New Thinking Beyond Traditional Manufacturing
The design of a 6-meter-high and almost 8-meter-wide bronze statue required the expertise of architects, engineers, and artisans. The preferred manufacturing process for bronze sculptures is lost-wax casting. Traditionally, a scale model is formed from clay and then molded in silicone to create a wax reproduction, which is used to form a ceramic shell into which the bronze is cast. This complex and labor-intensive process can be significantly simplified with 3D printing, particularly PMMA 3D printing, which revolutionizes the workflow.
Like other 3D printing technologies, the design is created digitally. Artists increasingly use digital design technologies for greater creative freedom and easy modifications. For the Boston Common sculpture, CAD design was also used to create a digital model. The Walla Walla Foundry in Washington, known for its expertise in art casting, was selected for the manufacturing process. Using two VX1000 PMMA 3D printers from voxeljet, they complemented traditional foundry technologies with modern 3D printing methods.
The Ideal Complement to Traditional Foundry Technologies
At the Walla Walla Foundry, the CAD files were scaled and divided into 608 individual parts, which were then produced on the VX1000 Binder Jet 3D printers. This technology allows optimal use of build space with the highest precision. Additionally, a complete model of the sculpture was printed to assess proportions and handling of the individual parts.
The 3D printers use binder jetting technology. The digital CAD file is sliced into thin layers, each selectively printed with PMMA powder. After completion, the parts are cleaned and post-processed, such as infiltrating with wax to create a smooth surface. The PMMA models are treated like traditional wax models: after forming the ceramic shell, the PMMA is melted out and replaced with bronze. The individual parts were then welded and patinated, with the final statue, including its framework, weighing 19 tons. The entire production process took two years.
How 3D Printing is Ushering in the Future of Sculpture
Today, "The Embrace" stands in Boston Common as a testament to justice and progressive change. It is not only a symbol of the legacy of Martin Luther King and his family but also an example of the unmatched precision and efficiency achieved through the combination of modern 3D printing technology with traditional art and lost-wax casting. This technology enables artists and architects to realize monumental visions without the constraints of traditional casting methods.
