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Browse AllWith the increasing demand for material microimaging analysis, there is a growing need for advanced precision grinding and polishing equipment, especially for metals, ceramics, and composites. Existing automated systems struggle with handling complex material challenges. This paper presents a fully automated adaptive grinding and polishing machine based on an STM32 microcontroller that handles multi-material samples. The system includes modules for sample access, cleaning, pad replacement, human-computer interaction, and equipment communication. The STM32 microcontroller executes grinding and polishing tasks based on instructions from the host computer while dynamically adjusting PID control parameters using an improved weighted average optimization algorithm. This approach enhances control accuracy, stability, and overall surface treatment quality compared to traditional PID control methods.
This paper examines the temperature distribution during pipe cutting and the impact of the heat-affected zone on the mechanical microstructure and properties of steel pipes. Utilizing testing equipment such as K-type thermocouples, a MESTL-WELD thermocouple spot welding machine, and a DC5516H 16-channel temperature data logger, temperature tests were conducted on Φ 1016 × 17.5 mm X70M spiral seam submerged arc welded steel pipes and Φ 1016 × 21 mm X70M straight-seam submerged arc welded steel pipes. The results indicate that the maximum test temperatures during cutting were 953.8 °C and 1216.6 °C, respectively, with the duration of temperatures exceeding 400 °C at each test point not exceeding 30 seconds. By fitting the relationship curve between the peak temperatures of each test point and the cutting distance using the ExpDec3 model, it was found that the cutting distance corresponding to a temperature of 580 °C was 12 mm. Furthermore, mechanical microstructure and property tests were performed on the pipe body at different positions of the HAZ. Except for an anomaly in the yield strength of the rod-shaped tensile specimens of the Φ 1016 × 21 mm X70M welded pipe body, no other abnormalities were detected. Macroscopic metallographic examination revealed that the axial length of the HAZ at the end of the cut pipe did not exceed 7 mm. Microhardness testing showed significant fluctuations in the microhardness of the pipe body at the end of the cut pipe, while the microhardness of the pipe body beyond 10 mm from the end gradually returned to normal.
This paper investigated the small deformation control of a large vertical vacuum vessel, a critical component in aerospace testing with stringent deformation limits under specific test conditions. Building on engineering experience and economic considerations, we designed oversized and multi-array external reinforcement rings tailored to the vessel’s spatial geometry to enhance its stiffness and stability. A novel integrated structural design was proposed, which mechanically couples the vacuum vessel with the concrete foundation via embedded components, specifically, by configuring optimized embedded parts at the vessel’s base and external reinforcement ring bottom, and then welding and binding these parts to the foundation’s embedded elements. This design significantly boosted the vertical vessel’s overall structural strength, rigidity, and stability. Ansys Workbench was used to simulate and analyze the vacuum vessel under different experimental conditions, and finite element simulations of the vessel under diverse experimental conditions validated that the integrated design achieves low stress and minimal deformation, compliant with test requirements. Post-installation deformation measurements further confirmed good agreement between experimental data and simulation results, verifying the model’s accuracy. The proposed fixed support structure addresses the limitations of traditional support systems for small-deformation applications and offers a new design paradigm for vertical vessel supports in high-precision engineering scenarios.
Additive manufacturing (AM) processes facilitate the production of components with high geometrical complexity, presenting substantial opportunities for innovation in demanding sectors such as aerospace and biomedical engineering. A significant challenge impeding their broader application is the characteristic surface roughness of as-fabricated parts, which results from the layer-wise construction and the presence of partially melted powder particles. While electrochemical polishing (EP) represents a viable post-processing technique for achieving a smooth surface finish, a comprehensive understanding of how the non-equilibrium microstructures characteristic of AM materials interact with the EP process remains incomplete. This investigation centers on the electrochemical polishing behavior of Ti-6Al-4V alloy fabricated by direct energy deposition (DED), utilizing a sodium chloride-ethylene glycol electrolyte. The findings reveal that the material's distinct engenders anisotropic anodic dissolution. This behavior is attributed to the differential electrochemical potentials among the constituent phases and their crystallographic orientations, which consequently narrows the operational process window for effective, uniform polishing. This preferential dissolution of certain phases results in the formation of a subtle, micro-scale topographical variation that mirrors the orientation of the original columnar grain structure. Notwithstanding this microstructural influence, the EP treatment proved highly successful in refining the surface finish, substantially decreasing the average surface roughness from 0.350 μm to 0.042 μm. Concurrently, the treatment led to a significant enhancement in the alloy's corrosion resistance, attributed to an oxide layer. These findings underscore the critical necessity of accounting for microstructural characteristics when developing optimized electrochemical polishing protocols for additively manufactured components.
The inconsistency in bearing data distributions under diverse conditions often affects the representations of the faulty data and leads to indistinct decision boundaries and even negative transfer resulted from overlapping class distributions, greatly limiting the accuracy of the diagnosis model. To cope with the challenge, a pseudo-label-guided dual-supervised alignment (PDSA) method is developed for bearing fault diagnosis across diverse operating scenarios in this paper. To address the fixed alignment strategy issue, an adaptive distribution alignment layer is incorporated to ResNet18 to achieve dynamic data distribution alignment under varying condition, To enhance classification performances, a dual-supervised mechanism, comprising shallow-layer supervised contrastive learning is introduced through target domain pseudo-labels in target domain and deep-layer regularization class consistency. Experiments on two publicly available bearing datasets demonstrated this model realizes refined class-level alignment, strengthens fault states representation, and shows notable superiority in both accuracy and robustness.
Topology optimization (TO), while powerful for generating high-performance structural layouts, often yields designs with enclosed voids that hinder manufacturability in powder-based additive manufacturing (AM). To address this, this paper proposes an Adaptive Virtual Temperature Field (AVTF) method that enforces the connectivity constraint. The approach integrates a projection-based density filtering and flood fill algorithm to detect enclosed voids, combined with an adaptive penalty scheme that autonomously adjusts the virtual temperature penalty factor to eliminate disconnected regions. AVTF operates via a low-cost geometric feedback mechanism. Numerical examples demonstrate that the method effectively eliminates enclosed voids with only a marginal increase in compliance while significantly reducing the maximum virtual temperature. The resulting designs exhibit fully connected material layouts, ensuring powder removability. The method provides a practical and robust pathway toward AM-ready topology optimization, bridging the gap between structural performance and manufacturability.