Design for Industry Machining a masterpiece with digital tools

Crafting works of art from metal isn’t anything new. Many of us would instantly think of the Statue of Liberty or the Ei el Tower, while those versed in contemporary art may think of the Chicago Picasso or Sir Antony Gormley’s Angel of the North. But how would one combine several famous works of art using stainless steel and artificial intelligence (AI) to create a new modern masterpiece?

In partnership with Sandvik Group, Sandvik Coromant developed a statue that will go down in art history. Made using AI modeling and cutting-edge manufacturing solutions, the sculpture combines the styles and influences of Michelangelo, Auguste Rodin, Käthe Kollwitz, Kotaro Takamura, and Augusta Savage — uniting some of history’s most famous artists from a period spanning 500 years. Weighing 500 kg and standing 150 cm tall, the Impossible Statue was o cially inaugurated at

Tekniska Museet, Sweden’s National Museum of Science and Technology, in April 2023.

“We needed a phenomenally precise digital simulation to help us machine the statue,” said Henrik Loikkanen, technology area manager at Sandvik Coromant. “Digital manufacturing means we can prove that whole complex machining process beforehand. The only time we spend on machines, therefore, is actual production time. It also meant we didn’t produce a single scrap component during the entire project.”

The team started with a 2D design and translated the model into a complete 3D image. They used depth estimators to build the 3D model, human pose estimators to refine the body, video game algorithms to generate realistic fabric, and specialized AI to reintroduce fine details lost in previous steps. Mastercam software converted a design for a statue with over six million surfaces and complex details.

Digital manufacturing tools made the Impossible Statue possible and reduced scrap components.

“We treated producing the statue as we’d treat machining highly specialized, complex parts like those found in the aerospace industry,” said Loikkanen. “An additional challenge came from the statue’s chosen material — stainless steel from Alleima — as ISO M materials are notoriously di cult to machine. The material group is characterized by its high work hardening rates and poor chip-breaking properties during machining. Careful attention, therefore, must be paid to the tools selected for machining the material.”

Sandvik Coromant chose several tools to help sculpt each intricate part of the statue. The Coromant Capto tooling interface was used to connect the arm and head to the torso of the statue; solid round tools from the CoroMill Plura and Dura families were responsible

Loikkanen (le ) and Pettersson (right) converted a 2D design to a 3D model and used a digital twin for testing.

| courtesy of Sandvik for finishing all the statue’s surfaces and features; and CoroMill MH20, a high-feed milling cutter launched in 2021, was used to machine the bulk of the stainless steel removed from the workpiece.

Naturally, machining the impossible isn’t without challenges, and the team made several adaptations to its machining strategy.

“The initial 3D model was not the type of model CAD/CAM systems can work with,” said Loikkanen. “It had to be converted from a 3D-mesh model, which is essentially a shell of surface polygons commonly used in 3D animation studios, to a solid 3D model with density, and that was a pretty challenging process. Once completed, the model was sectioned into 17 pieces, and all interfaces between them had to be modeled with a tight fit to make the intersections invisible when the parts were put together. It took time to get everything perfect.”

“We also had some challenges during rough machining due to the size of the component in relation to the machines,” said Jakob Pettersson, CAM and machining specialist at Sandvik Coromant. “This was solved by simulating NC-code and finding all the areas where we would reach the machine work envelope limit and by altering the CAM sequence.”

In the end, a statue that seamlessly blends the works of five artists was made possible. But developing a never-seen-before statue wasn’t the only accomplishment.

“Along the way, we implemented several techniques that can be applied to future digital machining projects,” said Loikkanen. “Because of the pure amount of programming work, building the statue would have been impossible without a digital twin. All the testing was done digitally to save time that would otherwise be spent on trial-and-error testing. This is certainly something we can apply in future projects to save time and reduce the number of scrap components.”

Now on display for art and technophiles alike to admire, the statue serves as a reminder of the creativity both digital and physical manufacturing tools can accomplish. DW

Sandvik Coromat www.sandvik.coromant.com