Experimental study and sensitivity analysis of force behavior in cortical bone milling

Area of Science:

• Biomedical Engineering
• Orthopedic Surgery
• Materials Science

Background:

• Bone milling force is critical in orthopedic surgery, influencing tool longevity and preventing bone damage.
• Cutting forces are affected by machining parameters, tool characteristics, and bone tissue properties.

Purpose of the Study:

• To investigate the influence of various machining parameters on bone milling forces.
• To quantitatively assess the sensitivity of bone milling force to input parameters using statistical methods.
• To optimize milling parameters for minimizing cutting forces in orthopedic applications.

Main Methods:

• Response surface methodology was employed for statistical modeling and experimental design.
• Sobol statistical sensitivity analysis was used to determine the impact of each parameter.
• Derringer algorithm was utilized for response optimization.

Main Results:

• Bone milling force decreases with increased rotational speed but increases with feed rate and cutting depth.
• Higher tool diameter leads to increased cutting force; milling perpendicular to osteon orientation requires less force.
• Sensitivity analysis identified cutting depth (51.4%) and feed rate (21.9%) as the most influential parameters.

Conclusions:

• The study provides insights into optimizing bone milling parameters for orthopedic surgery and tool design.
• A minimum cutting force of 3.76 N was achieved with specific optimized parameters (4mm tool diameter, 3000 rpm, 100 mm/min feed rate, 1 mm cutting depth).
• Findings can aid in developing safer and more efficient robotic surgery systems and orthopedic tools.