diecasting

Diecasting is a metal casting process in which molten metal is injected at high pressure into a steel mold, or die, and then solidifies to form a finished part. The dies are highly engineered and reused, enabling high-volume production with good surface finish and dimensional accuracy. Common die-cast alloys include zinc and its alloys, aluminum, magnesium, and copper-based alloys. Diecasting is favored for small to medium-sized parts with relatively thin walls and complex geometries.

There are two main machine types: hot-chamber and cold-chamber. In hot-chamber machines, the injection mechanism is immersed in the molten metal, best for zinc and similar alloys. Cold-chamber machines melt the metal separately and inject it under high pressure, suitable for aluminum, magnesium, and copper alloys. The basic steps are: clamping the die, injecting molten metal at high speed and pressure, filling and cooling, opening the die and ejecting the part, followed by trimming and finishing.

Die design includes gating, runners, vents, and ejector pins; complex parts may use slides to create undercuts. Dies endure many cycles and can be expensive to produce, but offer long service life with proper maintenance. Tolerances are tight, allowing near net-shape parts with smooth surfaces, reducing subsequent machining.

Applications include automotive components such as housings and connectors, consumer electronics enclosures, household hardware, and power tools. Advantages: high production rates, good dimensional accuracy, excellent reproducibility, and good surface finish. Limitations: high upfront tooling costs, restrictions on part size and wall thickness, potential porosity and inclusions if vents are inadequate, and material limitations. Post-processing often includes trimming, deburring, and surface finishing.

Environmental and safety considerations involve energy use, fume control, and recycling of scrap metal.