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Damage evolution and removal behaviors of GaN crystals involved in double-grits grinding

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International Journal of Extreme Manufacturing 2024年第2期6卷 469-484页

作者： Chen Li Yuxiu Hu Zongze Wei Chongjun Wu Yunfeng Peng Feihu Zhang Yanquan Geng State Key Laboratory of Robotics and System(HIT) Harbin Institute of TechnologyHarbin 150001People’s Republic of China Key Laboratory of Microsystems and Microstructures Manufacturing(HIT) Harbin Institute of TechnologyHarbin 150001People’s Republic of China College of Mechanical Engineering Donghua UniversityShanghai 201620People’s Republic of China Department of Mechanical and Electrical Engineering Xiamen UniversityXiamen 361005People’s Republic of China

Elucidating the complex interactions between the work material and abrasives during grinding of gallium nitride(GaN)single crystals is an active and challenging research area.In this study,molecular dynamics simulations were performed on double-grits interacted grinding of GaN crystals;and the grinding force,coefficient of friction,stress distribution,plastic damage behaviors,and abrasive damage were systematically investigated.The results demonstrated that the interacted distance in both radial and transverse directions achieved better grinding quality than that in only one direction.The grinding force,grinding induced stress,subsurface damage depth,and abrasive wear increase as the transverse interacted distance increases.However,there was no clear correlation between the interaction distance and the number of atoms in the phase transition and dislocation length.Appropriate interacted distances between abrasives can decrease grinding force,coefficient of friction,grinding induced stress,subsurface damage depth,and abrasive wear during the grinding process.The results of grinding tests combined with cross-sectional transmission electron micrographs validated the simulated damage results,i.***.amorphous atoms,high-pressure phase transition,dislocations,stacking faults,and lattice distortions.The results of this study will deepen our understanding of damage accumulation and material removal resulting from coupling between abrasives during grinding and can be used to develop a feasible approach to the wheel design of ordered abrasives.

关键词： grinding double-grits molecular dynamics damage material removal gallium nitride

Rice Variety Classification Based on Optimized Near-Infrared Spectral Classification Model

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Rice science 2024年第1期31卷 6-9,I0009-I0012页

作者： YANG Sen WANG Zhenmin ZHANG Houqing SONG Wenlong College of Computer and Control Engineering Northeast Forestry UniversityHarbin 150040China The 49th Research Institute of China Electronics Technology Group Corporation Harbin 150000China

Accurate classification of rice variety is essential to ensure the brand value of high-quality rice products.Considering the impact of sample state on modeling optimization algorithms,rice samples after grinding and sealing were selected.To enhance the accuracy of rice variety classification,we introduced a spectral characteristic wavelength selection method based on adaptive sliding window permutation entropy(ASW-PE).

关键词： sealing Infrared grinding

Tribological Mechanism of Graphene and Ionic Liquid Mixed Fluid on grinding Interface under Nanofluid Minimum Quantity Lubrication

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Chinese Journal of Mechanical Engineering 2023年第4期36卷 79-96页

作者： Dexiang Wang Yu Zhang Qiliang Zhao Jingliang Jiang Guoliang Liu Changhe Li School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdaoChina Key Lab of Industrial Fluid Energy Conservation and Pollution Control(Qingdao University of Technology) Ministry of EducationQingdaoChina

Graphene has superhigh thermal conductivity up to 5000 W/(m·K),extremely thin thickness,superhigh mechanical strength and nano-lamellar structure with low interlayer shear strength,making it possess great potential in mini-mum quantity lubrication(MQL)grinding.Meanwhile,ionic liquids(ILs)have higher thermal conductivity and better thermal stability than vegetable oils,which are frequently used as MQL grinding fluids.And ILs have extremely low vapor pressure,thereby avoiding film boiling in grinding.These excellent properties make ILs also have immense potential in MQL grinding.However,the grinding performance of graphene and ionic liquid mixed fluid under nano-fluid minimum quantity lubrication(NMQL),and its tribological mechanism on abrasive grain/workpiece grinding interface,are still unclear.This research firstly evaluates the grinding performance of graphene and ionic liquid mixed nanofluids(graphene/IL nanofluids)under NMQL experimentally.The evaluation shows that graphene/IL nanofluids can further strengthen both the cooling and lubricating performances compared with MQL grinding using ILs only.The specific grinding energy and grinding force ratio can be reduced by over 40%at grinding depth of 10μm.Work-piece machined surface roughness can be decreased by over 10%,and grinding temperature can be lowered over 50℃at grinding depth of 30μm.Aiming at the unclear tribological mechanism of graphene/IL nanofluids,molecular dynamics simulations for abrasive grain/workpiece grinding interface are performed to explore the formation mechanism of physical adsorption film.The simulations show that the grinding interface is in a boundary lubrication state.IL molecules absorb in groove-like fractures on grain wear flat face to form boundary lubrication film,and graphene nanosheets can enter into the grinding interface to further decrease the contact area between abrasive grain and workpiece.Compared with MQL grinding,the average tangential grinding force of graphene/IL nanofluids can decrease up to 10.8%.The interlayer sh

关键词： grinding Nanofluid minimum quantity lubrication Graphene Tribological mechanism

Development of a new high-shear and low-pressure grinding wheel and its grinding characteristics for Inconel718 alloy

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Chinese Journal of Aeronautics 2022年第12期35卷 278-286页

作者： Bing LIU Yebing TIAN Jinguo HAN Linguang LI Zhiqiang GU Xintao HU School of Mechanical Engineering Shandong University of TechnologyZibo 255049China Institute for Advanced Manufacturing Shandong University of TechnologyZibo 255049China

Nickel-based alloy has been widely used due to its outstanding mechanical properties.However, Nickel-based alloy is a typical difficult-to-machine material, which is a great constrain for its application in the manufacturing field. To improve the surface quality of the ground workpiece, a new high-shear and low-pressure grinding wheel, with high ratio of tangential grinding force to normal grinding force, was fabricated for the grinding of selective laser melting(SLM) manufactured Inconel718 alloy. The principle of high-shear and low-pressure grinding process was introduced in detail, which was quite different from the conventional grinding process. The fabrication process of the new grinding wheel was illustrated. A serial of experiments with different processing parameters were carried out to investigate the grinding performance of the developed grinding wheel via analyzing surface roughness and surface morphology of the ground workpiece.The optimal processing parameters of high-shear and low-pressure grinding were obtained. The surface roughness of ground workpiece was reduced to 0.232 μm from the initial value of 0.490 μm under the optimal grinding conditions. It was found that the initial scratches on the ground workpiece were almost completely removed after the observations with the metalloscopy and the fieldemission scanning electron microscopy(FE-SEM). The capability of the newly developed highshear and low-pressure grinding wheel was validated.

关键词： grinding grinding wheel High-shear and low-pressure grinding Inconel718 alloy Selective laser melting(SLM)

Vision Sensing-Based Online Correction System for Robotic Weld grinding

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Chinese Journal of Mechanical Engineering 2023年第5期36卷 97-108页

作者： Jimin Ge Zhaohui Deng Shuixian Wang Zhongyang Li Wei Liu Jiaxu Nie Hunan Provincial Key Laboratory of High Efciency and Precision Machining of Difcult Machine Material Hunan University of Science and TechnologyXiangtan 411201China Institute of Manufacturing Engineering Huaqiao UniversityXiamen 361021China ZOOMLION Heavy Industry Science and Technology Co. Ltd.Changsha 410000China

The service cycle and dynamic performance of structural parts are afected by the weld grinding accuracy and surface consistency. Because of reasons such as assembly errors and thermal deformation, the actual track of the robot does not coincide with the theoretical track when the weld is ground ofine, resulting in poor workpiece surface quality. Considering these problems, in this study, a vision sensing-based online correction system for robotic weld grinding was developed. The system mainly included three subsystems: weld feature extraction, grinding, and robot real-time control. The grinding equipment was frst set as a substation for the robot using the WorkVisual software. The input/output (I/O) ports for communication between the robot and the grinding equipment were confgured via the I/O mapping function to enable the robot to control the grinding equipment (start, stop, and speed control). Subsequently, the Ethernet KRL software package was used to write the data interaction structure to realize realtime communication between the robot and the laser vision system. To correct the measurement error caused by the bending deformation of the workpiece, we established a surface profle model of the base material in the weld area using a polynomial ftting algorithm to compensate for the measurement data. The corrected extracted weld width and height errors were reduced by 2.01% and 9.3%, respectively. Online weld seam extraction and correction experiments verifed the efectiveness of the system’s correction function, and the system could control the grinding trajectory error within 0.2 mm. The reliability of the system was verifed through actual weld grinding experiments. The roughness, Ra, could reach 0.504 µm and the average residual height was within 0.21 mm. In this study, we developed a vision sensing-based online correction system for robotic weld grinding with a good correction efect and high robustness.

关键词： Online correction system Robot grinding Weld seam Laser vision sensor

Burr formation mechanism and morphological transformation critical conditions in grinding of nickel-based superalloy honeycomb cores

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Chinese Journal of Aeronautics 2023年第11期36卷 434-451页

作者： Haihang WANG Jie CHEN Chenguang WANG Guoqiang GUO Qinglong AN Weiwei MING Ming CHEN State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China AVIC Chengdu Aircraft Industrial(Group)Co. Ltd.Chengdu 610092China Shanghai Spaceflight Precision Machinery Institute Shanghai 201600China

Nickel-based Superalloy Honeycomb(NBSH) is widely used in aerospace field due to the high temperature resistance, high specific strength and light weight. However, the NBSH is extremely prone to form burrs during processing. The unreasonable burr morphology causes insufficient welding strength or false welding between NBSH and skin, resulting in premature failure of the parts. Hence, the burr formation mechanism and morphological transformation critical conditions in grinding NBSH were investigated based on finite element method(FEM) and experiments. Furthermore, the orthogonal experiments were carried out to investigate the effects of grinding parameters on burr and obtain the suitable parameter intervals to restrain the flash burr formation. The results indicate that due to the absence of supporting material, the extruded material of edge transforms into the Fourth Deformation Zone(FDZ). The FDZ rotates a certain angle due to the extrusion of abrasive particle, which leads to the fact that the FDZ cannot be removed and remains on the honeycomb wall, thus forming micro burr. If the material removal per unit time is large, the chip is not removed from FDZ. The parts that should have been chips are bonded with micro burr to form a flash burr. To restrain the flash burr formation, the suitable intervals of grinding depth,grinding speed and feed speed are 5–15 μm, 60–70 m/min and 500–1000 mm/min, respectively.

关键词： Burr grinding Honeycomb Mechanism Nickel-based superalloy

Modelling of grinding mechanics:A review

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Chinese Journal of Aeronautics 2023年第7期36卷 25-39页

作者： Qingyu MENG Bing GUO Qingliang ZHAO Hao Nan LI Mark JJACKSON Barbara SLINKE Xichun LUO Center for Precision Engineering School of Mechatronics EngineeringHarbin Institute of TechnologyHarbin 150001China School of Aerospace The University of Nottingham NingboNingbo 315100China School of Integrated Studies College of Technology and AviationKansas State UniversitySalinaKS 67401USA Department of Mechanical and Aerospace Engineering University of California DavisDavisUSA Centre for Precision Manufacturing DMEMUniversity of StrathclydeGlasgowUK

grinding is one of the most widely used material removal methods at the end of many process chains.grinding force is related to almost all grinding parameters,which has a great influence on material removal rate,dimensional and shape accuracy,surface and subsurface integrity,thermodynamics,dynamics,wheel durability,and machining system deformation.Considering that grinding force is related to almost all grinding parameters,grinding force can be used to detect grinding wheel wear,energy calculation,chatter suppression,force control and grinding process simulation.Accurate prediction of grinding forces is important for optimizing grinding parameters and the structure of grinding machines and fixtures.Although there are substantial research papers on grinding mechanics,a comprehensive review on the modeling of grinding mechanics is still absent from the literature.To fill this gap,this work reviews and introduces theoretical methods and applications of mechanics in grinding from the aspects of modeling principles,limitations and possible future trendencies.

关键词： Force modeling grinding grinding mechanics Macro force Micro force Model application

Fiber-reinforced composites in milling and grinding:machining bottlenecks and advanced strategies

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Frontiers of Mechanical Engineering 2022年第2期17卷 1-35页

作者： Teng GAO Yanbin ZHANG Changhe LI Yiqi WANG Yun CHEN Qinglong AN Song ZHANG Hao Nan LI Huajun CAO Hafiz Muhammad ALI Zongming ZHOU Shubham SHARMA School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao 266520China School of Mechanical Engineering Dalian University of TechnologyDalian 116024China Chengdu Tool Research Institute Co. Ltd.Chengdu 610500China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Mechanical Engineering Shandong UniversityJinan 250061China School of Aerospace University of Nottingham Ningbo ChinaNingbo 315100China School of Mechanical Engineering Chongqing UniversityChongqing 400044China Mechanical Engineering Department King Fahd University of Petroleum and MineralsDhahran 31261Saudi Arabia Hanergy(Qingdao)Lubrication Technology Co. Ltd.Qingdao 266100China Department of Mechanical Engineering IK Gujral Punjab Technical UniversityPunjab 144603India

Fiber-reinforced composites have become the preferred material in the fields of aviation and aerospace because of their high-strength performance in unit weight.The composite components are manufactured by near netshape and only require finishing operations to achieve final dimensional and assembly tolerances.Milling and grinding arise as the preferred choices because of their precision processing.Nevertheless,given their laminated,anisotropic,and heterogeneous nature,these materials are considered difficult-to-machine.As undesirable results and challenging breakthroughs,the surface damage and integrity of these materials is a research hotspot with important engineering significance.This review summarizes an up-to-date progress of the damage formation mechanisms and suppression strategies in milling and grinding for the fiber-reinforced composites reported in the literature.First,the formation mechanisms of milling damage,including delamination,burr,and tear,are analyzed.Second,the grinding mechanisms,covering material removal mechanism,thermal mechanical behavior,surface integrity,and damage,are discussed.Third,suppression strategies are reviewed systematically from the aspects of advanced cutting tools and technologies,including ultrasonic vibration-assisted machining,cryogenic cooling,minimum quantity lubrication(MQL),and tool optimization design.Ultrasonic vibration shows the greatest advantage of restraining machining force,which can be reduced by approximately 60%compared with conventional machining.Cryogenic cooling is the most effective method to reduce temperature with a maximum reduction of approximately 60%.MQL shows its advantages in terms of reducing friction coefficient,force,temperature,and tool wear.Finally,research gaps and future exploration directions are prospected,giving researchers opportunity to deepen specific aspects and explore new area for achieving high precision surface machining of fiber-reinforced composites.

关键词： milling grinding fiber-reinforced composites damage formation mechanism delamination material removal mechanism surface integrity minimum quantity lubrication

Enhanced Heat Transfer Technology Based on Emission Reduction and Carbon Reduction in Cutting and grinding

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Chinese Journal of Mechanical Engineering 2023年第4期36卷 1-3页

作者： Changhe Li Yanbin Zhang Shubham Sharma School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao 266520China Department of Mechanical Engineering and Advanced Materials Science Regional Center for Extension and DevelopmentCouncil of Scientific and Industrial Research(CSIR)-Central Leather Research Institute(CLRI)Jalandhar 144021India

Huge carbon emissions in machining process,which characterized by high energy consumption and usage of non-renewable resources,is becoming an obsession in the past decades.In the face of the international strategy of carbon peak,it is imperative to eliminate the usage of mineral cutting fluids and reduce energy consumption and carbon emissions by green cutting/grinding technologies,such as dry cutting,minimum quantity lubrication(MQL).

关键词： grinding lubrication eliminate