Investment Castings Manufacturers and Supplier

Lost-wax casting is a precision casting process that involves creating a wax model, which is then coated with a ceramic shell. The shell is heated, causing the wax to melt and flow out, leaving a cavity. Molten metal is then poured into the cavity, and after cooling, the desired metal casting is formed. This method allows for the production of complex shapes and high-precision parts, making it widely used in industries such as aerospace, automotive, and medical equipment. The advantages of lost-wax casting include high surface finish quality, excellent dimensional accuracy, and high material utilization efficiency.

History of Investment Casting

The origins of lost-wax casting can be traced back to the late Neolithic period. Around 3500 BCE, the earliest examples of lost-wax casting appeared in regions such as Mesopotamia, Egypt, India, and China, where people used this technique to create bronze objects, jewelry, religious artifacts, small statues, and other metal tools. With advancements in material science, the lost-wax casting process further evolved, and the introduction of ceramic shell technology improved the quality and precision of castings. Lost-wax casting has developed into a highly precise craft, widely used in artistic creation, jewelry design, and especially in the manufacturing of industrial parts, where accuracy has greatly improved. Modern lost-wax casting now blends traditional craftsmanship with contemporary technology, continually adapting to changing demands, showcasing the progress of the technique and the relentless pursuit of fine craftsmanship.

The Application of Investment Casting

Lost-wax casting differs from conventional machining in that it utilizes multiple precision casting processes, allowing complex metal parts to be formed without compromising the mechanical properties of the material during the casting process. This method enables the creation of intricate shapes, leading to material cost savings and reduced time and expenses associated with complex machining.

The Investment Casting Process

• Mold Design and Production: The process begins with the client providing part drawings for evaluation of shape features and intended use, followed by the design and production of the wax injection mold, typically made of aluminum alloy.
• Wax Pattern Creation: Wax injection is used to create wax patterns of the required parts. Multiple wax patterns are attached to a wax rod, forming a wax tree, which allows for the simultaneous casting of multiple parts, thereby improving efficiency. Before creating the mold shell, the wax tree must be cleaned to prevent release agents and dust from affecting the slurry coating process.
• Shell Making: The wax model is dipped into ceramic slurry. If necessary, the wax model is rotated to ensure even coating thickness. After being coated with slurry, refractory sand is sprinkled over the model to enhance the mold's strength and heat resistance. The shell is then left to dry and harden. This process is repeated multiple times to form a robust shell; larger models require more shell-making cycles.
• Dewaxing: The wax tree is placed in a boiler where high temperatures are used to melt and drain the wax, leaving behind the ceramic shell. The shell is then placed in a sintering furnace for high-temperature sintering to remove moisture and any residual wax.
• Casting: The required metal material is melted according to the specifications of the casting. The molten metal is poured into the preheated shell. Preheating the shell before casting helps prevent cracks due to temperature differences. Once the casting is completed and cooled, the shell is removed using a shell-breaking machine and sandblaster. The castings are then cut off from the tree using a cutting machine.
• Post-Processing: This stage includes removing the gating system, grinding, heat treatment, reshaping, CNC precision machining, polishing, and sandblasting to enhance the accuracy, performance, and appearance of the final product.
• Quality Inspection and Shipping: The final product is inspected to ensure it meets the drawing dimensions and appearance standards specified by the client. Once the inspection is complete, the products are packaged according to regulations and prepared for shipment.

The Materials of Investment Casting

Lost-wax casting can utilize various metal materials, including steel, aluminum alloys, titanium alloys, and brass. The ceramic materials used in the process must have excellent high-temperature resistance, strength, and chemical stability to withstand the molten metal's high temperatures. Stainless steel is a commonly used material for this purpose.

The Accuracy and Quality

The precision and quality of lost-wax casting are primarily determined by temperature control, model accuracy, the strength of the ceramic shell, and cooling speed. By strictly controlling these process parameters, casting defects such as porosity, cracks, and dimensional deviations can be effectively minimized.

Industries Served by Investment Casting Manufacturers

Due to its ability to produce complex shapes and achieve superior surface finish, lost-wax casting is widely used in fields requiring high precision and performance. Gateway uses this technology to manufacture a variety of products for customers, selecting materials and post-processing techniques according to specific requirements to meet demands for accuracy, strength, and appearance. Dimensional control begins with the wax model, and a vacuum slurry machine is used to enhance the quality of the ceramic shell, leading to high production yields that offer significant cost advantages.

Gateway's common products include:

• Safety Equipment: High-strength, saw-resistant parts such as security door lock systems.
• Transportation Industry: Engine and transmission system components for aircraft and vehicles.
• Kitchen and Bathroom Fixtures: High-standard, heat-resistant, and durable hardware.
• Industrial Equipment: Valves, pump bodies, and other components requiring high wear resistance and corrosion resistance.
• Artworks: Custom art pieces with complex shapes and various surface finish requirements.