Advances in Manufacturing

An analytical method for assessing the initiation and interaction of cracks in fused silica subjected to contact sliding

Chang-Sheng Li, Na Zhao, Liang-Chi Zhang, Jian-Jun Ding, Lin Sun, Duan-Zhi Duan, Cheng-Wei Kang, Zhuang-De Jiang

2023, 11(3): 363-377. doi:10.1007/s40436-023-00444-2

摘要 ( 171 )

PDF (466KB) ( 114 )

参考文献 | 相关文章 | 多维度评价

Understanding the fracture behavior of fused silica in contact sliding is important to the fabrication of damage-free optics. This study develops an analytical method to characterize the stress field in fused silica under contact sliding by extending the embedded center of dilation (ECD) model and considering the depth of yield region. The effects of densification on the stress fields were considered by scratch volume analysis and finite element analysis. Key mechanisms, such as crack initiation and morphology evolution were comprehensively investigated by analyzing the predicted stress fields and principal stress trajectories. The predictions were validated by Berkovich scratching experiment. It was found that partial conical, median and lateral cracks could emerge in the loading stage of the contact sliding, but radial and lateral cracks could be initiated during unloading. It was also found that the partial conical crack had the lowest initiation load. The intersection of long lateral cracks makes the material removal greater.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-023-00444-2

Prediction of temperature field in machined workpiece surface during the cutting of Inconel 718 coated with surface-active media

Qing-An Yin, Zhan-Qiang Liu, Bing Wang

2023, 11(3): 378-389. doi:10.1007/s40436-023-00445-1

摘要 ( 138 )

PDF (371KB) ( 44 )

参考文献 | 相关文章 | 多维度评价

The heat generated and accumulated on the machined surface of an Inconel 718 workpiece causes thermal damage during the cutting process. Surface-active media with high thermal conductivity coated on the workpiece to be machined may have the potential to reduce the generation of cutting heat. In this study, a theoretical model for predicting the instantaneous machined surface temperature field is proposed for surface-active thermal conductive medium (SACM)-assisted cutting based on the finite element and Fourier heat transfer theories. Orthogonal cutting experiments were performed to verify the results predicted using the proposed surface-temperature field model. Three SACMs with various thermal conductivities were used to coat Inconel 718 surface to be machined. Thermocouples embedded into the workpiece were used to measure the cutting temperature at different points on the machined workpiece surface during the cutting process. The experimental results were in agreement with the predicted temperatures, and the maximum error between the experimental results and predicted temperatures was approximately 9.5%. The cutting temperature on the machined surface decreased with an increase in the thermal conductivity of the SACM. The graphene SACM with high thermal conductivity can effectively reduce the temperature from 542 ℃ to 402 ℃, which corresponds to a reduction of approximately 26%. The temperature reduction due to SACM decreases with an increase in the distance between the temperature prediction point and machined workpiece surface. In conclusion, the cutting temperatures on the machined workpiece surface can be reduced by coating with SACM.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-023-00445-1

Smoothing strategy for corner of small curvature radius by abrasive waterjet machining

Jian-Feng Chen, Ye-Min Yuan, Hang Gao, Tian-Yi Zhou

2023, 11(3): 390-406. doi:10.1007/s40436-023-00443-3

摘要 ( 147 )

PDF (534KB) ( 57 )

参考文献 | 相关文章 | 多维度评价

Abrasive waterjet (AWJ) is widely applied in 2D machining as it offers high machining efficiency and low machining cost. However, machining a 3D surface, especially for a small curvature radius freeform surface (SCRFS), results in over-erosion of the corner, and has been one of the greatest issues of AWJ. To solve this problem, a local smoothing algorithm for SCRFS is developed by the junction of two linear segments at the corner by inserting cubic second-order B-spline to smooth the nozzle path and posture under the setting tolerance error, which is aimed to avoid over-erosion due to the change in dwell time. Analytical solutions of the smooth corner position and orientation of the nozzle path are obtained by evaluating a synchronization algorithm. According to the set tolerance error of the nozzle position and orientation, the interpolation of the smooth path of the corner meets the constraint conditions of the linear feed drive. Path simulation and experimental results show that the proposed method is validated by the experimental results and has been applied to the integral blisk machining of an aero-engine.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-023-00443-3

Predictive defect detection for prototype additive manufacturing based on multi-layer susceptibility discrimination

Jing-Hua Xu, Lin-Xuan Wang, Shu-You Zhang, Jian-Rong Tan

2023, 11(3): 407-427. doi:10.1007/s40436-023-00446-0

摘要 ( 186 )

PDF (495KB) ( 83 )

参考文献 | 相关文章 | 多维度评价

This paper presents a predictive defect detection method for prototype additive manufacturing (AM) based on multilayer susceptibility discrimination (MSD). Most current methods are significantly limited by merely captured images, disregarding the differences between layer-by-layer manufacturing approaches, without combining transcendental knowledge. The visible parts, originating from the prototype of conceptual design, are determined based on spherical flipping and convex hull theory, on the basis of which theoretical template image (TTI) is rendered according to photorealistic technology. In addition, to jointly consider the differences in AM processes, the finite element method (FEM) of transient thermal-structure coupled analysis was conducted to probe susceptible regions where defects appeared with a higher possibility. Driven by prior knowledge acquired from the FEM analysis, the MSD with an adaptive threshold, which discriminated the sensitivity and susceptibility of each layer, was implemented to determine defects. The anomalous regions were detected and refined by superimposing multiple-layer anomalous regions and comparing the structural features extracted using the Chan-Vese (CV) model. A physical experiment was performed via digital light processing (DLP) with photosensitive resin of a non-faceted scaled V-shaped engine block prototype with cylindrical holes using a non-contact profilometer. This MSD method is practical for detecting defects and is valuable for a deeper exploration of barely visible impact damage (BVID), thereby reducing the defect of prototypical mechanical parts in engineering machinery or process equipment via intellectualized machine vision.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-023-00446-0

An iterative blending integrating grinding force model considering grain size and dislocation density evolution

Zi-Shan Ding, Yun-Hui Zhao, Miao-Xian Guo, Wei-Cheng Guo, Chong-Jun Wu, Steven Y. Liang

2023, 11(3): 428-443. doi:10.1007/s40436-023-00436-2

摘要 ( 217 )

PDF (522KB) ( 95 )

参考文献 | 相关文章 | 多维度评价

The dynamic force load in grinding process is considered as a crucial factor affecting the quality of parts, and a better understanding of the mechanism of force generation is conducive to revealing the evolution of material microstructure more precisely. In this study, an iterative blending integrating grinding force model that comprehensively considers the impact of grain size and dislocation density evolution of the material is proposed. According to the grinding kinematics, the interaction of grit-workpiece is divided into rubbing, plowing, and chip formation stages in each grinding zone. On this basis, the evolution of material microstructure in the current chip formation stage will affect the rubbing force in the next grinding arc through flow stresses, which in turn will influence the total grinding force. Therefore, the flow stress models in rubbing and chip formation stages are firstly established, and then the dislocation density prediction model is established experimentally based on the characteristics of grain size. The effects of the evolution of grain size and dislocation density on the grinding forces during the grinding process are studied by means of iterative cycles. The results indicate that the implementation of an iterative blending scheme is instrumental in obtaining a higher accurate prediction of the grinding force and a deeper insight of the influence mechanisms of materials microstructure on grinding process.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-023-00436-2

Real-time K-TIG welding penetration prediction on embedded system using a segmentation-LSTM model

Yong-Hua Shi, Zi-Shun Wang, Xi-Yin Chen, Yan-Xin Cui, Tao Xu, Jin-Yi Wang

2023, 11(3): 444-461. doi:10.1007/s40436-023-00437-1

摘要 ( 145 )

PDF (564KB) ( 46 )

参考文献 | 相关文章 | 多维度评价

Keyhole tungsten inert gas (K-TIG) welding is capable of realizing single-sided welding and double-sided forming and has been widely used in medium and thick plate welding. In order to improve the accuracy of automatic weld identification and weld penetration prediction of robot in the process of large workpiece welding, a two-stage model is proposed in this paper, which can monitor the K-TIG welding penetration state in real time on the embedded system, called segmentation-LSTM model. The proposed system extracts 9 weld pool geometric features with segmentation network, and then extracts the weld gap using a traditional algorithm. Then these 10-dimensional features are input into the LSTM model to predict the penetration state, including under penetration, partial penetration, good penetration and over penetration. The recognition accuracy of the proposed system can reach 95.2%. In this system, to solve the difficulty of labeling data and lack of segmentation accuracy, an improved LabelMe capable of live-wire annotation tool and a novel loss function were proposed, respectively. The latter was also called focal dice loss, which enabled the network to achieve a performance of 0.933 mIoU on the testing set. Finally, an improved slimming strategy compresses the network, making the segmentation network achieve real-time on the embedded system (RK3399pro).

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-023-00437-1

Research and application of the angular rolling technology for plate mill

Zhi-Jie Jiao, Jun-Yi Luo, Zhi-Qiang Wang, Zhi-Peng Xu, Chun-Yu He, Zhong Zhao

2023, 11(3): 462-476. doi:10.1007/s40436-022-00428-8

摘要 ( 180 )

PDF (541KB) ( 63 )

参考文献 | 相关文章 | 多维度评价

Angular rolling technology can overcome the size limitation of plate mill equipment and product heavy steel plate with large unit weight or improve the production efficiency of small width spreading ratio product. With the DEFORM software, the numerical simulation study of the angular rolling process was carried out, and the relation laws of the width, rolling force and strain of the rolled piece under different angular rolling process conditions were obtained. The simulation results show that with the rotation angle increasing, the width of the rolled piece increases. Comparing with the conventional rolling process, the rolling force changes gradually during the biting and throwing stage of the angular rolling pass. With the rotation angle increasing, both the equivalent strains in the thickness direction and in the width direction gradually increase. According to the pattern and dimension’s changing formula in the double-pass angular rolling process, the prediction model of angle, reduction and width spreading is built. The opening value of side guide is set for the rotation angle controlling. For one 5 000 mm heavy plate mill, the automation control system was modified, and the angular rolling technology was applied online. The absolute deviation of target width does not exceed ±20 mm and the relative deviation does not exceed 1%. The large unit weight plate that cannot be rolled with traditional process, can be produced now, and the annual output increases by 10 000 t.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00428-8

Stage identification and process optimization for fast drilling EDM of film cooling holes using KBSI method

Jian Wang, Xue-Cheng Xi, Ya-Ou Zhang, Fu-Chun Zhao, Wan-Sheng Zhao

2023, 11(3): 477-491. doi:10.1007/s40436-022-00434-w

摘要 ( 142 )

PDF (565KB) ( 58 )

参考文献 | 相关文章 | 多维度评价

Fast drilling electrical discharge machining (EDM) is widely used in the manufacture of film cooling holes of turbine blades. However, due to the various hole orientations and severe electrode wear, it is relatively intricate to accurately and timely identify the critical moments such as breakout, hole completion in the drilling process, and adjust the machining strategy properly. Existing breakout detection and hole completion determination methods are not suitable for the high-efficiency and fully automatic production of film cooling holes, for they almost all depend on preset thresholds or training data and become less appropriate when machining condition changes. As the breakout and hole completion detection problems can be abstracted to an online stage identification problem, in this paper, a kurtosis-based stage identification (KBSI) method, which uses a novel normalized kurtosis to denote the recent changing trends of gap voltage signals, is developed for online stage identification. The identification accuracy and generalization ability of the KBSI method have been verified in various machining conditions. To improve the overall machining efficiency, the influence of servo control parameters on machining efficiency of each machining stage was analyzed experimentally, and a new stage-wise adaptive control strategy was then proposed to dynamically adjust the servo control parameters according to the online identification results. The performance of the new strategy is evaluated by drilling film cooling holes at different hole orientations. Experimental results show that with the new control strategy, machining efficiency and the machining quality can be significantly improved.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00434-w

Experimental study on surface integrity refactoring changes of Ti-17 under milling-ultrasonic rolling composite process

Zheng Zhou, Chang-Feng Yao, Liang Tan, Ya Zhang, Yi Fan

2023, 11(3): 492-508. doi:10.1007/s40436-022-00435-9

摘要 ( 153 )

PDF (590KB) ( 33 )

参考文献 | 相关文章 | 多维度评价

Ultrasonic rolling is an advanced non-cutting surface strengthening method that combines traditional rolling with ultrasonic vibration. In this research, the experiment of orthogonal end milling-ultrasonic rolling composite process has been carried out. The surface integrity refactoring changes and its mechanism of Ti-17 titanium alloy during the milling- ultrasonic rolling composite process has been studied and analyzed by the test and analysis of the surface geometric characteristics, residual stress, microhardness and microstructure before and after ultrasonic rolling. The residual stress and microhardness gradient distribution were characterized by cosine decay function and exponential decay function. All indicators of surface integrity were significantly improved after ultrasonic rolling. The study demonstrates that the reduction effect of the surface roughness by ultrasonic rolling process is inversely proportional to the initial surface roughness value. The ultrasonic rolling can only change the distribution form of the surface topography when the initial surface roughness is small. In addition, the improvement effect of ultrasonic rolling on surface compressive residual stress and microhardness decreased with the increase of initial milled surface roughness and surface compressive residual stress due to the factors such as energy absorption efficiency and mechanical properties changes of surface materials. A better ultrasonic rolled surface can be obtained by controlling the roughness and residual compressive stress of the initial milling surface to a small level.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00435-9

Research on conductive-material-filled electrodes for sidewall insulation performance in micro electrochemical machining

Guo-Dong Liu, Yu-Lan Zhu, Sheng-Gui Liu, Chao-Jiang Li

2023, 11(3): 509-522. doi:10.1007/s40436-022-00429-7

摘要 ( 224 )

PDF (556KB) ( 152 )

参考文献 | 相关文章 | 多维度评价

In micro electrochemical machining (ECM) processes, stray corrosion causes undesired metal dissolution and the deterioration of shape accuracy. Adopting a sidewall-insulated electrode is an effective approach to suppressing stray corrosion. Most sidewall-insulated electrodes are made of metal substrate and non-metallic thin films. Nevertheless, the thin-film insulating materials attached to a metal substrate are susceptible to damage in an electrolytic environment. This study presents a novel concept of the conductive-material-filled electrode for better sidewallinsulation performance. The micro-scale quartz tube serves as the insulating substrate. Commercially available conductive fillers including metal wire, molten metals, and silver powder are filled inside the working cathode of the quartz tube. Consequently, the metal-wire-filled electrode, moltenmetal-filled electrode, and nano-powder-filled electrode are designed and fabricated. From the verification results of electrode toughness, material removal rate, and surface topography, the metal-wire-filled electrode and moltenmetal-filled electrode exhibit the same performance as a traditional metal-based electrode and much better durability. By contrast, the nano-powder-filled electrode is unable to withstand long-term ECM processes because of the loss of cured powder particles. In ECM experiments, microstructures with steep sidewalls (taper angle <9.7°) were machined using the metal-wire-filled electrode and molten-metal-filled electrode, which could replace the traditional electrode, achieving a longer service life and superior sidewall-insulation performance.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00429-7

Development of metal-organic deposition-derived second-generation high-temperature superconductor tapes and artificial flux pinning

Dong-Xu Wang, Jing Chen, Di-Fan Zhou, Chuan-Bing Cai

2023, 11(3): 523-540. doi:10.1007/s40436-023-00447-z

摘要 ( 153 )

PDF (535KB) ( 63 )

参考文献 | 相关文章 | 多维度评价

The second-generation high-temperature superconductor tape (2G-HTS, also known as a coated conductor) based on REBaCuO (REBa₂Cu₃O_7-δ) exhibits high current density and potential cost-effective price/performance, compared with conventional superconducting materials. Using commercial 2G-HTS tapes, more than a dozen cable vendors had been manufacturing REBCO cables, such as the latest kilometer-class REBCO cable, which was incorporated into a civil grid on December 2021, as part of the recordbreaking 35-kV-voltage superconductor cable demonstration project in downtown Shanghai. This paper describes the development of HTS-coated conductors, then outlines the various technological routes for their preparation, reviews the artificial flux pinning of coated conductors, and finally summarizes the technological breakthroughs, the latest research advances, and provides an outlook on their application prospects.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-023-00447-z

Prediction model of surface integrity characteristics in ball end milling TC17 titanium alloy

Xue-hong Shen, Chang-Feng Yao, Liang Tan, Ding-Hua Zhang

2023, 11(3): 541-565. doi:10.1007/s40436-022-00416-y

摘要 ( 161 )

PDF (576KB) ( 57 )

参考文献 | 相关文章 | 多维度评价

Surface integrity is important to improve the fatigue property of components. Proper selection of the cutting parameters is extremely important in ensuring high surface integrity. In this paper, ball end milling of TC17 alloy has been carried out utilizing response surface methodology. The effects of cutting speed, feed per tooth, cutting depth, and cutting width on the surface integrity characteristics, including surface roughness (R_a), surface topography, residual stress, and microstructure were examined. Moreover, predictive metamodels for surface roughness, residual stress, and microhardness as a function of milling parameters were proposed. According to the experimental results obtained, the surface roughness increases with the increase of milling parameters, the (R_a) values vary from 0.4 μm to 1.2 μm along the feed direction, which are much lower compared to that along the pick feed direction. The surface compressive residual stress increases with the increase of feed per tooth, cutting depth, and cutting width, while that decreases at high cutting speed. The depth of the compressive residual stress layer is mostly in the range of 25-40 μm. The milled surface microhardness represents 6.4% compared with the initial state; the work-hardened layer depth is approximately 20 μm. Moreover, plastic deformation and strain streamlines are observed within 3 μm depth beneath the surface. The empirical model of surface integrity characteristics is developed using the results of ten experiments and validated by two extra experiments. The prediction errors of the three surface integrity characteristics are within 27%; the empirical model of microhardness has the lowest prediction errors.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00416-y

当期目录