Quais são as diferenças de custo entre fundição a vácuo e fundição convencional?

The choice between high-vacuum die casting and conventional die casting represents a fundamental trade-off between initial part cost and long-term value, as enhanced mechanical properties are achieved. While high vacuum die casting incurs higher upfront tooling and process costs, it can provide significant savings in post-processing and performance, making it a cost-effective solution for structurally critical components.

Initial Investment and Tooling Costs

The most substantial cost difference between these two processes occurs during the tooling and setup phase, where high-vacuum systems introduce greater complexity and expense.

High-vacuum die casting requires a significantly more sophisticated and robust mold design. The tool must be engineered with advanced sealing systems around vents and parting lines to maintain a very low cavity pressure (typically below 100 millibars). This involves precision-machined seals and often requires the use of higher-grade, more durable Tool Steel S7 or premium H13 Steel to withstand the demanding sealing and thermal cycles.

Furthermore, the integration of the external vacuum system—including valves, pumps, and control modules—represents a significant capital expenditure not required for Conventional High-Pressure Die Casting. Consequently, the initial mold cost for high-vacuum tools can be 20% to 50% higher than for conventional molds of similar size and complexity.

Operational and Cycle Time Considerations

The operational costs of the two processes diverge due to differences in cycle time, material yield, and part quality.

A high-vacuum process often has a slightly longer cycle time due to the critical evacuation step required before the shot. However, this is frequently offset by a major reduction in scrap rates. By removing air from the die cavity, high vacuum drastically minimizes gas porosity, resulting in a higher first-pass yield with fewer defective parts.

This directly reduces material waste, especially when using more expensive alloys such as A356 Aluminum Alloy, which are often chosen for vacuum-assisted casting to achieve maximum mechanical properties. The superior as-cast quality also means that costly non-destructive testing—such as X-ray inspection for internal porosity—may be required less frequently or with reduced scanning intensity.

Post-Processing and Heat Treatment Savings

The most significant cost advantage of high-vacuum die casting emerges during secondary processes and performance-related treatments.

Conventional die-cast parts often contain entrapped air that forms pores within the walls. These pores expand or blister during thermal treatments, making Heat Treatment risky or impossible. As a result, designers must accept lower mechanical properties or increase wall thickness to compensate.

High-vacuum die castings, being largely pore-free, are fully compatible with solution heat treating and aging processes (T5, T6, T7). This allows the alloy to reach its full mechanical potential—enabling thinner, lighter, and stronger parts. Furthermore, the improved integrity of vacuum-cast components reduces defects during Die Castings Post Machining, as machined surfaces are far less likely to expose porosity that renders a part unusable.

Summary of Cost Drivers

Conclusion on Cost-Effectiveness

The decision is application-specific. For non-structural components with simple geometry, Conventional High Pressure Die Casting offers the lowest part price.

However, for safety-critical, thin-walled, or structural components—such as those in Custom Automotive Parts or large Computer Hardware frames—the higher initial cost of high vacuum die casting is justified. It enables part consolidation, lightweighting, and superior performance, ultimately providing a lower total cost of ownership for the engineered system.