Design and performance analysis of low damage anti-skid crescent drills for bone drilling

Abstract

Background: With orthopedic surgery increasing year on year, the main challenges in bone drilling are thermal damage, mechanical damage, and drill skid. The need for new orthopedic drills that improve the quality of surgery is becoming more and more urgent.

Methods: Here, we report the skidding mechanism of drills at a wide range of inclination angle and propose two crescent drills (CDTI and CDTII). The anti-skid performance and drilling damage of the crescent drills were analyzed for the first time. Inclined bone drilling experiments were carried out with crescent drills and twist drills and real-time drilling forces and temperatures were collected.

Results: The crescent drills are significantly better than the twist drill in terms of anti-skid, reducing skidding forces, thrust forces and temperature. The highest temperature is generated close to the upper surface of the workpiece rather than at the hole exit. Finally, the longer crescent edge with a small and negative polar angle increases the rake angle of the cutting edge and reduces thrust forces but increases skidding force and temperature. This study can promote the development of high-quality orthopedic surgery and the development of new bone drilling tools.

Conclusion: The crescent drills did not skid and caused little drilling damage. In comparison, the CDTI performs better in reducing the skidding force, while the CDTII performs better in reducing the thrust force.

Keywords: Bone drilling; Drilling Force; Skid resistance; Temperature.

Fig. 1

Analysis of drill skid a schematic diagram of drilling forces b fixed coordinate system c rotational coordinate system d chip area difference when $\beta <\frac{\pi }{2}-\varphi$ e Chip area difference when $\beta >\frac{\pi }{2}-\varphi$ f A detailed view of (d)

Fig. 2

a Relationship between the chisel edge length and the chip area difference b relationship between the inclination angle and the chip area difference.

Fig. 3

Design of CDs a Type I b Type II c schematic diagram of drill tip d Distribution of the rake angle of the crescent drill type I (CDTI), the crescent drill type II (CDTII) and the TD

Fig. 4

Inclined drilling operations of bones a experimental setup b schematic illustration of experimental platform

Fig. 5

Curves of the skidding force $F_X$ at $\beta$ = 15° (a, c, e) and 45° (b, d, f) when the drill enters and skidding force under different drilling parameters g f = 25 mm/min (h) f = 50 mm/min

Fig. 6

Images of the hole entrance and their ideal contours with inclination angles of 15°, 30°, 45° and 60°

Fig. 7

Thrust force under different drilling parameters a f = 25 mm/min b f = 50 mm/min

Fig. 8

Analysis of drilling temperature a Thermal imaging and data acquisition of the bone drilling b Maximum temperatures of the hole wall at Q2 and Q5 c Temperature generated by the TD d Temperature generated by the CDTI e Temperature generated by the CDTII