Investigation of The Drill Length Effect on Hole Tolerances

Yaman K., Bicakci N., Özgedik A.

JOURNAL OF POLYTECHNIC-POLITEKNIK DERGISI, vol.20, no.4, pp.765-775, 2017 (ESCI) identifier


In this study, the effect of tool length on hole tolerance of Ti6Al4V alloy was examined by drilling with long and short HSS drill according to the most suitable cutting parameters determined by previous experiments. For this purpose, holes were drilled in a Ti6Al4V alloy plate with a thickness of 25.40 mm in a 3-axis CNC milling machine using 8 mm diameter uncoated short and long HSS drills. Nominal hole diameters and deviations from the mean concentricity, perpendicularity and circularity are measured. Tool wear images on drills were investigated with a digital microscope. As a result of the drilling operations applied with short and long HSS tools under the same cutting conditions, it was found that the tool wear in the long tool was less than that in the short one, whereas the dimensional and geometric tolerances of the holes drilled by the long drill were worse than the short tool.