Machine tool builder creates work of art

A combination of different AI programs resulted in a 3D mesh model consisting of nine million polygons with no density. This had to be converted into a solid model that the CAD and CAM programs could work with.

With its experience crafting from metal, Sandvik Coromant engineered a new kind of art and the help of artificial intelligence (AI). Henrik Loikkanen, technology area manager, and Jakob Pettersson, CAM and machining specialist, at Sandvik Coromant at Sandvik Coromant, combined their metal cutting expertise with AI-generated, stainless steel synthesis to create a reimagined replica of history’s most famous works of art.

The sculpture combines the work of Michelangelo, Auguste Rodin, Käthe Kollwitz, Kotaro Takamura and Augusta Savage, some of history’s most famous artists from a period spanning 500 years.

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

The actual machining was made using a wide range of Sandvik Coromant tools for turning, milling and drilling. Not a single part of the statue had to be scrapped and remade throughout the process, as they had been digitally perfected before the start of machining. Images curtesy of Sandvik Coromant.

Some unique challenges were involved in the statue’s design. “We needed a phenomenally precise digital simulation to help us machine the statue,” said Loikkanen. “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.”

After finalizing the statue’s design with AI and virtually simulating optimal ways to manufacture the statue using digital twinning, it was time to commence machining. “We treated producing the statue as we’d treat machining highly specialized, complex parts like those found in the aerospace industry,” Loikkanen said. “An additional challenge came from the statue’s chosen material—stainless steel from Alleima—as ISO M materials are notoriously 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 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 finished 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.

The model was sectioned into 17 components, where each one of these had to be designed and programmed, along with the interfaces between them.

“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,” said Pettersson.

The CoroMill MH20’s can machine at long overhangs typically, which makes it beneficial to the aerospace sector. It’s designed with difficult-to-machine components in mind. In contrast to the conventional four-edge concept, the MH20 is designed with a two-edge insert, which means the weakest section of the insert is far away from the main cutting zone, delivering greater reliability and protection against wear. Petersson said 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.

CoroMill Plura HD is for heavy-duty applications in steel and stainless steel end milling. The tool comes with Zertivo 2.0 coating, developed by Sandvik Coromant’s R&D team to improve process security and productivity. 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.

Metrolog X4 inspection software was used to compare the finalized statue to the 3D model.

The machining process for the statue had challenges: first, converting the initial 3D model into something that could work with CAD, and also, the sheer size of the component in relation to the machine. It required simulating NC-code and finding all the areas where the machine work envelope limit was reached in order to alter the CAM sequence.

Weighing 500 kilograms and standing at 150 cm tall, the Impossible Statue was officially inaugurated at Tekniska Museet, Sweden’s National Museum of Science and Technology, in April 2023. The statue serves as a reminder of the creativity both digital and physical manufacturing tools can accomplish. “I’m incredibly proud we’ve pulled this off,” Loikkanen said. “Hopefully those visiting Tekniska Museet, and anyone else who sees that statue, can appreciate that it’s an artwork like no other.”