Laboratory for Manufacturing and Sustainability

Removal of burrs at cross-drilled hole intersections is often tedious and expensive due to limited accessibility. Automated edge finishing of crossholes has been practiced successfully using robot-assisted, flexible abrasive brush deburring, and non-traditional, mass finishing methods such as electrochemical deburring (ECD), abrasive slurry, and thermal deburring. These methods are very efficient but most require specialized equipment and dedicated cleaning operations to remove chemicals or trapped brush bristles. The Orbitool is an on-line, localized deburring alternative to brushes recently developed by JWDone Company. The Orbitool is a mechanized cutting tool with carbide edges specifically designed for crosshole deburring. Mechanized cutting provides greater selectivity and control of dimensional specifications compared to brushing and mass finishing methods. Furthermore, it can be implemented using existing machine tool equipment and cleaning procedures. As with any deburring tool, its desired capability is burr removal in the shortest time possible while meeting dimensional and surface quality requirements. To this end, process maps of chamfer width and surface roughness of the deburred edges, plotted against process parameters, were developed in this study. Workpieces consisted of Al 6061 T6 bars with zero-offset, perpendicular cross-holes with a diameter of 7.94 mm (5/16 in.). The experiments were conducted using Orbitools with a diameter of 6.35 mm (1/4 in.) and 36 cutting edges. The effect of the process inputs and their mutual interaction was assessed using Taguchi methods. The results show that proper selection of process parameters yield consistent and effective removal of burrs at cross-drilled intersections while achieving surface roughness values that range from 15 to 65 ?m at the chamfers.