250 research outputs found
Additive Manufacturing as a Technique for In Situ Repair and Renovation of Marine Crankshaft Journals
No full text[EN] This article presents the analysis and redesign of an equipment aimed at repairing in-situ the journal surface of a marine diesel engine crankshaft, based on laser cladding technology. The paper outlines the comprehensive research conducted to study the device, identify its weaknesses and establish a strategy to improve it. To address this task, we shall describe (i) a study of the working environment, (ii) performance of functional analysis using computer-aided engineering tools and finite element analysis of the current prototype, (iii) a study of the results and identification of problematic areas, (iv) proposed improvements based on the results, (v) the presentation of a 3D model with the proposed improvements.Morales-Casas, A.; Torims, T.; Gutiérrez, SC. (2019). Additive Manufacturing as a Technique for In Situ Repair and Renovation of Marine Crankshaft Journals. Key Engineering Materials (Online). 799:263-269. https://doi.org/10.4028/www.scientific.net/KEM.799.263S263269799T. Debroy et al., Additive manufacturing of metallic components – Process, structure and properties,, in Prog. Mater. Sci., vol. 92, pp.112-224, (2018).S. Nowotny, S. Scharek, E. Beyer and K. H. Richter, Laser beam build-up welding: Precision in repair, surface cladding, and direct 3D metal deposition,, in J. Therm. Spray Technol., vol .16, no 3, p.344–348, (2007).S. Nowotny, Beschichten, Reparieren und Generieren durch Präzisions-Auftragschweißen mit Laserstrahlen,, Vak. Forsch. und Prax., vol. 14, no 1, pp.33-37, (2002).T. Torims, A. Ratkus and A. Logins, The Application of Laser Cladding to Marine Crankshaft Journal Repair and Renovation,, ASME conference proceedings, pp.1-10, (2014).H. Koehler, K. Partes, T. Seefeld and F. Vollertsen, Influence of laser reconditioning on fatigue properties of crankshafts,, Phys. Procedia, vol 12, no PART 1, pp.512-518, (2011).H. Koehler, K. Partes, T. Seefeld and F. Vollertsen, Laser reconditioning of crankshafts: From lab to application,, Phys. Procedia, vol 5, no PART 1, pp.387-397, (2010).T. Torims, G. Pikurs, A. Ratkus, A. Logins, J. Vilcans and S. Sklariks, Development of technological equipment to laboratory test in-situ laser cladding for marine engine crankshaft renovation,, Procedia Eng., vol 100, pp.559-568, (2015).T. Torims, A. Ratkus, M. Zarins, V. Brutans and J. Vilcans, In-Situ Laser Build-Up Welding of Shipboard Crankshafts,, Appl. Mech. Mater., vol 234, pp.39-46, (2012).Golten S., 1960, US Patent No 2,937,479 Crankshaft Journal Grinder
First proof-of-concept prototype of an additive manufactured radio frequency quadrupole
No full textContinuous developments in additive manufacturing (AM) technology are opening up opportunities in novel machining, and improving design alternatives for modern particle accelerator components. One of the most critical, complex, and delicate accelerator elements to manufacture and assemble is the radio frequency quadrupole (RFQ) linear accelerator, which is used as an injector for all large modern proton and ion accelerator systems. For this reason, the RFQ has been selected by a wide European collaboration participating in the AM developments of the I.FAST (Innovation Fostering in Accelerator Science and Technology) Horizon 2020 project. The RFQ is as an excellent candidate to show how sophisticated pure copper accelerator components can be manufactured by AM and how their functionalities can be boosted by this evolving technology. To show the feasibility of the AM process, a prototype RFQ section has been designed, corresponding to one-quarter of a 750 MHz 4-vane RFQ, which was optimised for production with state-of-the-art laser powder bed fusion (L-PBF) technology, and then manufactured in pure copper. To the best of the authors’ knowledge, this is the first RFQ section manufactured in the world by AM. Subsequently, geometrical precision and surface roughness of the prototype were measured. The results obtained are encouraging and confirm the feasibility of AM manufactured high-tech accelerator components. It has been also confirmed that the RFQ geometry, particularly the critical electrode modulation and the complex cooling channels, can be successfully realised thanks to the opportunities provided by the AM technology. Further prototypes will aim to improve surface roughness and to test vacuum properties. In parallel, laboratory measurements will start to test and improve the voltage holding properties of AM manufactured electrode samples
INITIAL HIGH ELECTRIC FIELD – VACUUM ARC BREAKDOWN TEST RESULTS FOR ADDITIVELY MANUFACTURED PURE COPPER ELECTRODES
No full textAdditive Manufacturing (AM) is already wellestablished for various manufacturing pplications,
providing many benefits such as design freedom, novel and complex cooling designs for the parts and different performance improvements, as well as significantly reducing the production time. With the mentioned characteristics, AM is also being considered as a
technology for manufacturing a Radio Frequency Quadrupole (RFQ) prototype. For this application, an important parameter is the voltage holding capability of the surfaces. Furthermore, the voltage holding capability of pure copper surfaces manufactured by AM is of interest for the accelerator community at large for prospective future developments. To characterize these properties, a series of high electric field tests were performed on pure copper electrodes produced by AM, using the CERN pulsed highvoltage DC system. The tests were carried out with AM produced electrodes with large surface roughness. During
the testing process, a high vacuum was maintained. The electric breakdown rate was also monitored to ensure not to exceed the breakdown limit of 10ିହ breakdowns per pulse. The achieved results provide the first, initial reference values for the performance of AM built pure
copper electrodes for vacuum arc breakdown testing. Initial results prove the capability of AM electrodes to hold a high electric field, while having low breakdown rates. These are crucial results for further AM technology usage for different AM pure-copper accelerator components
Surface finishing of additive manufacturing parts for particle accelerators
No full textSignificant progress towards the suitability of Additive Manufacturing (AM) metal parts for the production of linear accelerator components has been made in recent years. One significant factor for the suitability of AM parts to produce linac rf structures is the surface quality of the parts. Due to the inherently higher surface roughness of AM metal parts, post-processing is necessary to reach surfaces suitable for rf operation. We present most recent results of surface post-processing trials with AM parts from stainless steel
Evaluation of geometrical precision and surface roughness quality for the additively manufactured radio frequency quadrupole prototype
No full textA multidisciplinary collaboration within the I.FAST project teamed-up to develop additive manufacturing (AM) technology solutions for accelerators. The first prototype of an AM
pure-copper Radio Frequency Quadrupole (RFQ) has been produced, corresponding to 1⁄4 of a 4-vane RFQ. It was optimised for production with state-of-the-art laser powder bed fusion
technology. Geometrical precision and roughness of the critical surfaces were measured.
Although the obtained values were beyond standard RFQ specifications, these first results are
promising and confirmed the feasibility of AM manufactured complex copper accelerator
cavities. Therefore, further post-processing trials have been conducted with the sample RFQ to improve surface roughness. Algorithms for the AM technological processes have also been
improved, allowing for higher geometrical precision. This resulted in the design of a full 4-vane RFQ prototype. At the time of the paper submission the full-size RFQ is being manufactured and will undergo through the stringent surface quality measurements. This paper is discussing novel technological developments, is providing an evaluation of the obtained surface roughness and geometrical precision as well as outlining the potential post-processing scenarios along with future tests plans
Experimental analysis of end mill axis inclination and its influence on 3D areal surface texture parameters
No full text[EN] The surface quality of machined parts depends highly on the surface texture that reflects the marks of the tool during the cutting process. The traditional theoretical approach indicates that these marks are related to the cutting parameters (e.g. cutting speed, feed, depths of cut), the machining type, the part material, the tool, etc. The influence of these factors has been widely studied by researchers and they have been considered in milling process models proposed to predict the final surface texture.
Nevertheless, if an accurate prediction is desired, these milling models must include different geometrical errors influencing the cutting edges path on the part. In this paper, we present the results of a study showing the influence of real mill-axis inclination on 3D surface texture. Therefore, experiments with simple, end mill tool operation, with constant cutting parameters and four different cutting directions (the directions that we labelled as North, South, East, and West) in accordance with the machine coordinate system were performed. Using optical 3D areal surface texture measurement techniques with the Bruker Contour device, we obtained areal surface texture parameters for analysis. Descriptive statistical analysis and one-way ANOVA analysis were performed to detect the factor significances and their influence on 3D areal surface texture parameters. The results from ANOVA and graphical analysis clearly identified tool-axis inclination in the South and West directions. If a relationship between tool-axis inclination and surface texture parameters can be demonstrated, this calculation can be included in the model of 3D surface texture formation. Improving the mathematical model with all possible errors occurring in high speed machining operations helps to obtain more precise texture parameter Sz results for simple end mill operation. The model is suitable for complicated machining operations with ball end mill tools.Logins, A.; Rosado Castellano, P.; Torims, T.; Gutiérrez, SC.; Sergejev, F. (2017). Experimental analysis of end mill axis inclination and its influence on 3D areal surface texture parameters. Proceedings of the Estonian Academy of Sciences. 66(2):194-201. doi:10.3176/proc.2017.2.09S19420166
EVALUATION OF GREEN LASER SOURCE ADDITIVE MANUFACTURING TECHNOLOGY FOR ACCELERATOR APPLICATIONS WITH ULTRA-HIGH VACUUM REQUIREMENTS
No full textAdditive Manufacturing (AM) offers different benefits such as efficient material usage, reduced production time and design freedom. Moreover, with continuous technological developments, AM expands in versatility and different material usage capabilities. Recently new energy sources have been developed for AM – green wavelength lasers, which provide better energy absorption for pure copper. Due to high thermal and electrical conductivity of copper, this novel AM technology is highly promising for various industries, particularly, there is a huge interest to use it for accelerator applications. In particular, these AM produced accelerator components should reach the associated Ultra High Vacuum (UHV)
requirements. In this study, vacuum membranes of pure copper were produced by AM using a green laser source, in different thicknesses and built angles. Furthermore, a vacuum membrane helium leak tightness test was performed at room temperature by using a high-sensitivity mass spectrometer. Comparison of these test results was performed with previously established results. Through this study, novel knowledge and initial results are provided
for green laser source AM technology usage for applications for UHV accelerator components
Development of additively manufactured 750 MHz RFQ
No full textAdditive manufacturing (AM) technologies, especially powder bed fusion, are rapidly taking their place in the technological arsenal of the accelerator community. A wide range of critical accelerator components are being manufactured additively today. However, there is still much scepticism as to whether additive manufacturing can address the stringent requirements set to complete accelerator components. Therefore, as an advanced proof-of-principle, a full-size, pure-copper Radio Frequency Quadrupole (RFQ) prototype was developed and additively manufactured in the frame of the I.FAST EU project. Gradually improved RFQ prototypes and related pure copper samples manufactured by laser powder bed fusion were submitted to a series of standard tests at CERN to demonstrate that this novel technology and suitable post-processing can deliver the required geometrical precision, surface roughness, voltage holding, vacuum tightness, and other relevant parameters. The results obtained are very promising and could be of great benefit to the linac community at large. The paper is outlining the technological developments and RFQ design improvement process along with the obtained results and future endeavours
Explorative studies of an innovative superconducting gantry
No full textThe Heavy Ion Therapy Research Integration plus (HITRIplus) is an European project that aims to integrate and propel research and technologies related to cancer treatment with heavy ion beams. Among the ambitious goals of the project, a specific work package includes the design of a gantry for carbon ions, based on superconducting magnets. The first milestone to achieve is the choice of the fundamental gantry parameters, namely the beam optics layout, the superconducting magnet technology, and the main user requirements. Starting from a reference 3 T design, the collaboration widely explored dozens of possible gantry configurations at 4 T, aiming to find the best compromise in terms of footprint, capital cost, and required R&D. We present here a summary of these configurations, underlying the initial correlation between the beam optics, the mechanics and the main superconducting dipoles design: the bending field (up to 4 T), combined function features (integrated quadrupoles), magnet aperture (up to 90 mm), and angular length (30° – 45°). The resulting main parameters are then listed, compared, and used to drive the choice of the best gantry layout to be developed in HITRIplus. © 2023 Institute of Physics Publishing
Non-Standard Approach Can Help, when Sticking in Distributed Parameters
No full textThe author has developed a non-standard
approach yielding a remarkable progress in investigation of oscillatory instability. In such a
way it is possible to obtain some simple approximate but reliable enough solution considering
oscillatory variations. The solution enables the comparison with experimental data. The
report reflects the basic principles of method, shows the diagrams demonstrating the
interrelations between oscillating variables, the loci of phasors determining the stability
conditions and some remarkable conclusions made on such basis
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