Future and challenge of 3D printed bone external fixator: Statics stress simulations of polycarbonate Taylor spatial frame ring

Abstract

The key design requirement of bone external fixator is the distal-proximal stabilization of fracture site. To fulfill the requirement, lightweight metals such as aluminum are commonly used as their main structure. However, in recent years, high strength plastic or Carbon Fiber Reinforced Plastic (CFRP) start to be used since they can provide better strength to weight ratio over the metals. Unfortunately, this material is not affordable, especially if some complex geometry components included. 3D printing is a disruptive technology in producing a plastic product. Since this device became a trend, it spread out around the world with various kind of plastic filament. Some of them considerable strong, durable, and comparable to lightweight metal. With the capability to produce high complexity product, 3D printing may challenge older fabrication techniques for creating more affordable bone external fixator. However, there are some weaknesses of 3D printed plastics such as strength affected printing orientation. This research aims to show how a 3D printed polycarbonate external fixator component holds the load compares to 6061 T6 aluminum in a simulation environment. 155mm Full Ring Component of the Taylor Spatial Frame was used as the comparison case. Static stress simulations were run in Autodesk Fusion 360. 20% tensile strength reduction was applied to represent strength decrement in Z-axis direction of printed component. As a conclusion, 3D printed polycarbonate may be an alternative due to the promising simulation results. Since there are several stronger material than polycarbonate available and there are also several process types provide better strength than FDM, this technology will have a bright future as bone external fixator fabrication process.