected into the dies, it rapidly cools and solidifies into the final part, called the casting.
The Applications in Die Casting
The castings that are created in this process can vary greatly in size and weight, ranging from a couple ounces to 100 pounds. One common application of die cast parts are housings – thin-walled enclosures, often requiring many ribs and bosses on the interior. Metal housings for a variety of appliances and equipment are often die cast. Several automobile components are also manufactured using die casting, including pistons, cylinder heads, and engine blocks. Other common die cast parts include propellers, gears, bushings, pumps, and valves.
One final consideration of diecasting is the number of side-action directions, which can indirectly affect the cost. The additional cost for side-cores is determined by how many are used. However, the number of directions can restrict the number of cavities that can be included in the die. For example, the die for a part which requires 3 side-core directions can only contain 2 cavities. There is no direct cost added, but it is possible that the use of more cavities could provide further savings.