Additive manufacturing technologies are opening new opportunities in term of production paradigm and manufacturing possibilities. Nevertheless, in term of environmental impact analysis supplementary ...research works require to be made in order to compare and evaluate them with traditional manufacturing processes. In this article, we propose to use Life Cycle Assessment (LCA) method and to associate decision criteria to support the selection of manufacturing strategies for an aeronautic turbine. The dimensionless criteria allow to define environmental trade-offs between additive and subtractive methods. This study provides an approach generalizable to other parts and processes.
In general, surface of additively manufactured (AMed) metal products has large roughness due to arrangement of bead shapes, and surface irregularities such as spatter and cavity. Furthermore, surface ...elemental composition of AMed products may be changed from that of metal powder. In this study, efficient surface smoothing and repairing of AMed metal products by large-area electron beam irradiation were experimentally investigated. Experimental results show that spatter and cavity can be completely removed and surface roughness significantly reduces. Elemental composition of AMed surface can be also changed to that of original metal powder due to the removal of oxidized surface.
The study aims at investigation of structure, properties and machinability rate of raw and thermal treated titanium-based powder material used to produce the thin-walled components by one of the most ...widespread additive manufacturing technologies, electron beam melting (EBM). The microstructure and material properties of raw EBM parts in horizontal cross-section and in vertical ones are different, i. e. the raw EBM samples structure and properties are anisotropic. To reduce anisotropy by modifying microstructure of EBM parts, a thermal treatment (hot isostatic pressing, HIP) was applied. In addition, when using additive manufacturing, the part surface roughness is quite coarse while the dimensions may be out of tolerance. Thus, making the end product after additive manufacturing often requires a finishing cutting operation. Examining the quality of end product in terms of geometric tolerance and thin walls thickness stability is also included in this study. In particular, when milling thin-walled parts produced by EBM technology, the form accuracy and the surface roughness are the functions of variable wall stiffness which is estimated in a local cutting zone. This fact must be taken into account when selecting the cutting conditions. For this purpose, a specially designed measuring information system has been used to control the vibrations during machining process.
Machining of biocompatible materials: a review Saptaji, Kushendarsyah; Gebremariam, Mebrahitom Asmelash; Azhari, Mohd Azmir Bin Mohd
International journal of advanced manufacturing technology,
07/2018, Letnik:
97, Številka:
5-8
Journal Article
Recenzirano
The need for more effective and efficient manufacturing processes to transform the biocompatible materials into high standard artificial human body components (implants) is rapidly growing. Machining ...of biocompatible materials as one of the key processes in manufacturing of implants need to be improved due to the significant effects of machined surface quality to the compatibility and osseointegration with human organs such as tissues, bones, and environment of the human body. The challenges of machining biocompatible materials due to their applications as bio-implants in the human body and the nature of materials properties and microstructures have been explored and solved by various researchers. This article reviews the trends and developments of the machining of biocompatible materials. A range of possible machining technologies and strategies on various biocompatible materials using conventional (milling, turning and drilling) and non-conventional or advanced (abrasive water jet machining (AWJM), ultrasonic machining (USM), ion beam machining (IBM), laser beam machining (LBM), electrical discharge machining (EDM), and electron beam machining (EBM)) are presented and discussed. This review also examines the emerging new technologies such as additives manufacturing and hybrid processes as potential solutions and future research trends in order to fulfill the high standard requirements for a wider range of applications of the biomaterials.
Creating systems for monitoring technology processes based on concentrated energy flows is an urgent and challenging task for automated production. Similar processes accompany such processing ...technologies: intensive thermal energy transfer to the substance, heating, development of the melting and evaporation or sublimation, ionization, and expansion of the released substance. It is accompanied by structural and phase rearrangements, local changes in volumes, chemical reactions that cause perturbations of the elastic medium, and the propagation of longitudinal and transverse waves in a wide frequency range. Vibrational energy propagates through the machine's elastic system, making it possible to register vibrations on surfaces remotely. Vibration parameters can be used in monitoring systems to prevent negative phenomena during processing and to be a tool for understanding the processes' kinetics. In some cases, it is the only source of information about the progress in the processing zone.
Recently, electron beam machining technology has been used in various ways depending on the industrial field. It is used in technologies in the fields of shipbuilding, aerospace, and transportation. ...In the case of the existing electron beam machining technology, a technology for welding or joining two materials was proposed. In this paper, in order to perform electron beam drilling, a multi-hole is created by increasing the instantaneous vaporization pressure during electron beam machining through a vaporized amplification sheet. A vaporized amplification sheet was prepared for electron beam drilling. The vaporized amplification sheet was made of a 1:3.25 combination of silicone and brass powder. Also, in order to bond the produced vaporized amplification sheet to the SUS 304 stainless steel, a primer was applied on the surface of the metal material to firmly bond the two materials with different properties. If the bonding is weak, the effectiveness decreases due to pressure leakage during electron beam machining. Multi-holes were processed using the fabricated material to fix an acceleration voltage of 120 kV and a current of 12 mA. Also, to compare the multi-hole shape and the processing result, the comparison was performed according to the exposure time of the electron beam. The lower the exposure time, the more fine holes were secured, and as the exposure time increased, the molten pool phenomenon occurred, and processing was not performed in the experimental results.
The article presents methods for obtaining small-diameter holes in the manufacture of metal filter elements for airborne vehicles. The advantages of using high-tech electro-physicochemical ...technologies in the manufacture of filters are substantiated. Experimental studies of the strength characteristics of filters manufactured using electron-beam and electroerosion perforation methods were performed. Conducted research works contribute to improving the manufacturability of products of new generations of technology, which is important for mechanical engineering.
Electron beam machining (EBM) is a well-established technology for various industries. Conventional EBM systems use high-voltage for electron beam generation. The EBM could be used for various ...processing such as drilling, welding and surface modification by converting kinetic energy of electrons to thermal energy of the substrate. The core technology of EBM is electron beam generation. Traditionally, magnetic lens systems are used to focus the electron beam and magnetic coils are used for beam deflection. However, most EBM systems available on the market are designed for macro size work-piece machining purposes. These machines have large chambers and equipped with high power supplies. Thus causes difficulty for micro-machining on small work-pieces. Therefore, in order to perform micro-machining for tiny work-piece, a desk-top EBM system with a vacuum chamber smaller than 5 L was developed dedicated for micro machining processes. A transformer of microwave oven is used as power supply. As an electron beam source by using concave cathode, which focuses the resulting electron beam in argon ambient. Argon ambient also allows to avoid contamination during the process of machining. In order to obtain excellent results of micro machining operation on smaller work-pieces, the electron beam behavior of the desk-top EBM was investigated in this study. The experimental results show that dissimilar materials welding, small hole drilling and surface modification could be carried out by this desk-top EBM. It is expected that the desk-top EBM can be used for commercial applications especially for micro machining in near future.
Abstract
Hard to cut metals are widely machined with the help of Wire EDM process which overcomes major challenges in the conventional machining processes. For generation of micro-features and ...complex three dimensional structures Wire EDM is considered above other unconventional machining process like abrasive jet, laser, plasma and electron beam machining. Wire EDM provides better dimensional accuracy, machining rate and surface finish, with flexibility to alter process parameters. Importance and utilization of micro or nano parts in aerospace, medical, missiles & ballistics and automobile requires machining process like μ-WEDM to obtain desired features and intricate geometries. This study approaches and enlightens the work areas where micro level features have been generated using Wire EDM by different researchers, using diverse experimentation, modeling and optimization approaches for Wire-EDM. Finally, conclusion and future scope at the completion of the chapter binds up the present study.
Cemented carbide has many excellent properties. However, it is sometimes difficult to apply conventional surface finishing or surface modification methods for the cemented carbide. The possibility of ...surface modification by large-area electron beam irradiation, namely EB polishing was discussed. The surface structure of the EB polished cemented carbide was observed by TEM. The hardness and the water repellency were tested. Also, the separation force of molded resin from the surface was measured for evaluating the releasability of the resin. The water repellency and the releasability of the molded resin could be improved by EB polishing, because the surface structure changed.
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