Rather than using the accuracy of an industrial robot to place polymer material at some point allocated by a human designer, the role of the robot here is merely directive. The speed and path of the robotic end effector acts as a force on the stream of extruded polycarbonate, allowing the material to be ‘slung’ around corners, bundled in valleys and stretched across ridges in the geometry of the form work. Furthermore, the robot directs a stream of material from the apex of the form work, allowing the material to flow across an effective topography and rapidly produce a functional surface without this surface needing to be described digitally or with a high degree of precision. This pouring or drizzling logic lends itself to particular qualities and effects as material that travels further across the surface of the form work also undergoes significant cooling, and thus has a tendency to curve, fold and bond to existing polycarbonate in very different ways.
The project explores a productive tension in the double meanings of moulding and casting by using these terms to describe influences on material behaviour as well as constraints on material form. Typically a cast part ‘fails’ when material behaves in unanticipated ways (such as bubbling, cracking, warping, seeping or collapsing). The PolyLace prototypes embrace these ‘failures’ in the ‘casting’ of the underlying form work as each failure begins to affect the form and qualities of its immediate local surroundings. In contrast to 3d printing processes, redundancy is built in the PolyLace processes in the form of repeated and overlapping extrusions such that errors accumulate to produce greater formal diversity rather than catastrophic structural failure.
PolyLace is an ongoing project that is now working towards incorporating feedback between material behaviour and robotic motion using simple vision systems. A camera will monitor the coverage and depth of the extruded polycarbonate over the surface of the mould, and effect the speed and location of the robotic tool path in order to learn from and direct the relationship between robotic motion and surface quality. This system will be employed in the fabrication of lightweight office partitions and screening systems.