The Buyer's Guide to Die Casting

Die casting has been around since the mid-1800s. Today it's the go-to process for producing precision metal parts at scale — from automotive transmission housings to consumer electronics enclosures. If you're evaluating die casting for a project, here's what you need to know to make informed sourcing decisions.

How Die Casting Works

Molten or semi-molten metal is injected into a hardened steel mold at high speed and pressure. The metal solidifies under pressure, producing parts with tight tolerances (CT3–CT6), smooth surface finish (Ra 0.8–3.2μm), and tensile strengths up to 415 MPa. Many die castings can be used directly without secondary machining.

The Upside

• Speed: Highly automated production cycles — ideal for high-volume runs
• Precision: Near-net-shape parts that often skip secondary machining
• Integration: Inserts can be cast in, eliminating assembly steps
• Consistency: Mold-based production ensures part-to-part repeatability

The Limitations

• High upfront cost: Machines + molds + alloys = significant tooling investment. Not viable for small batches.
• Size constraints: Machine clamping force limits the maximum part size
• Porosity: Gas entrapment during high-speed filling can cause internal voids — meaning most die castings can't be heat-treated or welded
• Alloy restrictions: Limited to aluminum, zinc, magnesium, and copper alloys

Choosing the Right Metal