Sheet Steel Chair
0.9mm stainless steel sheet
620 x 480 x 720
The net of a chair is nitrogen assisted laser-cut in 0.9mm stainless steel,folded by hand and secured with double sided VHB foam tape, combining a computer controlled industrial process with hand assembly. Using pre-finished stainless steel enables the chair to be folded post-production, as no finishing is required to protect the steel.
I produced over 30 paper models of my Sheet Steel Chair before sending the file to Cirrus Laser for the first steel prototype to be cut. I discussed the laser-cutting process extensively with Dave Connoway, who runs Cirrus Laser, and it was information regarding sheet metal availability, sheet sizes, steel quality, vector-file types and the cutting process itself, that enabled me to develop the design of my chair so quickly, and error free.
Laser-cutting is an industrial process requiring specialist technology and facilities. Inputting coordinates by hand into the adjacent computer operated
traditional laser-cutting machines. This was a time consuming process that made laser-cutting an expensive technique when only cutting a few of the same component. Modern lasercutting machines are still controlled by computer, but the data can be drawn in any vector-based computer program and sent to the machine remotely. The process is very quick to set up, meaning it is now almost as economical to cut just one component as it is to cut thousands of the same piece.
The actual time it takes for the laser to cut the template of my chair in steel is just over three minutes.
I have explored the low volume production capabilities of modern laser-cutting in the fabrication of my chair, concentrating particularly on the use of sheet metal. I liked the idea of incorporating an additional handprocess with which to reinforce the one-off or low batch potential of laser cutting. Bending sheet steel accurately is normally impossible without the use of a hydraulic press. Again, this is an industrial process requiring expensive set-up times, and so it was important to eliminate the need for such a process. Bending the laser-cut template into a chair by hand completes the production of my Sheet Steel Chair. I incorporated lozenge shape perforations along the bend lines, similar to the way score lines are included on origami ‘net’ to facilitate folding. These slots make
bending the metal accurately in a given place by hand very easy. The slots also
remove over 70% of the metal along the bend line, significantly reducing the force required to bend the metal. I used two short pieces of MDF to help bend the faces without distorting the flat surfaces.
Industrial strength double-sided tape is used to permanently fix thefolded panels together. The VHB tape, produced by 3M, is easily applied by hand, compared to traditional permanent fixing methods such as welding and riveting that are
performed in the factory using industrial equipment. The tape also distributes the acting tensile forces along the entire join. A flat, greasefree surface is the only requirement in order to achieve a permanent bond between the metal surfaces of the chair. Once a strip of the VHB tape has been applied to the appropriate surface, the backing paper is removed and the corresponding face pressed against it. An instant and permanent bond is achieved. Adhesion of the last two faces completes the production of the chair.