Composite material systems involving impinging flame jets on flat surfaces are critical in applications requiring precise thermal management and energy efficiency. A prominent example is Teflon-coated steel cookware, where the Teflon layer not only provides a nonstick surface but also influences thermal performance. Optimal coating thickness is essential: excessive thickness can reduce heat transfer efficiency, while insufficient thickness may compromise adhesion and durability. This study investigates the thermal interaction between a premixed flame jet and a Teflon-coated steel substrate using high-fidelity simulations in OpenFOAM. A conjugate heat transfer approach captured the coupled heat fluxes between the flame, steel substrate, and Teflon layer. Teflon thicknesses ranging from 0.01 to 0.20 mm were systematically analyzed to evaluate their effect on heat transfer performance. Simulation results enabled the development of a thermal efficiency model as a function of Teflon thickness, achieving a high correlation (R² = 0.9923). The proposed model offers quantitative guidance for optimizing coating thickness, providing a practical tool for the design and manufacturing of thermally efficient cookware.
Drilling of Fiber Metal Laminates (FMLs) is a very important manufacturing operation, as the metal-composite layered structure tends to undergo delamination, burrs, and dimensional errors. Although to date research work has mainly focused on cutting conditions, drilling tools, and lubrication methods for improved performance, the role of surface engineering on metal sheets prior to laminate fabrication has not received significant consideration. In this study, the effect of the variation of feed rate values during the drilling operation of FMLs with laser-textured titanium sheets is examined. Specifically, prior to FML consolidation, a unidirectional pattern with spacing characteristics of 200 µm was created on the titanium sheets; then, drilling tests using twist drill bits were carried out at a fixed cutting speed while varying the feed rate on two levels. The results show that a higher feed rate value induces both greater thrust force – and therefore improved adhesion resistance at the interface between the various materials of the multilayer – and a deterioration in the surface quality of the hole, increasing the occurrence of fiber pull-out and metal transfer phenomena.
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.
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.
Conventional hard-bait lure prototyping relies on manual shaping, full-body additive manufacturing or early-stage injection moulding, each associated with limitations in geometric repeatability, development time or tooling cost. This paper evaluates a hybrid approach combining thermoformed PETG outer shells with additively manufactured internal frames to produce batches of geometrically consistent lure bodies with tuneable internal mass layouts. Across several educational development projects, the process enabled fast replication of outer form, systematic variation of ballast and harness configuration, and prototype assembly suitable for qualitative hydrodynamic observation. Compared with full additive manufacturing or manual crafting, the method reduced fabrication effort for multi-variant batches and delivered mould-like surface quality. Joining reliability of shell halves emerged as the dominant limitation, with elastic polyurethane adhesives outperforming brittle cyanoacrylate and poorly controllable low-energy fusion. The results position thermoforming as a methodologically valuable prototyping tool where external geometry is stable but internal behaviour requires iterative adjustment. Future work should address seam design, cage-shell tolerances and sealing repeatability to support quantitative hydrodynamic testing and assess whether the process has potential beyond prototyping applications.
