Casting is an ancient manufacturing technique dating back to the 1890s. Two common casting techniques available today are investment casting and die casting. Although these techniques share the same basic principles, investment casting has specific differences from die casting. Investment casting involves injecting wax into aluminum cavities. On the other hand, the die casting process forces molten metal into the mold cavity under high pressure.
What is investment casting
The investment casting process is centered on the principle of lost wax casting. It involves coating the wax pattern by dipping it in a refractory slurry. At this initial stage, the mould becomes "invested" in the refractory.
Once the final coating has hardened, the wax is heated and melted, allowing the mold cavity to hold the shape of the part. The manufacturer then pours molten metal into the cavity, essentially replacing the wax mold with metal. Finally, the metal cools and solidifies inside the mold before removing the casting.
The main advantages of investment casting
Here are the various benefits of using investment casting for your project:
flexible design
Investment casting ensures design freedom, making it ideal for complex parts. It is compatible with a variety of materials, including aluminum alloys, cast iron and non-ferrous alloys. Furthermore, this casting technique is widely adaptable and has no size, shape or thickness limitations.
Tighter tolerances and complex shapes
The technology is a precision casting method that provides consistent close tolerances and complex shapes. Typical tolerances for investment casting are between +/-0.010'' +/-0.004". Unlike similar processes, investment casting helps achieve near-net shape and final shape components. Therefore, it helps avoid further post-processing and associated costs.
Excellent surface finish
The wax pattern used in this process comes with a standard 125 microfinish. As a result, it produces parts with precise and smooth surfaces that are superior to other casting processes. Investment castings do not have a parting line because only one mold is involved in their processing. Sometimes, the action doesn't need to be done.
Customizable size range
Depending on your project requirements, you can obtain small and large castings from this process. Manufacturers can cast parts as small as 0.1kg to 100kg. Furthermore, investment casting does not require a lot of demand prior to production. It can produce as low as 10 pieces while still saving costs.
What is die casting
The die casting process involves melting non-ferrous alloys and injecting them into molds that have been created within a die casting machine. There are two main industrial die casting processes:
Aluminum die casting
Hot Chamber Die Casting - This process involves melting metals and injecting them into a mold at high pressure using a hydraulic system. Suitable for low melting point metals such as zinc, magnesium, lead, and tin alloys.
Cold Chamber Die Casting – Unlike the hot chamber process, this process pours molten metal into a cold chamber and then into a mold. In this case, the pressure is higher, usually between 2000 and 20000 psi. Suitable for high melting point metals such as aluminum.
After the molten metal is injected, it rapidly cools and solidifies to form the final casting. Castings of this process vary in size and weight, making them ideal for a variety of applications.
The main advantages of die casting
While there are several advantages and disadvantages of die casting, here are the main advantages of the process:
high mechanical properties
Castings made using this process have excellent mechanical properties. When molten metal solidifies under pressure, the product appears dense, fine, and crystalline. These parts are rigid with high strength and stiffness. They are also highly conductive and durable.
High dimensional accuracy
Components manufactured by die casting maintain their dimensional accuracy over a long period of time. They also hold tighter tolerances with minimal variation. Thus, the process facilitates the manufacture of complex parts for machines that require higher precision standards. Additionally, it helps eliminate the need for further processing.
Create complex thin-walled parts
The use of aluminium die castings ensures the production of lightweight complex parts with an excellent strength-to-weight ratio. This advantage gives it an edge over many other metal castings. Die casting can make aluminum parts with a thickness of about 0.5mm. The wall thickness of zinc parts can be as low as 0.3mm.
smooth finish
Die cast parts have smooth, consistent crystalline surfaces. If you use a well-shaped mold in the right conditions, you'll get smooth and fine parts. You may not need any additional post-processing operations other than custom products. This can help you reduce overall cycle time.
Investment Casting vs Die Casting: Which Is More Cost-Effective?
When comparing the production costs of investment casting versus die casting, throughput plays an important role. If your production volume exceeds 10,000 pieces, then die casting will be more cost effective than investment casting. Due to the greater automation of die casting, manufacturers can produce more parts in less time.
Investment casting tools
On the other hand, investment casting is more cost-effective for small batches of less than 10,000 pieces. Die casting machines are more expensive, and small batch production cannot make up for the cost of die casting. Investment casting requires less machinery, which saves tooling costs. Additionally, investment castings generally do not require secondary machining. Therefore, you can save further processing costs.
If you're having trouble deciding on the best technology for your project, you'll need to seek professional help. Jccasting is ready to provide you with the best and most reliable investment casting and die casting services. Our experienced technicians are well versed in these casting techniques and will provide expert advice to help you get the best results from your project.
