By Rose Eaton, Light Metal Age.
The Al Davis Memorial Torch is an impressive 3D structure newly installed at the Raider’s Allegiant stadium in Las Vegas, Nevada. Constructed to commemorate the team’s influential late owner, the nine-story-high torch was constructed of 225 3D-printed blocks made of carbon fiber-reinforced polycarbonate, each weighing approximately 350 lbs. The substructure was finished with 1,143 machined aluminum façade panels. Inscribed near the top of the freestanding structure is a quote from Davis himself, “The fire that burns the brightest in the Raiders organization is the will to win.”
Dimensional Innovations (DI), based in Overland Park, Kansas, designed the structure with a team of 18 employees who invested more than 50,000 hours over two years in developing, creating, and installing the memorial torch. The firm 3D-printed the PC blocks nearly continuously for more than seven months. Based on the 93 ft structure’s unique shape and precision requirements, DI purchased a large scale additive manufacturing (LSAM) machine from Indiana-based Thermwood Corporation. The polycarbonate blocks themselves were supplied by Techmer PM, Tennessee, which formulated and supplied 120,000 lbs of Electrafil®, the carbon fiber-filled PC material. The result of the collaboration, according to DI, is the world’s largest 3D-printed structure.
Shining Aluminum Façade
“The Raiders specifically requested that a large portion of the surface be clad in real metal for aesthetic reasons,” said Ben Hansen, R&D engineer, Dimensional Innovations. “It needed to be 7075 due to the surface finish requirements. There was a very specific look that we were trying to achieve and we found that alloy to be best.”
DI partnered with Ultratech Aerospace, Kansas, on this shiny exterior cutting the 1,143 unique aerospace grade aluminum panels. The panels were water-jet cut from 5 ft x 12 ft plate stock that was 5/8 inches thick. Each aluminum panel was 5-axis machined to its unique shape and then painted with a protective and uniform ceramic coating using a robot that DI engineered and programmed specifically for this task.
The back of each panel is flat with tapped holes, which were stud-mounted to individual facets on the printed structure. Because of the faceted mounting geometry the plates are all about 0.5 inches thick in the center, but at the edges some of them are as thin as 0.050 inches in areas of high surface curvature.
Teamwork
DI worked closely with Mark Davis, current owner of the Raiders and son of Al Davis, along with other leaders from the organization to ensure the torch paid homage to the influential owner. In addition, DI collaborated with Manica Architecture, Allegiant stadium architect and original conceptual designer of the torch; A. Zahner; Astound Group; Bob D. Campbell & Co. for the torch’s structural engineering; and Purdue University in its design and creation.