05 November 2024, Volume 60 Issue 21
    

  • Select all
    |
  • LU Yongxiang
    Journal of Mechanical Engineering. 2024, 60(21): 1-3. https://doi.org/10.3901/JME.2024.21.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The world manufacturing has entered a new era, and the global manufacturing landscape is showing a new pattern. While the United States maintains a global lead in high-tech and advanced military equipment manufacturing, ordinary manufacturing is gradually becoming less substantial and showing a trend of decline year by year. Since the reform and opening up, Chinas manufacturing has shown unique advantages and rapid development, with expectations to surpass the United States by 2035. This article analyzes the characteristics and competitive advantages of Chinas manufacturing. The 20th National Congress of the Communist Party of China has set the great goal of achieving a modernized China as a powerful manufacturing nation in the middle of 21th century. Chinas manufacturing will make great contributions to the wisdom, green, low-carbon, and sustainable development of China and human society!
  • LI Peng, WANG Liuyin, WANG Gang, MA Shugen
    Journal of Mechanical Engineering. 2024, 60(21): 4-13. https://doi.org/10.3901/JME.2024.21.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problems of low obstacle avoidance efficiency and collision of some joints with obstacles in micro snake robots, a new whole-body obstacle avoidance strategy for snake robots is proposed based on model predictive control. A guidance strategy is also proposed that is applicable to the unique structure of snake robots. The proposed obstacle avoidance strategy can both accurately follow the target path when there is no obstacle and efficiently avoid obstacles when there is an obstacle and quickly return to the original path. Different from the existing strategies that can only guarantee that the head or center of mass of the snake robot does not collide with obstacles, our proposed strategy can guarantee that all joints do not collide with obstacles, and the efficiency of obstacle avoidance is improved without considering the maximum collision volume or assuming that the snake’s tail moves strictly according to the trajectory of the snake’s head. In addition, by analyzing the effect of the changing drive structure of the snake robot on the turning efficiency under the fixed gait, a guidance strategy applicable to this type of robot with changing turning efficiency is proposed to avoid the oscillation phenomenon of the robot repeatedly shuttling through the desired path. The effectiveness of the proposed strategies is verified by extensive simulations and experiments.
  • LIU Shangfei, WANG Junzheng, LIU Dongchen, ZHAO Jiangbo, SHEN Wei, WANG Shoukun
    Journal of Mechanical Engineering. 2024, 60(21): 14-26. https://doi.org/10.3901/JME.2024.21.014
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In response to the demand for highly mobile, large payload and long duration mobile robot platforms for major natural disaster rescue missions, a multifunctional parallel six-wheel-legged rescue robot is proposed. A leg structure with pneumatic balance transmission linkages is designed to enhance load capacity. A power system using a combination of high-power-density batteries and a gasoline engine generator is adopted to improve endurance. A 7-degree-of-freedom manipulator is equipped to handle various tasks such as transportation and demolition. An environment perception platform incorporating multiple sensors and a remote operation control platform based on 5G communication network are built to enable remote human-robot interaction control. Both walking and driving locomotion modes are designed to satisfy the robot's basic motion requirements. Specifically, a variable body height and variable support surface wheel-legged compound locomotion mode is designed to tackle complex and harsh terrain conditions. A posture-stabilizing optimal controller is developed based on the robot's body dynamics model, working in conjunction with body height controller and foot force tracking controller to achieve active vibration isolation control during wheel-legged compound locomotion. The energy-saving effect of the pneumatic balance transmission linkages is validated through energy-saving tests. Obstacle crossing, trench crossing, and active vibration isolation experiments are conducted to validate the robot's capability in overcoming obstacles, stability on slopes and rugged terrains. These experiments lay the foundation for the robot to cope with harsh environments in disaster areas and accomplish rescue tasks.
  • JIN Tao, WANG Tianhong, PU Jing, ZHANG Quan, TIAN Yingzhong, LI Long
    Journal of Mechanical Engineering. 2024, 60(21): 27-37. https://doi.org/10.3901/JME.2024.21.027
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The rolling-contact continuum robot has good compliance and dexterity, and it can better perform maintenance and detection tasks in unstructured narrow environments. However, due to the different stacking configurations of rolling-contact units, the overall bending angle and the end attitude angle may be inconsistent during the motion of the robot, thus affecting the accessibility. In order to solve this problem, the rolling-contact joint unit is designed to construct three kinds of continuum robots with different stacking configurations, and their kinematic models are established by coordinate transformation method, respectively. Based on the mathematical model of the end bending angle and attitude angle, the deviation curve of the bending angle and attitude angle are compared while the end operating space are analyzed. On this basis, experiments are carried out to verify the movement of three rolling-stacked continuum robots in curved pipelines, and the results prove that the symmetrically stacked robot has a complete view and the best accessibility for narrow curved paths. This research provides technical support for the precise control of continuum robots in unstructured complex environments such as minimally invasive surgery and space exploration.
  • LIANG Dong, PANG Shukang, SONG Yimin, CHANG Boyan, JIN Guoguang, SUN Tao
    Journal of Mechanical Engineering. 2024, 60(21): 38-55. https://doi.org/10.3901/JME.2024.24.038
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The modelling and dimensional synthesis methodology for a class of high-speed parallel robot with articulated end structure is investigated. This class of parallel robot includes two configurations, which are composed of three approximately symmetrical active limbs and one UPU passive limb connecting the fixed platform and the end-effector. Different from the traditional Delta parallel robot, articulated end structure is adopted in the mechanism so that no moving platform is included in the robot which is much more lightweight to readily obtain excellent high speed / acceleration performance; meanwhile, offset design is conducted for the passive rods to guarantee the analytical expressions of forward and inverse position. First, screw theory is employed to analyze the degree of freedom of a typical configuration, and the expansibility of structure and motion is highlighted. Second, the complete kinematics and rigid-body dynamic models under different situations are established, and the reliability of them is verified by both numerical computation and mutibody dynamics software. On this basis, several dynamic performance indices are defined in the full consideration of inertia, velocity and gravity items, and the monotonicity analysis and genetic algorithm optimization are conducted with the aid of dimension / geometry and kinematic performance constraints. Finally, the kinematic performance of the novel parallel robot and the traditional Delta robot is compared under the same dimension parameters after optimization. The results manifest that, the novel parallel robot has better kinematic performance and has prosperous application prospect.
  • HUA Dezheng, SHEN Yurui, PENG Lai, WANG Qiyu, LIU Xinhua
    Journal of Mechanical Engineering. 2024, 60(21): 56-65. https://doi.org/10.3901/JME.2024.21.056
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to realize the cable-free drive of soft robot and avoid the mutual interference of multi-degree-of-freedom magnetic structure, a magnetically driven soft robot is proposed based on magnetorheological fluid. In terms of millisecond magnetization and non-coercivity of magnetorheological fluid, a dynamic driving mode of magnetic particle chains under gradient magnetic field is designed to realize the reconfigurable magnetization function of driven structures. Firstly, the structure model and production process of the magnetorheological soft robot are stated, and a rolling-deformation motion mode of the soft robot is established. The mechanical equilibrium equations for different motion stages are established by analyzing the dynamic relationship of the soft robot under magnetic field and stress field. The COMSOL finite element software is used to simulate the single-step motion state of the magnetorheological soft robot, and the feasibility of the rolling-deformation motion mode is verified under multiple physical fields. Finally, a magnetic field control experimental platform with robotic arm-permanent magnet is built to carry out the experimental tests of single-step, continuous, obstacle crossing, slope and straight-turn. The results show that the proposed soft robot can realize stable and continuous motion in any direction in the plane, and avoiding magnetic interference between internal structures, which provides new ideas for the structural design and driving method of magnetic soft robot.
  • WANG Nianwen, XU Li, YU Wanjiahui, ZHANG Lijie, XIE Ping, WAN Zhonghua
    Journal of Mechanical Engineering. 2024, 60(21): 66-85. https://doi.org/10.3901/JME.2024.21.066
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to solve the problems of weak comfort, low adaptability, cumbersome customization process and lack of design paradigm of existing knee and ankle foot rehabilitation products, an internal and external morphological configuration system and path of knee and ankle foot rehabilitation products based on information graph are proposed to guide the completion of the product scheme that is accurately adapted to patients and suitable for emotion. Firstly, an information model of the configuration system is proposed for the knee-ankle-foot rehabilitation products, and a morphological configuration design system of the knee-ankle-foot rehabilitation products guided by the information graph construction process is formed. Secondly, the morphological configuration requirements of knee ankle and foot rehabilitation products are informatized, and the internal and external configuration ontologies were constructed respectively. Thirdly, the information data is integrated, and the internal and external data of knee and ankle foot rehabilitation products are collected and cleaned through three-dimensional measurement and visual cognition theory and technology, so as to form a parametric index system and morphological configuration library for the internal morphology, and a product semantic database and morphological configuration library for the external morphology. Then, the physical link between the knee-ankle-foot parametric index system and the internal morphological configuration library, the correlation between the product semantic database and the external morphological configuration library is set and the entity link is completed, and the internal and external morphological configuration information of the knee-ankle-foot rehabilitation product is stored and the information graph was constructed by Neo4J. Finally, the informatization of design decision-making is completed, and a design retrieval system for knee, ankle and foot rehabilitation products is built to guide the design of rehabilitation products. Through the study of the configuration method of knee ankle and foot rehabilitation products, the shape and configuration law and perceptual shape configuration orientation are explored, and the precise adaptation of knee and ankle foot rehabilitation product form configuration path based on information graph is formed, which meets the comfort and emotional needs of users, and provides new research ideas for the shape configuration design of knee and ankle foot rehabilitation products.
  • LI Yongyao, JIANG Lei, LIU Yufei, DU Yu, CONG Ming
    Journal of Mechanical Engineering. 2024, 60(21): 86-98. https://doi.org/10.3901/JME.2024.21.086
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    When grasping objects, humanoid robotic hands need to possess motion adaptability while demonstrating good flexibility and grasping stiffness when interacting with unstructured environments. Therefore, this research proposes a novel design and manufacturing method for rigid-soft coupling humanoid robotic hands based on grasping stiffness enhancement method, inspired by the natural rigid-soft structure and grasping characteristics of human fingers. Firstly, the principle of rigid-soft coupling design for humanoid robotic fingers and the methodology for selecting finger parameters are presented. The study then expands the application of these principle and methodology to accommodate multi-joint fingers. Secondly, an in-depth analysis of the deformation of the finger's flexible body under external forces, both before and after enhancing grasping stiffness, is conducted to achieve stable grasping with a two-fingered gripper. On this basis, a multi-material layering manufacturing method for rigid-soft coupling humanoid robotic fingers is proposed, along with the overall structural design of the humanoid robotic hand. Finally, a series of experimental studies on grasping with the rigid-soft coupling humanoid robotic hand is performed to validate the effectiveness of the proposed method, followed by a comprehensive discussion of potential alternative applications for the rigid-soft coupling fingers.
  • XIE Feng, LI Hongyang, ZHEN Shengchao, WEI Huawei
    Journal of Mechanical Engineering. 2024, 60(21): 99-111. https://doi.org/10.3901/JME.2024.21.099
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A robot collision detection method based on Butterworth bandpass filtering to construct a second-order momentum observer is proposed to address the issue of possible collisions between six axis industrial robots and the surrounding environment and humans during operation. By decoupling the generalized momentum and external torque of robots, the observation index of the second-order momentum observer is defined as the deviation value between the theoretical momentum and actual momentum of the robot. A collision detection algorithm based on the second-order momentum observer is derived, and a Butterworth bandpass filter is used to optimize the observer gain to reduce errors caused by noise. The effectiveness of this collision observer is verified through simulation. Then, a particle swarm optimization algorithm based on decreasing weights is applied to identify the overall dynamic parameters of the six-axis robot, and the least squares method is used to sequentially solve the minimum parameter set of each joint. Finally, dynamic parameter identification and collision detection experiments are conducted on the ROC6 six axis industrial robot platform. The experimental results show that when the robot collides during operation, the momentum observer designed can detect it in about 0.3 s, and the detected collision force threshold is 21.5 N, which can effectively protect the safety of humans and robots.
  • LIU Zitan, MA Shuaijun, YAN Ke, FANG Bin, HONG Jun
    Journal of Mechanical Engineering. 2024, 60(21): 112-121. https://doi.org/10.3901/JME.2024.21.112
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Roller bearings are widely used in rotating systems because of their great load-bearing capacity and compact structure. However, the composite contact form and variable motion state between roller bearing components make the dynamics modeling difficult, and the accuracy of the current general multi-body dynamics software for solving the composite contact of roller bearings is limited by it. In this regard, a five-degree-of-freedom dynamics modeling method for roller bearings based on spatial coordinate system is proposed. Tapered roller bearings, which have the most complex geometric contact characteristics, are chosen for the study. By resolving the instantaneous geometric position relationship between the bearing components, the differential equations of the bearing component dynamics are established, and the WSTIFF I3 solution algorithm is used to ensure the accurate resolution of the composite contact process between the bearing components. Based on the two-roller gravity-free model and the analytical verification under the no-slip speed condition, the simulation results are less than 1% error from the theoretical value. The modeling method and its ability to simulate time-varying contact forces in complex operating conditions provide a new analytical approach to solving contact stresses and life prediction of roller-type bearings.
  • WANG Weimin, LIU Yanzhen, LIN Yulong, LI Tianqing
    Journal of Mechanical Engineering. 2024, 60(21): 122-131. https://doi.org/10.3901/JME.2024.21.122
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Surge is a typical fault of engine, which is extremely harmful, especially under the state of acceleration, so timely diagnosis and early warning is especially critical. The traditional early warning method of surge is based on pressure pulsation signals, which are difficult to install and has a limited identification range of the sensors. The blade tip timing technology is widely concerned in the condition monitoring of turbomachinery. The traditional blade asynchronous identification algorithm does not adequately analyze the under-sampling problem, and the identification accuracy is greatly affected by the frequency aliasing. So through the change of the frequency and amplitude characteristics of the blades, a method is proposed for surge warning and blade frequency identification. The lumped parameter model of blades considering detuning and coupling is established, the frequency difference is corrected by the combination of APFFT and traditional FFT, the natural number are obtained by the apfft and the traversal algorithms. The accuracy of natural number is introduced and the obviousness of frequency difference is proposed as a criterion to obtain an accurate asynchronous recognition algorithm. A numerical simulation model is used to simulate the displacement under-sampling data of the blade collected by the BTT sensor during multi-frequency resonance, and comparing the identification results of the two algorithms, the maximum error of the proposed modified algorithm is 0.845% and 0.053% for the difference and frequency identification, respectively, which is much lower than that of the traditional algorithm, which is 1.556% and 0.097%, and the accuracy of the proposed algorithm is verified. Experiments are carried out on the large fan blade test bench, the frequency amplitude characteristics of blade in the stage of surge are investigated, real-time warning of surge is realized according to the amplitude effective value and alarm threshold, and the proposed algorithm is used to identify the blade asynchronous vibration frequency. The experimental results show that the setting of the blade amplitude alarm threshold during surge is in good agreement with the displacement results, and the average of asynchronous vibration frequency is 1 261.2 Hz, and the maximum deviation is 4.8%. This method can provide real-time non-contact surge warning for turbomachinery, and provide technical support for asynchronous frequency identification and damage monitoring of turbine rotating blades.
  • TIAN Jing, GAO Chong, GUAN Jiaoyue, FU Pengzhe, LIU Shiyun, YAO Yudong
    Journal of Mechanical Engineering. 2024, 60(21): 132-143. https://doi.org/10.3901/JME.2024.21.132
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The anti-vibration and anti-loosening performance of the self-locking nut with closure is obviously better than that of the common nut, and it is widely used in the connection structure of the aeroengine. However, due to the complex shape of the self-locking nuts, it is difficult to accurately model them and lack of relevant simulation research. Firstly, the thread expression in the receptacle area of self-locking nut is derived, and a high-fidelity model of self-locking nut is established by combining the standard bolt model generation method. Then, the effects of structural parameters such as thickness, volume and length of self-locking nut's closure area and load parameters such as initial preload, amplitude of excitation load and friction coefficient of contact surface on the loosening characteristics of self-locking bolt-nut connection structure are simulated and analyzed. Finally, loosening characteristics test of self-locking nuts with closure is carried out. The results show that the residual preload increases by 12.2%, 11.4% and 7.7% respectively with the increase of structural parameters. The initial preload and the friction coefficient of the contact surface increase the residual preload by 37.1% and 6.9% respectively, while the increase of the amplitude of the exciting load decreases the residual preload. When the amplitude of initial preload and excitation load changes, the corresponding average error of simulation is 3.79% and 3.55% respectively. The above results prove the accuracy of the high-fidelity modeling method in this paper, which lays a foundation for simulation research and self-locking mechanism exploration of the closure self-locking nut, and also provides guidance for structure optimization and engineering application of the nut.
  • JIN Guoguang, WANG Zhimin, CHANG Boyan, LIANG Dong, ZHOU Yang
    Journal of Mechanical Engineering. 2024, 60(21): 144-155. https://doi.org/10.3901/JME.2024.21.144
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The metamorphic mechanisms with clearance joint are studied to have important theoretical significance and practical application value for mechanical design and manufacture. The dynamic model of the metamorphic mechanism with clearance joint is established, and the general analysis method of the motion stationarity of the metamorphic mechanism with clearance joint is given. Taking the planar five-bar metamorphic mechanism with clearance joint as an example, the L-N contact force model and the modified Coulomb friction force model are used to simulate the normal contact force and tangential friction force at the clearance joint, and the dynamic model of the metamorphic mechanisms with clearance joint is established based on the Newton-Euler method. The influence of the existence of clearance on motion precision of the metamorphic mechanisms is mainly studied, and a quantitative precision analysis method is presented by using root mean square error and coefficient of variation. The effects of crank speed, clearance size and friction coefficient on the motion stationarity of the metamorphic mechanisms with clearance joint are studied. The results show that as the crank speed and clearance value increase, the vibration of the mechanism intensifies and the stationarity of motion decreases. Dynamics of the metamorphic mechanisms with clearance joint has strong nonlinear characteristics, and has highly sensitive and dependent on the change of clearance parameters.
  • FANG Pan, SUN Hechao, CAI Ketao, HOU Yongjun, KANG Weitang
    Journal of Mechanical Engineering. 2024, 60(21): 156-167. https://doi.org/10.3901/JME.2024.21.156
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problems of low screening efficiency and poor vibration isolation performance of single-body vibration system with same frequency actuation, a dual-body vibration absorption system with multiple-motor and double-frequency actuation is designed. To explore the dynamic characteristics of the vibrating system, the vibration isolation performance and the synchronization mechanism are studied. Firstly, the dynamic model of the system with multiple degrees of freedom is established by Lagrangian method. And the steady-state solutions of the screen box are calculated by transfer function method. Secondly, the necessary conditions for the system to implement the stable double-frequency synchronization are determined by using the improved small parameter method and Lyapunov criterion. Then, the effect of the system parameters such as excitation frequency, rotor mass ratio and motor position on synchronization state, synchronization stability and vibration isolation capability is discussed. Finally, an experimental prototype is designed to verify the correctness of the theory model, numerical analysis method and simulation results. The research found that the synchronization is significantly affected by the rotor mass and the position of motor installation. The farther the distance of motor position, the stronger the synchronization. Besides, the excitation frequency of the low frequency motor is closer to the natural frequency of the oscillating body, the better vibration isolation effect.
  • ZHANG Fengling, ZHANG Dawei, AI Yanting, TIAN Jing, WANG Zhi
    Journal of Mechanical Engineering. 2024, 60(21): 168-179. https://doi.org/10.3901/JME.2024.21.168
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A method named synchronized switch damping on inductor (SSDI) is proposed to aim at the issue of vibration localization in mistuned bladed-disk (blisk) structures of aero-engines. Firstly, the operational principle of the SSDI method is introduced, and its vibration reduction mechanism is analyzed. Subsequently, a lumped parameter model of the blisk is established, and the dynamic equations for the mistuned blisk are derived. Four cases are considered including open-circuit state, SSDI shunting, series-connected SSDI piezoelectric network, and parallel-connected SSDI piezoelectric network. Furthermore, a novel evaluation factor - the energy homogenization factor - is proposed, and the effectiveness of SSDI in suppressing localization of mistuned blisks under these four cases is compared. Finally, a dual-beam system with an SSDI piezoelectric network is employed for experimental validation, simulating the aero-engine's blisks. The results demonstrate that the parallel-connected SSDI piezoelectric network not only achieves better damping performance with fewer switches, but also significantly suppresses the vibration localization in mistuned blisks. Moreover, SSDI piezoelectric network does not need for electrical parameter optimization, showing significant potential for practical applications.
  • WEI Yongqiao, LIU Wenwen, GUO Rui, LUO Lan, WANG Shaojiang, QI Xiaohu, ZHANG Jianquan
    Journal of Mechanical Engineering. 2024, 60(21): 180-195. https://doi.org/10.3901/JME.2024.21.180
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to explore the propagation mechanism of contact fatigue crack of the Cylindrical Gear with Variable Hyperbolic Circular-arc-tooth-trace gear(VH-CATT), guide the design optimization of gear and reduce the crack propagation speed, a numerical calculation model of contact ellipse of VH-CATT cylindrical gear is established based on the curvature characteristics of gear. The contact trajectory of tooth surface ellipse is analyzed by finite element method and numerical calculation method, and the dangerous position of gear crack is determined. The extended finite element method (XFEM) is used to analyze the propagation law of contact fatigue cracks in VH-CATT cylindrical gears. By establishing the stress intensity factor analysis model of VH-CATT cylindrical gear, the influence of modulus, tooth line radius and crack preset angle on mode I stress intensity factor is analyzed. The results show that in the stage of long crack propagation, the larger the gear modulus, the larger the stress intensity factor of the crack in the direction of tooth width and tooth core. The stress intensity factor of the crack front in the long crack propagation stage can be effectively reduced when the radius of the tooth line is large. When the crack preset angle is large, the stress intensity factor in the direction of tooth width and tooth core also increases.
  • DAI Songjie, ZHANG Hui, CHEN Jiawei, GOU Hanchi, GUO Shili, DONG Guangneng
    Journal of Mechanical Engineering. 2024, 60(21): 196-206. https://doi.org/10.3901/JME.2024.21.196
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the two-component slippage model, the Genetic Algorithm is used to optimize the boundary slippage region of sectorial thrust bearing with the objective of low friction coefficient. The tribological properties of sectorial thrust bearing with whole no-slippage, whole slippage, half-slippage and optimized slippage surface are discussed and compared, and the mechanism is revealed. Meanwhile, the influence of width, convergence rate and slippage length of bearing on the improvement of tribological performance is analyzed, and tribological experiments of four different slippage surfaces are conducted . The results show that an asymmetric stepped trapezoidal boundary slippage region optimization scheme is obtained by optimizing the boundary slippage region of sectorial thrust bearing, and the optimized region narrows gradually along the direction of lubricating oil flow at the bearing inlet; The bearing capacity of the optimized slippage surface is increased by 96.1%, 279.5% and 8.7%, and the friction coefficient is decreased by 58.0%, 59.8% and 13.2%, respectively, compared with that of whole no-slippage, whole slippage and half-slippage surface. The mechanism may be that the optimized slippage surface increases the flow of inlet lubricating oil and enhances the hydrodynamic pressure effect. For sectorial thrust bearings with smaller width, smaller convergence rate and larger slippage length, this asymmetric stepped trapezoidal boundary slippage surface can significantly improve the tribological properties. The optimized slippage surface has been verified to have a smaller friction coefficient compared to the other three slippage surfaces through tribological experiments, which has reference value for the design and engineering application of sectorial thrust bearings.
  • YAO Xuedong, LI Wei, WEN Zefeng, ZHOU Zhijun, ZHOU Shenglu
    Journal of Mechanical Engineering. 2024, 60(21): 207-218. https://doi.org/10.3901/JME.2024.21.207
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Floating fasteners, as a type of resilient fasteners, provide a low vertical stiffness for metro tracks by supporting the low jaw and web of the rail. However, they intensify the high-frequency wheel–rail interaction. To analyze the influence of flexibility of wheelset and track on the wheel–rail transient rolling contact behavior, three-dimensional finite element model of wheel–rail transient rolling contact for metro tracks with floating fasteners are established by ABAQUS. The model combines implicit and explicit algorithms of the FE method. The influence of wheelset flexibility on wheel–rail contact parameters is analyzed when the wheelset with traction force passed over the rail with smooth surface, dent and periodic irregularity. The contact parameters are mainly the wheel–rail transient contact force, contact patch and contact stress. The simulation results show that the influence of wheelset flexibility on the wheel–rail force is small when the rail surface is smooth. However, its influence on the wheel–rail contact patch and contact stress is obvious. Under an impulse excitation of the dent, the wheelset flexibility has a significant effect on the wheel–rail vertical forces at frequencies of 350–600 Hz, which is related to the reverse rotation and first-order bending modes of the wheel. The contact patch area and maximum contact stress of the rigid wheelset are about 59%–82% and 140%–162% for those of the flexible wheelset, respectively. Under an excitation of the periodic irregularity, the wheel–rail vertical forces above 580 Hz are affected only by the wheelset flexibility due to forced vibrations of the wheel–rail system.
  • ZHU Shaoyu, ZHANG Xiangjun, SUN Jun, WANG Dagang
    Journal of Mechanical Engineering. 2024, 60(21): 219-231. https://doi.org/10.3901/JME.2024.21.219
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    When dealing with the combined influence of the couple stress effect and the turbulent flow effect, the coupling effect between the two is not considered. To analyze the comprehensive influence of the couple stress effect and turbulence effect more accurately, the modified turbulence Reynolds equation considering the coupling effect between the two is derived from the momentum equation of lubricant flow. Compared with the existing uncoupled model equations, the modified turbulent Reynolds equation, the coupled model equation, has a smaller calculation value for the dimensionless maximum film pressure of the bearing under the same eccentricity ratio, couple stress parameters, and average Reynolds number. At the same time, the modified turbulent Reynolds equation was used to analyze the variation of bearing performance parameters with eccentricity ratio under different couple stress parameters and average Reynolds number. It was found that with the increase of eccentricity ratio, the larger the couple stress parameter or the average Reynolds number, the larger the dimensionless maximum film pressure and dimensionless load capacity of the bearing. At the same time, the change of the couple stress parameter does not affect the dimensionless side leakage of the bearing. In addition, the proposed modified turbulent Reynolds equation applies not only to journal bearings but also to high-speed hydrodynamic lubricated bearings such as thrust bearings and elliptical journal bearings.
  • ZHANG Guotao, CAI Weijie, TONG Baohong, TU Deyu, LIU Qingyun
    Journal of Mechanical Engineering. 2024, 60(21): 232-242. https://doi.org/10.3901/JME.2024.21.232
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The precipitation and resident behavior of bubbles on liquid-infused porous surfaces significantly affect the gas-liquid two-phase flow field and the functional properties of porous surfaces. The subjects of the study are microporous pores of both stainless steel and polytetrafluoroethylene (PTFE) materials. A numerical model is established to analyze the changes in bubble precipitation morphology and the effect of bubble residence behavior on the gas-liquid two-phase flow field and to reveal the bubble resident characteristics and stable resident mechanism on the porous surface. The study shows gas precipitates as a convex interface in stainless steel pores. The bubbles reside and grow steadily in the orifice until the precipitation volume is too large, and the bubbles neck and detach from the orifice. PTFE pore gas precipitation in the form of a concave interface. The bubble resides at the orifice briefly and then undergoes several destabilization processes such as lateral spreading, retraction, necking, and detachment. When the bubble precipitates, its three-phase contact line pinning causes a vortex phenomenon in the flow field. The surface vortex of stainless steel occurs near the bubble center and the gas-liquid interface; the surface vortex of PTFE occurs in the bubble center, near the gas-liquid interface, and in the liquid surface film. Therefore, PTFE surface bubbles strongly perturb the gas-liquid two-phase flow field and are prone to resident instability. The resident behavior of the bubbles on the porous surface is affected by the three-phase contact line state. And the bubbles are stable when the three-phase contact line is pinned, while the bubbles no longer remain stable after the three-phase contact line is unpinned. Compared to hydrophobic PTFE, air bubbles are more likely to reside stably on hydrophilic stainless steel surfaces, to ensure stable lubrication and drag reduction on the surface.
  • WU Hongyu, NIU Wendong, SONG Yang, HAO Yuxing, WANG Shuxin, YAN Shaoze
    Journal of Mechanical Engineering. 2024, 60(21): 243-253. https://doi.org/10.3901/JME.2024.21.243
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As an ocean exploration platform with low energy consumption, underwater glider has received wide attention in recent years. With the maturity of the glider technology, its application scenarios continue to expand. For the underwater fixed-point exploration mission of the glider, the novel design scheme of motion trajectory, inspired by the block driving principle of brachistochrone problem, is studied. In the shallow water area with the higher current intensity, the glider adjusts its net buoyancy to a larger value, which will make the glider obtain the larger velocity to quickly pass through this area and ensure the motion accuracy. In the deep water area with the smaller current intensity, the glider adjusts its net buoyancy to a smaller value and changes the position of movable mass block to reduce the pitch angle and obtain the sufficient horizontal displacement. On this basis, the glider control parameter optimization to determine the optimal trajectory design scheme is executed by using dynamic model and Non-dominated sorting genetic algorithm II. The optimization objective is to minimize the position error and energy consumption of the glider reaching the target exploration area, and the constraint condition is that the position error and motion time do not exceed their allowable values. The Petrel-II glider is taken as the research object to carry out the simulation research, and the numerical examples illustrate that the proposed trajectory design scheme is more suitable for underwater fixed-point exploration mission than the conventional glider operation mode.
  • MENG Lei, ZHOU Ping, YAN Ying, GUO Dongming
    Journal of Mechanical Engineering. 2024, 60(21): 254-262. https://doi.org/10.3901/JME.2024.21.254
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The hemispherical resonator gyroscope (HRG) represents one of the most precise gyroscopes available in present times. The manufacturing accuracy of its core component, the hemispherical resonator (HR), directly governs the operational performance of the gyroscope. Due to limitations inherent in the grinding and polishing processing, the production of high performance resonators cannot be accomplished in a single manufacturing step. Instead, localized tuning becomes necessary based on the results of performance deviation tests. The uncertainties associated with the tuning process significantly impact the yield of resonators. Imposing excessively stringent precision requirements on the tuning process would result in exorbitant manufacturing costs and substantial expenses. This study adopts the methodology of high performance manufacturing in the fabrication of hemispherical resonators with superior capabilities. It investigates the influence of uncertainty in the tuning process on the frequency splitting of the resonator’s core parameter. The sensitivity analysis demonstrates that the low-frequency axis and its orthogonal direction on the rim exhibit the highest demands for process uncertainty. Tolerance analysis reveals that the aforementioned tuning methods can solely achieve the production of high performance hemispherical resonators through reduction in mass removal and enhancement of processing stability. Conversely, employing a four-position orthogonal tuning on the surface of the hemisphere demonstrates low sensitivity and wide tolerances, thereby diminishing the requirements for minimal mass removal and uncertainty in performance arising from the manufacturing processes. Building upon these findings, a spherical adjustment method is proposed that takes into account the uncertainties inherent in the process, and its efficacy is validated through numerical simulations of the frequency splitting adjustment processing. This research holds significant importance in enhancing the efficiency of hemispherical resonator tuning and identifying the most appropriate requirements for tuning processes based on performance specifications.
  • NIU Jingyi, LU Siwei, ZHANG Beining, YANG Chuncheng, LI Dichen
    Journal of Mechanical Engineering. 2024, 60(21): 263-274. https://doi.org/10.3901/JME.2024.21.263
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    3D printing of variable-component composites is a cutting-edge direction in the development of additive manufacturing, which is an important technology to realise gradient material structure. Online regulation of process parameters to adapt to the material component changes during 3D printing is a difficult problem in manufacturing variable-component composites. Combining machine learning algorithms with 3D printing process, and on the basis of small-sample training in additive manufacturing, establishing an algorithmic model of the relationship between process parameters and extruded volume, so as to explore the effectiveness of machine learning algorithms to regulate the process parameters of variable-component composites 3D printing. The screw extrusion 3D printing equipment is used to collect experimental data for different material components. Five machine learning algorithms, SVR support vector regression, BP neural network, RF random forest, RBF neural network and Kriging model, were used to predict the extrusion volume, which is used to adjust the process parameters according to different material components. From the results, it can be seen that when extrusion volume prediction is performed, the training sample size should be more than 30 groups in order to ensure the prediction results. Moreover, SVR algorithm is the most suitable for the small sample size prediction situation among the five machine learning algorithms, and it has the highest extrusion volume prediction accuracy. 3D printing experiments of variable-component composites are carried out, and the process parameters are adjusted according to the material components during the printing process. The sample pieces are printed with good quality, which verifies the effectiveness of the SVR algorithm to regulate the process parameters.
  • SHANG Shuai, YANG Jianjun, SUN Peng, LI Zhenghao, WANG Luowei, LI Hongke, ZHANG Houchao, WANG Rui, SUN Wenzheng, YAN Xiaotian, LIU Chaohong, LAN Hongbo, ZHU Xiaoyang
    Journal of Mechanical Engineering. 2024, 60(21): 275-291. https://doi.org/10.3901/JME.2024.21.275
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In response to the challenges of process complexity, unstable interlayer electrical connections, and difficulties in achieving high-density integration of electronic components in existing manufacturing methods for multilayer flexible and stretchable electronics, a novel integrated manufacturing approach is proposed. This method is based on multi-material 3D printing and collaborative use of multiple nozzles. Through experimental comparisons and results analysis, the study unveils the significant influence and patterns of key printing process parameters, including printing speed, printing pressure, printing platform temperature, and nozzle diameter, on the thickness of dielectric material layers, intra-layer conductors, interlayer interconnect wire width, and overall printing quality. Consequently, an optimal range for printing parameters is identified, ensuring the direct formation of interlayer interconnect wires with a vertical printing height of up to 13 mm, thereby achieving stable electrical connections among multiple layers of circuits. Utilizing the proposed method, a rational multilayer circuit layout, and optimized process parameters, flexible PDMS dielectric material and high-stretchability nanosilver ink conductive material were employed to print multilayer flexible circuits with varying integration densities. The demonstrated performance showcases that this method provides a novel multi-material integrated manufacturing solution for multilayer flexible and stretchable electronic circuits.
  • YIN Zengbin, YU Kejuan, YE Jiadong, YUAN Juntang
    Journal of Mechanical Engineering. 2024, 60(21): 292-299. https://doi.org/10.3901/JME.2024.21.292
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A new type of temperature sensing smart tool is designed and manufactured taking advantage of resistance-temperature characteristics of negative temperature coefficient thermal sensitive ceramics and excellent wear resistance of structural ceramics. The smart tool body and temperature sensing module are composed of α/β-SiAlON structural ceramic and LaCrO3-Al2O3 thermal sensitive ceramic, and prepared by spark plasma sintering and microwave sintering, respectively. The cutting performance and temperature sensing function of the smart tool are tested by high-speed machining nickel-base superalloy GH4169. The smart tool shows excellent cutting performance, and when vc=200 m/min, f=0.1 mm/r, ap=1.0 mm, the material removal amount is 1.4 times higher than that of the commercial ceramic tool WG300, meanwhile, as well as, the smart tool possesses good temperature sensing function. The maximum sensing temperature is above 700 ℃, temperature sensing sensitivity is high, and the response time is nanosecond.
  • MA Tuo, JIANG Ping, LI Xinrong, MA Shouyang, LIU Fada
    Journal of Mechanical Engineering. 2024, 60(21): 300-311. https://doi.org/10.3901/JME.2024.21.300
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Function solving is the core part of product conceptual design. In the process of product design, due to the complexity of product technical requirements and user requirements, the functional solution is prone to deviation and uncertainty, which leads to the degradation of the whole design quality. Based on the above problems, the "Z" mapping transformation between functional and structure adjacent domains is used to decompose functions and determine the original understanding, and the correctness of Function solution is determined based on the functional independence axiom. Function analysis system technique is used to determine the functional correlation, establish the axiomatic design matrix, and determine the design type. Finally, the FAST model is used to characterize the results of the axiomatic design function solution and determine the design scheme. The roller machine tool is taken as an example to solve the problem, and a reasonable design result is obtained by axiomatic design and FAST layer by layer analysis, which verifies the validity of the model. The integrated solution model of axiomatic design and FAST combines the advantages of axiomatic design solution and FAST analysis to improve the design quality and accuracy.
  • WANG Zhiyong, LI Wenqiang, ZHANG Yu
    Journal of Mechanical Engineering. 2024, 60(21): 312-319. https://doi.org/10.3901/JME.2024.21.312
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To realize the machining of straight bevel gears with a single cutter disk on a domestic CNC spiral bevel gear machining machine, based on the principle of spatial kinematics, and on the premise of ensuring that the relative position and relative motion relationship between the workpiece axis and the cutter disk axis remain unchanged, the relative position and relative motion relationship between the cutter disk and the workpiece in the double cutter disk gear milling machine tool are equivalent converted to the Free-form machine tool, and the motion expressions of each numerical control axis of Free-form machine tool with time as independent variable are obtained; The position coordinates of the motion axis of the Free-form machine are calculated at each machining moment by Matlab and the NC machining program is written; based on Vericut simulation software, a Free-form machining environment is established and the machining process is simulated. The simulation results verified the correctness of the motion conversion method and CNC machining program; The milling tooth machining experiment is conducted on the actual Free-form machine tool, and the tooth profile error of the actual tooth surface of the experimental workpiece relative to the theoretical tooth surface is detected by the gear measurement center, and the tooth profile error is within 10.8 μm; the contact area of the gear pair is inspected by rolling inspection machine, and the actual meshing contact area is consistent with the TCA result. The results of simulation machining and actual gear cutting machining experiments verify the correctness of the equivalent conversion method for machine tool machining motion.
  • FANG Zifan, SHU Chengyu, HUANG Ruihong, ZHAO Shuang, HOU Chunyao, DONG Yuanfa
    Journal of Mechanical Engineering. 2024, 60(21): 320-335. https://doi.org/10.3901/JME.2024.21.320
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to solve the problem of low efficiency of ecological dispatching operation portal of hydropower station, an intelligent operating portal architecture for ecological dispatching of hydropower station is proposed, and its basic functions are realized through a test platform. Based on the working environment and requirements, the intelligent characteristics of the ecological dispatching intelligent operation door crane of hydropower station are analyzed, and the overall architecture of the ecological dispatching intelligent operation door crane of hydropower station is proposed. The key technologies such as path planning, trajectory generation, tracking and intelligent anti-swing control technology, interference detection technology of slot entry, blockage detection technology of slot entry, and intelligent operating system are studied, and the correlation between each module and subsystem, information interaction mode and intelligent realization method of operating door machine are studied. The results of simulation and experiment show that the architecture and key technologies of the intelligent operation of the ecological dispatching operation of hydropower station can meet the requirements of intelligent operation of the ecological dispatching operation of hydropower station, realize unmanned automated operation and intelligent decision-making, effectively improve production efficiency and reduce operation safety risks. The proposed system architecture and its key technologies can be applied to the intelligent upgrading and transformation of the ecological dispatching operation door engine of hydropower station.
  • LEI Yu, XU Zhilong, XU Xipeng, GAO Jiashun, GUO Bicheng
    Journal of Mechanical Engineering. 2024, 60(21): 336-348. https://doi.org/10.3901/JME.2024.21.336
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With the rapid development of micro/nano fabrication, the microstructures of products in the medical, electronic and energy fields are becoming more and more complex and require higher precision, while the microstructures are prone to burrs in the cutting process, which greatly restricts the quality and performance of the products. Starting from the formation of burrs during the cutting of microstructures, the research status of the microstructure burr formation mechanism is discussed, and the prediction and characterization methods of microstructure burr size are introduced. The influence of factors such as cutting parameters, process planning, tool design and material modification on burr size is analyzed, and the burr control methods are summarized. The microstructure burr removal methods are classified, and the burr removal methods and effects of different microstructures are reviewed, the bottleneck problems in the removal of microstructure burrs are discussed, and the development trend of microstructure burr removal methods is pointed out.
  • LI Shaochuan, XIAO Guijian, CAO Huajun, WANG Yingxin, ZHAO Zeyong, ZHUO Xiaoqin, HUANG Yun
    Journal of Mechanical Engineering. 2024, 60(21): 349-364. https://doi.org/10.3901/JME.2024.21.349
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Nickel-based superalloys are prone to surface damage during machining, and its service performance has strong correlation with surface texture and defects. Meanwhile, complex load puts forward isotropic processing requirements. Combining flexible and low damage of belt grinding and texture optimization of ultrasonic-assisted machining, two-dimensional ultrasonic-assisted belt grinding method is proposed. The abrasive trajectory under different parameters is analyzed, and the influence of ultrasonic direction, amplitude and phase on material removal is analyzed based on single-particle scratch test. The influence of process parameters on surface integrity and uniformity of GH4169 is also revealed. Results show that two-dimensional ultrasonic-assisted belt grinding has texture optimization effect, and can obtain uniform plastic deformation layer. Reticulum-like texture can be prepared and the anisotropy of surface integrity can be suppressed. Phase difference of 90°improves surface integrity and consistency. Large amplitude can increase residual compressive stress and reduce surface roughness. Low feed speed result in small roughness and large residual compressive stress.
  • LIU Dewei, LI Changhe, QIN Aiguo, LIU Bo, CHEN Yun, ZHANG Yanbin
    Journal of Mechanical Engineering. 2024, 60(21): 365-377. https://doi.org/10.3901/JME.2024.21.365
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Milling force is an important cutting signal for tool state control. Milling force predict accurately can effectively sensing of tool wear. However, the technical bottleneck of the current industrial applications is that the accuracy of the milling force model cannot meet the demands of intelligent sensing, which due to the change of the insert and workbench interference mechanism under the coupling of tool runout and geometric features. A milling force mathematical model considering tool runout. Firstly, the insert geometry model under the influence of tool runout is investigated, and the actual cutting area of the insert is determined based on the geometry and microelement method. Secondly, the insert and workbench geometric interference relationship under the influence of tool runout and geometric feature coupling is revealed based on machining kinematics, the instantaneous undeformed cutting thickness is determined, and the milling force mathematical model of indexable face milling cutter considering tool runout is established. Next, the milling force coefficient identification method is analyzed based on the oblique angle cutting theory, and the orthogonal cutting experiment is carried out to determine the milling force coefficient. Finally, the accuracy of the model is verified by milling ZG32MnMo, and the influence of tool runout on cutting forces are analyzed by numerical simulation. The results show that the mean values of prediction errors of the theoretical model considering tool runout compared to the experimental values for the minimum, maximum, magnitude and average values of milling force are 7.0%, 7.3%, 8.3%, 7.0%, respectively, which is a reduction of 46.4%, 13.0%, 36.4%, and 13.2%, respectively, in comparison with the conventional milling force model. The milling force model considering tool runout provides an important reference for realizing tool wear and improving machining state stability.
  • LI Zekun, LIANG Zhiqiang, CAI Zhihai, LI Xuezhi, LUAN Xiaosheng, ZOU Shikun, LI Hongwei, LIU Xinli, LI Juan, WANG Fei
    Journal of Mechanical Engineering. 2024, 60(21): 378-386. https://doi.org/10.3901/JME.2024.21.378
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to improve the fatigue performance of high load-bearing structural parts of ultra-high strength steel (45CrNiMoVA), a composite strengthening method of laser shock peening and ultrasonic surface rolling (LSP-USR) is proposed. A series of experiments including the composite strengthening of laser shock peening and ultrasonic surface rolling are carried out. The influence of composite strengthening on the surface integrity of ultra-high strength steel is revealed by using SEM, TEM and other detection methods. The results show that composite strengthening can effectively reduce surface roughness. Compared with laser shock peening strengthening and ultrasonic surface rolling strengthening, the roughness decreases by 44.1% and 8.3% respectively, and the finishing effect of ultrasonic surface rolling strengthening plays a key role. The maximum residual compressive stress on the surface layer after composite strengthening can reach −1 274 MPa, which appears within 0.2-0.3 mm from the surface, and the depth of the residual compressive stress affected layer exceeds 1.4 mm. The distribution regularity of residual stress after composite strengthening reflects the superposition of two processes, and the depth of the influence layer of ultrasonic surface rolling strengthening is about 0.5 mm. Within 0.5 mm from the surface, the residual stress distribution is similar to that of a single ultrasonic surface rolling strengthening, while beyond 0.5 mm from the surface, the residual stress distribution is similar to that of a single laser shock peening strengthening. After composite strengthening, the surface material exhibits significant plastic deformation and obvious grain refinement. The effectiveness of the composite strengthening method of laser shock peening and ultrasonic surface rolling is proved, which is of great significance to the development of surface strengthening technology of high load-bearing structural parts of ultra-high strength steel.
  • WU Guolong, ZHANG Yuqing, QIN Xinhui, WU Hao, WANG Ye, CHEN Zhijun, YAO Jianhua
    Journal of Mechanical Engineering. 2024, 60(21): 387-396. https://doi.org/10.3901/JME.2024.21.387
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In view of the problems of traditional laser gas nitriding, such as difficult to deal with large areas and easy to crack, a bionic structured laser gas nitriding method is proposed to improve the wear and corrosion resistance of titanium alloy surface by combining laser nitriding with texture. The bionic structured surfaces of stripe, square, positive triangle and positive hexagon are designed and fabricated, and the microhardness, microstructure and phase composition of the bionic structured units are analyzed in detail. The wear resistance and cavitation resistance of integral and structured nitriding samples are compared and analyzed, and the failure mechanism is studied. The results show that the average hardness of the nitride layer is 850 HV0.3, and the surface and middle part of the nitride layer are composed of dendrites and nitrogenous solid solution. The phase composition of the nitride layer includes α-Ti, TiN and TiNx(0<x<1).The wear of the nitride layer is mainly abrasive wear, and the change of surface structure plays a role in alleviating the cavitation damage. The wear resistance of the overall nitrided and structured nitrided specimens is about 3 times higher than that of the matrix, and the friction coefficient and wear amount of the nitrided specimens with the regular hexagonal structure are the lowest. The improvement of the cavitation resistance of the structured nitrided specimens is the result of the joint action of the surface hardness increase and the hardness characteristics between soft and hard. The laser nitriding composite biomimetic weaving technology is used to effectively improve the vapor corrosion resistance and wear resistance of the titanium alloy surface, and the prepared nitriding layer was uniform and crack-free.
  • WANG Ziming, HOU Qingjian, XU Lijiang, WANG Yuefei, XIAO He, CHEN Ni, LI Liang
    Journal of Mechanical Engineering. 2024, 60(21): 397-406. https://doi.org/10.3901/JME.2024.21.397
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the difficult processing problem of Al2O3 HTCC, a hybrid processing method of laser-micro milling is proposed. The morphology, dimensions and mechanical properties of the residual metamorphic layer of nanosecond laser-machined aluminum oxide co-fired substrates are investigated followed by milling tests. The results show that the tightly bound alumina particles form a loose metamorphic layer attached to the substrate surface under laser action. The etching depth of the grooves increases with the increase of laser power and the decrease of scanning speed and filling spacing in different degrees between 170-537 µm, 167-493 µm and 170-303 µm, respectively, while the etching width varies between 515-643 µm. The overall hardness of the residual metamorphic layer of the substrate after laser modification was reduced by 82%-96.2% down to 53.9 HV. Compared to pure milling, the laser-micro-milling resulted in improved tool serviceability, largely intact cutting edges and tool profiles, and a reduction in the post-processing surface roughness by 60%-65% down to 0.204 µm.