The Versatility of Vacuum Casting
Accelerate Your Design Process with Rapid Prototyping and Low-Volume Production
This blog post revisits the well-known vacuum casting (occasionally known as urethane casting or RTV) process, focusing on its practical application for engineers familiar with prototype development and low-volume production.
Why Choose Vacuum Casting?
Engineers value efficient and cost-effective solutions. Here’s how vacuum casting as a prototyping to production technology delivers:
- Versatility: Vacuum casting allows for a wide range of material properties, from rigid and high-strength urethanes to flexible and elastomeric formulations. Tailor the material to your specific application demands.
- Rapid Prototyping: Vacuum casting excels at creating complex parts with fine detail quickly, accelerating your design validation process.
- Economical for Short Runs: Compared to traditional casting methods, vacuum casting offers a cost-effective option for low-volume production runs, ideal for small batches or pilot projects.
Vacuum Casting Process Breakdown
- Master Pattern and Mould Creation:
- Your supplier will utilise your existing design files to create a master pattern through methods like CNC machining or 3D printing if the part has intricate detailing or is complex.
- A high-quality silicone mould is then created by encapsulating the master pattern with liquid silicone. Once cured, the mould is split open, allowing for master pattern removal.
- Urethane Mixing:
- Most vacuum casting utilises two-part urethane systems consisting of a resin and a hardener. Precise mixing is crucial for proper curing and a uniform final product.
- Vacuum Casting:
- Unlike traditional casting, the mixed urethane is poured into the silicone mould within a vacuum chamber. This vacuum environment removes trapped air, ensuring the material fills even the most intricate features of the mould.
- Curing:
- Curing time depends on the specific urethane formulation and part size. Some cure at room temperature, while others require heat for faster processing.
- De-moulding and Finishing:
- After curing, the mould is carefully opened to extract the cast part. This may involve minor trimming or finishing touches to achieve the desired final specifications.
Vacuum Casting Material Options:
A spectrum of urethane materials caters to diverse engineering needs:
- Rigid Urethanes: Ideal for components requiring high strength and dimensional stability.
- Flexible Urethanes: Excellent for components requiring flexibility and impact resistance.
- Clear Urethanes: Well-suited for applications demanding optical clarity, such as lenses or prototypes.
- High-Temperature Urethanes: Perfect for components exposed to elevated temperatures without compromising performance.
Applications of Vacuum Casting in Engineering:
- Rapid Prototyping: Vacuum casting facilitates the creation of functional prototypes quickly and cost-effectively, enabling rapid design iteration and validation.
- Low-Volume Production: Vacuum casting offers a cost-efficient solution for producing small batches of specialised components or custom parts.
- Functional Parts & Encapsulation: Vacuum casting produces high-quality parts for various applications, including electrical components, housings, and functional prototypes.
Vacuum casting presents a valuable tool for engineers by offering a versatile, rapid, and cost-effective method for prototyping and low-volume production. Its ability to accommodate complex geometries and a wide range of material properties makes it a compelling choice for diverse engineering projects.
