Generation of fractal toolpaths for irregular shapes of surface finishing areas

This paper presents two patterns of fractal toolpaths for irregular shapes of surface finishing areas such as a parallelogram, a trapezoid, a circle, a rhombus, an octagon, and combinations of those shapes. Surface finishing processes are used to smooth the surface form by eliminating the surface waviness left by tool marks or EDM spark erosion. Thus the surface finishing processes usually need to be performed only on several local working areas instead of global form machining. However, most of the shapes of these surface finishing areas are irregular. In this paper, fractal toolpaths have been investigated and generated for such irregular shape areas for automated surface finishing processes. A prototype CAM software has also been developed to generate the NC programs and an automated surface finishing system (ASFS) with a CNC machining center to which are attached electrical finishing tools was used to verify these fractal toolpaths. Experimental results have verified the feasibility of fractal toolpaths for different shapes of finishing areas.