The paper outlines the achievements and challenges in the additive manufacturing (AM) application to veterinary practice. The state-of-the-art in AM application to the veterinary surgery is presented, with the focus of AM for patient-specific implants manufacturing. It also provides critical discussion on some of the potential issues design and technology should overcome for wider and more effective implementation of additively manufactured parts in veterinary practices. Most of the discussions in present paper are related to the metallic implants, manufactured in this case using so-called powder bed additive manufacturing (PB-AM) in titanium alloy Ti-6AL-4V, and to the corresponding process of their design, manufacturing and implementation in veterinary surgery. Procedures of the implant design and individualization for veterinary surgery are illustrated basing on the four performed surgery cases with dog patients. Results of the replacement surgery in dogs indicate that individualized additively manufactured metallic implants significantly increase chances for successful recovery process, and AM techniques present a viable alternative to amputation in a large number of veterinary cases. The same time overcoming challenges of implant individualization in veterinary practice significantly contributes to the knowledge directly relevant to the modern medical practice. An experience from veterinary cases where organ-preserving surgery with 3D-printed patientspecific implants is performed provides a unique opportunity for future development of better human implants.
One of the complex tasks in mass production of RF electronics is printing the communication antenna using electrically conductive ink. For example, this is very common for radiofrequency identification (RFID) tags. Electrical properties of the ink are mostly determined by conductive (e.g. silver) particles mixed into the ink solution and the way they 'connect' in the cured ink. It is also desirable to minimise the amount of ink used per antenna, because high-conducting metals like silver used in the ink are rather expensive. Metal-based inks have limited conductivity, so the thicker the cured ink layer will be the better the antenna radiation efficiency can be achieved, but also the higher will be the costs. In the paper, the authors report on the investigations of the possibility of minimising the amount of ink used per antenna. This can be achieved by printing thicker ink layers, where antenna structures are known to have high current density. Two common antenna structures and a dedicated antenna for passive RFID are used in the investigation. The main result of the paper is that radiation efficiency depends primarily on the total amount of ink used for printing the antenna, rather than on the variations of the layer thickness within the antenna structure.
The current paper is devoted to classification of powder-bed additive manufacturing (PB-AM) techniques and description of specific features, advantages and limitation of different PB-AM techniques in aerospace applications. The common principle of “powder-bed” means that the used feedstock material is a powder, which forms “bed-like” platform of homogeneous layer that is fused according to cross-section of the manufactured object. After that, a new powder layer is distributed with the same thickness and the “printing” process continues. This approach is used in selective laser sintering/melting process, electron beam melting, and binder jetting printing. Additionally, relevant issues related to powder raw materials (metals, ceramics, multi-material composites, etc.) and their impact on the properties of as-manufactured components are discussed. Special attention is paid to discussion on additive manufacturing (AM) of aerospace critical parts made of Titanium alloys, Nickel-based superalloys, metal matrix composites (MMCs), ceramic matrix composites (CMCs) and high entropy alloys. Additional discussion is related to the quality control of the PB-AM materials, and to the prospects of new approaches in material development for PB-AM aiming at aerospace applications.
Properties of the hydroxyapatite obtained by electrochemical assisted deposition (ED) are dependent on several factors including deposition temperature, electrolyte pH and concentrations, applied potential. All of these factors directly influence the morphology, stoichiometry, crystallinity, electrochemical behaviour, and particularly the coating thickness. Coating structure together with surface micro- and nano-scale topography significantly influence early stages of the implant bio-integration. The aim of this study is to analyse the effect of pH modification on the morphology, corrosion behaviour and in vitro bioactivity and in vivo biocompatibility of hydroxyapatite prepared by ED on the additively manufactured Ti64 samples. The coatings prepared in the electrolytes with pH = 6 have predominantly needle like morphology with the dimensions in the nanometric scale (~30 nm). Samples coated at pH = 6 demonstrated higher protection efficiency against the corrosive attack as compared to the ones coated at pH = 5 (~93% against 89%). The in vitro bioactivity results indicated that both coatings have a greater capacity of biomineralization, compared to the uncoated Ti64. Somehow, the coating deposited at pH = 6 exhibited good corrosion behaviour and high biomineralization ability. In vivo subcutaneous implantation of the coated samples into the white rats for up to 21 days with following histological studies showed no serious inflammatory process.
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