Four axis hot-wire foam cutter controlled by Mindstorms EV3

Abstract

The purpose of the study was to develop a 4-axis numerically controlled hot-wire foam cutter suitable for flying aircraft modelling purposes. Numerically controlled foam cutter had to be able to cut intricate shapes out of foam material such as extruded polystyrene by using 3D virtual model. The study reviewed existing foam cutters built by modellers all around the world and set priorities for a new system, such as usage of common 3D format for input and common programming language for software. Unconventional mechanical design for the foam cutter was realized with Lego Mindstorms Ev3 parts. C++ language was used to program the Ev3 brick. A new algorithm was developed for approximation of triangulated models in STL format with ruled surfaces that are possible to cut with a straight hot wire. The built foam cutter and its software were tested for production of fuselage of an airplane. The machine did not reach sufficient accuracy of cut, but showed a wide range of capabilities for cutting of sophisticated shapes. Questions covered in the study may be helpful for those who wants to built a numerically controlled machine, in particular, the foam cutter.