Sandvik Coromant
Sandvik Impossible Statue

Fun Innovations Friday: The Impossible Statue

May 5, 2023
Combining the works of Michelangelo, Rodin, Kollwitz, Kotaro, and Savage, an impossible engineering feat was made possible with Sandvik Coromant's expertise.

Metal has long been used to craft works of art from sculptures to statues. The first ones that come to mind for most people are the Statue of Liberty or the Eiffel Tower, while art enthusiasts may think of the Chicago Picasso or Sir Antony Gormley’s Angel of the North. What hasn't been done though is creating a piece of art that combines several famous works into one modern masterpiece. An amalgamation if you will. And what definitely hasn't been done is creating this masterpiece with stainless steel and AI.

When Sandvik Coromant engineers Henrik Loikkanen and Jakob Pettersson were tasked with creating an AI-generated, stainless steel synthesis of some of history’s most famous works of art, their metal cutting expertise was put to the test. And what has resulted from this test is a statue that's fit for the history books.

Made with AI modeling and manufacturing solutions, the sculpture combines the poses of Michelangelo’s work, the musculature craftmanship of Auguste Rodin, the somber tones of Käthe Kollwitz, Kotaro Takamura’s Japanese influence, and Augusta Savage’s inspirational defiance to unite some of history’s most famous artists from a period spanning 500 years.

Weighing 1,100 pounds (500 kg) and standing 4.9 feet (150 cm) tall, the Impossible Statue was officially inaugurated at Sweden's National Museum of Science and Technology, Tekniska Museet, in April.

As we already know, creating a statue like this hasn't been done before. So how exactly did Loikkanen, Pettersson, and their team craft this blend of art and science?

When AI Meets Art

AI has been around for some time even though we're just seeing the commercial aspects of it, with intelligent machines performing activities that normally require human intelligence, such as visual perception, speech recognition, decision-making, language translation, and problem-solving. The concept of AI dates back decades, with the earliest program written in 1951 by Christopher Strachey, later director of the Programming Research Group at the University of Oxford.

But the emergence of new, conversational AI programs such as Google’s Bard and ChatGPT have opened up the floodgates with even more applications of the technology. Even so much so that Google's AI creator quit and left us with a word of warning on what this technology can possibly do in the future.

So achievements with AI definitely seem almost limitless, especially with it now helping to create not just images, but a tangible piece of art.

After establishing a 2D design that brought together the styles of the five artists, Sandvik began translating the model into a complete 3D image. Using 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 that were lost in previous steps, the team was ready to turn the design into reality. Using Mastercam software, a design for a statue with over six million surfaces and complex details was converted.

There were some unique challenges involved in the statue’s design.

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

Machining the Impossible

After finalizing the design with AI and virtually simulating the best ways to manufacture the statue using digital twins, they commenced machining.

Loikkanen says they treated the process of creating a statue as they would treat machining any highly specialized, complex parts like those found in the aerospace industry. He went on to say that another challenge was the stainless steel material which can be difficult 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 used several tools to help them sculpt each intricate part of the statue. They used the Coromant Capto tooling interface to connect the arm and head to the torso of the statue, the CoroMill Plura and Dura solid round tools for finishing surfaces and features, and the high-feed milling cutter CoroMill MH20 to machine the bulk of the stainless steel removed from the workpiece.

“We have more than 10,000 standard products covering drilling, milling, reaming, and threading in our back catalog,” explained Jakob Pettersson, CAM and Machining Specialist at Sandvik Coromant.

“But we couldn’t select just any tool to create the Impossible Statue. To pull off such a manufacturing feat, we needed to be laser-focused in our selection.”

“We had to give the method and tooling selection extra thought in order to use as little tooling as possible and thereby limit waste. Rough machining of the statue was done with a mix of solid carbide end mills from the CoroMill Plura and Dura families. The rough profiling of the final shape had to be made with rather long tooling. Here, a combination of MH20 high-feed cutters mounted on heavy metal shanks was the perfect fit. The use of end mills from our solid round tools offering greatly sped up the process and therefore reduced energy consumption.”

The CoroMill MH20’s ability to machine at long overhangs typically makes it beneficial to the aerospace sector. It’s designed with difficult-to-machine components in mind and is designed with a two-edge insert to keep the weakest section of the insert far away from the main cutting zone, delivering greater protection against wear. It also means that machining against a corner or wall will not impact the next edge or leading corner, ensuring an equal performance per edge.

Sandvik says that the CoroMill Plura HD is its first choice for heavy-duty applications in steel and stainless steel, offering safe and efficient solid-end milling. The tool comes with an added benefit in the form of Zertivo 2.0 coating, developed by Sandvik Coromant’s R&D team to improve process security and productivity even further.

CoroMill Dura is designed to be a one-for-all tooling solution. The end mills can be used in all processes needed to produce a component―including roughing, finishing, semi-finishing, and ramping.

A Manufacturing Masterpiece

Naturally, those weren't the only challenges they came across and as they went along, had to adapt their strategies several times.

“The initial 3D model was not the type of model CAD/CAM systems can work with. 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," said Loikkanen.

“We also had some challenges during rough machining due to the size of the component in relation to the machines,” added Pettersson. “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 for Sandvik Coromant. “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 a huge amount of 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.”

“The programming and simulation process became faster and faster for each component,” added Pettersson.

“Machining took about the same time throughout, mainly because the cutting data and tooling selection never changed that much. This point brought me to one conclusion: the extensive product data and recommendations we give are accurate and are easily attained either from our website, tool guide, Tool Library or even integrated directly in CAM systems themselves. Surely, this is of great value to our customers and addresses one of the more work-intensive tasks in closing the digital loop around CAM programming.”

That statue is now on display for people to admire and serves as a reminder of the creativity both digital and physical manufacturing tools can accomplish. “I’m incredibly proud we’ve pulled this off,” concluded Loikkanen.

“Hopefully those visiting Tekniska Museet, and anyone else who sees that statue, can appreciate that it’s an artwork like no other. The techniques we used and the methods we employed really show what Sandvik Coromant can do. We truly know metal cutting, even when tackling a challenge nobody’s ever seen before," added Pettersson.

To learn more about Sandvik’s Impossible Statue, visit

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