Which materials can be used for rapid sand-cast prototypes?

Aluminum Alloys: The Standard for Prototype Casting

Aluminum alloys are the most common choice for rapid sand-cast prototypes due to their excellent castability, good strength-to-weight ratio, and wide availability. Alloys like A356 are particularly favored for prototypes because they offer superior ductility and pressure tightness, and they respond very well to post-machining and anodizing if a cosmetic or protective finish is required. Other excellent choices include A360, known for its high pressure tightness and fluidity to fill complex molds, and the widely used A380 for its overall good combination of strength, corrosion resistance, and castability.

Ferrous Metals for Strength and Heat Resistance

When a prototype requires higher strength, wear resistance, or the ability to withstand elevated temperatures, ferrous metals are used. Ductile Iron and Gray Iron are commonly cast for automotive and heavy machinery components. For applications demanding high strength or some corrosion resistance, various grades of carbon and low-alloy steel can be successfully rapid sand-cast. While less common for pure prototyping due to higher melting points, they are essential for functional validation in demanding environments.

Non-Ferrous and Copper-Based Alloys

For prototypes requiring specific properties like high corrosion resistance, excellent conductivity, or non-magnetic characteristics, other non-ferrous alloys are suitable. Copper-based alloys such as brasses and bronzes can be used. For example, Brass 360 offers excellent machinability, while Aluminum Bronze C95400 provides high strength and outstanding corrosion resistance, making it ideal for marine and industrial component prototypes.

Rapid Pattern Compatibility is Key

The defining feature of "rapid" sand casting is the use of patterns created via 3D Printing or CNC Machining. The material selection is not limited by the rapid pattern itself; these patterns can be used to create sand molds for virtually any metal that can be traditionally sand-cast. This allows our die castings Engineering team to select the optimal material based on the prototype's functional requirements—whether it's lightweight aluminum for a housing or durable ductile iron for a structural bracket—without the long lead times of traditional pattern-making.