Machining of biocompatible materials — Recent advances

Abstract

Machining of biocompatible materials is facing the fundamental challenges due to the specific material properties as well as the application requirements. Firstly, this paper presents a review of various materials which the medical industry needs to machine, then comments on the advances in the understanding of their specific cutting mechanisms. Finally it reviews the machining processes that the industry employs for different applications. This highlights the specific functional requirements that need to be considered when machining biocompatible materials and the associated machines and tooling. An analysis of the scientific and engineering challenges and opportunities related to this topic are presented. Cutting, biomedical, biocompatible materialsTitanium acetabular head Titanium femoral stem Composite Bone

Evaluation of Surface Topography after Face Turning of CoCr Alloys Fabricated by Casting and Selective Laser Melting

“…According to [7,27] in case of proper alloying, the microstructure of the CoCr alloys is composed mainly of γ-phase and carbides of the M 23 C 6 type. However, in numerous works concerning the cobalt-base alloys, their microstructure consists of a mixture of γ-Co and ε-Co phases [3,5,9,13]. It is dependent on solidification process and/or heat treatments applied to cobalt-base alloys due to the promotion of fcc→hcp transformation [5].…”

“…It is worth indicating that the effect of phase change is an increase of mechanical properties of these materials. The occurrence of γ-phase determines ductility, while the-ε phase has higher strength, and enhances the corrosion and wear resistance due to the limited number of slip systems [5,7,13].…”

“…Observations of the microstructure using optical microscopy showed that in both materials characteristic structures were obtained. The microstructure of traditional-cast specimen exhibited a typical dendritic solidification microstructure consisting of dendrites and an interdendritic region [4,5,8,13,15,29]. The SLM samples exhibit a peculiar macro-structure, similar to "fish scales", relative to the weld pools of each laser pass and to layer stack [3].…”

“…The intensity of occurrence and the size of the observed defects on the surface increased with increasing feed value- Figure 8. The presence of extensive and deep surface defects causes a significant increase in the values of GPS indicators, which can be caused on the one hand by the porosity of the material (removal of the material layer reveals the free spaces hidden under it), and on the other by the occurrence of significant friction forces and an increase in temperature between the surface of the tool and the workpiece subjected to plastic deformations [10,13,25]. It has also been observed that surface defects and some porosity of samples after SLM-that are exposed during cutting-are also partly rolled (Figure 7a).…”

“…material layer reveals the free spaces hidden under it), and on the other by the occurrence of significant friction forces and an increase in temperature between the surface of the tool and the workpiece subjected to plastic deformations [10,13,25]. It has also been observed that surface defects and some porosity of samples after SLM-that are exposed during cutting-are also partly rolled (Figure 7a).…”