Sustainability in the Aerospace, Naval, and Automotive Supply Chain 4.0: Descriptive Review.

The search for sustainability in the Supply Chain (SC) is one of the tasks that most concerns business leaders in all manufacturing sectors because of the importance that the Supply Chain has as a transversal tool and due to the leading role that it has been playing lately. Of all the manufacturing sectors, this study focuses on the aerospace, shipbuilding, and automotive sectors identified as transport. The present study carries out a descriptive review of existing publications in these three sectors in relation to the sustainability of the Supply Chain in its 4.0 adaptation as an update in matters that are in constant evolution. Among the results obtained, Lean practices are common to the three sectors, as well as different technologies focused on sustainability. Furthermore, the results show that the automotive sector is the one that makes the greatest contribution in this sense through collaborative programs that can be very useful to the other two sectors, thus benefiting from the consequent applicable advantages. Meanwhile, the Aerospace and Shipbuilding sectors do not seem to be working on promoting a sustainable culture in the management of the Supply Chain or on including training programs for their personnel in matters related to Industry 4.0.

On the Machinability of an Al-63%SiC Metal Matrix Composite.

This paper presents a preliminary study of aluminium matrix composite materials during machining, with a special focus on their behavior under conventional processes. This work will expand the knowledge of these materials, which is considered to be strategic for some industrial sectors, such as the aeronautics, electronics, and automotive sectors. Finding a machining model will allow us to define the necessary parameters when applying the materials to industry. As a previous step of the material and its machining, an experimental state-of-the-art review has been carried out, revealing a lack of studies about the composition and material properties, processes, tools, and recommended parameters. The results obtained and reflected in this paper are as follows; SiC is present in metallic matrix composite (MMC) materials in a very wide variety of sizes. A metallographic study of the material confirms the high percentage of reinforcement and very high microhardness values registered. During the machining process, tools present a very high level of wear in a very short amount of time, where chips are generated and arcs are segmented, revealing the high microhardness of the material, which is given by its high concentration of SiC. The chip shape is the same among other materials with a similar microhardness, such as Ti or its alloys. The forces registered in the machining process are quite different from conventional alloys and are more similar to the values of harder alloys, which is also the case for chip generation. The results coincide, in part, with previous studies and also give new insight into the behavior of this material, which does not conform to the assumptions for standard metallic materials, where the hypothesis of Shaffer is not directly applicable. On the other hand, here, cutting forces do not behave in accordance with the traditional model. This paper will contribute to improve the knowledge of the Al-63%SiC MMC itself and the machining behavior.

Shipbuilding 4.0 Index Approaching Supply Chain.

The shipbuilding industry shows a special interest in adapting to the changes proposed by the industry 4.0. This article bets on the development of an index that indicates the current situation considering that supply chain is a key factor in any type of change, and at the same time it serves as a control tool in the implementation of improvements. The proposed indices provide a first definition of the paradigm or paradigms that best fit the supply chain in order to improve its sustainability and a second definition, regarding the key enabling technologies for Industry 4.0. The values obtained put shipbuilding on the road to industry 4.0 while suggesting categorized planning of technologies.

Kerf Taper Defect Minimization Based on Abrasive Waterjet Machining of Low Thickness Thermoplastic Carbon Fiber Composites C/TPU.

Carbon fiber-reinforced thermoplastics (CFRTPs) are materials of great interest in industry. Like thermosets composite materials, they have an excellent weight/mechanical properties ratio and a high degree of automation in their manufacture and recyclability. However, these materials present difficulties in their machining due to their nature. Their anisotropy, together with their low glass transition temperature, can produce important defects in their machining. A process able to machine these materials correctly by producing very small thermal defects is abrasive waterjet machining. However, the dispersion of the waterjet produces a reduction in kinetic energy, which decreases its cutting capacity. This results in an inherent defect called a kerf taper. Also, machining these materials with reduced thicknesses can increase this defect due to the formation of a damage zone at the beginning of cut due to the abrasive particles. This paper studies the influence of cutting parameters on the kerf taper generated during waterjet machining of a thin-walled thermoplastic composite material (carbon/polyurethane, C/TPU). This influence was studied by means of an ANOVA statistical analysis, and a mathematical model was obtained by means of a response surface methodology (RSM). Kerf taper defect was evaluated using a new image processing methodology, where the initial and final damage zone was separated from the kerf taper defect. Finally, a combination of a hydraulic pressure of 3400 bar with a feed rate of 100 mm/min and an abrasive mass flow of 170 g/min produces the minimum kerf taper angle.

Impact of Chemical Post-Processing in Fused Deposition Modelling (FDM) on Polylactic Acid (PLA) Surface Quality and Structure.

The application of techniques to improve the surface finish of pieces obtained by fused deposition modelling, as well as other functional aspects, is of great interest nowadays. Polylactic acid, a biodegradable material, has been considered a possible substitute for petroleum-based polymers. In this work, different chemical post-processing methods are applied to polylactic acid pieces obtained by fused deposition modelling and some characteristics are studied. Structural, thermal, and crystallinity property changes are analyzed according to the treatments applied. This can prevent degradation, eliminate the glass transition phase of the material, and thereby increase the thermal resistance by about 50 °C. An improvement in the roughness of the pieces of up to 97% was also found.

Influence of PLA Filament Conditions on Characteristics of FDM Parts.

Additive manufacturing technologies play an important role in Industry 4.0. One of the most prevalent processes is fused deposition modelling (FDM) due to its versatility and low cost. However, there is still a lack of standardization of materials and procedures within this technology. This work aims to study the relationship of certain operating parameters and the conditions of poly(lactic acid) (PLA) polymer with the results of the manufactured parts in dimensional terms, surface quality, and mechanical strength. In this way, the impact of some material characteristics is analyzed, such as the pigmentation of the material and the environmental humidity where it has been stored. The manufacturing parameter that relates to these properties has been the extrusion temperature since it is the most influential in this technology. The results are quite affected especially by humidity, being a parameter little studied in the literature.

Three-dimensional chemical mapping using non-destructive SEM and photogrammetry.

The slice and view approach in electron microscopy defines an ensemble of destructive techniques that is widely used for studying in 3D the structure and chemistry of samples with dimensions ranging from µm to mm. Here, a method is presented for measuring with high resolution and quantitatively the morphology and chemical composition of the surface of a sample in 3D. It is non-destructive and therefore, it is complementary to slice and view methods. The scheme is based on the fusion of conventional scanning electron microscopy (SEM) imaging, multi-view photogrammetry and compositional mapping using energy dispersive X-ray spectroscopy (EDXS). We demonstrate its potential by performing an accurate study of adhesion wear of a tungsten carbide tool that is difficult to obtain using conventional characterization techniques.

Tool Wear Mechanism in Cutting of Stack CFRP/UNS A97075.

The aeronautics industry's competitiveness has led to the need to increase productivity with one shot drilling (OSD) systems capable of drilling stacks of dissimilar materials (fibre/metal laminates, FML) in order to reduce riveting times. Among the materials that constitute the current aeronautical models, composite materials and aluminium (Al) and titanium (Ti) alloys stand out. These one-pass machining techniques produce high-quality holes, especially when all the elements that have to be joined are made of the same material. This work has followed a conventional OSD strategy and the same cutting conditions applied to CFRP (carbo-fibre-reinforced polymer), Al and CFRP/Al stacked sheets to know the wear mechanisms produced. With this purpose, results were obtained by using current specific techniques, such as microstructural analysis, monitoring of the shear forces and analysis of macrogeometric deviations. It has been determined that when these drilling techniques are applied under the same cutting conditions to stacks of materials of a different nature, the results of the wear mechanisms acting on the tool differ from those obtained when machining each material separately. This article presents a comparison between the effects of tool wear during dry drilling of CFRP and UNS A97075 plates separately and when machined as stacks.

Application of Pin-On-Disc Techniques for the Study of Tribological Interferences in the Dry Machining of A92024-T3 (Al⁻Cu) Alloys.

One of the main criteria for the establishment of the performance of a forming process by material removal is based on cutting tool wear. Wear is usually caused by different mechanisms, however, only one is usually considered as predominant or the controller of the process. This experimental research is focused on the application of Pin-on-Disc wear tests, in which the tribological interference between UNS A92024-T3 Aluminum⁻Copper alloy and tungsten carbide (WC⁻Co) has been studied. The main objective of this study is focused on the determination of the predominant wear mechanisms involved in the process, as well as the characterization of the sliding and friction effects by using SEM and Energy Dispersion Spectroscopy (EDS) techniques, as applied to WC⁻Co (cutting tool material)/Al (workpiece material) which are widely used in the aerospace industry. Performed analysis prove the appearance of abrasive wear mechanisms prior to adhesion. This fact promotes adhesion mechanisms in several stages because of the surface quality deterioration, presenting different alloy composition in the form of a Built-Up Layer (BUL)/Built-Up Edge (BUE).

EFEITO DO EXERCÍCIO FÍSICO SOBRE A SAÚDE E SOBRECARGA DE MÃES DE CRIANÇAS E ADOLESCENTES COM PARALISIA CEREBRAL / EFFECT OF EXERCISE ON HEALTH AND BURDEN OF MOTHERS OF CHILDREN AND ADOLESCENTS WITH CEREBRAL PALSY / EFECTO DEL EJERCICIO SOBRE LA SALUD Y SOBRECARGA DE LAS MADRES DE NIÑOS Y ADOLESCENTES CON PARÁLISIS CEREBRAL

RESUMO Introdução: A paralisia cerebral (PC) é considerada a incapacidade física mais comum na infância. Essa doença afeta profundamente a saúde e o bem-estar dos indivíduos acometidos e também pode influenciar múltiplos aspectos da vida de seus cuidadores, especialmente as mães. Objetivo: Avaliar o efeito de um programa de exercício resistido sobre a qualidade de vida relacionada à saúde (QVRS) de mães de crianças e adolescentes com PC. Método: Vinte e duas mães sedentárias cuidadoras de crianças e adolescentes com PC, aptas à prática de exercício resistido, participaram de um programa de exercício resistido de intensidade moderada, em 2 sessões semanais durante 12 semanas. Todos os participantes responderam ao questionário de QVRS, Short Form Questionnaire (SF-36), à escala de sobrecarga Caregiver Burden Scale (CBS) e ao Inventário de Depressão de Beck (BDI) antes e após o programa de intervenção. Os escores dos questionários pré e pós-intervenção foram comparados pelo teste de Wilcoxon e a magnitude das diferenças foi medida pelo tamanho do efeito. Resultados: A mediana de idade das mães foi de 41 anos e variou de 18 a 58 anos. A mediana da idade das crianças/adolescentes foi de 14 anos, variando 3 a 21 anos. Após a intervenção foram encontrados aumentos significativos nos escores do SF-36 (p < 0,05), exceto nos domínios aspectos físicos e aspectos emocionais, que já obtiveram pontuação máxima pré-intervenção. Os escores do CBS e do BDI tiveram redução significativa pós-intervenção (p < 0,05). Conclusão: A prática regular de exercícios resistidos tem impacto positivo sobre a QVRS, a percepção de sobrecarga e a intensidade de sintomas depressivos de mães cuidadoras de crianças e adolescentes com PC.

ABSTRACT Introduction: Cerebral palsy (CP) is considered the most common physical disability in childhood. This disease profoundly affects the health and well-being of affected individuals and can influence multiple aspects of the life of their caregivers, especially mothers. Objective: To evaluate the effect of a resistance training program on health-related quality of life (HRQoL) of mothers of children and adolescents with CP. Methods: Twenty-four sedentary mothers caregivers of children and adolescents with CP, able to practice resistance training, participated in a resistance training program of moderate intensity of 2 sessions per week for 12 weeks. All participants answered to HRQoL questionnaire, SF-36, Caregiver Burden Scale (CBS) and Beck Depression Inventory (BDI) before and after the intervention program. The scores of the questionnaires before and after the intervention were compared using the Wilcoxon test and the magnitude of the differences was measured by effect size. Results: The median age of the mothers was 41 years, ranging from 18 to 58 years. The median age of children and adolescents was 14 years, ranging from 3 to 21 years. The SF-36 scores were significantly higher after the intervention (p<0.05), except in the domains physical aspects and emotional aspects, which already scored the highest value before the intervention. CBS and BDI scores were significantly reduced after intervention (p<0.05). Conclusion: The regular practice of resistance training has a positive impact on HRQoL, burden perception and intensity of depressive symptoms of mothers caregivers of children and adolescents with CP.

RESUMEN Introducción: La parálisis cerebral (PC) es considerada la discapacidad física más común en la infancia. Esta enfermedad afecta profundamente la salud y el bienestar de los individuos afectados y también puede influir en muchos aspectos de la vida de sus cuidadores, especialmente las madres. Objetivo: Evaluar el efecto de un programa de ejercicios de resistencia en la calidad de vida relacionada con la salud (CVRS) de las madres de niños y adolescentes con parálisis cerebral. Método: Veinte y dos madres sedentarias cuidadoras de niños y adolescentes con PC, aptas para la práctica de ejercicios de resistencia, participaron en un programa de ejercicios de resistencia de intensidad moderada, de 2 sesiones por semana durante 12 semanas. Todos los participantes respondieron el cuestionario CVRS, el Short Form Questionnaire (SF-36), la escala de sobrecarga del cuidador Caregiver Burden Scale (CBS) y el Inventario de Depresión de Beck (BDI) antes y después de la intervención. Las puntuaciones de los cuestionarios antes y después de la intervención se compararon mediante la prueba de Wilcoxon y la magnitud de las diferencias fue medida por el tamaño del efecto. Resultados: La edad mediana de las madres fue de 41 años, con un rango de 18 a 58 años. La mediana de edad de los niños/adolescentes fue de 14 años, con rango 3 a 21 años. Después de la intervención se encontró un aumento significativo en los resultados de SF-36 (p < 0,05), excepto en los dominios aspectos físicos y aspectos emocionales, que han obtenido la máxima puntuación antes de la intervención. Las puntuaciones de la CBS y la BDI tuvieron una reducción significativa después de la intervención (p < 0,05). Conclusión: La práctica regular de ejercicios de resistencia tiene un impacto positivo en la CVRS, la percepción de la sobrecarga y la intensidad de los síntomas depresivos de las madres cuidadoras de niños y adolescentes con PC.