Vito Basile

Efficient thermal management is a key factor in improving the sustainability and productivity of injection moulding processes, particularly at the micro-scale where thermal transients strongly affect part quality and cycle stability. This work investigates the thermal behaviour of hybrid moulds composed of polymeric support plates manufactured in Precision Resin V01 and stainless-steel inserts manufactured by additive manufacturing. An experimental campaign was carried out on a micro-injection moulding machine to characterize the intrinsic thermal response of the mould under uncooled conditions. Temperatures were monitored through embedded thermocouples and used to develop and calibrate a three-dimensional transient numerical model in COMSOL Multiphysics. Particular attention was devoted to the identification and calibration of heat transfer coefficients at the injection and extraction interfaces, which were found to play a dominant role in governing insert temperature evolution. The calibrated model accurately reproduces the experimental thermal transients, with deviations below 10%, demonstrating its reliability as a predictive tool for analysing mould thermal behaviour and supporting early-stage design and process optimization. The results highlight the advantages of hybrid architectures in promoting thermal stability and provide a robust methodology for modelling heat exchange in unconventional mould configurations.

The growing demand for high-performance, sustainable micro-moulded components requires integrated approaches to material and process selection. The study presents a Life Cycle Engineering (LCE) framework for the integrated selection of materials and manufacturing technologies for micro-injection molds, combining Life Cycle Assessment (LCA), Life Cycle Costing (LCC), and multi-criteria decision models. The methodology implements multicriteria cost impact maps and ternary LCA–LCC–technical performance model, allowing for result normalization and sensitivity analysis with respect to criterion weighting. The framework is applied to molds fabricated from steel, aluminium alloy, polyether-ether-ketone (PEEK), and high-temperature resin, using both subtractive and additive processes, with topological optimization. Mass reductions of up to 22% achieved through optimization translate into cost and environmental impact savings of 30–45% during production and use phases, although with potential service life reductions of up to 50% for polymeric materials. LCA and LCC analyses highlight production and use as the dominant life cycle phases, with end-of-life (EoL) impacts being comparatively minor. Sensitivity analysis shows that: (i) cost-prioritized scenarios select optimized steel molds; (ii) scenarios prioritizing lightweight design and environmental performance select advanced polymers and additive manufacturing; (iii) balanced scenarios identify PEEK as the optimal solution. The proposed framework enables the concurrent selection of material and technology aligned with design objectives and geometric optimization, providing quali-quantitative support for sustainability-oriented industrial decision-making across the life cycle.

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.

Ultra-high molecular weight polyethylene (UHMWPE) is widely used in orthopedic and prosthetic applications due to its excellent wear resistance and biocompatibility. However, its high molecular weight presents significant challenges in terms of processing and formability, particularly at the micro scale. This study investigates the flowability characteristics of a new melt-processable UHMWPE in micro-disc geometries to evaluate its suitability for advanced prosthetic applications. Micro-injection molding experiments assessed the material’s behavior under various thermal conditions. The influence of parameters such as temperature, pressure, and disc dimensions has direct effects on the flow behavior of UHMWPE and was analyzed by simulation and experiments. Results indicate that while UHMWPE exhibits limited flow under conventional conditions, optimized processing parameters can enhance discs’ formability without compromising the material’s structural integrity, avoiding defects. These findings provide critical insights for the microfabrication of UHMWPE thin components in next-generation prosthetic devices, enabling improved design precision and functional performance.

In this paper, we present an experimental procedure to enhance the dimensional accuracy of fabrication via stereolithography (SLA) of features at the sub-mm scale. Deviations in sub-mm hemispherical cavity diameters were detected and measured on customized samples by confocal microscopy. The characterization and experimental observations of samples allowed the identification of inaccuracy sources, mainly due to the laser beam scanning strategy and the incomplete removal of uncured liquid resin in post-processing (i.e., IPA washing). As a technology baseline, the measured dimensional errors on cavity diameters were up to −46%. A compensation method was defined and implemented, resulting in relevant improvements in dimensional accuracy. However, measurements on sub-mm cavities having different sizes revealed that a constant compensation parameter (i.e., C = 85, 96, 120 μm) is not fully effective at the sub-mm scale, where average errors remain at −24%, −18.8%, and −16% for compensations equal to 85, 96 and 120 μm, respectively. A further experimental campaign allowed the identification of an effective nonlinear compensation law where the compensation parameter depends on the sub-mm feature size C = f(D). Results show a sharp improvement in dimensional accuracy on sub-mm cavity fabrication, with errors consistently below +8.2%. The proposed method can be extended for the fabrication of any sub-mm features without restrictions on the specific technology implementation.

In this paper, we present an experimental procedure to enhance the dimensional accuracy of fabrication via Stereolithography (SLA) of features at the micro-scale. Using a custom benchmark part, deviations in feature dimensions (micro-pores diameters and depths) were detected and measured by confocal microscopy. Samples characterization and experimental observations allowed the identification of inaccuracy sources, mainly due to the laser beam scanning strategy and to the incomplete removal of uncured liquid resin in post-processing (i.e., IPA washing). As a technology baseline, the measured dimensional errors on pores diameters were up to -46%. A compensation method of the nominal laser spot diameter (85m) was defined and implemented resulting in relevant improvements in dimensional accuracy of 9.8% and 11.3% on full-open pores diameter and depth, respectively. Further investigation was performed on a customized test part to adjust the calibration procedure. The measurements revealed that the estimate of the laser beam spot size is 968m. Measurements on micro-pores having different sizes revealed that a constant compensation parameter (i.e., C=85, 96, 120m) is not fully effective at the micro-scale, where average errors still remain at -24%, -18.8%, and -16% for compensations equals to 85, 96 and 120m, respectively. A further experimental campaign allowed the identification of an effective nonlinear compensation law where the compensation parameter depends on the micro-feature size C= f (D). Results show a sharp improvement in dimensional accuracy on micro-pore fabrication, with errors consistently below +8.2%. The proposed compensation method can be extended for the fabrication of any micro-features without restrictions on the specific technology implementation. Concerning the inaccuracy introduced by the laser path, experimentation with a customized part allowed the optimization of the part orientation to reduce the errors and their differences along the X and Y machine axes.

As the complexity of micro-products increases, the micro-manufacturing processes, tool setups, and measurement processes have to be more precise and efficient. Combining them in a multi-stage process chain can effectively improve production accuracy and performance and reduce limitations and production costs. This paper focuses on the process chains for the manufacturing of micro-products and presents the state of the art, highlighting the specific characteristics of the existing models of process chains for micro-manufacturing. Based on the critical review of these characteristics, an evolution of the process chain model for micro-manufacturing is proposed, considering machining, measurement/characterization, referencing processes, and their combination into a suitable sequence. The proposed model accounts for relevant aspects of micro-manufacturing, such as size effects and technological fingerprints at the microscale. This paper also discusses the hierarchical properties of multiple micro-manufacturing process chains and some specific techniques to address the critical issue of referencing processes. Furthermore, some relevant case studies involving micro-electrical discharge machining, micro-injection molding, additive manufacturing, and micro-milling are presented to demonstrate how the micro-manufacturing potentiality can be increased using process chains.

In articular joint implants, polymeric inserts are usually exploited for on-contact sliding surfaces to guarantee low friction and wear, a high load-bearing capacity, impact strength and stiffness, and biocompatibility. Surface micro-structuring can drastically reduce friction and wear by promoting hydrostatic friction due to synovial fluid. Ultra-High Molecular Weight Polyethylene (UHMWPE) is a suitable material for these applications due to its strong chemical resistance, excellent resistance to stress, cracking, abrasion, and wear, and self-lubricating property. However, surface micro-texturing of UHMWPE is hardly achievable with the currently available processes. The present study investigates UHMWPE’s micro-textured surface replication capability via injection molding, comparing the results with the more easily processable High-Density Polyethylene (HDPE). Four different micro-texture cavities were designed and fabricated on a steel mold by micro-EDM milling, and used for the experimental campaign. Complete samples were fabricated with both materials. Then, the mold and samples were geometrically characterized, considering the dimensions of the features and the texture layout. The replication analysis showed that HDPE samples present geometrical errors that span from 1% to 9% resulting in an average error of 4.3%. In comparison, the UHMWPE samples display a higher variability, although still acceptable, with percentage errors ranging from 2% to 31% and an average error of 11.4%.

Flexible electronics is one of the most promising trends in the electronics industry, with increasing implementations in several application fields. However, in industrial applications, the assembly of film-based coverlays is still performed manually, representing a bottleneck in the whole production cycle, a source of defects caused by human errors, and introducing fatiguing tasks, such as the removal of the protective film covering the base material. In a novel methodology, this latter challenge is achieved by relying on the mechanical action of a rotating tool impacting the protective film. Such a process is typically stochastic and dependent on several parameters related to the tool-coverlay interaction, and the flexibility of film-type introduces further complexity. The aim of this paper is to investigate the influence of working conditions on the reliability of the process (i.e., success rate of the removal of the protective film). Finite element method (FEM) simulations are used to investigate and assess the stiffness exhibited by the component in response to the impacting force; therefore, a favorable gripping configuration is identified. An experimental campaign of the automated process is presented, aimed at assessing the effects of process parameters (tool rotating speed, adhesive thickness, approaching speed) on the protective film detachment. The results show that the process is predominantly affected by component-specific parameters, which, in turn, are significantly dependent on material supply conditions. Finally, useful insights are drawn to optimize the process and improve the design of the gripper of the robotized workcell.