From October 27-31, 2014, my studio group (Digital Transformation) and Studio MAD participated in a workshop aimed at learning how to use the school’s CNC 5-axis milling machine through the creation of a “lighting object.” Students were put into three working groups, with two subgroups in each. One subgroup was responsible for the form of the lighting object, and the other group was responsible for the surface patterning.
I was placed in the form subgroup. We used Grasshopper to modify the properties of a cylindrical mesh and the Kangaroo plugin for Grasshopper to apply gravity and basic force dynamics to the form. Our aim was to create a shape made of planarized quads that would eventually be milled out of plywood sheets in the CNC mill. Kangaroo has a helpful component called “planarize quads” which tries to force the shape to be planar on each side so it can be cut out of flat sheets.
The form we arrived at provided a simple enough shape to be cut out of three large sheets of plywood while creating an architectural typology that justified use of the CNC mill.
The next step was to prepare the form for cutting on the CNC mill. This was done by labeling each quad in the form and then placing them flat.
We decided that the structure would be held together by binding and used another Grasshopper sketch to create evenly-spaced holes around the perimeter of each sheet. The binding sketch found the perimeter of the shape, created an offset perimeter a certain distance inwards, and then placed holes at equal intervals.
The patterning subgroup provided us with a series of contoured holes to place on the face of each quad. During this process we extruded the quads to match the thickness of the plywood. With the binding holes and contours placed, we then arranged the quads onto the plywood sheets and prepared the Alphacam files, which would be used by the CNC machine to interpret our Rhino drawing.
Preparing the Alphacam files was a difficult process, as almost none of the students in the workshop had used the software before. We relied heavily on the workshop instructors to guide us through this process. In order to prepare a Rhino drawing for export to the CNC machine, the basic steps are to import the Rhino geometry into Alphacam, select your cutting tools and define your tool paths. The Alphacam file is then exported to the CNC machine as G-code.
Part two will detail the milling and assembly process.