What is Investment Casting? Process & Applications

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From turbine blades in aerospace to precision components in medical devices, many industries rely on parts that are strong, accurate, and complex in shape. One of the most effective ways to produce these parts is through investment casting.

This article explains what investment casting is, how the process works step by step, and where it is applied across modern industries.

What is Investment Casting?

Investment casting, also known as lost-wax casting, is a manufacturing process used to produce metal parts with high precision and fine detail. The process begins with a wax model of the part to be produced, which is coated in layers of ceramic to form a hard shell. After the wax is removed, the empty cavity inside the shell is filled with molten metal that solidifies into the exact shape of the original model.

Because the ceramic mold captures such detail, investment casting can deliver net-shape or near-net-shape parts that often require little or no additional machining. This ability to combine accuracy with design flexibility makes it a preferred method in industries such as aerospace, automotive, energy, medical devices, and industrial machinery.

Investment Casting Process (Step-by-Step)

The investment casting process follows a meticulous sequence of steps to transform a wax model into a high-precision metal part:

• Create Wax Pattern

  The investment casting process begins with the creation of a wax pattern. This can be done in two ways: by injecting molten wax into aluminum molds, or by using 3D printing technology to produce the wax pattern directly. Both methods aim to replicate the exact geometry of the final metal component.

• Wax Tree (Sprue) Assembly

  Multiple wax patterns are assembled onto a central wax sprue to form a structure known as a wax tree. This assembly typically consists of a main trunk and several branches, creating a complete gating system for the casting process.

• Shell Building (Dipping and Sanding)

  The wax tree assembly is repeatedly dipped into a ceramic slurry and coated with refractory sand to build a strong outer ceramic shell. After each layer is applied, the mold is left to air dry before the next coating is added.

• Dewaxing

  Once the ceramic shell is fully built and dried, the entire wax tree is placed into a high-temperature steam autoclave or furnace. The heat melts and removes the wax from inside the shell, leaving behind a completely hollow ceramic mold.

• Mold Firing / Preheating

  After dewaxing, the empty ceramic shell is fired in a high-temperature furnace. This firing process serves two main purposes: it burns off any remaining wax and moisture, and it strengthens the ceramic structure. This step increases the mold's heat resistance and mechanical strength, preparing it for the molten metal.

• Metal Pouring

  Molten metal (held at the required pouring temperature) is poured into the preheated ceramic mold. Depending on the part's specifications and complexity, either gravity casting or vacuum casting methods may be used. As the metal flows into the mold cavities, it takes on the exact shape of the original wax pattern and solidifies within the ceramic shell.

• Shell Removal

  Once the metal has cooled and solidified, the outer ceramic shell is removed using a knockout machine, high-pressure water jets, or sandblasting. This step reveals the rough metal casting underneath, ready for further finishing processes if needed.

• Cut-off and Finishing

  After casting, the individual parts are cut off from the gating system or main sprue. The remaining gates and risers are removed, followed by essential post-processing steps such as deburring, grinding, heat treatment, or machining, depending on the application requirements. In some cases, additional surface treatments such as sandblasting, electroplating, or anodizing may be applied to improve surface quality or durability. To ensure the parts meet strict specifications, quality inspections are performed to verify dimensions, tolerances, and mechanical properties.

Applications: Key Industries & Components

Investment casting is utilized across various high-stakes industries for its ability to produce complex, high-integrity parts:

• Medical Tool Components

  

  Manufacturing components for the medical industry represents one of the most demanding applications of investment casting. Unlike general industrial parts, medical devices require an exceptional level of precision, flawless surface integrity, and absolute material purity to meet stringent safety and regulatory standards.

  This field pushes the boundaries of the casting process, demanding microscopic detail, complex internal features, and burr-free surfaces right out of the mold. Common applications include surgical instruments, orthopedic implants, and dental prosthetics, where failure is not an option. The use of specialized, biocompatible materials further adds to the manufacturing complexity.

  Learn more on Grand Latitude’s website about how our advanced investment casting technology supports the production of critical medical instruments.

• Pump Components

  

  Pump and fluid-handling components are exposed to harsh working environments, including high pressure, abrasive wear, and corrosive media. To ensure reliability, materials must resist these stresses while maintaining structural integrity.

  Investment casting is well-suited for pump parts such as impellers, casings, bearing housings, and diffusers. It supports the use of corrosion-resistant alloys like stainless steel, bronze, and nickel-based materials, helping manufacturers achieve durable and long-lasting performance.

  Explore more pump components on the Grand Latitude’s website.

• Valve Components

  

  Investment casting is a preferred method for manufacturing valve components—including bodies, bonnets, and balls—that require leak-proof integrity and a sound metallurgical structure. This is especially critical for valves operating in high-pressure or high-temperature service.

  The process excels at forming complex internal passages as a single piece, which minimizes the need for secondary machining and enhances the component's reliability.

  Get more insights into valve components on Grand Latitude’s website.

• Mechanical Parts

  

  In machinery and automation, components like rocker arms, connecting rods, brackets, and housings must combine load-bearing strength with stable geometry.

  By consolidating complex shapes into single castings, investment casting reduces assembly steps and welding points, resulting in improved durability and simplified production.

  Visit Grand Latitude’s website to see all mechanical parts products.

• Architectural Hardware Components

  

  In architecture and design, investment casting is ideal for producing hardware with a focus on aesthetics, such as stainless steel door handles, railing joints, and glass clamps.

  The process delivers a smooth surface finish and can faithfully reproduce fine details, making it suitable for high-end, customized hardware where both appearance and durability are important.

  Learn more about Grand Latitude’s holder for railing system.

Why Choose Grand Latitude’s Investment Casting Service?

Grand Latitude specializes in precision components for the medical field, including surgical instrument parts, such as retractors' handles. These parts require smooth surfaces, tight tolerances, and consistent quality to meet demanding safety and performance standards. By mastering these challenges, we bring the same discipline and process control to every product we handle.

Our capabilities span the full investment casting workflow: mold design, wax model creation, shell building, metal pouring and finishing. We work with a wide range of alloys and apply strict quality control at every stage, ensuring reliable results across applications from industrial machinery and fluid systems to medical instruments.

With proven experience in medical-grade casting, we help customers across industries achieve the precision, quality, and durability required for critical applications. Contact Grand Latitude today to explore the most suitable investment casting solution for your needs.