When Ottawa, Ontario, was selected as the capital of the then province of Canada in 1857, it was necessary to find a site for the buildings that would house Parliament. The highest point in the city, a steep hill overlooking the mighty Ottawa River, was chosen by the powers that be.
Despite being over 149 years old, Canada’s Parliament buildings needed renovation, a role that was developed by industrial robots (Kuka Robotics Canada, a subsidiary of Kuka Roboter GmbH in Germany), especially the ornamentation part. . Allowing the rehabilitation of the three buildings.
The use of digital fabrication for the rehabilitation of sculptural elements was analyzed by the Immersive Media Studio of Carleton University in association with the Directorate of Heritage Conservation (PWGSC).
PWGSC agreed to restore the first stone piece in the East Block, which weighs 2.3 tons and is located above the entrance to the central courtyard. It depicts an owl amid thistles and in dire need of a replacement, with certain areas of detail stripped away by decades of deforestation and freeze-thaw cycles.
The restoration process begins with the development of a duplicate of the original stone carving. In other words, the traditional gypsum casting process was changed to a digital relief process based on photogrammetry.
A replica of the sculpture was milled from high-density polyurethane foam using a 3-axis CNC router at Carleton University School of Architecture based on the digital model.
Subsequently a sculptor, in this case the Dominion Sculptor of Canada (a sculptor expressly hired to care for Parliament buildings and other federal sites), rebuilt the destroyed areas with modeling clay. Resulting in digital sculpting once again.
A series of prototype parts were milled from foam using a KUKA KR 120 R2700 extra HA robot incorporated by New Age Robotics based on this second digital model, combining the sculptor’s clay work and digitally reconstructed molding. The final relief sculpture was milled from sandstone using the KUKA / New Age Robotics milling method after the appropriate milling parameters were determined.
The sandstone was milled 1.5 mm from the surface of the digital model by the robot. This provided material for Dominion Sculptor to extract using conventional stone cutting techniques while applying details and textures to the entire surface of the relief sculpture.
The great challenge of this project was the stone, it was incredibly rough and the technique used was very slow to start, which did not generate the wear of the tools in minutes. During the experimental process, we lost money.
New Era Robotics, on the other hand, was determined to make it work. They used diamond carbide tips and an imported VEM spindle that is cooled from the center.
In the end, the robotic sculpture was built at a rate four times faster than the manual sculpture. The relief sculpture was spliced onto the facade of the East Block building.