Adaptive modification over drill bit geometry to control thrust forces in surgical bone drilling: A finite element study with in vitro experimental validation

Abstract

Bone drilling is one of the frequently used machining processes in orthopedic and dental surgeries. Although experimental studies that aimed to control either mechanical or thermal damage during surgical bone drilling were successfully carried out, further reduction in the thrust force and temperature required a suitable modification to the drill bit geometry. In this study, the margins and flank faces of a 3.20 mm diameter twist drill bit modified with dimples, crescents, triangles, and grooves were analyzed using finite element analysis linked to the modified Johnson-Cook model. To validate the results obtained from the simulations, the drill bits were textured with different patterns and then bone drilling experiments were conducted using the Gaurav BMW 35^® three-axis vertical machining center. The study observed that a twist drill bit with grooves oriented at a 45° inclination over the margins and flank faces could effectively reduce the thrust force and temperature than other drill bits considered. Compared to the normal drill bit, the drill bit with grooves oriented at a 45° inclination over the margins and flank faces could reduce the maximum thrust force by up to 20.14% and the temperature by 6.81%. The outcomes of this study can be used to adaptively incorporate suitable geometric modifications over the margins and flank faces of the drill bit, thereby preventing mechanical and thermal damage during bone drilling procedures.