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

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

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

Material model assessment in Ti6Al4V machining simulations with FEM

Ti6Al4V alloy is a well-known difficult-to-cut material used in different industrial applications, to achieve the expected component quality, proper definition and control of the machining process parameters must be accomplished. To address this problem, simulations with finite element method (FEM) seem to be an interesting engineering tool to model and optimize machining processes. Nevertheless, the model capability in capturing the behaviour observed in real machining processes is associated with the definition of the model and parameters that describe the workpiece flow stress. This contribution aimed to study the performance of built-in AdvantEdge-2DTMmaterial laws applied in Ti6Al4V orthogonal cutting simulations under dry conditions. The numerical models were created under three levels of cutting speed, a constant feed rate and depth-of-cut, a variable tool rake angle (of 20° and -6°/0 °), but also using four Ti6Al4V constitutive laws, namely, one suggested in AdvantEdgeTM library, a Johnson- Cook (JC) model, a Power law (PL) and a PL coupled with ductile damage model. Experimental results were used to assess the numerical models’ accuracy in predicting the machining forces and metal chips. Satisfactory results regarding the machining forces prediction were achieved with all material laws, yet when the damage criterion was coupled with the constitutive laws (PLD and AE standard material law), the simulations were also were able to achieve the expected chip morphology (serrated metal chips). Keywords: Ti6Al4V, AdvantEdge, orthogonal cutting, power law, Johnson-Cook material model, machining forces, saw-tooth chips.publishe

Toolpath and machining parameters optimisation of the cavities of a knee prosthesis tibial insert

The main purpose of this paper is to demonstrate the applicability of conventional cutting tools in the machining of a custom tibial insert of a knee prosthesis. This study also aims to reduce the roughness and minimize the production time. In this work the optimisation of cutting strategies and parameters was achieved through the design and construction of a test-part containing the most important complex surfaces of the femoral cavities, the focus of the study. The milling was carried out in accordance with the Design Of Experiment and the Taguchi method and was performed in two stages to reduce the number of analysed factors. The achieved parameters are applied to the machining of a modelled tibial insert made of UHMWPE, using a NC machine with three axes. The initial parameters studied were the cutting method, axial and radial depth of cut, the direction of the feed and the feed rate. Three strategies were studied: two Blend, resulting in radial and spiral toolpaths, and one Parallel. According to the spiral strategy, an arithmetical mean roughness of R a = 1.1 μm was obtained, representing an improvement of 45% relatively to the initial phase value of 2.0 μm, with the Parallel toolpath. An overall improvement of 34% in time efficiency of the finishing operation was achieved after changing the machine settings. This study supports the conclusion that high-speed milling is an expeditious process to produce customized tibial inserts.publishe

Correlative microscopy analysis of surface topography in machining Ti-6Al-7Nb

Titanium alloys, namely Ti-6Al-7Nb, are used in the biomedical industry. The study of surface topography is crucial for the development of medical components. The objective of this work is to propose the correlative microscopy technique developed for the analysis of surfaces machined by the turning process of Ti-6Al-7Nb alloy. This technique was based on the association of the 3D reconstruction by extended depth- of-field method from Optical Microscopy (OM) with the Scanning Electron Microscopy (SEM) and microanalysis modes. The correlative microscopy allows a correspondence between the cutting conditions and the material properties, through the analysis of the machined surface.in publicatio

Recent developments in sustainable manufacturing of gears: a review

Abstract: Environment awareness is of the utmost importance to all socially responsible manufacturers. To be competitive on a global scale manufacturing needs to be aligned with various strict environmental regulations. The manufacturing industry at large is striving to improve productivity and product quality while maintaining a clean and sustainable environment. This can only be achieved by adopting sustainable techniques of manufacturing which include minimizing the number of manufacturing steps by employing advanced and alternative methods, environment-friendly lubricants and lubrication techniques while machining, reducing wastage, active waste management and minimizing energy consumption etc. Gear manufacturing industries, the major service providers to all other industrial and manufacturing segments are also focusing on to implement the techniques targeting overall sustainability. Some of the recent developments to achieve sustainability in gear manufacturing can be summarized as reducing the use of mineral-based cutting fluids by employing alternative lubrication techniques i.e. minimum quantity lubrication (MQL) and dry machining, material saving, waste reduction, minimizing energy consumption and maintaining economic efficiency by reducing the number of gear manufacturing stages (eliminating the necessity of finishing processes) by utilizing advanced methods such as gear rolling and wire electric-discharge machining (WEDM), and finally increasing productivity by minimizing tool wear at high gear cutting speeds through the use of alternative tool materials and coatings. This paper reviews and amasses the current state of technology for sustainable manufacturing of gears and also recommends ways to improve the productivity and quality while simultaneously ensuring environmental sustainability

Modelos estadísticos para el análisis de la maquinabilidad de materiales compuestos de matriz poli (éter-éter-cetona)

En este artículo se recurre a métodos estadísticos para analizar la maquinabilidad de  mate-riales compuestos de matriz termoplástica.Se aplicará el análisis ANOVA para cuantificar la influencia de los parámetros funcionales de corte sobre la evolución de las fuerzas de corte y del acabado superficial.Se proponen modelos de predicción, basados en técnicas de regresión múltiple, que permi-tan anticipar el comportamiento de estos materiales ante unas condiciones de corte dadas. Finalmente, se presentan los resultados de los tests de confirmación para validar los modelos propuestos.In this paper statistic techniques are employed to analyze the machinability of thermoplastic composite materials. Analysis of variance (ANOVA) is used to quantify the influence of cutting parameters on cutting forces and surface finish.Predictive models, based on multiple analysis regression, are carried out to predict the be-haviour before cutting conditions. Finally, the results of confirmation test are presented, to validate the proposed models

3-D reconstruction by extended depth-of-field in tribological analysis: Fractal approach of sliding surface in Polyamide66 with glass fiber reinforcement

The objective of this work was to inspect the fractal behavior of sliding surfaces in Polyamide66 with 30% glass fiber reinforcement. Tribological tests were performed under different conditions and the fractal values were correlated to tribological parameters and evolution of morphological aspects along the surface. Elevation maps of the sliding surfaces were built from images obtained from a conventional optical microscope. Extended depth- of-field method allowed the ordering of stacks of images to quantitative investigation of behavior of surfaces. A robust method to establish the threshold between micro-scale and macro-scales for multi-fractal behavior was proposed, allowing to compare mono-fractal behavior with the ‘‘structural’’ (micro scale) and ‘‘textural’’ (macro- scale) mixed fractal components. It was found that fractal dimension data were depended on tribological con- ditions and positions along sliding surfaces.publishe

On the analysis of temperatures, surface morphologies and tool wear in drilling CFRP/Ti6Al4V stacks under different cutting sequence strategies

In drilling CFRP/Ti6Al4V stacks, the cutting sequence strategy, which determines the coupling effects of each phase machining, affects significantly the machinability of the sandwiched material as well as the tool wear characteristics. The present paper contributes to a scientific understanding of the effects of different cutting sequence strategies on the drilling performance of multilayer CFRP/Ti6Al4V stacks when using uncoated tungsten carbide and diamond-coated drills. Experimental quantification of the in-situ temperatures during the stack drilling was conducted using the method of infrared thermography camera and the instrumentation of drill bits by embedded thermocouples. Drilling forces, exit burr heights of the titanium holes, surface morphologies of the composite holes and tool wear signatures were analyzed. The results indicate that drilling from titanium to CFRP leads to higher magnitudes of the composite cutting temperatures while it benefits the reduction of the stack thrust forces, the improvement of the composite surface morphologies as well as the decrease of the exit titanium burr heights. Additionally, the coupling effects of drilling temperatures and chip adhesion are the influential factors leading to the disparate effects of the cutting sequence strategy on the drill wear progression. Drilling from titanium to CFRP reduces the drill adhesion and flank wear extents owing to the brushing effects of the composite drilling. The diamond-coated drills are confirmed superior to the uncoated ones in terms of lower drilling temperatures, lower drilling forces, minimal hole surface damage, less tool wear while machining the CFRP/Ti6Al4V stacks.publishe