In manufacturing, the goal is to create products affordably, without compromising on accuracy, and to be able to produce such products at high volume. Of course, anyone with experience in manufacturing knows that manufacturing is about compromise, and it's usually not possible to achieve all three of these. Investment casting is a process that defies this norm, which is why it shows up consistently in crucial industries like medical devices and aerospace production.
Working with a domestic investment casting foundry could help to streamline your manufacturing process, resulting in better lead times and high-quality production. Let's look at how the process works in some more detail.
Precision Without Secondary Machining
Investment casting begins with a wax pattern that is a replica of the final part. That pattern is coated in a ceramic shell. The wax is melted out before molten metal fills the cavity. According to the Open University, the ceramic captures the fine details right down to the surface texture, meaning this process can manufacture products that meet strict dimensional tolerance requirements, including:
- Components that contain thin walls
- Components that have complex curves
- Products that have intricate internal passages
This precision impacts costs. Every machining operation that is no longer required reduces your expenses and speeds up the process. On parts with complex internal geometry, secondary machining may not even be physically possible without investment casting, getting the shape close first.
Cost Structure at Low and Mid Volume
The tooling costs for investment casting are relatively low when compared to processes like die casting or injection molding. The wax injection dies are typically machined from aluminum rather than hardened tool steel. This brings the tooling costs at a domestic investment casting foundry down significantly.
Speed and lower cost of entry mean that investment casting is viable for smaller manufacturing runs. Using die casting to do a few hundred pieces isn't viable because the tooling expenses would outweigh profits, but such a modest production run is possible with investment casting.
The process doesn't require the massive capital equipment that die casting demands, so overheads stay proportional throughout the project.
Scalability Without Retooling
With some types of manufacturing, if the scope of the project changes during production, it adds a lot of new expenses to the project. For example, if you're doing stamping or forging, you'll need to invest in new tooling when the expected volume of production shifts.
According to the OSTI, with investment casting, whether you're creating 500 parts or 5,000, you're using the same tooling. Foundries can easily adjust by staggering pours rather than commissioning new molds.
If you're manufacturing parts susceptible to unpredictable demand, investment casting makes sense. You can also use the same process for both prototyping and production. A first-article part cast from a 3D-printed pattern can easily transition to a wax-injected production pattern without needing to change the following:
- The alloy
- The shell system
- The quality benchmarks
Trade-Offs to Consider
Of course, there are still some limitations. Design factors like wall thickness limits, alloy selection restrictions, and shell dry times all impact the process. But if you can make investment casting work, it's an affordable and versatile type of production.
If you're interested in learning more about other topics related to product development and manufacturing, see our other blog posts.
This article was prepared by an independent contributor and helps us continue to deliver quality news and information.