Analysis of Secondary Adhesion Wear Mechanism on Hard Machining of Titanium Aerospace Alloy

Titanium alloys are widely used in important manufacturing sectors such as the aerospace industry, internal components of motor or biomechanical components, for the development of functional prostheses. The relationship between mechanical properties and weight and its excellent biocompatibility have positioned this material among the most demanded for specific applications. However, it is necessary to consider the low machinability as a disadvantage in the titanium alloys features. This fact is especially due to the low thermal conductivity, producing significant increases in the temperature of the contact area during the machining process. In this aspect, one of the main objectives of strategic industries is focused on the improvement of the efficiency and the increase of the service life of the elements involved in the machining of this alloy. With the aim to understand the most relevant effects in the machinability of the Ti6Al4V alloy, an analysis is required of different variables of the machining process like tool wear evolution, based on secondary adhesion mechanisms, and the relation between surface roughness of the work-pieces with the cutting parameters. In this research work, a study on the machinability of Ti6Al4V titanium alloy has been performed. For that purpose, in a horizontal turning process, the influence of cutting tool wear effects has been evaluated on the surface finish of the machined element. As a result, parametric behavior models for average roughness (Ra) have been determined as a function of the machining parameters used

Effect of process parameters and optimization of CO2 laser cutting of ultra high performance polyethylene

The aim of this work is to relate the cutting edge quality parameters (responses) namely: upper kerf, lower kerf, ratio of the upper kerf to lower kerf and cut edge roughness to the process parameters considered in this research and to find out the optimal cutting conditions. The process factors implemented in this research are: laser power, cutting speed and focal point position. Design of experiment (DoE) was used by implementing Box-Behnken design to achieve better cut qualities within existing resources. Mathematical models were developed to establish the relationship between the process parameters and the edge quality parameters. Also, the effects of process parameters on each response were determine. Then, a numerical optimization was performed to find out the optimal process setting at which the quality features are at their desired values. The effect of each factor on the responses was established and the optimal cutting conditions were found

MICRO MILLING OF METALLIC MATERIALS - A BRIEF OVERVIEW

Micro milling is an important process of mechanical micromachining, with practical application in aerospace, automotive, mould and die, biomedical, military and microelectronics packaging industries. This article will give a brief overview of the effects and conditions of micro milling with an emphasis on minimum chip thickness, size effect, cutting forces, cutting temperature, tool wear and tool failure, burr formation and surface quality. The case study presented in the present paper refers to the micro milling of an aluminium alloy

Digital tribology and the industry 4.0: a note

Industry 4.0 or the Fourth Industrial Revolution is driven by innovative technologies that have profound effects on production systems. Recent research results and industrial experiments show paradigm shifts in problem solving, which affect many areas, including tribology. Quantitative information obtained through the digital approach of the tribological study in the interface regions of the contact pairs, exhibit a strong potential for the optimization of the productive processes as a whole. In this sense, the concepts of Digital Tribology, presented here, are perfectly aligned with the new technologies in this era of digitalisation and emergence of intelligent, efficient and autonomous solution required by industry 4.0.in publicatio

Higher education for sustainability: a bibliometric approach—what, where and who is doing research in this subject?

Contextualization: From a very early age, assuming more prominence over the last decades, issues related to sustainability have been taking on a particular interest in the field of research. Although initially the basic concern was at the level of environmental sustainability, the truth is that, progressively, education for sustainability, deeply linked to the science of sustainability, constitutes, together with the latter, the scientific basis for education for the sustainability in higher education, thus emerging a research niche capable of providing greater openness and interaction between higher education institutions and their surroundings. Main aims of the study: Due to the importance that this issue assumes, this article seeks to address the issue of sustainability in higher education, giving particular focus to the analysis at the level of studies that have been developed, which are the main countries and institutions where this has been most researched, as well as which main researchers have been working on this issue. Methodology: For this purpose, and using information taken from the Scopus Database, a bibliometric analysis was carried out, which based on the items “higher education” and “sustainability” allowed to identify a set of 4410 publications. Main results: The results obtained allow to conclude that the number of publications in this area has been observing a significant increase over the last 30 years, with the United States, UK, Spain, Australia and Germany emerging as the countries which publish the most, and within these the Leuphana Universitat Luneburg, RMIT, Hochschule fur Angewandte Wissenschaften Hamburg, Manchester Metropolitan and the Arizona State universities that most publish in this field of research. The five main researchers in the field of higher education for sustainability, were also highlighted. Main contributions: Theoretical and practical contributions were highlighgted, namely, the contribution for government entities and the respective HEIs to reflect on the possible synergies to be developed, as well as to establish strategies and policies promoters of a more efficient and effective investment in research in higher education for sustainabilit

Sustainability in the modernization of higher education: curricular transformation and sustainable campus - a literature review

Supported by a literature review, the present article looks to address the issue of sustainability in the modernization of higher education. Education for sustainability and the encouragement of a sustainable lifestyle are increasingly present in the academic and professional training of individuals. Progressively more responsible for the environment in which they operate, individuals, in order to preserve their quality of life and, above all, ensure quality of life for future generations, begin to assume new behaviors, such as the rationalization of energy and water consumption, reducing the use of paper, recycling products, and eliminating the use of plastics, among other behavioral changes. In this context, considering higher education institutions as a vital source for the development of sustainability and, consequently, a key lever in the definition and implementation of strategies conducive to sustainable development, it is through the teaching, training, research, and development carried out by them that these behavioral changes occur. Aware of this issue’s relevance, the present article, consisting of a critical review of the literature, seeks to answer a set of questions, such as “What role do academic managers, teachers and students assume in the search for sustainability?”; “What measures/actions have been developed by the HEIs in terms of curricula reform and the promotion of a sustainable campus?”; “What sustainability metrics are used in higher education?”. Giving particular emphasis to some studies about sustainability in different HEIs, the results of the research allow us to conclude that education for sustainability is seen as a tool of crucial importance in the current decade of the 21st century.(undefined

The effect of minimum quantity lubrication in the intermittent turning of magnesium based on vibration signals

The present work shows an experimental investigation on intermittent turning based on vibration signals. The dependence of vibrations on the feed rate, minimum quantity lubrication (MQL) flow rate and the type of the interruption of the workpiece is evaluated. The results indicate that a part of the vibrations depends on the flow rate of the MQL system and its interaction with the feed rate, finding no dependency on the type of interruption. The influence of the MQL system is greater when machining at the lower feed rate. In addition, a strong relation between surface roughness and vibrations is identified. However, this relation is quite different depending on the environment used. In general, under dry conditions, the higher the vibrations the higher the surface roughness, while the opposite occurs when the MQL system is used.publishe

Advanced cutting tools and technologies for drilling carbon fibre reinforced polymer (CFRP) composites: a review

Carbon fibre reinforced polymer (CFRP) composites have excellent specific mechanical properties, these materials are therefore widely used in high-tech industries like the automobile and aerospace sectors. The mechanical machining of CFRP composites is often necessary to meet dimensional or assembly-related requirements; however, the machining of these materials is difficult. In an attempt to explore this issue, the main objective of the present paper is to review those advanced cutting tools and technologies that are used for drilling carbon fibre reinforced polymer composites. In this context, this paper gives a detailed review and discussion of the following: (i) the machinability of CFRP including chip removal mechanisms, cutting force, tool wear, surface roughness, delamination and the characteristics of uncut fibres; (ii) cutting tool requirements for CFRP machining; and (iii) recent industrial solutions: advanced edge geometries of cutting tools, coatings and technologies. In conclusion, it can be stated that advanced geometry cutting tools are often necessary in order to effectively and appropriately machine required quality features when working with CFRP composites.publishe

O Homem E A Terra: Natureza Da Realidade Geográfica

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