Urethane Casting Services

Large batch prototypes through our sister company Mack Prototype


Urethane casting offers a versatile and cost-effective method to bring your prototypes, parts, and products to life. Whether you are embarking on a prototyping journey or seeking a streamlined approach for low to medium production volumes, our urethane casting services are designed to accommodate your project’s unique requirements. 

Urethane casting, also known as polyurethane casting, is a dynamic manufacturing process that bridges the gap between rapid prototyping and full-scale production. It involves creating parts and prototypes by using molds and casting liquid polyurethane material into them. Urethane casting is often used to produce low to medium volumes of parts with complex geometries and functional prototypes. With its exceptional precision and ability to simulate various materials and properties, urethane casting has become the go-to choice for industries ranging from aerospace to consumer goods.

Our experienced team is not just about casting; it’s about transforming your conceptualizations into tangible reality. We bring a wealth of expertise to the table, ensuring that each project benefits from precision, efficiency, and a keen eye for detail. From material selection to the finishing touches, we are dedicated to delivering results that surpass expectations.

Mack group logo pic showing hierarchy of 3d printing services.

As a part of Mack Group, Synectic has the resources and internal network necessary for rapidly scaling designs from prototype development to production. With our vertical integration model, you get collaboration between companies benefiting you by:

  • Keeping your project, including design, prototyping, and manufacturing, in one place.
  • Producing products quicker without costly overhead.
  • Reducing issues seen with traditional design transfers by 95%.

Under our direction, Mack Prototype will cast your urethane parts for assembly at Synectic’s new product introduction area. As you scale up and graduate to high-volume production, we will be with you every step of the way as your product gently transfers to one of Mack Molding’s manufacturing facilities.

Request a urethane casting quote from Mack Prototype

Looking for cost-effective large batch prototypes?


Prototyping & Product Development

Whether you're an inventor, product designer, or engineer, we can transform your ideas into tangible prototypes. Urethane casting allows for the quick creation of functional prototypes, saving time and resources in the development process.

Custom Part Production

We excel at producing low to medium-volume runs of custom parts. Urethane casting offers an excellent alternative to costly injection molding for smaller production quantities, with no compromise on quality.

Material Variety

One of the key advantages of urethane casting is its ability to simulate a wide range of materials, from rigid to flexible, translucent to opaque. This flexibility makes it a suitable choice for diverse applications.

Tolerance and Precision

Our state-of-the-art equipment and experienced team ensure that your urethane cast parts meet precise specifications and tolerances. This makes it ideal for industries where accuracy is paramount.



In this white paper we explore the world of urethane casting, its benefits, applications, and why it is a game-changer.


Master Model Creation

Your project begins with the creation of a master model. This model is typically fabricated using advanced manufacturing techniques such as 3D printing, CNC machining, or traditional sculpting methods. This master pattern undergoes a finishing process, receives a light primer paint, and is then affixed to a parting line board. Additional components, like cores or side actions, are incorporated at this stage to ensure the completeness and accuracy of the master pattern. The master model is the cornerstone of the entire process, and its precision and quality directly impact the final cast parts. This step requires careful consideration of your design, as any imperfections or inaccuracies in the master model will be replicated in the subsequent urethane castings.

Mold Making

With the master model in hand, the next step is to create a mold that will be used to produce multiple copies of your parts. Silicone rubber is commonly used to make molds due to its flexibility, durability, and ability to capture intricate details. The master pattern, now positioned on the parting line board, is enveloped on one side by a mold box. This box is subsequently filled with RTV silicone rubber, creating the first half of the mold. After the silicone rubber cures, the parting line board is detached, and the process is repeated for the other half of the mold. This meticulous construction of the mold ensures precision and fidelity to the original master pattern.

Urethane Molding Preparation

Following the creation of the mold, the master pattern is extracted and preserved, serving as an engineering model or enabling the generation of additional molds as needed. The mold is now prepared and primed for the urethane molding phase.

Urethane Molding Process

This crucial step injects a conventional polyurethane resin into the RTV mold at low pressure. The resin is then allowed to cure within pressurized tanks maintained at 65 PSI for a specified period, ensuring the proper material density is crucial for the final parts’ desired characteristics.

Precision Meter Mixing

Mack Prototype employs a precision meter mixing system to facilitate rapid part production. This system is adept at handling UL94-VO rated, 80D polyurethane, available in either black or white. The resulting material exhibits a notable heat deflection of 200º F. Alternatively, a manual mix and gravity pour process can be employed for projects requiring different material properties.

Part Removal and Finishing

Once your cast parts have fully cured, they are carefully removed from the molds. The post-extraction phase involves thorough finishing work to eliminate any excess flash and ensure standard part cleanup. Additional finishing steps are undertaken for a polished and aesthetically pleasing final product. This may include painting the parts to meet specific aesthetic requirements, a particularly important consideration for elements with customer-facing surfaces. Any fine features or dimensions requiring tight tolerances can also be machined in the post-processing phase.

Urethane Casting Frequently Asked Questions

Urethane casting, also known as polyurethane casting or vacuum casting, is a manufacturing process that uses liquid polyurethane resins to create production-quality replicas of a master model. It’s commonly used for rapid prototyping and low to medium production volumes.

Advantages include cost-effectiveness for low to medium volumes, rapid prototyping capabilities, material versatility, the ability to replicate complex geometries, and quick turnaround times.

Urethane casting finds applications in various industries, including aerospace, automotive, medical, consumer goods, electronics, art, and more. Its versatility makes it suitable for a wide range of projects.

Urethane casting materials can simulate various properties, including hardness, flexibility, transparency, and color. The specific material chosen depends on the desired characteristics of the final part.

The lifespan of a silicone mold depends on factors such as the complexity of the mold, the type of urethane material used, and the number of casting cycles. Typically, silicone molds can be used for multiple casting cycles before replacement.

No, urethane casting is best suited for low to medium production volumes. While it offers cost-effective solutions, other manufacturing methods like plastic injection molding may be more efficient for large-scale production.

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