Material Shrinkage in Die Casting: What It Is and How We Compensate for It

All metals shrink as they cool—and in die casting, this solidification shrinkage must be anticipated during tooling design. If ignored, it can lead to undersized parts, internal voids, or warped features.

The key to success? Understanding each alloy's behavior and designing shrinkage compensation directly into the mold.

📉 Typical Shrinkage Rates:

• Aluminium (ADC12): ~0.6%

• Zinc (Zamak 3): ~0.3–0.4%

• (Note: Exact rates depend on wall thickness, part geometry, and cooling uniformity)

Sample shrinkage simulation

🔍 Where Shrinkage Affects You:

1. Dimensional Accuracy

   Tool cavities are made slightly oversize to account for alloy contraction. The more complex the part, the harder it is to control uniform shrinkage.

2. Internal Voids (Shrinkage Porosity)

   As thick sections cool slower, they draw material from within—creating internal pockets. Proper gating and overflows help mitigate this.

3. Warpage / Distortion

   Uneven wall thickness or inadequate cooling leads to residual stress and bending—especially in large, flat parts.

🛠️ How LVIO Compensates:

• We work closely with toolmakers to scale cavity features based on 3D simulations

• Use flow & solidification analysis to predict high-risk zones

• Recommend design modifications—like ribs or uniform wall thickness—to reduce thermal imbalance