Die casting and investment casting are popular manufacturing methods for creating complex metal parts. Each process has advantages and disadvantages, making them suitable for different applications and production scenarios.
What Is Investment Casting?
Investment casting, or lost wax casting, is a precision manufacturing method that creates complex metal parts with excellent surface finish and tight dimensional tolerances. It enables the use of various alloys, including stainless steel Casting, carbon steel casting, and nickel based alloy casting materials.
Common Applications of Investment Casting
Investment casting is favored in industries that require high mechanical performance, corrosion resistance, and accurate precision, such as:
- Aerospace: turbine blades, brackets, control system parts
- Marine hardware: propeller components, stainless steel cleats, mounting
- Oil & gas: pump housing, valve bodies, impellers, clamps
- Defense & firearms: triggers, latches, mounts
- Medical equipment: orthopedic tools, surgical clamps
- General industry: gear cases, levers, couplings
What Is Die Casting?
Die casting uses pre-made tool steel dies in the shape of the desired components. Molten material is forced into a die at high pressures and left to cool. Once solidified, the cast piece is ejected from the die using ejector pins.
Common Applications of Die Casting
- Automotive: transmission cases, brackets, wheels
- Electronics: heat sinks, housing
- HVAC: blower wheels, motor covers
- Consumer goods: appliance frames, light fixtures
- Aerospace (non-critical parts): covers
Investment Casting vs. Die Casting: Which Method is Best for My Parts?
When selecting which method is best suited for your unique production, you will want to consider the following variables:
- Material: If you are interested in using non-ferrous metals, both methods are an option, but if you would like to use copper or stainless steel alloys, then investment casting is the best option.
- Budget: Investment casting versus die casting is a more labor-intensive process that drives up the cost. Ultimately, it will come down to tooling. Die casting requires more tooling and almost always needs secondary machining processes, making it more cost-effective for longer production runs.
- Design Complexity: Investment casting offers greater flexibility in both design complexity and ability to make changes to a part. You can easily incorporate product numbers and logos with this method. Die casting can not provide this level of detail.
- Part Size: Investment casting has size limitations because the wax pattern must be securely gated for repeated dipping to make a ceramic mold. It can accommodate parts and components ranging from one ounce to about 200 pounds. With die casting, there are fewer restrictions, but the general rule is the larger the part, the larger the tooling costs.
- Cycle time: Die casting is the clear winner with the ability to produce upwards of 45 shots per minute. Additionally, this process can be fully automated vs. investment casting, which requires additional labor.
- Surface Finish: Investment cast parts have finishes superior to die casting with a standard of 125 micro finish.
- Tolerance: This depends on both the shape of the part and its material. In general, die cast parts up to 25mm start at +/- 0.050mm tolerance and increase as the part size increases. Similarly, investment cast parts of the same size start at +/- 0.250mm and will increase as the part increases.
