Die Casting

Process Definition & Working Principle

High Pressure Die Casting (HPDC), commonly referred to as Die Casting, is a highly efficient, automated manufacturing process in which molten non-ferrous metal is injected under extreme hydraulic pressure into a precision-engineered, two-part steel die. The process is characterized by high filling velocities and rapid cooling rates, which yield thin-walled parts with close dimensional tolerances and excellent surface finishes.

Physical Principles of Operation

The injection and solidification sequence is divided into three distinct phases of plunger motion:

Kinematics, Axes, & Machine Configuration

Die casting machines are heavy-duty hydraulic presses classified into two main configurations based on the method used to deliver molten metal into the die: hot-chamber and cold-chamber machines.

Hot-Chamber Machines

In hot-chamber configurations, the injection mechanism (plunger cylinder and a curved channel known as the gooseneck) is continuously submerged in a bath of molten metal contained in an integral furnace.

• Application: Limited to low-melting-point alloys (zinc/Zamak, lead, tin, and lightweight magnesium alloys).
• Operating Injection Pressure: $15$ to $30\text{ MPa}$.
• Advantages: Rapid cycle rates (up to 1000–2000 shots per hour for small parts) because metal is drawn directly from the bath; minimized oxidation of the molten metal.

Cold-Chamber Machines

In cold-chamber machines, the melting furnace is separate. Molten metal is metered and poured (via a mechanical ladle or vacuum feeder) into the horizontal shot sleeve before each shot.