Cirp Annals-Manufacturing Technology最新文献

Additive manufacturing creates parts by depositing a preform, typically layer by layer. Subtractive manufacturing involves removing material from a preform to create parts. Hybrid machine tools combine both additive and subtractive processes in the same workspace. They can be used to create parts that meet functional tolerance and surface finish requirements, or to create features that are difficult to produce using additive or subtractive processes alone. This paper describes hybrid metal additive/subtractive machine tools. It covers design considerations, sensors and controls, process management, programming and software, and the impact on the design space. It also identifies future research challenges.

The transition from the ‘Holocene-like’ interglacial state towards the Anthropocene epoch, driven by human activities, poses risks of triggering tipping points of the Earth system. Such risks create the need for target-based product design strategies, that are aligned with the environmental carrying capacities, such as the planetary boundaries framework. In this study, we introduce a stepwise approach to determine absolute environmental sustainability targets during the product development process. The approach integrates top-down factors such as planetary boundaries, IPCC carbon budgets and sharing principles shaping these targets. Furthermore, we assess the influence of bottom-up factors such as the selection of raw material suppliers and production location in achieving them. The application of the approach is illustrated for the case study of a traction battery. The potential future applications and limitations of the proposed stepwise approach are discussed.

Electric vehicle; Sustainable development; Absolute sustainability

A new abrasive flow polishing method with a ferromagnetic blockage placed inside tube was proposed for finishing internal surface of slender tubes with varying diameters. A mathematic model was established to calculate the blockage's profile. Results indicate that the special designed ferromagnetic blockage provides an effective tool to adjust the flow velocity and pressure, and thus controlling local material removal. Axial tool marks were removed by rotating the workpiece during polishing. A uniform internal surface (Sa < 40 nm) was achieved when finishing a puncture needle with diameters ranging from 0.3 to 0.7 mm (initial Sa 600 - 1200 nm).

Safety concerns severely impede industrial adoption of emerging human-robot collaborative manufacturing systems. A human-centric anomaly detection framework rooted in decision theory is proposed for integrated safety and quality assurance—which is a marked departure from earlier, quality- or safety-exclusive process control approaches. The framework adapts deep learning models to track fast robot motions from surveillance cameras and provides real-time, risk-metered alerts of anomalous trajectory deviations with theoretical guarantees. Application to a shared human-robot assembly line suggests that the framework can outperform conventional statistical process control methods in reducing safety risks and allows for straightforward extensions to more involved manufacturing settings.

Dynamic optical interferometric measurement method directly uses the liquid level as the reference surface, which immerses the tested object in liquid, and the interferograms are generated based on the optical path difference between the surfaces of the liquid and the object. The phase shift is realized by adjusting the incident angle of the laser with a rotation reflector. A generalized inhomogeneous phase shift algorithm is developed to suppress the micro-vibration of the liquid surface by the iterative least squares method combined with a confidence matrix. The high performance of the proposed method has been well verified in simulation and experiment.

Embedded printing enables the fabrication of integrated and enveloped internal geometries. Upflow, a geometrical deviation resulting from nozzle-translation-induced hydrodynamics, may affect the printing accuracy during embedded printing, in particular, nested printing where multiple layers are disturbed simultaneously during embedded printing internally nested structures within pre-deposited yield-stress structures. For the first time, this study identifies and characterizes two distinct upflow patterns including the interfacial upflow between the depositing and enclosure matrices during nested printing. Furthermore, a four-step upflow mitigation strategy is proposed and evaluated, and its effectiveness is demonstrated in printing a brain limbic system with significantly improved printing fidelity.

Polishing torque holds significance in monitoring the chemical mechanical polishing (CMP) process due to its close correlation with material removal. This study introduces a new model-based technique for estimating the material removal rate (MRR) using in-process data from CMP machines. The proposed method employs either the sequential least squares method or Kalman filter for real-time state estimation. Real-time estimation of MRR enables material removal control without relying on conventional endpoint detection (EDP) technologies. The accuracy of the proposed approach is validated through oxide CMP experiments, demonstrating precise estimation of the center-slowed MRR profile towards the end of the pad life.

The formability of the ultra-thin (0.1 mm) titanium sheet is improved by introducing an intermediate electropulsing treatment in a two-step stamping process. This improvement is attributed to the enhancement in both the work hardening capability and total elongation. A short-duration electropulsing treatment (∼2 s) significantly reduces the twin density and dislocation pile-up, while also expediting the formation of equi-axed recrystallized grains in the pre-deformed titanium sheets. With its excellent time- and cost-efficiency, the proposed process has the potential to be seamlessly integrated into conventional multi-step stamping lines to extend the forming limits of ultra-thin titanium sheets.

A kinematic model of rotary dressing - cylindrical grinding for lead pattern prediction is presented. Analysis of dressing and grinding parameters, dressing forces, and wheel imbalance effects has been conducted, providing a comprehensive look at the interrelationships between them and the resulting lead pattern. For model validation, a series of experimental tests has been performed, where workpiece and simulation lead has been characterized according to MBN 31,007–7 standard. Results emphasize the significance of modelling and translate it into a useful tool for selecting optimal dressing and grinding parameters for achieving specific surface qualities where lead is minimised or eliminated.

Broaching is a key technology for the manufacturing of fir-tree slots. Due to the high-temperature-resistant materials used, a high mechanical load is applied to the workpiece during machining. Because of the filigree workpiece structure, the high mechanical load leads to a geometrical deviation of the machined webs which are formed by two consecutive fir-tree slots on the rotor circumference. Therefore, a methodology was developed to predict the resulting geometrical workpiece deviation. It was shown and validated in analogy experiments that the minimum achievable deviation is a function of the web geometry independent of the number of calibration cutters.