In Berlin, a designer’s eye approaches a sand casted staple

It’s a chair. There are usually four legs and a place to sit. But there is a big difference between seating with style versus a practical but not eye-catching folding chair, for example. 

“The main aim was to work out a sand casted object which goes beyond the limits and established rules of this classical production technology,” David Geckeler, industrial designer and CEO at Geckeler Michels, Berlin, says of sand casting, a process used to produce his original three-legged “Fragment” chair. “As a designer, you have to keep your unprejudiced view on things, you have to question the things you know, so you can be inspired.” 

The chair is designed for mass production and no welding is necessary because it’s a mono-block object. Sand casting is an ancient technology, back to 3,200 BCE, according to some histories, with Assyria and China being the first to cast bronze and copper objects. Simply put, a cast gets molded by sand and the hollow mold is filled with molten metal to form the cast object. The process is infinitely repeatable. “After cooling and demolding the cast, and smashing the sand mold, the mono-block chair is born,” Geckeler explains. 

Working closely with Magma Soft programming to find the parameters of the cast based on a digital 3-D CAD model, Geckeler’s firm was able to adjust fill, temperature, air and conduct finite element method (FEM) analyses. According to Magma, using a casting process simulation during early casting development is useful because it ensures all components are ready and correct parameters are set for use in the casting process. 

Three legs work just as well as four

That the chair design features three legs rather than four is not what makes it so different. Rather, it’s the three-dimensional CAD-driven approach Geckeler used to achieve the one-piece results. The chair had to be designed so that the gating system within the casting process would work under the stress of weight applied. Magma software helped determine exactly how to achieve the desired strength with the given design. Geckeler tested his model and adjusted the specifications of the aluminum chair. 

In addition to furnishings, Magma’s software is being used for sand cast components in wind power apparatuses and for automotive engine blocks. The software helps determine tensile stresses, “induced by ‘pulling’.” These stresses result in cracks, and the part fails as a result. The software, Magma says, helps determine the geometry of the component being produced and tensile stresses, avoiding such failures.

Geckeler enjoys picking the brains of fellow designers no matter their field of expertise. “I appreciate metalworkers’ and craftsmen’s skills,” he says, discussing with them different projects fellow fabricators are working on. His advice to innovators is to “keep on thinking, be creative and be open for new solutions.” MM