Which Process is Right for Your Project?
Rather than pit these two processes against one another, we'll simply run through some key considerations when it comes to settling on a casting process. Keep in mind that there isn't a one-size-fits-all solution. Each product, project and company are different. Review the 7 considerations below to decide whether investment casting (IC) or die casting (DC) fits the bill.
1. Design Complexity
How complex is your design geometry? This will play a major part in selecting the right process. IC offers great design flexibility since you can cast intricate shapes and easily incorporate design features, such as logos and other information, into the component. You can also achieve precise dimensional results, complex geometries and thin-walled parts. DC offers good dimensional results but cannot produce the level of intricacy that IC can.
2. Material Selection
A wide range of alloys (including both ferrous and non-ferrous metals) can be used in IC, offering greater material options than DC. This allows for casting alloys that might be challenging to machine. Most DC are made from non-ferrous metals like zinc, copper, aluminium, magnesium, lead, pewter and tin-based alloys.
3. Annual Usage
One of the biggest misconceptions about IC is that it only makes sense for large order quantities. While you can opt for IC for smaller production runs, the final call usually comes down to tooling costs. Start by deciding your desired payback period for the tool and crunch some numbers to see if IC is actually the best option. DC is ideal for large production runs and high-volume projects since it produces excellent consistency and repeatability but comes with a higher tooling price tag.
4. Part Size
IC can accommodate parts from an ounce up to about 200 pounds. There is some limitation to the size of parts that can be investment cast simply because the wax pattern must be securely gated to a sprue for repeated dipping in the ceramic slurry. DC also comes with its own size limitations, but they tend to be less restrictive than IC; however, the larger the part, the larger the tool, the larger the tooling cost.
IC can really deliver on tight tolerances, while DC produces good tolerances. As a general rule, the smaller the casting, the greater the dimensional accuracy. Very large investment castings might lose some dimensional accuracy, so DC could be a better option for large-scale pieces.
IC ordinarily costs more than DC because it's a highly manual process that produces superior dimensionality and excellent surface finishes. But the final cost truly comes down to tooling. IC can be designed for minimal machining, reducing both time and cost. DC comes with higher tooling costs and typically requires at least some secondary machining to properly finish the product. For these reasons, DC is most cost-efficient for high-volume runs.
7. Finish Requirements
The surface finish of IC is superior to other casting methods, reducing the need for excessive secondary machining. A 125 micro finish is standard, and better finishes can be achieved with the help of other finishing techniques like polishing or blasting. While DC produces good surface finish, more machining is usually needed to get the product to its final state.