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Guerrero G.R.,University of Cordoba, Spain | Sevilla L.,University of Malaga | Soriano C.,Advanced Manufacturing Technologies Unit
Applied Surface Science | Year: 2015

This work compares laser and pyrolysis removal procedures of the fluorinated ethylene propylene FEP-rich coatings applied on EN AW-5251 H34 aluminium magnesium alloy sheets. The study has been conducted in three successive FEP coating application-removal cycles. Roughness, yield and tensile strength, elongation percentage, hardness, grain size and constituent particles distribution of the processed samples have been analyzed. According to the results, it is concluded that similar mechanical properties has been obtained for both removal technologies, being the laser decoating removal rates lower than those achieved by the pyrolytic procedure. However, the laser decoating process is consolidated as an industrial alternative against the dangerous and harmful (to the environment) pyrolytic extraction systems. © 2015 Elsevier B.V. All rights reserved. Source

Cascon I.,Advanced Manufacturing Technologies Unit | Sarasua J.A.,Advanced Manufacturing Technologies Unit
Procedia CIRP | Year: 2015

Most of the existing mechanistic (semiempirical) models for turning are orientated towards continuous cut and are applicable neither to nonaxisymmetric parts, nor to the particular case of interrupted turning, so common in real workpieces. Some commercial software packages which simulate machining process by FEM enable to calculate interrupted cut. However, their high computational cost limits the simulations to a very short length of cut, hardly completing one cutting revolution. By contrast, mechanistic models are not as computationally expensive as FEM ones. Despite their limited accuracy, they give approximate estimations of cutting forces during a whole tool path. Consequently, they are extremely useful to detect critical tool path steps, adapt cutting parameters and avoid machine overload. This study presents a mechanistic model to predict orthogonal turning forces in 3 directions (XYZ), torque and power consumption along the machining path of non-axisymmetric parts. The model communicates with CAM software by automatically transferring information about tool path and geometry from the CAM to the mechanistic model in standard format, contained in CL (Cutter Location) and STL (Stereolithography) files, respectively. Thus, the model is suitable to be integrated into any commercial CAM software. The simplicity of the model, the communication with CAM and an easy-to-use interface aim to spread out the applicability of the model among machining companies. The results of the study are validated by comparing simulations to experimental turning tests. © 2015 The Authors. Published by Elsevier B.V. Source

Rodriguez-Vidal E.,Advanced Manufacturing Technologies Unit | Lambarri J.,Advanced Manufacturing Technologies Unit | Soriano C.,Advanced Manufacturing Technologies Unit | Sanz C.,Advanced Manufacturing Technologies Unit | Verhaeghe G.,Faurecia
Physics Procedia | Year: 2014

A two-step method for the joining of opaque polymer to metal is presented. Firstly, the metal is structured locally on a microscale level, to ensure adhesion with the polymeric counterpart. In a second step, the opposite side of the micro-structured metal is irradiated by means of a laser source. The heat thereby created is conducted by the metal and results in the melting of the polymer at the interface. The polymer thereby adheres to the metal and flows into the previously engraved structures, creating an additional mechanical interlock between the two materials. The welding parameters are fine-tuned with the assistance of a finite element model, to ensure the required interface temperature. The method is illustrated using a dual phase steel joined to a fiber-reinforced polyamide. The effect of different microstructures, in particular geometry and cavity aspect ratio, on the joint's tensile-shear mechanical performance is discussed. © 2014 The Authors. Published by Elsevier B.V. Source

Leunda J.,Advanced Manufacturing Technologies Unit | Garcia Navas V.,Advanced Manufacturing Technologies Unit | Soriano C.,Advanced Manufacturing Technologies Unit | Sanz C.,Advanced Manufacturing Technologies Unit
Surface and Coatings Technology | Year: 2014

The effect of tempering after laser cladding of a high alloyed powder metallurgical tool steel was studied for die repairing purposes. In particular, a high power diode laser with scanning optics was employed for tempering. The laser tempering temperature was proven to be a critical factor in improving the mechanical properties of the coatings. In order to measure and evaluate the effect of different processing parameters (mainly laser power and linear speed) on the achieved temperature, an infrared camera and a two-color pyrometer were used. The tempering effect was mainly evaluated through cross-section microhardness profiles. The microstructure of the coatings was also studied using optical and scanning electron microscope, and the volumetric fraction of retained austenite was determined by X-ray diffraction. Experimental results demonstrated that laser tempering is a useful and appealing technique to improve the hardness of laser deposited coatings of high alloyed tool steels, which is a clear advantage when large parts have to be repaired or reinforced by laser cladding. © 2014 Elsevier B.V. Source

Fernandez D.,Advanced Manufacturing Technologies Unit | Garcia Navas V.,Advanced Manufacturing Technologies Unit | Sanda A.,Advanced Manufacturing Technologies Unit | Bengoetxea I.,Advanced Manufacturing Technologies Unit
MM Science Journal | Year: 2014

The use of super-alloys, most of them Ni- or Ti-based, has significantly increased during the last decade. Industries such as the aerospace,energy or transport, use these kinds of materials due to their excellent properties that combine hardness, high temperature strength and thermal shock and corrosion resistance. These desirable material properties make these alloys extremely difficult to machine, since high values of temperature and shear forces are easily achieved and a quick cutting tool wear turns out to be an important process constraint. Thus, with the objective to overcome this phenomenon, several methods can be used; the most common one is to add large amounts of water-based or oil-based cutting fluids directly into the cutting zone. However, nowadays other less conventional fluids are also being studied with the aim of achieving a more ecological and efficient process in the machining of these difficult-to-cut materials. Examples of this are vortex cold air or cryogenic cooling, among others. In this study a comparison between different cooling methods in turning of Inconel 718 is presented, which is the most commonly used nickel based alloy in the industry. Tool life and workpiece surface finish has been analyzed in each case, searching the pros and cons of each cooling technique. The results reveal the possibility of replacing traditional pollutant cooling fluids by other more ecologically friendly alternatives © 2014, MM publishing Ltd. All rights reserved. Source

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