Metal Casting

Die Casting Cost Per Part: Tooling, Cycle Time, and Alloy Cost

Die casting cycle time = fill time + intensification time + solidification + die open/close + spray cycle. Here is how to calculate it, where the time goes, and how thermal analysis identifies improvement.

Die casting cycle time = injection/fill time + intensification time + solidification time + die open time + part ejection time + spray/blow-off time + die close time. For a medium-size aluminum die casting, typical breakdown: fill time 0.03-0.1s, intensification 1-3s, solidification 8-20s, die open 2-4s, ejection 1-3s, spray 6-15s, close 2-4s. Total: 20-50 seconds. Solidification is usually the largest single element, accounting for 30-50% of cycle time. Spray cycle is the second largest and the most adjustable without metallurgical risk.

Solidification time is determined by alloy, wall thickness, and die temperature. Thinner sections solidify faster. A 3mm wall aluminum section solidifies in approximately 5-8 seconds under typical die temperature conditions (180-250C for aluminum alloys). Increasing die cooling (more circuits, higher flow, lower coolant temperature) directly reduces solidification time. For every 10C reduction in die temperature at the critical thick section, solidification time typically decreases 8-15%.

Spray cycle optimization is the fastest way to reduce cycle time without changing the die or alloy. Spray parameters that affect cycle: spray time, mist vs. blow-off ratio, and coverage pattern. A spray that covers 90% of the die in 8 seconds versus 12 seconds saves 4 seconds per cycle. Robotic spray systems with optimized programs achieve better coverage and shorter spray cycles than manual spray. On a 35-second cycle, reducing spray from 12 to 7 seconds is a 14% cycle reduction.

Die temperature control is the fundamental variable. Uncontrolled die temperature leads to flash, porosity, and cycle time variation. Thermal regulation systems (TRS) that actively control die temperature within ±5C dramatically improve dimensional consistency and enable cycle time reduction by allowing controlled fast cycles rather than conservative cycles with large buffers for temperature variation. TRS investment ($15,000-$40,000 per die) pays back in yield improvement and cycle time reduction within 6-18 months on high-volume programs.

Porosity is the primary quality cost driver in die casting. Gas porosity from air entrapment and shrinkage porosity from solidification both weaken parts and cause machining blow-outs. Reducing porosity requires: proper venting design, controlled injection velocity profiles (slow first stage, fast second stage), reduced die lubricant application (excess lubricant generates gas), and degassing of the alloy melt. X-ray inspection on critical machined areas identifies porosity before expensive machining, but the real fix is process control that prevents it.

Published 2026-05-28.