Investment Casting, also known as Precision Investment Casting or Lost Wax Casting, is a modern improvement of the ancient lost mold casting technique.
This process has its roots in the oldest casting technologies and has seen significant development over the years. With the help of modern computer technology, robotics, and advanced casting technology, investment casting accounts for 15% of the world’s industrial cast parts. In various industries, we can see the products of investment casting.
Investment Casting Introduction
The term “investment” in investment casting historically has the meaning of “clothing” or “surrounding.” Various materials are used throughout the investment casting process. Models are typically made of wax, while shells can be made of ceramic, plaster, or plastic. The final casting can be made of almost any alloy, depending on the specific requirements of the finished product.
Investment Casting Process
Creating the Model
The first step in investment casting is to create a wax model. The wax pattern is designed to have the same details as the finished part. To reduce co-production of the product, the wax pattern usually leaves thermal shrinkage allowance.
Attaching the Wax Model and Creating the Tree
After the wax pattern production, multiple wax components must be assembled into a wax tree to form a pouring system, with gates and runners. The design of the pouring system depends on the required finished part’s size and configuration; one tree can handle multiple wax patterns.
Creating the Mold Shell
After the tree assembly, the mold shell must be created. The entire wax model component or tree is dipped into a ceramic slurry, covered with refractory sand, and then dried.
To achieve the required shell thickness, this process is repeated several times. The shell’s thickness partly depends on the product’s size and structure.
Once the ceramic shell is dried, it will become sturdy enough to retain molten metal during casting.
Wax Removal
After the shell completion, the next step is wax removal. The entire assembly is placed in a steam autoclave that melts the wax in the shell, including any remaining wax soaked in the ceramic shell burned in the furnace. After the residual wax patterns and gating materials are completely removed, a ceramic mold is left with a cavity of the desired cast part shape.
Under these high-temperature operations, the strength and stability of ceramic material will significantly increase.
Melting and Casting
This step involves heating the mold to a specific temperature and then filling it with molten metal to form the metal part.
Almost any alloy metal can be used for this process. Metal melting can be chosen based on the alloy’s chemical properties, either in air melting or vacuum melting.
Shell Removal
After the casting has cooled sufficiently, the mold shell must be removed from the casting. The gates and runners are cut off the casting.
The above steps detail the specific investment casting process. If the product requires it, special treatments may be needed, including sandblasting, grinding, and machining. Finally, non-destructive testing is required to ensure the casting’s quality and integrity.
Investment Casting Applications
Investment casting is a widely used casting process. As it can produce complex and precise parts, it is widely applied in various industries. Here are some key application areas:
Aerospace Industry
Investment casting is widely used in the aerospace industry. It is employed in manufacturing critical parts of aircraft engines, including turbine blades, vanes, and other components requiring high precision and reliability. The high accuracy of investment casting products and the ability to use high-performance alloys make it an ideal choice for the aerospace industry.
Automotive Industry
In the automotive industry, investment casting can produce complex shapes and highly durable parts, including those used to produce engine components, gears, brake parts, and steering system components.
Medical Industry
In the medical industry, investment casting can provide high precision and complex-shaped products, including surgical instruments, orthopedic implants, and common medical device components.
Military and Defense
In the military and defense sector, investment casting can provide durable parts able to withstand harsh conditions, including firearms, missile systems, and other military equipment components.
Energy Industry
In the energy sector, investment casting is used to produce power generation equipment components, including gas, steam, and wind turbine components. It can also be used to produce parts for oil and natural gas extraction and refining equipment.
Maritime Industry
Investment casting can use alloys with corrosion-resistant properties, one of the reasons it is used in the maritime industry. It is employed in manufacturing ship engines, propellers, and other maritime equipment components.
Investment Casting Materials
nvestment casting offers various metallic materials for components. During the selection of metals, multiple factors need to be considered, including mechanical properties, corrosion resistance, heat resistance, and product cost. Here are some common metals used in investment casting:
Steel Alloys: Steel is one of the most widely used materials in investment casting, including carbon steel, stainless steel, and tool steel.
Aluminum Alloys: Aluminum is favored for its lightweight characteristics and corrosion resistance. Aluminum alloys are commonly used in aerospace, automotive, and electronic industries.
Copper Alloys: Copper alloys have excellent thermal conductivity and electrical conductivity. Common copper alloys include bronze and brass.
Titanium Alloys: Titanium is known for its high strength-to-weight ratio and excellent corrosion resistance, especially in corrosive environments.
Nickel Alloys: Nickel-based alloys are known for their high-temperature resistance and corrosion resistance. They are often used for gas turbine engine parts, chemical processing equipment, and high-temperature applications.
Cobalt Alloys: Cobalt-based alloys are used for their wear resistance and high-temperature characteristics. They are commonly used for cutting tools, valves, and components subject to high wear and corrosion.
Precious Metals: Investment casting is also used for gold, silver, and platinum. These metals are used in jewelry making and high-end decorative applications.
Superalloys: Superalloys are a group of high-performance materials with excellent mechanical strength, heat resistance, and corrosion resistance. They are used in aerospace, power generation, and other high-tech applications.
Advantages of Investment Casting
Investment casting has numerous advantages, making it a preferred choice in many industries. Here are some of the main benefits:
- Investment casting can produce complex designs that would be impossible otherwise, reducing the need for surface finishing and machining.
- Investment casting can also produce near-net-shape designs with excellent dimensional tolerances according to customer requirements.
- Investment casting offers flexibility in material selection, with a variety of metals and high-performance alloys available.
Investment Casting Manufacturers
Manek Casting is an investment casting manufacturer in China. If you need investment cast parts, we can offer unparalleled casting services.
At Manek Casting, we possess state-of-the-art casting equipment and an experienced technical team, as well as a professional sales team. We can provide the most economical investment casting solutions based on your requirements for part quantity, materials, and processing methods.
