Elastomeric Polyurethane (EPU) 45 is a high-performance photopolymer resin engineered for the Carbon Digital Light Synthesis™ (DLS™) process. This material stands out for its unique combination of elasticity, durability, and exceptional energy-damping capabilities. Designed to behave like a high-performance elastomer, EPU 45 enables the production of rubber-like parts that are not only flexible and tough but also adept at absorbing impact forces, making it a pivotal material for creating functional prototypes and end-use components in demanding industries with additive manufacturing services.
EPU 45 is a strain-rate-sensitive material, meaning it stiffens dynamically in response to high-velocity impacts to dissipate energy more effectively. At lower-impact speeds, it remains soft and flexible for comfort. This characteristic allows for the creation of complex lattice geometries that are tuned for both comfort and protection, outperforming many traditional foams and elastomers in its ability to manage impact energy.
With a Shore A hardness of 77A, EPU 45 provides a firm yet flexible feel. It possesses a high elongation at break of 290%, allowing it to stretch and deform significantly without tearing or failing. This resilience, combined with a tear strength of 28 kN/m, makes it highly durable for parts that must endure repeated flexing, compression, or stretching during their operational life such as parts made using injection molding tooling.
For product developers, particularly in the medical device sector, material safety is paramount. EPU 45 has been tested and meets the requirements for USP Class VI certification, which indicates a high level of biocompatibility. This makes it a suitable candidate for certain skin-contact devices, such as comfort padding, seals, or wearable components where patient safety is a primary consideration.
EPU 45 maintains its functional properties across a viable temperature range for many components, with a glass transition temperature of 86°F (30°C). It also exhibits good hydrolysis resistance, allowing it to perform reliably in humid environments without significant degradation of its mechanical properties over time.
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The primary use for EPU 45 is in protective equipment where energy absorption is critical. Its ability to dampen force makes it ideal for helmet liners, athletic padding, and protective gear inserts. By leveraging complex lattice structures, designers can create parts that are lightweight, breathable, and offer superior protection compared to conventional foam materials.
The rubber-like consistency and good compression set of EPU 45 make it a strong choice for producing custom gaskets, seals, and flexible connectors. It can create a reliable seal that prevents leaks and withstands repeated compression cycles. This is particularly valuable in creating custom sealing solutions for complex assemblies where off-the-shelf options are not suitable.
In industrial machinery, electronics, and automotive components, unwanted vibrations can lead to noise and component failure. EPU 45 is used to create custom dampers, grommets, and isolators that effectively absorb these vibrations, leading to smoother, quieter, and more reliable products. The design freedom of additive manufacturing solutions allows these parts to be perfectly tailored to the geometry of the assembly.
Given its biocompatibility, EPU 45 is increasingly used in the medical field. It is a material of choice for components like comfort pads on patient-worn devices, soft-touch grips for surgical instruments, or flexible grommets used in medical equipment. Its use can enhance both the performance and the patient-facing qualities of products developed through medical injection molding and additive processes.
The most direct counterparts to EPU 45 in the world of traditional manufacturing are Thermoplastic Polyurethane (TPU) elastomers. Like EPU 45, TPUs are widely used in injection molding for their toughness, abrasion resistance, and broad range of durometers. Both materials offer a similar rubber-like feel and are mainstays in producing parts that require flexibility and durability, such as footwear components, caster wheels, and industrial belts. TPUs are celebrated for their high tear strength and resistance to oils and chemicals, properties that EPU 45 also exhibits to a strong degree.
Where EPU 45 distinguishes itself is not in raw material properties alone, but in how it leverages the Carbon DLS additive process. While injection-molded TPU is ideal for high-volume production of relatively simple, uniform parts, it is limited by the significant upfront cost and time associated with creating molds. EPU 45 allows for the production of highly complex geometries, such as intricate lattices and internally structured components, without the need for tooling. This empowers engineers to design parts that are functionally optimized for performance, like variable-density padding, in ways that are impossible or cost-prohibitive with traditional molding. It provides a bridge from prototyping to production using the same high-performance material, offering a level of design freedom that traditional elastomers cannot match.
While highly capable, EPU 45 and the additive process used to print it generally carry a higher per-part cost compared to high-volume injection molding with commodity TPUs. This makes it less economical for very simple, mass-produced items where the advanced geometric capabilities are not required.
For producing hundreds of thousands or millions of simple parts, the cycle times of plastic injection molding are unmatched. While the Carbon DLS process is one of the fastest additive methods available, it cannot compete with the speed of traditional molding for high-volume, low-complexity components.
Printing with EPU 45 requires adherence to design principles specific to the DLS process. Factors such as support structures, part orientation, and designing for proper drainage of the liquid resin must be considered to achieve successful prints. This can introduce a learning curve for design teams accustomed only to designing for injection molding.
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Choosing EPU 45 is a decision to prioritize performance, design freedom, and speed to market. This material is the ideal solution when creating elastomeric parts that demand exceptional impact absorption and resilience that go beyond what conventional materials can offer. Its true strength lies in its synergy with the Carbon DLS process, enabling the production of previously impossible geometries that are optimized for comfort, breathability, and protection. For industries like medical and high-performance consumer goods, EPU 45 allows for the creation of differentiated products with tangible benefits. It is the perfect choice for final parts where performance cannot be compromised and where custom, complex designs provide a competitive advantage.
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