Orthogonal Machining of Bone

Abstract

An investigation is described of the mechanics of orthogonal machining of bone. Experimental results are presented for the machining forces and specific energies for various cutting orientations, rake angles, and depths of cut. From microscopic observations on sections taken through the cutting zone, the chip formation process is seen to occur by a series of discrete fractures. A simple model is proposed to qualitatively describe the mechanics of chip formation. The energy expended by the cutting process under a wide variety of conditions is found to increase linearly with the surface area generated on the chip fragments, which is a further indication that chip formation during cutting of bone occurs by fracture.

Orthogonal cutting of cortical bone: Temperature elevation and fracture toughness

“…Wiggins [5] Liao et al [11] used literature fracture toughness value to determine the cutting depth at which the transition of chip formation changes. If this method is reversed, the fracture toughness can be determined at the cutting depth but it has to be exactly known at which depth the bone chips fracture for the first time along the shear plane.…”

“…[3] Additionally, the necessary emissivity constant of cortical bone has been formerly determined. [4] Wiggins and Malkin [5] as well as Jacobs [6] were the first to investigate the cutting forces of orthogonal cutting of cortical bone with respect to the osteonal cutting direction, tool rake angle and cutting depth. They found a non-linear relationship between cutting depth and cutting forces as well as a strong dependency of cutting direction on cutting forces, in relation to the bone micro-structure.…”

Analysis and optimization of bone machining for robotic orthopedic surgeries

“…A review of the test parameters used in the literature was performed, as seen in Table . It is clear that the cutting speeds utilized in the majority of the literature are far lower than that used in the recent study by Kianmajd et al ., and likewise the chip thicknesses were much larger. In fact, the current parameters used in surgery are even more extreme, with a cutting speed of 26 180 mm/s and chip thickness of 0.94–2.81 μm.…”

“…Researchers worked to establish how bone is cut during orthogonal machining. Experiments were performed on both bovine and human bone samples, and compared cutting force and specific cutting energy to the tool geometry, depth of cut, and cutting mode (the orientation of the cutting edge relative to the bone microstructure) . Both studies found that high‐rake tools (i.e.…”

“…A linear relationship was obtained between surface to volume ratio of individual chips and the specific cutting energy, implying a constant value for fracture surface energy. Additionally, the direction of cutting relative to the bone microstructure was found to influence cutting forces . A review of the test parameters used in the literature was performed, as seen in Table .…”