Álvaro Gómez-Parra

Tribological Wear Analysis of Laser Surface Treated Ti6Al4V Based on Volume Lost Evaluation

Surface modification of materials through thermal or chemical treatments and coatings development can be used to obtain improved behavior under abrasive and adhesive wear. A great variety of surface structures with different properties can be adapted to the most demanding requirements. This is due to the high number of parameters that can be controlled in each treatment, such as the technique used, the atmosphere, the use of additive elements to the base material, the thickness of the modified layers, etc., In order to monitoring more accurately the wear conditions on the alloy, tribological tests were carried out that enable to control anytime the application parameters of a process, thus generating very accurate, reliable and easier to evaluate data, than industrial machining processes. One of the most significant wear variables in the study is the change in volume of material experienced by the sample after the sliding process. This contribution aims at assessing the volume of worn material, analyzing the tribological behavior of surface treated by laser Ti6Al4V samples.

Processing and Quality Evaluation of Additive Manufacturing Monolayer Specimens

Although its importance has increased significantly, Additive Manufacturing is not yet a fully accepted industrial manufacturing process for load-carrying parts. The future success of the process group depends on its standardization. This work proposes a methodology for the design, manufacturing, and quality evaluation of specimens manufactured by Fused Layer Modeling that are composed of only one layer (so-called monolayers). The processing methodology and properties of monolayers have not been studied systematically yet. A first systematic design of monolayers for mechanical testing is presented. Rectangular and circular monolayers adapted to the loads of tensile and compression testing are manufactured using different trajectory strategies. Frequently occurring macro- and microgeometrical defects are evaluated and categorized in order to optimize the part quality. This work also studies the effect of some manufacturing parameters such as the gap between print head and machine bed, trajectory strategy, bed leveling, and temperatures on part quality. The most suitable specimens are tested mechanically in tensile or compression tests. In the case of study, tensile strength values are only 8.6% lower than the values for reference tests on the unextruded filament. However, the properties deviate more strongly for compression tests which may be due to the selected specimen geometry.

Influence of the Dry Turning Parameters on the Ultimate Tensile Strength (UTS) of UNS A92024 Samples

The influence of the forming process in the response into service of the manufactured workpieces, in the first instance, through the surface integrity can be evaluated. The concept of surface integrity includes the assessment of geometrical aspects like shape and dimensions, and physicochemical properties like hardness and corrosion resistance. This work reports on the results of a study of the influence of the turning parameters on the Ultimate Tensile Strength (UTS) of turned bars of UNS A92024 Aluminium-Copper alloy.

A Single Students' Experience for Visualizing Completely a Semester Subject

Manufacturing Engineering Processes Knowledge Area has developed an innovative teaching experience in order to give, only in one session, a complete view of a basic subject, Manufacturing Engineering. This experience has been developed on the basis of making a cube constructed in card by groups of students. Starting from this, the different steps of a manufacturing process have been identified, as well as the necessity of establishing a quality control for any of them. Moreover, the different material processing technology types have been distinguished, the concept of process performance has been introduced and the different possibilities for sequential and/or parallel processing have been analyzed. On the basis of this, the students have built the topics program of the subject, justifying its competences distribution. In the same way, the students have defined the related basic concepts. At the end of the course, a questionnaire containing the basic cognitive concepts was answered by them, 100% successfully.

An analysis of geometrical models for evaluating the influence of feed rate on the roughness of dry turned UNS A92050 (Al-Cu-Li) alloy

Abstract In this work, the results of a preliminary study on the dry turning of the UNS A92050-T84 alloy (Al–Cu–Li, third generation of Al–Li alloys) are shown. This study has been focused on the analysis of the final surface quality of the machined workpieces, in terms of average roughness (Ra). Dry turning tests have been performed, using symmetric WC-Co cutting-tools, with different feeds and cutting speeds. Two different geometrical models, linear and quadratic, have been proposed, together with a non-geometrical potential model, obtained by adjusting the measurements to empirical data. Although the linear geometrical model is far from the acquired data, this model is formally similar to the parametric model, in which the feed exponent is close to one. This model allows predicting roughness theoretically for similar range of cutting conditions.

Taylor’s Model Based Analysis of Turning Inserts Tool-Life in the Dry Turning of UNS R56400 Alloy

In this work a study of tool life of uncoated WC-Co inserts — utilized in the dry turning of Ti6A14V (UNS R56400) alloy — has been achieved. This study has been developed on the basis of the tool wear time monitoring as a function of cutting speed (V) for fixed feed (f) and cutting depth (d). Tool life (T) has been evaluated through the flank wear (VB) measurement, making use of ISO 3685 standard.VB (T,V) surfaces have allowed defining the cutting speed range where T is maximum. On the other hand T(V) curves have allowed establishing the influence of cutting speed on tool life. From these curves a potential model, in the way of Taylor’s model, has been proposed.Copyright