This article presents the development of a polymer filament extruder to recycle waste from 3D printing. As additive manufacturing grows within Industry 4.0, managing thermoplastic waste like PLA, ABS, and PET has become a key challenge. The proposed modular system includes a shredder, an extrusion unit, and a winding module to produce high-quality filaments with precise dimensions (1.75 ± 0.03 mm), ensuring compatibility with 3D printers. Aligned with circular economy principles, the system promotes material reuse and reduces environmental impact. Results confirm its technical and environmental feasibility, with potential for large-scale use. Future improvements may include recycling other polymers and using smart sensors and algorithms to optimize the process.

The fourfold increase in the number of publications devoted to the milling of thin-walled structures over the past ten years indicates, on the one hand, their increasingly widespread use in high-tech products and, on the other hand, the challenges faced by the industry in their manufacture, including the vibrations that accompany the milling process. Chatter leads to the formation of macrorelief on the machined surface in the form of waviness, which negatively affects the efficiency of products containing thin-walled structures. Various studies of the mechanism of waviness formation agree on the decisive role of regenerative chatter in this process. However, their occurrence requires the presence of initial waviness. To the reasons and principles behind its formation, the existing research does not provide an answer. Analysis of vibration oscillograms for both up-cut and down-cut milling leads to the conclusion that during the contact time between the tool and the part, a specific type of vibration occurs—attending free vibrations (AFV)—which have a distinct first wave and serve as a trigger for waviness formation. The study of the AFV influence on the formation of the machined surface macrorelief is the novelty of this work. Statistical analysis of the results obtained shows the relationship between the parameters of the AFV and those of the waviness. This article continues a series of publications on the results of research into the influence of technological parameters on those of AFV and waviness. It is devoted to the study of the impact of the radial cutting depth during up-cut and down-cut end milling of thin-walled structures. The obtained results demonstrate that the height of the waviness increases with the growth of the radial depth of the cut, both during up-cut and down-cut milling, while its step decreases during up-cut milling and increases during down-cut milling.

Lithium (Li) batteries have been part of any citizen’s daily life for about 30 years, although the knowledge about their potential dates to the early XX century. Being present in a wide range of applications, from small electronic appliances to hybrid or electric cars, Li has become essential to the most recent battery technology. In the need to change the harmful habits of fossil fuel usage, Li applications promise to provide a more sustainable way to deal with energy supply and improve energy storage devices efficiency. Resorting to Li carries the environmental burden of past battery technology since the materials used are well-known in the industry. Little changes have been made in Li battery manufacturing since it first became an industry, compromising its potential environmental benefits. The growing consumption drives efforts to extract Li and other scarce metals, but recycling rates are still too low for this industry to be considered a circular economy. Besides the quantifiable environmental indicators, many other intangible ones offer insight into the drawbacks and benefits of this emerging industry. In this study, the life cycle of Li-based energy storage devices is put into perspective from Li itself extraction, processing, and recycling. It was possible to identify many process variables in the Li life cycle using studies published in the last fifteen years, which can immediately reduce this promising technology’s environmental footprint. Besides immediate improvements, recycling has proven to be a highly efficient way to recover and reuse enormous amounts of Li and other materials in battery manufacturing. Beyond Li usage, a significant effort should be made to improve the supply of the remaining materials in a battery. This work intends to provide a comprehensive analysis using structured information about the Li life cycle, helping to understand the benefits and drawbacks of the intensive use of this kind of metal.

Cork has been one of the main pillars of the Portuguese economy for some decades and is today one of the most important natural materials exported from Portugal to the world. Nowadays, cork composites are used in products as diverse as sports flooring, wall memos, ladies’ bags and shoes. However, these composites need to be processed and one of the first steps to produce cork granules is their grinding process. Although cork has a relatively low mechanical resistance and hardness, the degree of abrasion generated by cork on grinding pads during the grinding process is considerable. This study aims to determine which type of wear mechanisms are strongly associated with the premature end of life of grinding pads, which occurs due to reduced cutting efficiency and the generation of cork granules outside the specifications. This study will allow to understand the best ways to extend the useful life of tools and improving the cost/benefit ratio. The results obtained led to an understanding of the phenomena induced in the inserts and generated promising alternative solutions using special materials and coatings, allowing to improve the behaviour of the inserts against wear, making this operation more efficient and profitable.

With the evolution of cities towards a model characterised by multiple urban centres, where housing and services coexist near, the way people move and how transport is ensured shifts from long-distance commuting to the concept of micromobility. This transformation necessitates the development of new mobility solutions adapted to this context, such as the subject of this study: the development of a coupling system for a bicycle child seat. To meet the emerging needs of the population, the proposed system aimed to improve existing market solutions. In this regard, the Design Science Research (DSR) methodology, which is well-suited for such development-oriented studies, was employed to guide the process. A set of initial design proposals were generated and evaluated based on their strengths and weaknesses. Subsequently, a selection matrix was applied to identify the two most promising concepts. Through an iterative design process, these two concepts were merged, refined, and enhanced, resulting in a product that features a mechanical clamping lever system, protected by an anti-theft locking mechanism and compliant with current safety regulations. Finally, the system’s structural performance was validated using Finite Element Analysis (FEA), which confirmed its resilience and mechanical integrity under the EN 14344:2004 standard’s proposed loading conditions, thus ensuring user safety and supporting the product’s position within the existing market.

The automotive sector is marked by intense competition, technological innovation, and a continuous need to improve efficiency, cut costs, and ensure responsible operations. In this scenario, industrial layout planning plays a crucial role, as it directly affects internal motion, logistical efficiency, and the ability to adjust to new challenges. This work addresses the requirement for an organization to create a new production area to meet its strategic growth demands. The research incorporated the Systematic Layout Planning (SLP) approach to formulate layout options and the Analytic Hierarchy Process (AHP) to assist in multi-criteria decision-making, taking into account factors such as operational efficiency, adaptability, safety, and sustainability. The data collected demonstrates the effectiveness of using SLP and AHP together as an organized approach to aid strategic decisions in the industrial sector. In addition to providing concrete answers to the company used to validate this approach, this study strengthens the scientific basis that proves that these tools, when used together, form a reliable framework for improving factory layouts in the automotive industry. The novelty of this paper lies in the hybrid application of Lean philosophy and its methods, combined with SLP and the AHP. By applying Lean principles, namely reducing possible waste to each alternative prior to the SLP and AHP comparative analysis across criteria, the approach yields more targeted and impactful results aligned with the main goals of any company. This contribution is especially significant because, unlike most research that focuses on changing existing layouts, the methodologies were successfully implemented in this case in the planning of a new automotive components production unit from the outset, filling an important gap in the literature and highlighting the relevance of economic and environmental sustainability.

In contemporary times, a corporation must provide rapid and faultless production to create differentiated, high-quality items that satisfy market need and standards, also taking into account the available industrial capacities. This study concentrates on optimizing the assembly line for pre-hospital transport equipment and instituting Standard Work across many workstations to enhance production efficiency. Consequently, operational excellence and strategies associated with continuous improvement were considered. Improvements in the assembly line and its edge facilitated a reduction in tasks, enabling a balanced workload among operators and optimizing the manufacturing process. A study was conducted on the durations and techniques employed in the different assembly processes and corresponding workstations for each product family. A comparison was conducted between the data reflecting the company’s baseline state and the outcomes achieved in this project. The implemented adjustments and their influence on the entire production process were assessed.