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Vacuum Casting - Urethane Casting

Bocheng has rich experience in vacuum casting. Over the years, we have used vacuum casting technology to provide the highest quality and highest standard plastic parts for thousands of customers in all walks of life. The advantages of vacuum casting are particularly numerous, such as high efficiency, low cost, and high material selectivity. But there are certain drawbacks, such as the difficulty of dimensional accuracy control and the relatively high scrap material.

What is Vacuum Casting?

Vacuum casting is a manufacturing technique that utilizes a vacuum to pull liquid casting material into a mold, distinguishing it from injection molding, which employs a screw to push liquid material into a mold.
The process offers significant advantages, particularly for parts with intricate details or undercuts. It commences with the creation of a master model, crafted by BOCHENG using CNC machining centers or, alternatively, 3D printing. This master model is then submerged in liquid silicone, which solidifies to form the mold.
After cutting and removing the master model, the silicone mold is ready for use. During this phase, casting resin is poured into the mold, with the vacuum eliminating bubbles and air pockets for a flawless finish.
The resin part undergoes curing in an oven and is extracted from the silicone mold after cooling, which can be reused approximately 20 times. Each cast part is an exact replica of the original master model, making it an ideal solution for rapid prototyping and producing small batches of high-quality parts.

Vacuum Casting FAQ

Why would I choose vacuum casting over injection molding?

Vacuum casting presents a more cost-effective option, particularly for low volumes, and boasts unique benefits such as an outstanding surface finish.

Can I produce production-quality parts using vacuum casting?

While vacuum casting excels at crafting visually impressive prototypes, it can also be employed for non-mechanical end-use parts such as cases and covers.

What happens to the silicone mould (s)? Can I keep them?

Silicone moulds utilized in vacuum casting have a limited lifespan, typically around 20 mouldings, and are consequently disposed of after use.

If you wish to retain the 3D printed or CNC machined master model, please reach out to us directly.

Advantages of Vacuum Casting

1.Quick Turnaround

BOCHENG offers a rapid production cycle, delivering up to 20 parts in 15 days or less, depending on the part specifications and volume.


Silicone molds are less expensive than the tooling used for injection molding, resulting in low prices.

3 Capable of producing large parts

BOCHENG can provide up to 20 parts in 15 days or less, depending on part specification and volume.

4 Superior surface finish to injection molding

The vacuum process removes air bubbles and allows the material to capture fine details.

5 Color options

Coloring pigments can be added to the resin for a variety of color options.

6 Repeatability

Silicone molds can be used around 20 times before they need replacing.

Vacuum Casting Technical Specifications

Typical lead timeUp to 20 parts in 15 days or less, depends on the part specification and volumes.
Accurate± 0.3% (with lower limit on ± 0.3 mm on dimensions smaller than 100 mm)
Minimum wall thicknessTo ensure that the mold is filled properly, a wall thickness of at least 0.75 mm is necessary. For best results, we recommend a wall thickness of at least 1.5 mm
Maximum part dimensionsThe size of the mold is limited by the dimensions of the vacuum chamber (1900 x 900 x 750 mm) and by the volume of the product (maximum volume: 10 liters)
Typical quantitiesUp to 25 copies per mold (depending on the mold’s complexity and the casting materials)
Color & FinishingPigment is added to the liquid polyurethane prior to casting, custom painting and texture.

Vacuum Casting Case

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