Fremont, Calif.-based additive manufacturing company Uniformity Labs has taken solar-powered car racing to the next level with its new AlSi10Mg aluminum alloy powder. The material has been shown to deliver increased throughput with ultralow porosity, yielding lightweight yet strong components.
One of the greatest limiting factors of solar car racing is that the vehicles are by definition limited to one energy source: the sun, which comes with intermittent reliability, and battery packs can be heavy, creating an efficiency conundrum. For this reason, vehicle design for solar cars is paramount. Carmakers must optimize the design for several factors, including aerodynamics, power efficiency and weight. Yet, Uniformity Labs may have taken a big chunk out of the battery weight problem.
Although Uniformity’s AlSi10Mg powder and corresponding optimized print processes have been applied to various components for multiple industries, the solar race car application illustrates its real-world utility. The company recently produced a roll cage for a solar race car on an in-house SLM 280 2.0 Dual Laser Powder Bed Fusion 3D printer using AlSi10Mg powder. The car is slated to compete in the 2021 Bridgestone World Solar Challenge, which invites teams to test their solar cars and be recognized for the skill and dedication required to build them. The international event, held on a 3,000-kilometer route through the Australian Outback, will be virtual this year due to the coronavirus pandemic, and it is designed to promote efforts to drive technology, innovation and sustainability further.
Through its new material, Uniformity achieved a roll cage with a 30 µm layer thickness that performs as well as a 60 µm thickness print. In addition, the company described the material as having a “fantastic surface finish” with “best-in-class” properties.
“This is an excellent example of how our innovation can significantly improve part design using our advanced powders and modern AM techniques,” said Adam Hopkins, founder and CEO of Uniformity Labs. “Our ultra-low porosity AlSi10Mg and print processes allowed the car development team to create a better part quickly, cheaply, and optimized for the necessary weight and safety parameters.”
The vehicle engineering team employed topological optimization techniques to design the AlSi10Mg roll-cage component with high strength and low material weight. Given that the project's cost and material performance were essential factors, the team opted for Uniformity’s AlSi10Mg powder rendered with additive manufacturing over a less promising carbon fiber.
The solar race car application may be just a taste of how AlSi10Mg could be used. With the heightened need for sustainable energy systems, especially in the transportation sector, lightweight components that can perform as well as heavier ones will be a boon, as they will boost efficiency.
“It’s easy to see how the processes used, and benefits afforded to the roll-cage production can apply to the creation of complex parts for use in mainstream industries such as aviation, auto, and consumer electronics,” Hopkins said. “That’s what our technology is all about.”
AlSi10Mg possesses the following mechanical and density attributes at a 30 µm layer thickness:
- Three times the throughput @ 99.8 percent+ density (average 99.9 percent)
- Ultimate Tensile Strength (Rm z) - 406± 14 MPa/ 251± 8 MPa
- Ultimate Tensile Strength (Rm xy) - 438± 18 MPa/ 247± 9 MPa
- Yield Strength (Rm z) 264± 8 MPa/148± 5 MPa
- Yield Strength (Rm xy) 291± 12 MPa/156± 4 MPa
- Fracture Elongation (Rm z) 3.7± 0.7%/14.2± 1.1%
- Fracture Elongation (Rm xy) 7.2± 1.1%/17.3± 2.0%
- Surface roughness in z direction (no treatment) (µm) 3.4± 0.9