Top 3 prototyping methods for die casting

What do you need from your prototype?

These days, consumers demand perfection from their products. To achieve this level of performance, manufacturers must put their products through rigorous testing to ensure optimal functionality. In many cases, tests take place over several iterations and require different levels of functionality throughout. Each of these tests requires an effective prototype.

Do you need to verify the strength of your component? Does your product require exact tolerances, and do you need to check the fit of the part? Do you need to revise the wall thickness in sections of the part for weight or fit?

The die casting process is not typically well suited to low-volume prototyping. However, that does not mean we cannot support you during the prototyping process. We have compiled an overview of the top three prototyping processes our customers use to test their die casting components. 

Spin casting

Spin casting is a process that forces metal into a rubber mould using centrifugal force. While spin casting was previously limited to materials specially formulated for low melting points, the process has evolved over time to produce components from materials similar to those used in die casting. Even if a spin caster cannot use the exact same material as a die caster, secondary heating operations can enable the spin-cast part to achieve the strength of a die cast component while retaining its exact geometries. The more complex the part, the more beneficial the spin casting process.

Prototyping with spin casting is ideal for low-volume projects with complex geometries that require a fast turnaround. Spin-cast parts can achieve virtually the same geometries and similar strengths as die cast parts, making them ideally suited to testing component fit during the prototyping process. Spin-cast parts have a lead time of approximately 1-3 weeks.

Machine from bar stock

Machining from bar stock is a process that provides speed and cost efficiency at low volumes. The process itself is fairly simple: a purified metal billet is cut to the required part size and shape using a lathe or CNC machine. At low volumes, the process is faster and less expensive than other manufacturing methods because the material is readily available and no tool needs to be designed or built. The drawback of machining from bar stock is that the part has low ductility and tolerances are limited by the radius of the cutter—in other words, the tolerances and geometries cannot be tighter than the curvature of the cutting mechanism itself.

If your prototype needs to pass stringent elongation and tolerance tests, machining from bar stock is not an effective option. However, the process is a good prototyping option for projects operating within a strict budget and timetable. Lead times for machining from bar stock can be as short as 1 week.

Machining from bar stock is also an effective way to assess the ultimate strength of die cast components. Generally speaking, parts machined from bar stock are approximately 15% weaker than die cast components in terms of ultimate and yield strength, as machined parts do not have the "skin" of a die cast component. However, our customers have often used machined prototypes to test the ultimate strength of their components. If the machined prototype passes a stress test, the die cast component will withstand even greater stress. If your component will be cast in aluminium in mass production, machining from a zinc and aluminium blend alloy can match the strength of an aluminium die cast component.

Want to know how to match a machined alloy to the strength of a die cast component? Contact one of our engineers to learn about machining prototyping possibilities.

Investment casting

For projects that require exact replica prototypes, we recommend investment casting. Since much can be learned from a prototype's function, the need for a quality prototype is critical. When designing metal components, an exact replica of your final part is the best prototype available. Investment casting enables design engineers to obtain a prototype with the exact geometry, tolerance, strength and function of the final die cast component. This is especially important for aluminium die castings used in applications subject to rigorous safety testing.

The investment casting process as a whole is well suited to low-volume metal components. However, the process can be slightly modified to meet prototyping requirements in a fraction of the time. Instead of building a hard tool, investment casting engineers can 3D print wax patterns to form part geometries, reducing lead time and cost. The part can then be cast normally using any investment casting metals. The resulting prototype is an exact replica of the final die cast part, so any secondary operation required by the customer can be applied to the part, including assembly, heat treatment, welding, plating and painting.

3D printed wax pattern and prototype produced in-house with our sister company, Signicast.

As with any manufacturing process, the price of a prototype increases as dimensional tolerance and inspection criteria become more stringent. Early involvement and input from technical engineers during the design stage enables customers to overcome traditional casting tolerance issues associated with prototyping. This is achieved through innovation and industry-leading technology to provide 100% conformance to specifications as-cast, delivered on time and at the lowest total cost. Prototype lead times with investment casting vary depending on part complexity, but generally take between 5 days and 4 weeks.

Which prototyping process is right for me?

The best prototyping process for your die cast component depends on many factors. You must consider budget constraints, material restrictions, the testing timetable and the rigour of the tests your prototype will undergo. If you are still unsure which process is right for you, contact one of our Dynacast engineers. We can manage your prototyping requirements and ensure your project has a strong foundation for transition to die casting mass production.