# Fabrication and Analysis of a Ti6 Al4V Implant for Cranial Restoration
## 1 Introduction
Out of the possible metallic materials that can be used Titanium Alloy (Ti6 Al4V) is considered as the most favored choice for the customized implants. This can be attributed to its biological compatibility, Osseo-integrative property, high strength to weight ratio, higher corrosion resistance, non-magnetic properties, high toughness, and mechanical resistance, etc., [16; 17; 18]. There are a multitude of different kinds of AM technologies in the market, but all of them follow the same principle of manufacturing three-dimensional (3D) objects from computer-aided design (CAD) models by depositing the raw material in a layer by layer manner. The various AM technologies available in the market are stereolithography (SLA), fused deposition modeling (FDM), selective laser sintering (SLS), 3D printing (3 DP), Electron Beam Melting (EBM), etc. These systems can be categorized depending on the bulk material (or the original state of the raw material), which can be liquid, solid or powder [19; 20; 21]. The AM technology employed in this work is EBM in order to fabricate the customized implant. One of the primary strengths of EBM is its ability to produce parts from titanium alloys (Ti6 Al4V). EBM has been widely utilized in the production of medical implants throughout Europe and the United States with a Food and Drug Administration (FDA) license [22]. It was initially marketed in 1997 by ARCAM AB Corporation, Sweden which has acquired more than thirty international patents involving EBM science or techniques [23]. The earlier studies have suggested EBM as a rational option for titanium alloy custom designed implants required in orthopedic, craniofacial and maxillofacial surgeries [24; 25; 26]. Unlike other traditional methods, EBM does not possess any limitation in terms of shape constraints and can produce complicated parts with nearly perfect accuracy. Indeed, the titanium alloy (Ti6 Al4V ELI) used in the current EBM process has proven to have good mechanical and chemical properties for implants [27; 28]. In this paper, a comprehensive approach for the design, fabrication, and validation of a customized cranial implant has been developed. The primary goal of this study is the introduction of a simple method to redesign and fabricate the defective part on the skull. The AM has been combined with digital image acquisition techniques, like computed tomography (CT) to achieve the mentioned objective. This work demonstrates the route from the patient's CT scan to the fabrication of titanium cranial implants and its validation. The DICOM (digital imaging and communication in medicine) files from CT were imported in a specific software (Mimics) and the segmentation approach was employed to cut the region of interest and produce the 3D model. The mirror reconstruction technique was utilized to generate the patient-specific implant on the injured portion of the skull. This design was then analyzed and compared with the cortical bone for mechanical properties through finite element analysis (FEA). Subsequently, the titanium cranial implant (\(\simeq\)1.76-2 mm thick) was fabricated from Ti6 Al4V ELI powder by using EBM technology. It was finally validated and investigated for appearance, accuracy, mechanical properties, and material composition.