How High Pressure Die Casting Works?

High-pressure die casting is a process in which liquid metal is injected into a mold cavity with high pressure and speed. A basic set-up consists of two vertical platens, bolsters, and a movable platen that holds the die halves in place. A hydraulically-driven piston is used to open and close the die. The metal is then poured into a shot sleeve before being introduced into the cavity of the mold.

Low-melting-point metals

High-pressure die casting uses a single plunger to force molten metal through a gate or feeder channel, while applying pressures ranging from seven to 207 MPa. The metal solidifies rapidly, and is then removed from the die. During the casting process, a flash may develop in the location where the two halves of the die meet. Trimming the die may eliminate this flash. High-pressure die casting requires a large amount of capital.

The use of iron and copper reduces the rate of aluminium attack on the dies, and copper increases the hardness of the casting, although excessive copper can cause cracking. The process requires high levels of Fe and can cause formation of intermetallic phases. These intermetallics affect the ductility and heat-treating capabilities of the casting. Typically, this process is not ideal for casting high-melting-point metals.

Nonferrous metals

High-pressure die casting of nonferrous metals is a technique used to produce metal parts using the pressurized melt. This process has its advantages, and can be performed at a high production rate and in specific flows. To use this process, the dies are heated to around 700°C. The pressure inside the dies is constant or increasing and enables the metal to remain in the die until it solidifies. When the dies are released, the residual liquid will flow back into the holding furnace, while the cast is removed from the machine.

HPDC is a process that is best suited for high volume production of near-net-shape parts. The thixotropic behavior of the slurry results in castings with high integrity. High-pressure die casting machines can produce SSM slurries using horizontal or vertical injection and clamping. The process has also been successfully commercialized by V-Forge and SAG.

Smooth surfaces

The process of high pressure die casting produces components with excellent dimensional accuracy and surface finish. The casting process can produce components with walls as thin as 3mm and surface roughness of 1.5 Ra. This process also minimizes secondary machining costs, but it is less flexible than gravity casting in design. The metal or alloy is injected into the mould under high pressure, resulting in rapid filling and a fine grain structure. This process reduces metal loss, speeds up production, and produces smooth surfaces.

In addition to producing smooth surfaces, high pressure die casting produces highly complex parts with close tolerances. Because the metal fills the cavity quickly, it becomes difficult to release the gas. In addition, the gas often settles underneath the surface, limiting the complexity of the finished product. The process is often used in aerospace and other industries that require precision and high-quality parts. High-pressure die casting is an ideal solution for a wide variety of applications.

Costs

The cost of material for high-pressure die-casting is a major factor in the overall cost of the production. The amount of material used will depend on the part volume and density, as well as the maximum wall thickness of the part. The die itself will be made of a hard tool steel. The higher the temperature of the molten metal, the longer the die will last. For this reason, a larger channel system is required than a small one, since smaller parts require less material.

The die itself is very heavy, usually weighing more than a thousand times the part weight. It must have additional cooling channels to prevent it from softening under the high pressure. It must also have ejector pins for removing the part after the casting process. The die must also withstand thermal shock and not soften at the shot temperature. Die materials are typically made of hardened tool steel, and the draft angles in the separation surfaces must be precise.