Swissloop Tunneling builds innovative tunnel boring machine

After a strong performance at Elon Musk's "Not-a-Boring Competition" in 2021, Swissloop Tunneling upgraded its award-winning tunnel boring machine. With some critical parts made by MakerVerse, an online platform for on-demand manufacturing, the team readied its powerful device for the 2023 competition in the United States.

Building a safe and efficient tunnel infrastructure requires cutting-edge tunnel boring machines to excavate through soil and rock. However, high costs and demanding logistics limit the technology. Improved tunneling would help make transportation alternatives like the hyperloop a reality.

To overcome those challenges, Elon Musk and his "The Boring Company" sponsor contests where hundreds of teams worldwide seek to build the best tunnel boring machine, with the five top teams selected to compete in person. Swissloop Tunneling is one of those teams pushing the boundaries of tunneling technology.

In 2021 in Las Vegas, the team of engineering students from ETH Zürich won the innovation and design award and finished second overall. For the 2023 competition, Swissloop Tunnelling's ambition was to continue its success with renewed systems in its machine."

The team turned to MakerVerse to upgrade their machine with several high-quality steel connectors built to withstand extreme conditions. 

The challenges

Swissloop Tunneling's machine, named Groundhog Beta, measures eight meters long, weighs 3,000 kilograms and has a diameter of 590 millimeters. Every component of Groundhog Beta must withstand burdensome workloads and high temperatures.

Since its last tournament, Swissloop Tunneling has been busy upgrading and optimizing its first machine, Groundhog Alpha. Especially the erosion and liner system have been redesigned for the new machine. Therefore, some parts had to be developed within the size of a prototype in the first phase, to validate designs and test further improvements.

For example, the liner system prototype was built at 1:5 scale before being scaled up to the final size. In the end, the team integrated the newly designed parts into Groundhog Beta and successfully completed its full-size version. 

One of the most critical sections of Groundhog Beta is the innovative tunnel lining system. The team integrated a polymer extrusion system into the machine to create safe and stable tunnel walls. The liner system prints a 15 mm thick tunnel wall to ensure the tunnel's structural integrity. This process uses a polymer granulate that's pumped into the tunnel through air pressure. There, the polymer gets melted via an extrusion screw. As a result, the polymers reach temperatures of up to 200 degrees Celsius and must be cooled via a 10 degrees Celsius cooling fluid.

These massive temperature ranges, plus the critical importance of the entire tunnel lining system, meant Swissloop Tunneling needed extremely high-quality parts from a trusted partner. Importantly, the parts needed to be affordable and delivered in time to meet tight deadlines.

A series of machined connecting rings join different components within the tunnel lining system. 

The solutions

MakerVerse, with its wide range of technologies, provided the crucial liner system prototype with several high-quality components at the needed prices.

Swissloop Tunneling sourced several steel connecting rings with more than 500 mm diameters using CNC machining. These connectors join different components within the tunnel lining system, such as the liquid cooling chamber. Another connector, this time made with Laser Powder Bed Fusion, sits at the head of the extruder and connects four different tubes.

From inside the tunnel boring machine

Swissloop Tunneling dealt with tight deadlines as they readied Groundhog Beta for the competition. With MakerVerse, they gained an open and transparent partner who kept them precisely up to date on the progress of their parts.

Notably, the quality of the parts was perfect for upgrading Groundhog Beta. MakerVerse's supply chain consists of only hand-picked, fully-vetted suppliers who have undergone a rigorous onboarding process. These quality control measures ensure the quality of every part ordered on the MakerVerse platform.

The results

Groundhog Beta measures 8 meters long. 

Swissloop Tunneling put the finishing touches on Groundhog Beta before bringing it to the United States for The Boring Company's Not-A-Boring Competition. Leading up to this point, the team conducted many design iterations and performed constant testing while considering their budget.

In the end, Groundhog Beta performed incredibly in the competition. The team won the prestigious innovation award and finished second overall.

Through this process, the team received high-quality parts and open communications from MakerVerse. "We're looking forward to working together again," said Camilla Chitvanni, Co-Head of Mechanical and Civil Engineering at Swissloop Tunneling. "All of us on the team appreciated the care and communications during the entire process." 

MakerVerse is committed to promoting student-driven innovation. In this case, instead of dealing with countless suppliers and worrying about deadlines, MakerVerse helped Swissloop Tunneling focus on what it does best: Building incredible tunnel boring machines.