Die Casting

Die casting injects molten nonferrous metal into hardened steel dies at high pressure to produce high-volume, thin-wall parts with excellent repeatability.

Overview

Die casting (high pressure die casting, HPDC) forces molten metal into a hardened steel mold at high pressure, then ejects the solidified part in seconds. It excels at near-net-shape parts with thin walls, fine detail, and consistent dimensions across high production volumes. Tooling is expensive but durable, and cycle times are short, so piece price drops quickly as volume increases.

Choose die casting when you need repeatable, production-ready metal parts with cast-in features (ribs, bosses, threads inserts, sealing grooves) and good cosmetic surfaces. Typical alloys are aluminum, zinc, and magnesium.

Tradeoffs: high upfront die cost and longer lead time; geometry must support draft, ejection, and gate/runner layout. Porosity risk can limit pressure-tightness and reduce weldability; critical sealing and structural areas often need machining, impregnation, or process controls (vacuum die casting).

Common Materials

  • Aluminum A380
  • Aluminum ADC12
  • Zinc Zamak 3
  • Zinc Zamak 5
  • Magnesium AZ91D

Tolerances

±0.003" to ±0.010"

Applications

  • Automotive transmission housings
  • EV inverter and power electronics housings
  • Hand tool and appliance gearboxes
  • Electronics enclosures and heat sinks
  • Lock bodies and hardware components
  • Small engine and pump housings

When to Choose Die Casting

Die casting fits high-volume production where tooling cost can be amortized and repeatability matters. It works well for thin-wall parts with ribs, bosses, and integrated features that would be costly to machine. Plan on secondary machining for tight datum features, bores, or sealing surfaces.

vs Sand Casting

Choose die casting when you need higher volume, thinner walls, and tighter, more repeatable dimensions with better surface finish. It also supports more cast-in detail and faster cycle times once the die is built.

vs Investment Casting

Choose die casting when production volumes are higher and you want faster cycles and lower piece price for nonferrous alloys. It’s also a strong fit for thin walls and high repeatability, accepting more DFM constraints (draft/ejection) than investment casting.

vs Permanent Mold Casting

Choose die casting when you need thinner sections, more intricate cast-in features, and higher throughput. Die casting typically holds dimensions more consistently at high volume, with higher tooling complexity and cost.

vs Centrifugal Casting

Choose die casting for complex external geometry and integrated features rather than axisymmetric parts. Die casting is better for thin-wall housings and hardware where you need consistent features across many cavities and fast cycles.

vs Shell Mold Casting

Choose die casting when you need higher production rates and more consistent dimensions for nonferrous parts. Shell molding can handle larger parts and different alloys, but die casting wins on cycle time and repeatability at volume.

Design Considerations

  • Add draft on all pull directions (often 1–3°) and increase draft on textured surfaces
  • Keep wall thickness as uniform as possible; use ribs to add stiffness instead of thick sections
  • Use generous fillets at wall intersections to improve fill and reduce hot spots and porosity
  • Place parting lines and ejector pin locations on non-cosmetic, non-sealing surfaces
  • Design bosses with proper core support and avoid deep, thin pins that drive die wear and breakage
  • Define machined datums and critical bores/seal faces up front; treat as secondary ops in the print