By Clare Scott

While additive manufacturing is a great technology on its own, it’s important not to overlook how useful it is when complementing other manufacturing methods. Take casting, for example. Metal casting is a method of production that has been around for thousands of years, which attests to its effectiveness – but that doesn’t mean it has no room for improvement. Additive manufacturing has shown itself to be an intriguing new way of creating patterns, cores, and molds for casting at lower cost and increased efficiency and accuracy.

CNC machining is the most common way of creating patterns for casting, but it has limitations that additive manufacturing can address. With AM, often-expensive tooling is not required as the pattern can be directly printed from a CAD file. CNC machining is also limited in the types of patterns it can produce, in a way that AM is not. Examples include AM’s capability of creating complex features such as internal channels or thin walls.

Pattern-making can even be eliminated altogether by using AM to create sand molds. This is quicker as it skips the step of manufacturing a pattern to be pressed into the sand and simply produces the mold from the CAD file. While AM has sped up the process of sand casting, die casting generally did not enjoy the same advantage, until recent developments from New Zealand company Foundry Lab.

Foundry Lab’s Digital Metal Casting technology begins with additively manufacturing a ceramic mold. A solid piece of metal is then placed into the mold’s reservoir and both are heated in a proprietary microwave furnace. The furnace raises the temperature of the ceramic mold until it melts the metal, filling the cavity and creating the casting. Unlike a sand mold, which breaks down after the casting is created, the ceramic mold holds its form and can be reused for multiple parts.

This could potentially be a game-changer for die casting. Traditionally, tooling for die casting can cost thousands of dollars and foundry lead times can be close to a year. This makes prototyping cast parts extremely difficult, if not impossible. CNC-machined and additively manufactured prototypes will differ in many ways from the final cast part, which makes them unattractive options.

Meanwhile, Foundry Lab’s method boasts a one-day lead time with inexpensive tooling. 3D printing the mold typically takes two to three hours, and casting the part takes 20 to 30 minutes. While digital casting’s production speed is lower than die casting, it’s still a good option for low-volume production. The method also offers engineers the option of making many inexpensive design changes while prototyping cast parts.

One misconception about AM is that it will replace older technologies like casting. This is untrue, as these technologies have been around for so long for a reason—they have many advantages that still make them the best option in many scenarios. However, AM, when used to enhance casting technologies, can make the process faster, less expensive, and overall easier.