Impro is a worldwide leader in investment casting, a metal forming process that typically uses a wax pattern surrounded by a ceramic shell to make a ceramic mold. When the shell dries, the wax is melted away, leaving only the mold. Then the casting component is then formed by pouring molten metal into the ceramic mold.

Investment Casting Process

The investment casting process can be broken down into the following steps:

• Wax Pattern Production

Typically, the investment casting process begins with the making of wax patterns. The wax is injected into metal dies and internal features are formed. Ceramic or water soluble cores are used to create complex internal features. Wax patterns are attached to a central gating system consisting of sprue and runners, forming a casting cluster pattern. This creates the various channels which facilitate the flow of molten metal into the cavity or cavities of the mold.

• Ceramic Shell Making

The casting cluster is submerged into a slurry of fine ceramic particles, coated with coarser particles, and dried into a shell encompassing the gate system and patterns. The process will be repeated until the shell becomes strong enough to tolerate the molten metal, at which point the wax is melted away from the shell in an oven to create space for the metal material, resulting in a single-piece mold. This wax can often typically be recovered and reused.

• Pouring

After being preheated to about 1000° C, the mold is ready to receive the molten metal. The metal is ladled into the gating system and travels into the mold using the natural downward force of gravity. Vacuum or pressure may also be applied to speed up this process.

• Cooling

The filled mold and the metal inside cool and solidify into the final part shape. Cooling times depend on multiple factors, such as part size, mold thickness, and material type.

• Casting Removal

Once the metal has cooled, the mold is broken and the casting is removed. This is often accomplished through the use of water jets, though other methods may be used as well. Once the mold is removed, the gating system must also be cut off with a saw or broken off using liquid nitrogen.

• Finishing

Many investment-casted components require finishing operations like grinding or sandblasting may be used to smooth the part where it was cut or broken at the gate. Heat treatment may also be used to harden final parts.

Advantages and Applications

Investment casting has many benefits, thus the process is implemented across a wide range of industries, including passenger car, commercial vehicle, high horsepower engine, hydraulic equipment, aerospace, construction equipment, agricultural equipment, recreational boat and vehicle, medical and energy.

Advantages

Investment casting is able to eliminate the need for secondary machining after casting and provides economies of scale over multiple production runs.

With an extensive selection of alloys to choose from, final parts display highly accurate and smooth surfaces, low tolerances, and feature lower weights with thin walls. The process allows for great design flexibility, and parts of almost any size or complexity can be produced. Other methods do not provide the same tolerance capabilities.

Applications

Components created via investment casting are central in numerous industries. Examples of compatible applications include:

Turbine blades
Engines
Medical devices
Fuel systems
Turbochargers
EGR systems

Impro’s Investment Casting Capabilities

Impro is capable of meeting material specifications according to ASTM, SAE, AISI, ACI, DIN, EN, ISO, and GB standards. We have more than 100 different ferrous and non-ferrous alloys with which we cast parts using complex design criteria. Our dimensionally and geometrically complex investment castings are produced to net shape, minimizing the need for secondary machining.

Our top-of-the-line equipment and automation process controls allow for consistent and repeatable tolerances as close as ± 0.1 mm. Our castings can also be produced in a wide size range—they may be as small as 10 mm long x 10 mm wide x 10 mm high and weigh as little as 0.01 kg, or as much as 1000 mm in length and weigh as much as 100 kg.

At Impro, we pride ourselves in offering our customers the highest-quality service from start to finish. Our services include:

• In-house tooling design and manufacturing capabilities
• Prototype development
• Process research and development
• Manufacturing flexibility
• Qualification and testing
• Value-added one-stop solutions

Our global clients include companies in the automotive, aerospace, and medical industries. We employ numerous non-destructive and laboratory test methods on site in our quality lab to verify the precision of internal structures and material compositions. Our highly-skilled engineers, chemists, and technicians handle order loads from a few pieces to several million per year.

Learn More

As the global leader in investment casting manufacturing, we take pride in offering only the best services on the market. Our passion for outstanding customer service fuels our drive for excellence. To learn more about our services or discuss options for your next project, reach out to the team today.