The third Digital Crafting workshop “CNC and Concrete: How to Mould” was held at the Danish Institute for Technology in Copenhagen August 18-19 2010. Asbjørn Søndergaard from Aarhus School of Architecture led the two-day workshop which allowed participants to work in small groups to create digitally fabricated foam formwork for a concrete prototype. Discussions and lectures during the workshop related to the question of how designers can use morphogenetic tools to allow for structural optimization and how designers can design material logic and performance into digital models.
During the workshop, the first day was spent largely working in groups in the classroom, creating the digital files for the forms and the fabrication data. At the end of the day this digital information was sent to the robot, and overnight the formwork was milled.
The design of the three prototype panels was carried out in groups. Each group designed one panel and then the panels came together to make a larger design, inspired by the game “exquisite corpse”. The overall design was that the three panels then could lean against each other and the load paths were designed for this configuration.
The pre-optimized, overall geometry of these was given in Rhino at the start of the workshop. These rectangular forms were taken into the topology optimization software where the load conditions were specified. The software gave results for the optimized forms, and these forms were then brought back into Rhino. This form was adjusted for manufacturing requirements, minimum thickness of concrete etc, using T-Splines, a plug in for Rhino. These adjustments allowed the further optimization using the criteria of manufacturing constraints. T-Splines was used to create the final forms and those were then exported to the CNC milling software where the tool paths for the robot were created. In groups, participants investigated different kinds of tool paths, which leave the mark of the robot´s tool in the form. The CNC software then exports the tool path to the robot and the robot cuts the form.
The next day, when the moulds were cut. We developed three different strategies for milling the elements. Differentiating the milling time we created three levels of detail from the very fine to the very rough. This differentiation was a practical decision as well as a probing one. As the cutting time in the short workshop was limited we varied the cutting time from 8 hours to 4 and finally 2. The different levels of detail gave very different aesthetic expressions.
After milling the reinforcing was set into the moulds, release agent added and the concrete poured and leveled. In the morning of the Seminar day, the concrete forms were carefully broken out of the milled moulds and cleaned off.
Report by Terri Peters