What is vacuum casting?
Vacuum casting is an advanced ...
Vacuum Casting Solutions
Experience unmatched quality and versatility with our urethane casting services. Specializing in custom formulations, we deliver durable, high-performance parts tailored to your unique specifications. From prototypes to production runs, trust our expertise to provide innovative solutions that exceed your expectations in various industries!
- Instant Quotes & DFM Feedback
- Production Grade Quality
- Parts as fast as 3 days
- All uploads are secure and confidential.
- Delivery Nationwide as Fast as 24 Hours
- Low-Volume Manufacturing
- Superior Quality Assurance
About the Urethane Casting Process
Urethane casting/Vacuum Casting or Polyurethane casting( also known as RTV molding, cast urethane, and silicone molding) is a fabrication method that uses silicone molds to produce production-quality plastic parts. At NPI, we have a massive range of plastic materials available, and we can cast parts as large and small, everything from headphones all the way up to 2m long car bumpers. This technique is ideal for creating prototypes to test your unique design.
Regarding tolerances, silicone molds can achieve approximately ±0.1 mm. After inspection and assembly, our vacuum casting services will produce additional silicone molds for more prototypes. Finished parts typically have a tolerance of ±0.15 mm. For vacuum casting parts exceeding 1000 mm in size, the tolerance can reach ±0.2 mm.
Urethane Casting Materials
Urethane cast parts are often compared to injection molding materials. For example, a tough urethane cast part may be described as an ABS-like, PC-like, or Nylon-like part. A soft and flexible material is described as “TPU-like or Rubber-like” . So our materials will be described like this.
Material
Picture
Description
Material Reference
Appearance
Soft-rubber-like
Vacuum casting is excellent choice for creating rubber parts and prototypes. Soft-rubber-like materials are useful in applications that demand flexibility and durability for industrial parts and consumer goods alike.
T0387,8400
Colorless Transparent, Yellow Transparent
PA-like
PX223, a PA-like material, is used in silicone molds for the production of parts that are highly durable and versatile with properties similar to nylon parts.
PX223
Black, Tawny
ABS-like
With vacuum casting, you can create high rigid ABS-like parts with good impact resistance and insulating properties. They are commonly used to make electronic housings, automotive parts and more.
Hei-Cast 8150, PZ858, 6160, P+600
Beige, Black, Milky white
PMMA-like
Urethane casting is a great choice for creating clear transparent parts. While inferior to true PMMA, PX-5210 has good transparency, is easy to polish, resistant to yellowing, and offers good UV resistance. This makes it suitable for a wide range of applications where clear parts are needed.
PX 5210
Transparent
PP-like
UP 5690 have mechanical properties similar to that of true PP and HDPE material. It is easy to process, has high impact resistance and good flexibility, and can be used for bumpers, equipment boxes, covers and anti-vibrant tools.
UP 5690
White, Black
PC-like
PX520 is used by casting in silicone moulds for the realization of prototype parts and mock-ups with mechanical properties similar to that of true PC material.
PX520
White, Clear
*Note: Table values are indicative. Actual specs can differ based on printer model, material, and settings. Delivery times depend on order volume and processing needs. Contact us for tailored recommendations on printing processes and parameters.
Technical Specifications for Urethane Casting
- Description
- Dimensions
Lead Time
Up to 50 parts in 10 days or less, depending on the part complexity and quantity.
Accuracy
±0.15mm/100mm, with the highest precision up to ±0.05 mm.
Maximum Part Dimensions
The vacuum chamber’s dimensions (1900 x 900 x 750 mm) and the product’s maximum volume (10 liters) determine the mold’s size limitation.
Wall Thickness
A minimum wall thickness of 0.75 mm is necessary for filling the mold properly. A wall thickness of 1.5mm～2.5mm is recommended.
Service Life of the Silicone Mold
Typical quantities are up to 20-25 copies per mold (depending on the casting materials and the mold’s complexity).
Surface Finish & Textures
Textured, colored, painted, coated, clear polished, insert, and over-molding can be obtained. Custom finishes are available for request.
Prototype and Parts Made Easy - Worldwide Delivery & Any Order Size
With many years of manufacturing experience, NPI offers the best solutions for all rapid prototyping and low to large volume manufacturing needs. We streamline the innovation cycle into four simple but effective steps.
01
Upload Your Design
02
Receive Design Analysis
03
Start Manufacruting
04
Receive Your Parts
8 Steps to Create Custom Vacuum Casting Parts
Discover how we craft custom vacuum casting parts with our streamlined 8-step process:
- Master Pattern Creation: Createmaster pattern using 3D printing or CNC machining to precisely replicate your design.
- Silicone Mold Construction: Next, create a durable silicone mold by enclosing the master pattern in liquid silicone rubber.
- Casting Material Preparation: prepare the material by mixing a two-part polyurethane resin or other casting material according to the manufacturer’s instructions. The resin is then poured into a mixing container.
- Vacuum Degassing: The mixed resin is placed in a vacuum chamber to remove air bubbles, ensuring a smooth, high-quality finish in the final part.
- Material Pouring: The degassed resin is carefully poured into the silicone mold through a designated opening.
- Curing: The filled mold is then lefe to cure for several hours, allowing the material to set and achieve its full strength.
- Part Demolding: After curing, carefully remove the part from the silicone mold, which can be reused for multiple casts (approximately 20-25 times).
- Finishing Touches: The final step involves trimming or sanding the part to eliminate any excess material or imperfections.
This efficient process allows us to deliver high-quality, custom vacuum casting parts tailored to your needs.
Surface Finishes for Urethane Cast Parts
The smooth, satiny texture of the parts results from the matte bead-blasting of the master pattern. Thus, transparent and translucent components with this finish will look frosted. The use of matte finishes confers benefits for frequently touched areas, as the visibility of fingerprints is reduced.
Semi-gloss finishes are characterized by some sheen, but not as much as high-gloss finishes. They fall between high-gloss and matte and leave a smooth, effortless-to-clean surface.
Creating a highly reflective, glossy finish requires polishing the master pattern before making the mold. The high gloss with a lot of sheen, provides the greatest degree of transparency for transparent components. High gloss finishes are handy for lenses, cosmetic models, and cleanable surfaces.
Before creating soft tooling, the master pattern is textured using paint and manual techniques. This improves grip and reduces scuff marks, especially on high-use surfaces like handles.
Runsom Precision offers post-processing services such as secondary finishing and painting options.
Precision Vacuum Casting for Diverse Industries
High-Quality Silicone Molding Parts
Vacuum Casting FAQs
Vacuum casting is a manufacturing process that involves creating parts by pouring a liquid material (usually polyurethane or other resins) into a silicone mold. This technique allows for high-precision prototypes and low to medium volume production runs.
The most common materials used for vacuum casting are polyurethane resins. However, various grades of polyurethane can be utilized to achieve different physical properties, including flexibility, hardness, and temperature resistance. Some other resins may also be used depending on specific project requirements.
The entire vacuum casting process can typically take a few days, depending on factors such as the complexity of the part, curing times, and the number of parts being produced. Creating the silicone mold itself may take 1-3 days, while curing the casting material usually requires several hours.
A silicone mold can usually be used to produce 20-25 parts before it starts to lose precision and detail. After this, the mold will likely need to be replaced to maintain high accuracy and quality.
Yes, vacuum casting is excellent for replicating fine details, making it an ideal process for creating high-fidelity prototypes and aesthetic models. The silicone mold captures intricate details from the master pattern effectively.
A silicone mold is created by surrounding a master pattern (which is often made using 3D printing or CNC machining) with liquid silicone rubber. Once the silicone cures, it forms a flexible mold that can be reused multiple times.
Post-processing is often necessary to achieve the desired surface finish. This may involve trimming, sanding, polishing, or painting parts. The level of finishing required will depend on the application's specific aesthetic and functional requirements.
When designing parts for vacuum casting, consider the following:
- Draft angles for easy demolding
- Wall thickness (generally between 2-5 mm)
- Reduced undercuts
- Fillets and radii to improve mold strength and finish
- Draft angles for easy demolding
- Wall thickness (generally between 2-5 mm)
- Reduced undercuts
- Fillets and radii to improve mold strength and finish
Yes, vacuum casting is typically suited for lower volume production and may not be the best option for very high-volume runs. Additionally, the range of materials available is more limited compared to injection molding, which can utilize various thermoplastics.
Yes, vacuum casting can produce functional parts, particularly for prototyping and testing. However, for high-performance applications requiring specific mechanical properties, injection molding or other methods may be more suitable.
Vacuum casting generally incurs lower initial tooling costs, making it more cost-effective for low to medium production volumes. Injection molding has higher upfront costs due to the steel molds but offers lower per-unit costs for larger production runs.
Turnaround time can vary based on part complexity, volume, and existing workflow, but it typically ranges from 1 to 2 weeks from design approval to final parts delivery. For expedited orders, we can achieve quicker turnaround times.
Yes, certain polyurethane resins can be formulated to be transparent or come in various colors. This allows for aesthetic versatility in prototypes and product designs.
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