Precision CNC Machining of Femoral Component of Knee Implant: A Case Study

Abstract

Abstract:The design and manufacturing of medical implants constitutes an active and highly important field of research, both from a medical and an engineering point of view. From an engineering aspect, the machining of implants is undoubtedly challenging due to the complex shape of the implants and the associated restrictive geometrical and dimensional requirements. Furthermore, it is crucial to ensure that the surface integrity of the implant is not severely affected, in order for the implant to be durable and wear resistant. In the present work, the methodology of designing and machining the femoral component of total knee replacement using a 3-axis Computer Numerical Control (CNC) machine is presented, and then, the results of the machining process, as well as the evaluation of implant surface quality are discussed in detail. At first, a preliminary design of the components of the knee implant is performed and the planning for the production of the femoral component is implemented in Computed Aided Manufacturing (CAM) software. Then, three femoral components are machined under different process conditions and the surface quality is evaluated in terms of surface roughness. Analysis of the results indicated the appropriate process conditions for each part of the implant surface and led to the determination of optimum machining strategy for the finishing stage.

Advanced Surface Modification for 3D-Printed Titanium Alloy Implant Interface Functionalization

“…The positive and negative ions in the electrolyte diffuse to the anode through the action of an electric field, and then the oxidation-reduction reaction occurs, forming a micro-nano structure on the titanium SCHEME 1 | Surface modification technologies and biological functionalization of 3D-printed titanium alloy implants. NC machining Using the control system sends out instructions to make the cutting tool make various movements that meet the requirements, and represent the shape and size of the workpiece in the form of numbers and letters for machining High Great Markopoulos et al (2018) 3D-printed technology Firstly, the 3D image is obtained by CT scanning, then the raw material powder is deposited layer by layer by computer-controlled 3D printer, and finally the molten material is cast into a pre-designed 3D shape surface (Park et al, 2008). Anodizing is usually performed under galvanostatic conditions, up to a determined cell voltage or the passage of a determined charge, or by potential sweep.…”

“…Titanium alloy has been extensively used in the medical fields of orthopedics, dentistry, and vascular surgery owing to its high strength, low density, high corrosion resistance, and excellent biocompatibility ( Domínguez-Trujillo et al, 2018 ). Traditional titanium alloy implants have been manufactured by iso-material mold casting or subtractive technologies such as machining, multipoint forming and NC machining ( Minto et al, 2020 ; Khorasani et al, 2016 ; Herzog and Tille 2021 ; Markopoulos et al, 2018 ). Hence, they are difficult to simulate the structure of cortical bone and cancellous bone in real bone tissue ( Bozkurt and Karayel, 2021 ).…”

Knee Implant Study and Evaluation With Axiomatic Design Method

“…In [2] the designs and the materials used in knee implants are thoroughly described. In this paper a novel approach is described.…”

“…The dynamics of the knee can be categorized in three segments. Load transferring from the upper part of the leg to the opposite and vice versa, vibration absorption and friction minimization and durability in dynamic loads [1,2]. All the above constitute the functional requirements of the knee implant design.…”

Optimization of the Cutting Regime in the Turning of the AISI 316L Steel for Biomedical Purposes Based on the Initial Progression of Tool Wear

“…These factors considerably increase tool wear, build-up edge formation, and increase the surface roughness [4][5][6]. Stainless steels are traditionally machined at cutting speeds ranging from 150 to 300 m/min, although these materials show good behavior at higher cutting speeds [7,8]. This aspect is remarkable due to the influence that surface roughness has on the behavior of austenitic stainless steel used as a biomaterial [9,10].…”