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Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2013., Cataloged from PDF version of thesis., Includes bibliographical references (pages 69-70)., A high resolution reconfigurable mold has been sought after for over 150 years. An ideal reconfigurable mold would be capable of producing detailed surfaces for use in molding and be capable of fast surface reconfiguration. Such a device would combine the fast speed and repeatability of formative processes, like injection molding, with the flexibility of additive processes, like 3D printing. An affordable, high resolution, reconfigurable mold could be a practical tool for a lean, short-run shop or factory, serving as a resin mold, fixturing surface or concrete formwork; to name only a few possible applications. Resembling the common pin art toy, a discrete element pin bed has often been proposed as a design for a reconfigurable mold. Conventional actuation strategies are often cumbersome and expensive, due to the quadratic increase in number of pin elements with increasing surface resolution. Very few designs exist that are capable of producing a reconfigurable pin array at sufficiently high resolution to compete with the cost of making a fixed geometry mold. A practical pin tool, an inexpensive but high resolution molding tool, could be an asset to shops and small business everywhere, but nothing like this currently exists. This thesis presents a concise design strategy, backed up by analytical arguments and empirical evidence which can used to construct an affordable, high resolution reconfigurable pin tool. We address the challenge of quadratic scaling by edge-addressing simple, nonlinear mechanisms to actuate each pin. Edge addressing, along rows and columns of pins, reduces the number of control inputs to a small, linearly increasing value. Nonlinear mechanisms at each discrete pin site allow for a predictable, localized expression of the edge addressed inputs. Two embodiments of this design strategy are proposed and tested. First, a diode/resistive heater array allows for electrical edge addressing and control of a fusible alloy brake to grip or release target, by Benjamin J. Peters., S.M.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011., Cataloged from PDF version of thesis., Includes bibliographical references (p. 34)., The digitally reconfigurable surface is a pin based mechanism for creating physical threedimensional contoured surfaces from a computer aided design (CAD) input. When the digital design is properly downloaded into the device, a pin array is collectively actuated to the desired geometry. A rubber interpolation layer is held onto the tops of the pins by vacuum pressure to prevent undesired dimpling of the surface caused by the discrete nature of the pin array. Prior art in this field of reconfigurable pin tooling (RPT) surfaces have mostly involved using large diameter pins with conventional linear actuators behind each pin. Such devices have rarely been commercially viable as the surface area and resolution of the surface scales poorly with the number of actuators and cost. The digitally reconfigurable surface developed theoretically only requires a single mechanically actuated plate, regardless of scale or resolution (number of pins or diameter of pins). The device works by pulling all of the closely packed steel pins simultaneously in one direction via a magnetic moving plate, and as they move, pins are individually clutched and held in position by a novel fusible alloy clutch array, integrated with input circuitry. When the magnetic plate reaches the end of its stroke, all pins are in the proper configuration. The simplicity of this actuation method allows for improved scalability (resolution and area) and low manufacturing cost for the device. In addition, the phase changing clutch array, when coupled with notched or threaded pins, has an excellent holding strength allowing for many possible high pressure molding applications on surfaces generated. It is my hope that this research will one day pave the way for a practical, commercially available, reconfigurable pin-based forming tool., by Benjamin J. Peters., S.B.