Investment Casting Process
Investment casting, or lost-wax casting, was first invented thousands of years ago, but is now seen as the future for the production of high-strength and lightweight metal components. Also known as precision casting, the investment casting process is used by many industries today because of its ability to create parts with strict tolerance requirements, requiring only minimal surface finishing or machining for completion.
To help you gain a better understanding of investment casting, here is a breakdown of the process.
Investment casting is the process of coating a wax pattern with a refractory material until the wax is melted and removed. Molten metal is then poured into the remaining shell, subsequently creating a casting. There are a wide variety of materials suitable for this process, including stainless steel alloys, brass, aluminum and more.
The flexibility of being able to utilize nearly any metal material makes investment casting suitable for a variety of industries and applications, such as aerospace, food service, gas and oil, firearms and more.
In addition to producing parts of intricate shapes and sizes, investment casting helps minimize material waste and conserve energy. It also provides manufacturers the ability to cast complex parts with superb surface finishes and high dimensional accuracy.
The steps for creation are contingent on several factors, including the alloy type and size of the part being created. As a leader in investment casting, Barron Industries couples our unparalleled knowledge and experience with state-of-the-art technology to determine the best course of action for your investment casting project.
So how does investment casting work? The process itself takes anywhere from two days to a week to complete. Here’s how it all comes together.
Creating the Pattern and Mold
The first step in the investment casting process is to formulate the pattern that mirrors the finished product. The patterns are constructed with wax via a metal injection die, which are then attached to runners to form a tree-like assembly.
Once the pattern tree is assembled, it’s then dipped into a ceramic slurry and covered with a coarse material. Barron’s six-axis dipping robot ensures consistency and uniformity of shell production in intricate and complex parts. When the slurry dries, it produces a ceramic shell around the wax tree. This process is repeated until the mold shell reaches its desired thickness and hardens completely.
Dewaxing, Melting and Casting
In order to melt away the wax, the assembly is then inserted into a steam autoclave or flash fire furnace. During this time, the residual wax within the ceramic shell is burned away. Both the wax pattern and additional gating material are removed, leaving only the ceramic mold cavity of the cast part.
In order to strengthen the mold and minimize the shell’s reaction when pouring begins, it is heated to temperatures ranging from 1000F-2000F. The mold is then filled with molten metal, which creates the metal casting. Most any alloy can be utilized through this process.
After the metal is poured, it will then need cool and solidify. When the mold has cooled adequately, the shell material is removed through a variety of methods, such as water jets, hammer knockout, vibration or steel grit blasting. The completed part is then cut away from the gating and runner systems.
Now it’s time to finish the parts using different techniques, including grinding, sand blasting, machining and coating. Once completed, the parts are inspected for any surface defects or other abnormalities.
Why Choose Barron Industries?
With nearly a century of experience, the experts at Barron Industries’ investment casting foundry specialize in melting and pouring all types of ferrous and non-ferrous alloys, including high-strength stainless steel, aluminum, armor and more. By following the necessary process controls and secondary thermal treatment parameters, our team is well equipped to meet any customer’s unique requirements.
Barron is AS9100 Certified and NADCAP accredited for our in-house NDT and welding.
Contact us to learn more about our services and how we can help solve all of your casting challenges. Whether it’s discussing metallurgy, mechanical properties, or materials, we will work with you to find the casting alloy that best suits your unique application and industry.