Investment Casting: How It Works and When to Use It

Investment casting—often called lost-wax casting—produces complex, high-fidelity metal parts with excellent surface finish and minimal machining. It is the method behind turbine blades, valve bodies, and surgical instruments. This guide explains how it works, which alloys suit it, and when it beats die casting or machining.

How Investment Casting Works

A wax pattern is made, coated in refractory ceramic to form a shell, the wax is melted out, and molten metal is poured into the cavity. After cooling, the shell is broken away. The result is a near-net-shape part with fine detail and no parting-line flash. Our investment casting line handles stainless, carbon steel, and specialty alloys.

Alloys and Fidelity

Almost any castable alloy works—304/316 stainless, carbon and alloy steels, cobalt, and nickel alloys. Tolerances of ±0.2–0.5 mm and surface finishes around Ra 3.2 µm are typical, with CNC machining reserved for sealing faces and datums.

vs. Sand and Die Casting

Sand casting is cheaper for large, simple parts but rougher. Die casting is faster and cheaper at very high volume for non-ferrous alloys but less detail on complex geometry. Investment casting wins on complexity and fidelity at low-to-mid volume.

Tolerances and Finish

Cast features often need only light deburring and passivation (for stainless). Critical dimensions are machined after casting for repeatability. Heat treatment and coating are applied as the application demands.

Applications

• Aerospace and turbine — complex, thin-walled, high-temp alloys.
• Medical and dental — fine detail, biocompatible alloys.
• Valves and pumps — near-net shapes that machine little.
• Hardware and décor — high-fidelity surfaces.

FAQ

When does investment casting pay off?
Complex geometry or low-to-mid volume where machining would waste material.

Which is better: sand or investment?
Sand for big simple parts; investment for detailed, tighter-tolerance parts.

Can you machine after casting?
Yes—critical faces are CNC-machined for fit and seal.

Why Choose Huaxiao for Investment Casting

Our investment casting service pairs casting, machining, and finishing so parts arrive production-ready. See how it compares with die casting and custom fabrication. Send your model for a quote.