Using aluminium to recreate nature
It is hard to pigeonhole Ed Carpenter. This Oregon-based artist has created dozens of stunning large-scale urban structures, from fanciful pedestrian bridges to majestic windows and monumental sculptures. His work consists largely of glass, steel, aluminium and lighting.
One of his most recent projects is “Harvest,” a 45-foot-high (13.7 meters) sculpture designed for the city of Lincoln’s Pinnacle Bank Arena Plaza. During the day, colorful arrays of light reflect over the plaza, while at night, programmed light sequences illuminate the sculpture.
While its form suggests a sheaf of wheat, symbolizing the bountifulness of this agricultural region, the sculpture is made of materials for an urban world – 55,000 pounds (nearly 25,000 kilograms) of stainless steel were used in its fabrication, along with 420 panels of laminated glass and 80 stainless steel cables. In the midst of all of this are aluminium extrusions, selected largely for their lightness, rigidity and non-corrosive properties.
“I needed a lightweight, durable way to attach the glass to the cables,” says Carpenter. “Extrusion allowed for a complex cross section to both attach the glass to the aluminium and to accept set screws to grip the cables.”
A napkin and a prototype
A rough sketch of what Carpenter wanted to achieve was submitted on a napkin to Sapa’s extrusion die group. The team quickly realized that some trial and error would be necessary in order to get an exact fit on the screws and bolts, and to avoid having to revert to costly custom threads.
The team accomplished this with very little extra time, cost or wasted material through Sapa’s electrical discharge machining (EDM) prototyping process. By making EDM prototypes, the geometry could be adjusted through multiple iterations until it was a perfect fit.
EDM prototyping offers the unique advantage of being able to make aluminium prototypes that are as close as possible to the final product. And these can be turned around in just under a week.
“I designed the extrusion and Sapa made it,” says Carpenter. “It was as simple as that.”
Interested in learning more?
If you are interested in learning more about using aluminium and EDM prototyping, then please contact Sapa and we will put you in touch with the right expert.