Papers by Keyword: Sustainable Manufacturing

Abstract: The mitigation of primary resource exploitation and their usage within linear economies ultimately leads to systematic leakages from economy and the depletion of natural resources. In contrast, a circular instead of a linear economy aims towards minimizing these leakages by reintroducing all resources to economy without negative externalities. Within the circular economy (CE), manufacturing plays a vital role for the conversion of resources towards products. For a manufacturing system, it is hence of critical importance to understand the implications and requirements of CE for production. The present study develops the Ready4CM “Ready For Circular Manufacturing” principle. Manufacturing systems are considered in the light of serving the needs of CE, where manufacturing flexibility, scalability and reconfigurability may pave the way but need to be controlled sufficiently to achieve resilience towards more drastic uncertainties of used materials. Not only focusing on process, but also on machine and tool, this paper contributes towards CE by identifying systematic aspects of circularity in manufacturing systems. We embedded our contribution in existing frameworks that calculate and balance sustainability potentials within circular economy while our approach, Ready4CM, aims to identify and summarize a comprehensive understanding of technical premises for manufacturing processes to serve and facilitate CE.

Abstract: This study evaluates the processability of recycled polypropylene (rPP) in pellet-based material extrusion (MEX) to support more sustainable additive manufacturing. Virgin polypropylene (PP) and post-consumer rPP obtained from end-of-life woven builder bags were processed in neat form and as PP/rPP blends with increasing recycled content. Melt-flow behavior was characterized using a Technological Melt Flow Index (TMFI), a process-specific metric reflecting the combined effects of temperature and screw rotation. Disk-shaped specimens were printed to assess deposition behavior through the build-up rate (BUR), which integrates shear flow in the extruder and elongational deformation during deposition. TMFI results show that rPP exhibits markedly higher flowability than virgin PP below 200°C, indicating potential for lower-temperature, energy-efficient processing. In contrast, printing experiments reveal that BUR systematically decreases with increasing rPP content. This trend indicates a transition to an elongation-dominated deposition regime, where rPP displays higher resistance to extensional deformation during deposition, resulting in narrower roads and reduced spreading. Regression analysis confirms that BUR is governed primarily by flow-rate setting (F%) and nozzle speed (Sp%), whereas nozzle temperature Te (°C) has only a minor influence within the investigated window. Overall, the results demonstrate the competing rheological effects introduced by recycling and highlight the need for tailored parameter optimization to enable higher rPP incorporation in pellet-based 3D printing.

Abstract: The direct reuse of End-of-Life (EoL) automotive sheet metal offers significant environmental benefits, particularly when panels are flattened rather than remelted. However, the geometric irregularity and variable formability of reclaimed sheets require joining solutions that operate with minimal tooling and are compatible with flat-die pressing. This work introduces a novel rivet-based joining-by-forming process designed to create a mechanical interlock using only flat tools, enabling integration into the same hydraulic press used for EoL panel flattening.Finite element simulations were performed to optimize rivet geometry and study flange formation, stress distribution, and failure mechanisms. The optimized rivet design achieves stable outward flaring under axial compression, producing a functional joint without shaped dies. Experimental tests on reclaimed automotive sheets validated the joining concept and confirmed the deformation behaviour predicted numerically.The proposed method provides a low-cost, low-energy joining strategy suitable for reclaimed steels of uncertain formability and supports the development of circular manufacturing routes based on the direct reuse of automotive sheet metal.

Abstract: Laser surface texturing (LST) is increasingly adopted to functionalize the surface in injection molding, enabling the control of interfacial and tribological phenomena without altering bulk material properties. While most studies have focused on mold cavities, the functionalization of ejection system components remains largely unexplored, despite its critical role in part release and process stability. This work presents a preliminary investigation of laser surface texturing for cylindrical ejector pins to promote lubricant retention at the pin–mold interface. A parametric study was first carried out on a flat to define a process window compliant with the maximum allowable groove depth constraint (20 µm). Based on this campaign, a stable ablation regime was identified and transferred to cylindrical ejector pins, where textures were fabricated along axial length. Different micro-texture geometries and spatial distributions were designed to generate controlled micro-reservoirs for lubricant retention. The textured surfaces were characterized in terms of groove depth, morphology and uniformity, confirming the feasibility of producing shallow and well-defined features within industrial constraints. The preliminary results demonstrate the technical feasibility of laser texturing on cylindrical ejector pins and its potential to modify the pin–mold interface. However, the comparative effectiveness of the different texture geometries in promoting lubricant retention will be further evaluated under extended service conditions. The study, therefore, establishes the basis for the functional optimization of textured ejection systems in injection molding applications.

Abstract: Bamboo has emerged as a sustainable and high-performance reinforcement material in composite structures due to its exceptional mechanical properties, rapid renewability, and environmental benefits. Despite increasing use, several challenges—including inconsistent fiber-matrix adhesion, moisture sensitivity, and lack of performance standardization—still limit its full-scale adoption. This article addresses these knowledge gaps by reviewing recent advances in bamboo fiber-reinforced composites (BFRCs), with emphasis on their applications in construction, automotive, aerospace, and biomedical engineering. The advantages of bamboo over synthetic fibers (e.g., glass/carbon fibers) include high specific strength (350 MPa), low density (0.8–1.4 g/cm³), biodegradability, and carbon sequestration potential. Critical processing techniques—such as alkali treatment, compression molding, and 3D printing—are analyzed alongside challenges like fiber-matrix adhesion and moisture absorption. With a growing emphasis on circular economy principles, BFRCs are poised to revolutionize sustainable material design.

Abstract: Sustainability is becoming a central pillar of manufacturing and Additive Manufacturing (AM) processes, thanks to their potentialities, seem to open a new path to reduce the environmental footprint. However, the surface finishing of AM parts is hardly ever adequate for high performances applications so post-process treatments are required. Thus, the assessment of sustainability should inevitably consider both steps. In this study, a Ti6Al4V cylindrical sample was firstly manufactured by Electron Beam Melting (EBM) and then machined by turning as post-treatment process. Surface roughness was measured either before and after the machining process both along the direction parallel and that perpendicular to the axis of the cylindrical sample and a Ra reduction of 84.14% and 95.74% were obtained, respectively. To evaluate the goodness of the machining process from the sustainability perspective, the Specific Energy Consumption (SEC) was calculated to evaluate the unit energy consumption for removal the mass unit. Moreover, power trends during the two turning passes have proved to be useful in understanding the different stages of the machining process, the cutting forces involved, and the amount of material removed.

Abstract: This paper presents an innovative Universal Multi-Parametric Model for designing devices using Magneto Rheological Fluids based on the explication of relationships between the functional requirements and the corresponding combination of related properties (chemical and physical)A rationale thus results to select the best MRF for a specific application. This might constitute a useful tool providing organized knowledge on the MRF world for scholars and practitioners approaching to the world of MRF technology as well as a support to engineers/designers during the early design tasks.

Abstract: High pressure cold spray has been showing increasing promise and application for structural repairs and coating applications where wrought like strengths are required. For example, numerous applications have been developed for repairing high cost and long lead time parts for the aerospace and defense market, such as aircraft skin panels, titanium hydraulic lines, aluminum valve actuator internal bores, hardened and chromed steel shafts, gas turbine engine parts, magnesium castings, and many more. These processes also have direct application in commercial markets like transportation and heavy industry. In particular, parts with lead times in excess of 12 months have been successfully repaired and re-introduced into service. This saves not only the direct cost of the part, but also returns the system to service much sooner. Additional benefits of field application with a hand-held nozzle assembly are also possible, particularly for power plants, refineries, and other large industrial plant operations. Cold spray consequently has a tremendous opportunity to enhance manufacturing sustainability by repairing parts that previously could only be replaced and recycled. It is environmentally friendly, as there are no toxic fumes or other harmful emissions from cold spray. Furthermore, because parts are being repaired and refurbished rather than replaced, there is tremendous cost, energy, and overall environmental benefit, making cold spray a “green” technology and an excellent technology for enhancing the long-term sustainability of high value assets.

Abstract: This study proposes of harmonizing the original approach of aluminium alloy recycling through hot press forging. By eradicating the melting phase, most of the waste generation can be significantly reduced. To cope with the technology revolution, the finite element is utilised to predict the material behaviour without practically executing the trial. By employing three-dimensional finite element analysis through DEFORM 3D, the evaluations were demonstrated by simulating the isothermal forging process. The flow stress of the material was modified to adequate with the aluminium-based metal matrix composite used in the actual experiment. To that extent, this study found out that the strain of the workpiece had gradually increased on each step. A reduction of ~10% of the flesh observed in the simulation is roughly the same as existed on the experiment workpiece. Above all, the simulation conducted abides by the standard and follows the actual practice that has been done previously. Through the finite element utilization, this study discussed the performance of the recycled based composite. The result presented here may facilitate improvement in the recycling issue and also conserved the environment for the better future.

Abstract: In recent years, the recycling of resources has become important because of the aggravation of global environmental concerns. In light of this, it is necessary to minimize the resource needs of current production systems. This concept is called sustainable development. When this concept is applied to machine tools, the assumption is that small parts should be processed using small machines. Additionally, the diversification of consumer needs and the ephemeralization of product life cycles are progressing in industry. As a result, the overall production system has changed from high-mix low-volume production manufacturing, to variant types in variable quantity. In this background, the cell production system is receiving attention as a production system that can achieve variant types in variable quantity. The cell production system also requires miniaturization and process consolidation of machine tools, which has given rise to the need to consolidate heat treatments, especially as part of the process consolidation of machine tools. Laser beams have proved to be effective heat sources when integrated into heat-treatment processes, such as quenching and tempering on machine tool tables. On the other hand, In the case of the thin plate, it is well known that the deformation of a plate occurs due to laser irradiation, as named a laser forming. The laser forming is also effective to generate the complex shape without a press die set. Thus, we propose that the hybrid process of laser heat treatment and forming of thin plate with a small power semiconductor laser, and demonstrate that the proposed method makes it feasible to generate the hardened sheet metal products with a compact machine tools. Moreover, considering the power consumption in laser quenching and forming process, we investigate an appropriate laser irradiation condition from a view of reducing the environmental burden.