Investment Casting
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What Is investment casting?
Investment casting (also known as lost wax investment casting or precision investment casting) produces parts with fine detail and an excellent as-cast surface finish. Investment casting produces internal or external features, thin walls, and internal passageways to reach a near-net shape. These features often lead to significant cost savings in material, labor, and machining compared to other metal casting processes.
In investment casting, a detailed wax pattern of the finished part is created and mounted onto a wax "tree" that includes the metal delivery system (gates and risers). The tree is alternately dipped into a ceramic slurry sprinkled with stucco material and then allowed to dry. This process is repeated until a thick shell exists over the wax pattern.
The wax pattern is then melted, leaving a cavity within the stucco material in the shape of the pattern. Molten metal is poured into this cavity. Once the metal solidifies, the shell is broken away through a shakeout process, and the gating material is removed, leaving the finished part.
MetalTek produces investment castings up to 40" diameter x 34" tall (1016 mm x 864 mm) with weight up to 1,000 lbs. (454 kg) ship weight at our investment casting foundry.
Investment casting does have a couple of drawbacks. It can be cost-prohibitive with smaller production runs due to upfront setup costs. Sand or die casting might be more applicable in that scenario. Extremely large metal parts are also better suited with other methods.
See the video to the right to learn more about the investment casting process.
Air Melt Alloy Investment Casting
Air induction melting casting technology is popular in the metal casting industry. Air melting has challenges with control at times, which can be aided by vacuum technology. MetalTek specializes in lost wax investment casting in alloys resistant to heat, wear, and corrosion. We are unique as an investment casting manufacturer with our ability to cast large parts. Value engineering helps manage programs to deliver the right part on time.
MetalTek also performs most Non-Destructive Testing (NDT) functions, including penetrant inspections, magnetic particle, and radiographic tests supporting investment castings. We also provide single-source responsibility for finish machining, polishing, electro-plating, and other secondary operations.
Investment Casting Video
When to use Investment Casting
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External shaping and tight tolerances exist
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Parts are shaped or non-symmetrical with fine detail
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Multiple and/or intricate internal passageways in design
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Dimensions are small to medium, typically under 1,000 lbs./454 kg
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Excellent as-cast surface finish is required
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Wall thickness is too thin for sand casting
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High upfront tooling costs relative to sand casting are acceptable
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Low volume allows printed patterns to replace upfront tooling
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Ongoing tool maintenance costs are not desired
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Machining of internal passageways is not possible
Investment castings at MetalTek are produced at Wisconsin Investcast. They are a fully integrated investment casting foundry. They can handle production needs from rapid prototyping, design for casting, wax pattern production, shell molding, and countless testing methods.