After working for slightly less than a year at RENNtech, a Florida-based shop that specializes in tuning and enhancing performance for European-made cars, product design engineer Dustin Hanna was presented with a unique opportunity.
RENNtech GLK350 SPEC.R HYBRID
Mercedes-Benz USA notified RENNtech that the shop had been chosen to compete in the Mercedes-Benz GLK Tuner Challenge, which provided four shops pre-production vehicles to modify according to themes, highlighting each respective shop’s versatility. The challenge had an impossibly tight deadline for the task at hand—RENNtech was given just 35 days to design and produce an off-road racer prototype of the Mercedes-Benz GLK to present at the upcoming SEMA Show, the premier automotive specialty products trade event. The car was to be modified according to a pre-approved Mercedes-Benz proposal, dictated by the provided theme. SEMA attendees, the public and online participants would then vote on their favorite vehicle to select a winner.
David Demitrion fabricates the rear wing.
A gas cap is inserted into the printed rear fender section.
Supercharging the Design Cycle with 3D
RENNtech, owned by renowned Mercedes-Benz high performance expert Hartmut Feyhl, offers drivers minor enhancements, parts, modifications or total revamps. The GLK Challenge was a great opportunity for the RENNtech shop, but it also posed a great dilemma.
“We had to make numerous body panels and parts you’d normally mold and produce with fiberglass or carbon fiber,” says Hanna. “We didn’t have the time or money for that. Our designers had to come up with a solution that would allow us to meet our deadline and prove more cost-effective than outsourcing the entire project.”
A front fender piece is attached to the body.
The prototype airbox.
Hanna looked at a number of 3D printing options to help speed completion of the project. He found that Dimension 3D printers, a Stratasys brand, offered an affordable solution that produced the kind of quality parts the job demanded.
“Producing strong, yet lightweight, parts in ABS plastic was a big factor for me in the decision to purchase the Dimension 3D Printer,” Hanna says. “We wouldn’t have completed the project with any other technology.”
Assembling the fender flare.
Hanna put the 3D printer to use for the GLK Challenge, producing prototypes to test multiple variations, review fitment, and prototype difficult-to-machine components, such as undercuts.
“We had one month to produce the GLK. Without the Dimension 3D Printer, we would have had to mold each of the pieces individually,” Feyhl says. “There is no way we would have finished the body kit in time.”
After successfully completing the project in just over a month, RENNtech presented its racer at the SEMA Show in front of thousands of industry experts and influencers.
Inspired by the famed Pikes Peak Hill Climb, the Rally Racer featured a host of upgrades, including a body kit, which was prototyped using 3D printing technology. RENNtech produced a total of eight body panels, an airbox, an engine cover and a steering wheel cover for its version of the mid-sized SUV. The largest part measured 36 x 20 x 6 in.
SEMA attendees, among others, voted in an online competition to determine the most impressive model. Competing against three other models, RENNtech was awarded top honors, taking home the winning trophy for the Mercedes-Benz GLK Tuner Challenge.
• To source the project to an outside bureau would have cost RENNtech 59% more.
• Relative to traditional methods, RENNtech saved more than $15,000 in all tooling and parts.
“The GLK Challenge gave us a great deal of scope for bringing together form and function. For our model, performance may have been the primary goal, but it also looks the part,” Feyhl says. “And, thanks to 3D printing technology, we achieved both in 35 days.”
Prior to having the printer, RENNtech was forced to use an outside bureau for all prototyping projects, big and small.
“If we couldn’t get a part prototyped by an outside bureau in time, we’d have to scan clay models or just guess,” Hanna says. “After the success of the GLK Challenge, we’ve found ourselves using the Dimension 3D Printer for everyday prototyping.”