RoboCut

Abstract

Hot-wire cutting is a subtractive fabrication technique used to carve foam and similar materials. Conventional machines rely on straight wires and are thus limited to creating piecewise ruled surfaces. In this work, we propose a method that exploits a dual-arm robot setup to actively control the shape of a flexible, heated rod as it cuts through the material. While this setting offers great freedom of shape, using it effectively requires concurrent reasoning about three tightly coupled sub-problems: 1) modeling the way in which the shape of the rod and the surface it sweeps are governed by the robot's motions; 2) approximating a target shape through a sequence of surfaces swept by the equilibrium shape of an elastic rod; and 3) generating collision-free motion trajectories that lead the robot to create desired sweeps with the deformable tool. We present a computational framework for robotic hot wire cutting that addresses all three sub-problems in a unified manner. We evaluate our approach on a set of simulated results and physical artefacts generated with our robotic fabrication system.

Tool geometry and motion design in CNC machining with offset control

“…The graphics community has also recently investigated ablative objects [Mahdavi-Amiri et al 2020], the use of three-axis CNC machines to divide 3D objects into surfaces that can be cut along a single continuous path [Rivers et al 2012], the introduction of semi-automatic path planning strategies to accurately position the machine, and the user's selection of multiple tool positions and their optimization to interactively reduce tooling on the surface errors. For softer materials, such as foam, the main ablative manufacturing method is thermal milling [Duenser et al 2020], where a unique transport system is proposed to thermally mill individual parts using dynamically bendable rods.…”

RobotSculptor: Artist-Directed Robotic Sculpting of Clay

“…Robotic manipulation of a wire-like tool has recently been studied in Duenser et al [2020], where an elastically deformable, heated rod cuts through blocks of polystyrene foam. That work focused on trajectory optimization for a small number of individual cuts using a comparably large tool, rather than on a global cutting strategy.…”

“…We follow an approach similar to the one proposed by Duenser et al [2020] for computing cut trajectories for an elastically deformable tool, manipulated by a two-armed robot. At the core of this approach lies the formulation of an optimization problem which matches the surface swept by the tool during movement (toolsurface) with the surface of the input model (target shape).…”

“…Optimization problem. Similarly to Duenser et al [2020], we formulate an unconstrained optimization problem of the form…”

Mocca

“…Cone joints are typically realized in the form of curved or piecewise-planar contacts between two parts (see Figure 2(c&d)), which have been demonstrated to have good mechanical properties such as reduced stress concentration in building structurally stable assemblies [Dyskin et al 2003;Javan et al 2016]. Parts with cone joints can be easily fabricated with 3D printing, CNC milling, and even hot-wire cutting for large-scale objects [Duenser et al 2020].…”