糖心原创

Inertia Friction Welding (IFW) produces near-net-shape joints with high geometric accuracy; however, most studies have simplified the process by neglecting machine tolerances, spindle dynamics, and system compliance.

This study investigates the causes of radial runout, a key indicator of weld quality linked to headstock-tailstock concentricity. An inverse modelling approach was developed to estimate weld interface pressure distributions and equivalent process loads using experimentally measured radial runout, spindle speed, and strain data collected during steel welding trials.

Results revealed significant circumferential variation in pressure distribution and non-axisymmetric loading, particularly during conditioning and burn-off stages. The derived process loads were then applied to a Timoshenko beam-based dynamic spindle model to evaluate the influence of system compliance on weld behaviour. Model predictions showed strong agreement with experimental measurements, with an average relative radial runout error of 0.085. The findings indicate that non-axisymmetric loads primarily arise from initial workpiece misalignment, while irregular runout is largely governed by machine compliance and response to non-ideal loading conditions.

This work presents additively manufactured conformable fixtures for machining low-stiffness freeform components. The proposed design uses arrays of deformable flexure pins to fill the space between locating features, providing near full-face support while accommodating geometric variability in workpiece blanks.The approach can be integrated into existing machining processes without requiring changes to tooling or cutting parameters.

Finite element modelling and experimental validation demonstrated that flexure eigenfrequencies can be predicted with an accuracy better than 5%, enabling reliable fixture design. Clamping studies showed that conformable support reduces required clamping forces by up to 60% and decreases clamping-induced deformation by more than 40% compared with conventional fixturing methods. Milling experiments further revealed that controlled flexure resonance can improve dynamic performance, reducing workpiece vibration by 25-34%.

The results demonstrate that conformable flexure-based fixturing provides enhanced support, reduced deformation, and improved machining stability for complex, delicate freeform geometries.

Injection moulding of ceramic components with non-uniform wall thickness is challenged by differential cooling rates, which can cause premature feedstock solidification, defects, and increased distortion during subsequent processing.

This study proposes a novel mould thermal control strategy based on region-specific temperature management using Peltier modules to independently heat and cool cavity features according to their geometry. Temperature profiles are optimised over time using a coupled Finite Element and Particle Swarm Optimisation (FE-PSO) framework to achieve uniform cooling rates throughout the component. The proposed approach is compared with conventional constant-temperature moulding and Rapid Heat Cycle Moulding (RHCM), both of which aim to maintain uniform cavity surface temperatures.

Results demonstrate that regional thermal control enables simultaneous solidification of features with surface-to-volume ratio differences of up to tenfold. Consequently, the method improves dimensional accuracy and reduces differential shrinkage compared with existing techniques. The findings demonstrate the potential of tailored thermal control to expand the capability of ceramic injection moulding for complex components with uneven wall thickness.

This work investigates the influence of tooling and fixturing systems on Linear Friction Welding (LFW), addressing limitations in existing models that assume idealised geometries, rigid assemblies, and perfect constraints. Machine kinematics and stiffness were first characterised to distinguish machine-related effects from tooling-induced behaviour. A repeatability study of welds produced under nominally identical conditions revealed process variations associated with tooling compliance and clamping conditions.

To analyse these effects, a novel indirect diagnostic methodology was developed, combining advanced signal-processing techniques to evaluate weld data across spatial, temporal, and spectral domains. The research also introduces the SMART specimen concept, a purpose-designed test artefact that enables controlled investigation of clamping defects and their influence on weld performance.

The proposed methodology provides new insights into the relationship between tooling design, process behaviour, and weld quality. Beyond LFW, the approach offers a practical framework for evaluating fixturing effects and process variability in a wider range of manufacturing and machining applications..

Manufacturing freeform components presents significant challenges in fixture design, as conventional systems often struggle to accommodate complex geometries or suffer from limitations such as high complexity, limited reliability, and part deformation. This study introduces a novel diaphragm-based fixturing system that uses compliant elements to securely hold complex components.

The concept was evaluated using an experimentally validated finite element model, showing strong agreement with measurements (average displacement error of 4.04%). Numerical and experimental investigations confirmed the system's ability to generate distributed clamping forces exceeding 1000 N while maintaining effective contact with the workpiece. An advanced prototype was developed and demonstrated deterministic positioning and repeatable holding of freeform geometries.

Performance was further assessed under demanding grinding conditions, where part displacement remained below 10 μm despite cutting forces exceeding 1000 N. Although some design limitations were identified, the results demonstrate that the proposed system provides a practical and effective industrial solution for locating and fixturing complex components.

Milling of large thin walled casings with complex features needs appropriate damping solutions toachieve required workpiece surface quality when utilising aggressive machining parameters. In thispaper a novel surface damping solution composed of a thin flexible layer mounted with distributeddiscrete masses attached with viscoelastic layer is presented. Damping of higher frequencies through aflexible layer and subsequent lower frequencies through added masses enables damping over a widebandwidth. Finite element modelling and validation of the proposed solution showed a significantdamping of workpiece and corresponding reduction in machining vibration by more than four times.

Thin-wall machining requires a detailed understanding of machine-tool and workpiece dynamics to minimise chatter and improve machining performance. While previous research has largely focused on stability, the interaction between tool and workpiece responses remains insufficiently explored. This study investigates the coupled dynamic behaviour of cutting tools and thin-wall structures with both open (cantilever plate) and closed (ring-type casing) geometries.

Experiments were performed using different tool overhangs and depths of cut, and machining vibrations were analysed in the time-frequency domain to examine tool-workpiece interactions during cutting and idle tooth engagement periods. Results highlight the significant influence of tool dynamics, particularly the first bending and torsional modes, on thin-wall milling impact behaviour. For open geometries, both tool and workpiece responses remained evident across all cutting conditions. In contrast, closed geometries exhibited increasing dominance of tool modes at higher depths of cut.

These findings improve understanding of impact dynamics and inform the design and application of effective passive damping solutions.

Segmented-ring assemblies are widely used in high-value industries such as aerospace and power generation, where assembly circularity is critical. This study investigates how manufacturing variation in individual ring segments affects overall assembly geometry and proposes two novel assembly strategies to minimise circularity errors: a radial Translation Build (TB) method and a Circumscribed Geometric (CG) method.

Both approaches are compared with a conventional Fixed Datum (FD) assembly process. The influence of angular, radial, flatness/parallelism, and chord length variations on final assembly circularity is analysed through mathematical modelling and experimental validation. Additional sources of variation, including differences between component and assembly sagitta and geometric stepping caused by adjacent segment radius mismatch, are also examined.

Results show that the CG method consistently delivers improved circularity compared with the FD benchmark. In contrast, the TB method provides better control of angular breaking errors but demonstrates less consistent circularity performance across varying assembly conditions.

Adhesive fixturing systems offer significant advantages over conventional workholding methods by improving tool accessibility, reducing clamping-induced deformation, and accommodating complex geometries.

This study evaluates an ultraviolet-activated structural adhesive system for holding aerospace-type components and assesses its suitability for high-performance manufacturing applications. The mechanical performance of the adhesive bond is investigated, with particular attention to the effects of surface finish, contamination, bonded geometry, and curing time. Building on these findings, several fixture concepts are developed to enable rapid location, bonding, and de-bonding while maintaining unobstructed access to machining surfaces. Prototype fixture demonstrators are evaluated in terms of maximum reaction forces, dynamic behaviour, and operational usability.

Results demonstrate that the adhesive-based approach provides reliable workholding performance while expanding the capability to fixture delicate and geometrically complex components. The study highlights the potential of advanced adhesive fixturing systems as a practical and flexible solution for demanding aerospace manufacturing applications.