Investment Casting Process 101: A Complete Guide

Are you familiar with the investment casting process many industries rely on for creating exact metal parts? In this blog, we’ll discuss this critical process, covering everything from how the process works to tips on finding the best-fit investment casting company partner.
For those newer to this process, let’s cover the basics first.

What is Investment Casting?

Investment casting – also known as lost wax or precision casting – creates metal parts for various industry needs with exceptional precision and complex geometries. Unlike other casting processes, investment casting allows for high levels of detail, making it suitable for materials that require complex shapes.

This casting type is a popular choice for manufacturers in industries that rely on high-quality, precise parts, including everything from aerospace to medical needs.

Truthfully, while most people don’t know this, some of the world’s most important industries rely on investment casting to do what they do – the parts created in the investment casting process help industries move forward.

How Does Investment Casting Work?

Investment casting begins by creating a wax pattern that is a replica of the part to be cast. This wax pattern is coated with a ceramic material that hardens to form a mold. Once the ceramic mold is ready, the wax is melted and drained away, leaving a hollow shell. Molten metal is then poured into the mold, filling every intricate detail.

After the metal has cooled, the ceramic shell is broken away, revealing a high-precision metal component ready for final finishing.

What Industries Use Investment Casting?

Investment casting is a highly versatile manufacturing process, ideal for industries that require precision, durability, and complexity in their components. The method produces parts that can withstand extreme conditions, fit intricate designs, and maintain strength over time, making it indispensable in the following key sectors:

Aerospace

In the aerospace industry, investment casting is essential for creating turbine blades, structural components, and other high-precision parts. These parts must withstand intense temperatures, high pressure, and prolonged stress while remaining lightweight to support fuel efficiency. Investment casting’s accuracy and ability to create complex shapes make it the preferred choice for aerospace manufacturers. These components must meet strict safety and performance standards, ensuring reliability in critical applications.

Automotive

Investment casting is pivotal in automotive manufacturing, where precision is essential for engine parts, fuel injection systems, and suspension parts. These castings must be robust and lightweight to improve vehicle performance and fuel efficiency. With the automotive industry’s high volumes and stringent quality requirements, durable, precisely cast parts ensure optimal vehicle function and safety.

Medical

The medical industry relies on investment casting to produce highly accurate, biocompatible components for surgical instruments, prosthetics, and medical implants. These parts often require intricate geometries to perform specific functions within the human body. Investment casting enables manufacturers to create these detailed shapes while using safe materials for medical applications.

Energy

For the energy sector, investment casting is critical for manufacturing components such as pump casings, valve bodies, and turbine components that must endure corrosive environments and high temperatures. Applications in power generation, oil and gas, and renewable energy demand components that maintain their integrity under challenging conditions. These durable, corrosion-resistant castings are produced to support energy infrastructure and equipment longevity, helping clients minimize maintenance costs and maximize uptime.

What is the Difference Between Sand Casting, Die Casting, and Investment Casting?

Each casting method offers unique benefits depending on production needs, cost, and material requirements.

Here’s a comparison of investment casting with sand and die casting:

Casting Type	Process Overview	Best Use	Pros	Cons
Investment Casting	Uses a wax model to create detailed metal parts	Complex shapes, high-precision	High accuracy, fine details	Longer process time, higher cost
Sand Casting	Uses a sand mold, which is broken after casting	Large, simple parts	Low cost, quick production	Rough surface, lower precision
Die Casting	Forces metal into a reusable mold under pressure	High-volume production, simple shapes	Fast, cost-effective for volume	Limited to certain types of metal

Overall, the Investment casting process excels when fine details and complex shapes are essential, making it the preferred choice for industries prioritizing quality and precision in their parts.

Overview of the Investment Casting Process

Investment casting involves several intricate steps to ensure each part meets strict specifications and high-quality standards. Here’s a breakdown of each stage in the process:

Step 1. Create the Wax Pattern

The investment casting process begins by crafting a detailed wax pattern that precisely replicates the final part’s design. This pattern is created using a wax injection mold, which shapes the wax into an exact duplicate of the intended component. Often, multiple wax patterns are joined to a central wax “tree” to allow for the creation of numerous parts in one mold.

This wax pattern is crucial. It captures every intricate detail carried through the casting process, ensuring the final metal component reflects the original design.

Step 2. Build the Ceramic Mold

Once the wax pattern is complete, it’s coated in a ceramic slurry to create a durable, heat-resistant mold. The pattern is repeatedly dipped into the slurry and sprinkled with fine sand to build up several layers, creating a thick ceramic shell around the wax. This shell is then left to dry and harden. The resulting mold can withstand the high temperatures needed for molten metal casting, preserving the exact details of the wax model. This step is essential to the investment casting process as it ensures that even the most complex designs retain their accuracy in the final product.

Step 3. Remove the Wax

After the ceramic shell fully hardens, the wax pattern is melted and drained away.

This process, often done through autoclaving (a steam-based process), leaves a hollow ceramic shell that perfectly replicates the wax model’s shape. By removing the wax, the shell becomes a precise mold ready to receive molten metal. This step ensures a seamless transition from wax model to metal casting, as the shell retains every detail without distortion.

Step 4. Cast the Metal

With the hollow ceramic shell prepared, molten metal is poured into the mold to form the final part. The choice of metal depends on the specific application and industry requirements, with materials such as stainless steel, aluminum, and various alloys commonly used. The molten metal fills the hollow cavity left by the wax, capturing all the intricate details and complex shapes.

This stage requires extreme precision, as temperature and pour rate must be carefully controlled to ensure a high-quality cast.

Step 5. Put on the Finishing Touches

Once the metal has thoroughly cooled and solidified, the ceramic shell is carefully broken away to reveal the cast part. Any remaining ceramic material is removed, and the part undergoes finishing processes to meet final specifications. Finishing may include machining, grinding, or polishing to refine the surface, ensuring the part meets exact tolerances and design requirements.

Quality inspections are conducted to verify that each component aligns with industry standards and client specifications. These finishing touches bring the casting to its final, functional state, ready for assembly or further processing.

Why is the Investment Casting Process Important?

A good investment casting process provides a high level of accuracy and detail unmatched by other casting methods, which is crucial for parts that must withstand high stress, temperature, or corrosive environments.

This process allows companies to create reliable, high-performing parts that help industries achieve consistent results and maintain safety standards.

5 Tips for Finding and Working with an Investing Casting Company

Choosing the right casting partner is essential for maximizing quality, cost-effectiveness, and production timelines.

Here are five tips to keep in mind:

1. Assess Quality Standards

Look for companies with strong quality control measures, ensuring each part meets specifications. Alcon’s commitment to quality sets them apart, and they provide consistent, reliable parts.

2. Look for a Diverse Industry Portfolio

A provider with experience across multiple industries can offer versatile solutions tailored to unique industry needs. Alcon has decades of experience in automotive, aerospace, and other sectors.

3. Evaluate Design Capabilities

The best casting companies offer design and engineering support to optimize parts before production begins, reducing costs and enhancing efficiency.

4. Validate Their Technical Expertise

Working with a team that understands the complexities of investment casting can make a difference in problem-solving and process innovation.

5. Consider Their Client Service Approach

A trusted casting partner treats clients as collaborative partners. Alcon builds lasting relationships with clients through open communication, transparency, and reliable service.

Meet the Alcon Industries Team – Professionals at Investment Casting for Furnaces

Alcon Industries combines over 40 years of expertise with a commitment to innovation, helping clients receive the highest quality castings on time and within budget.

Our investment casting process combines precision engineering with resource efficiency, producing components ideal for furnace design engineers needing specific, detailed designs. Our process minimizes material waste and energy consumption, making it both effective and environmentally considerate. With the capability to handle both low- and high-volume orders, we’re equipped to meet delivery schedules across diverse industries and applications.

Our furnace products include:

Alcon Industries’ team includes skilled design engineers, craftsmen, and support staff with decades of experience. Located in Cleveland, our team is ready to tackle challenges and create solutions tailored to your needs. Whether you need a quote, consultation, or specific part design, our team is here to help.

Ready to leverage the power of investment casting for your next project?
Contact our team today to discuss your specific needs and discover the Alcon difference!