The position-dependent feature in current vat photopolymerization-based additive manufacturing leads to challenges in controlling the dimensional accuracy of printed components.To overcome this intrinsic limitation,we...The position-dependent feature in current vat photopolymerization-based additive manufacturing leads to challenges in controlling the dimensional accuracy of printed components.To overcome this intrinsic limitation,we propose a time-dependent dynamic laser writing(DLW)approach for the precise volumetric printing of complex-shaped lenses.In the DLW-based volumetric printing,the formed surface is generated by accumulating the material growth functions(MGFs)on the scanning path,where the MGF is created by the laser direct irradiation with controlled energy doses.Benefiting from the stability of MGFs and the process homogenization,the DLW is less sensitive to process errors when compared to current vat photopolymerization-based additive manufacturing techniques.Furthermore,the continuous scanning leads to the naturally ultra-smooth feature of the printed surfaces.As a demonstration,a millimeter-scale spherical lens was printed in 5.67 min,achieving a three-dimensional(3D)form error of 0.135μm(root mean square,RMS)and a surface roughness of 0.31 nm(RMS).The printing demonstrated comparable efficiency while achieving form errors an order of magnitude smaller than those of state-of-the-art continuous layer-wise and volumetric printing methods.In addition,polymer lens arrays,freeform polymer lenses,and fused silica lenses were successfully printed,demonstrating promise for advancing the state-of-the-art in 3D printing of precision lenses.展开更多
The lightness and high strength-to-weight ratio of the magnesium alloy have attracted more interest in various applications.However,micro/nanostructure generation on their surfaces remains a challenge due to the flamm...The lightness and high strength-to-weight ratio of the magnesium alloy have attracted more interest in various applications.However,micro/nanostructure generation on their surfaces remains a challenge due to the flammability and ignition.Motivated by this,this study proposed a machining process,named the ultraprecision diamond surface texturing process,to machine the micro/nanostructures on magnesium alloy surfaces.Experimental results showed the various microstructures and sawtooth-shaped nanostructures were successfully generated on the AZ31B magnesium alloy surfaces,demonstrating the effectiveness of this proposed machining process.Furthermore,sawtooth-shaped nanostructures had the function of inducing the optical effect and generating different colors on workpiece surfaces.The colorful letter and colorful flower image were clearly viewed on magnesium alloy surfaces.The corresponding cutting force,chip morphology,and tool wear were systematically investigated to understand the machining mechanism of micro/nanostructures on magnesium alloy surfaces.The proposed machining process can further improve the performances of the magnesium alloy and extend its functions to other fields,such as optics.展开更多
Tissue curvature has long been recognized as an important anatomical parameter that affects intracellular behaviors,and there is emerging interest in applying cell-scale curvature as a designer property to drive cell ...Tissue curvature has long been recognized as an important anatomical parameter that affects intracellular behaviors,and there is emerging interest in applying cell-scale curvature as a designer property to drive cell fates for tissue engineering purposes.Although neural cells are known to undergo dramatic and terminal morphological changes during development and curvature-limiting behaviors have been demonstrated in neurite outgrowth studies,there are still crucial gaps in understanding neural cell behaviors,particularly in the context of a three-dimensional(3D)curvature landscape similar to an actual tissue engineering scaffold.In this study,we fabricated two substrates of microcurvature(curvature-substrates)that present a smooth and repeating landscape with focuses of either a concave or a convex pattern.Using these curvature-substrates,we studied the properties of morphological differentiation in N2a neuroblastoma cells.In contrast to other studies where two-dimensional(2D)curvature was demonstrated to limit neurite outgrowth,we found that both the concave and convex substrates acted as continuous and uniform mechanical protrusions that significantly enhanced neural polarity and differentiation with few morphological changes in the main cell body.This enhanced differentiation was manifested in various properties,including increased neurite length,increased nuclear displacement,and upregulation of various neural markers.By demonstrating how the micron-scale curvature landscape induces neuronal polarity,we provide further insights into the design of biomaterials utilizing the influence of surface curvature in neural tissue engineering.展开更多
Escalating competition within aquatic environments,particularly in oceans,underscores the imperative for innovative solutions in underwater operations.These solutions necessitate the development of intelligent underwa...Escalating competition within aquatic environments,particularly in oceans,underscores the imperative for innovative solutions in underwater operations.These solutions necessitate the development of intelligent underwater equipment,with robotic fish emerging as a promising contender.1 Leveraging advancements in robotics and artificial intelligence,robotic fish offer a suite of advantages that position them as transformative assets in underwater exploration and operations.Robotic fish are autonomous robots designed based on biomimetics principles that mimic the appearance of fish and can autonomously swim and perform specific tasks in water.展开更多
Field-assisted diamond cutting technology is a significant machining method that utilizes external energy fields to enhance the manufacturing performance.However,aimed the emergence of advanced high-performance materi...Field-assisted diamond cutting technology is a significant machining method that utilizes external energy fields to enhance the manufacturing performance.However,aimed the emergence of advanced high-performance materials,traditional single-field-assisted machining struggles to meet stringent precision requirements.Therefore,this study introduces an innovative and unique multi-energy field-assisted ultra-precision machining technology,in-situ laser-magnetic dual-field assisted diamond cutting(LMDFDC),to transcend the limitations of conventional single-field-assisted cutting methods and advance the machinability of challenging materials,notably the multi-principal-element high-entropy alloy(HEA).To elucidate the fundamental science questions of“what occurs,what changes,and what improves”in this work,the phenomenological behaviors of the dual-field coupling interaction are systematically investigated through advanced characterization techniques,spanning macroscopic surface integrity to microscopic atomic arrangement.This comprehensive study encompasses integrated analyses of four machining techniques for HEA workpiece,namely dual-energy field,two single-energy fields,and no-energy field.The research results indicate that the dual-field coupling effect demonstrates a leap in manufacturing performance through thermo-magneto-mechanical multi-physical synergistic interactions,primarily manifested in improved surface quality,reduced subsurface damage,suppressed diamond tool wear,and enhanced material removal stability.The significance of in-situ LMDFDC technology resides in propelling frontier academic developments in multi-physics coupled manufacturing theories while uncovering innovative machining approaches for next-generation high-performance materials.展开更多
Ultraprecision machining of titanium alloy(Ti-6Al-4V)remains challenging due to its low thermal conductivity,pronounced elastic recovery,and tool-workpiece adhesion,all of which degrade surface integrity and accelerat...Ultraprecision machining of titanium alloy(Ti-6Al-4V)remains challenging due to its low thermal conductivity,pronounced elastic recovery,and tool-workpiece adhesion,all of which degrade surface integrity and accelerate tool wear.This study systematically investigates the effect of a weak magnetic field(~0.015 T)on the single-point diamond turning and microgroove machining of Ti-6Al-4V flat surfaces,microgroove arrays,and microstructures.Four machining conditions were designed to decouple the magnetic field effect:no field(nM-nM),field applied only during microgroove cutting(nM-M),field applied only during finish turning(M-nM),and field applied throughout(M-M).Theoretical analyses and experiments have demonstrated that the rotation of the conductive titanium alloy within a magnetic field induces eddy currents,generating Lorentz damping,which suppresses vibrations in Y/Z directions,enhances cutting stability,and improves surface finish.The results showed that magnetic-field assistance significantly reduces both the principal cutting forces and noise levels,and that performance under M-nM conditions surpasses that under nM-M conditions,suggesting that the finishcutting process exerts a stronger influence on the quality of microgroove machining.Microstructures machined under M-M conditions exhibit exceptional dimensional accuracy and uniformity,with groove depths approaching a nominal value of 4μm(reaching~3.98μm under the M-M conditions)and minimal burrs or microcracks forming at boundaries.The findings enhance the understanding of the magnetic field-assisted ultraprecision cutting of titanium alloys,enabling the manufacturing of high-quality micro/nanostructures for applications in aerospace,biomedicine,and optical components.展开更多
In this study,surface modification of monocrystalline silicon with two doses of hydrogen ion implantation and the plunge cutting process were conducted to explore the influence of hydrogen ions on the cutting behavior...In this study,surface modification of monocrystalline silicon with two doses of hydrogen ion implantation and the plunge cutting process were conducted to explore the influence of hydrogen ions on the cutting behavior of silicon.The results show that ion implantation is capable of deteriorating or improving the machinability of silicon,depending on the implantation dose.More cleavages and a reduction of critical depth of cut(CDoC)were observed for the silicon with a low implantation dose in the cutting direction of<100>in comparison to bare silicon,while no cleavage and an increase of CDoC were achieved after implantation with a high dose in the same cutting direction.Besides,the ductile cutting and thrust forces of the silicon with the low dose are larger than the bare silicon,but the forces are significantly reduced for the silicon after the high dose of implantation.The variation of the cutting forces is due to the different required stresses to overcome ductile and fracture deformation of silicon.展开更多
Additive manufacturing,particularly 3D printing,has revolutionized the manufacturing industry by allowing the production of complex and intricate parts at a lower cost and with greater efficiency.However,3D-printed pa...Additive manufacturing,particularly 3D printing,has revolutionized the manufacturing industry by allowing the production of complex and intricate parts at a lower cost and with greater efficiency.However,3D-printed parts frequently require post-processing or integration with other machining technologies to achieve the desired surface finish,accuracy,and mechanical properties.Ultra-precision machining(UPM)is a potential machining technology that addresses these challenges by enabling high surface quality,accuracy,and repeatability in 3D-printed components.This study provides an overview of the current state of UPM for 3D printing,including the current UPM and 3D printing stages,and the application of UPM to 3D printing.Following the presentation of current stage perspectives,this study presents a detailed discussion of the benefits of combining UPM with 3D printing and the opportunities for leveraging UPM on 3D printing or supporting each other.In particular,future opportunities focus on cutting tools manufactured via 3D printing for UPM,UPM of 3D-printed components for real-world applications,and post-machining of 3D-printed components.Finally,future prospects for integrating the two advanced manufacturing technologies into potential industries are discussed.This study concludes that UPM is a promising technology for 3D-printed components,exhibiting the potential to improve the functionality and performance of 3D-printed products in various applications.It also discusses how UPM and 3D printing can complement each other.展开更多
基金supported by the Special funding for Jiangsu Province Innovation Support Program(Grant No.BZ2023058)the National Natural Science Foundation of China(Grant Nos.52275437 and U2013211)。
文摘The position-dependent feature in current vat photopolymerization-based additive manufacturing leads to challenges in controlling the dimensional accuracy of printed components.To overcome this intrinsic limitation,we propose a time-dependent dynamic laser writing(DLW)approach for the precise volumetric printing of complex-shaped lenses.In the DLW-based volumetric printing,the formed surface is generated by accumulating the material growth functions(MGFs)on the scanning path,where the MGF is created by the laser direct irradiation with controlled energy doses.Benefiting from the stability of MGFs and the process homogenization,the DLW is less sensitive to process errors when compared to current vat photopolymerization-based additive manufacturing techniques.Furthermore,the continuous scanning leads to the naturally ultra-smooth feature of the printed surfaces.As a demonstration,a millimeter-scale spherical lens was printed in 5.67 min,achieving a three-dimensional(3D)form error of 0.135μm(root mean square,RMS)and a surface roughness of 0.31 nm(RMS).The printing demonstrated comparable efficiency while achieving form errors an order of magnitude smaller than those of state-of-the-art continuous layer-wise and volumetric printing methods.In addition,polymer lens arrays,freeform polymer lenses,and fused silica lenses were successfully printed,demonstrating promise for advancing the state-of-the-art in 3D printing of precision lenses.
基金supported by the Special Actions for Developing High-performance Manufacturing of Ministry of Industry and Information Technology(Grant No.:TC200H02J)the Research Grants Council of the Hong Kong Special Ad-ministrative Region,China(Project No.:PolyU 152125/18E)+1 种基金the National Natural Science Foundation of China(Project No.:U19A20104)the Research Committee of The Hong Kong Polytechnic University(Project Code G-RK2V).
文摘The lightness and high strength-to-weight ratio of the magnesium alloy have attracted more interest in various applications.However,micro/nanostructure generation on their surfaces remains a challenge due to the flammability and ignition.Motivated by this,this study proposed a machining process,named the ultraprecision diamond surface texturing process,to machine the micro/nanostructures on magnesium alloy surfaces.Experimental results showed the various microstructures and sawtooth-shaped nanostructures were successfully generated on the AZ31B magnesium alloy surfaces,demonstrating the effectiveness of this proposed machining process.Furthermore,sawtooth-shaped nanostructures had the function of inducing the optical effect and generating different colors on workpiece surfaces.The colorful letter and colorful flower image were clearly viewed on magnesium alloy surfaces.The corresponding cutting force,chip morphology,and tool wear were systematically investigated to understand the machining mechanism of micro/nanostructures on magnesium alloy surfaces.The proposed machining process can further improve the performances of the magnesium alloy and extend its functions to other fields,such as optics.
基金supported by the Inter-Departmental Open Project of State Key Laboratory in Ultra-Precision Machining Technology(SKL-UPMT,No.P0033576).
文摘Tissue curvature has long been recognized as an important anatomical parameter that affects intracellular behaviors,and there is emerging interest in applying cell-scale curvature as a designer property to drive cell fates for tissue engineering purposes.Although neural cells are known to undergo dramatic and terminal morphological changes during development and curvature-limiting behaviors have been demonstrated in neurite outgrowth studies,there are still crucial gaps in understanding neural cell behaviors,particularly in the context of a three-dimensional(3D)curvature landscape similar to an actual tissue engineering scaffold.In this study,we fabricated two substrates of microcurvature(curvature-substrates)that present a smooth and repeating landscape with focuses of either a concave or a convex pattern.Using these curvature-substrates,we studied the properties of morphological differentiation in N2a neuroblastoma cells.In contrast to other studies where two-dimensional(2D)curvature was demonstrated to limit neurite outgrowth,we found that both the concave and convex substrates acted as continuous and uniform mechanical protrusions that significantly enhanced neural polarity and differentiation with few morphological changes in the main cell body.This enhanced differentiation was manifested in various properties,including increased neurite length,increased nuclear displacement,and upregulation of various neural markers.By demonstrating how the micron-scale curvature landscape induces neuronal polarity,we provide further insights into the design of biomaterials utilizing the influence of surface curvature in neural tissue engineering.
基金financially supported by the National Natural Science Foundation of China(grant nos.T2325018,62303117,and 62171274)the China Postdoctoral Science Foundation(grant no.2022M710093)+2 种基金National Postdoctoral Xiangjiang Program under Grant XJ2023018Natural Science Foundation of Fujian Provincial under Grant 2024J01278supported by a research grant funded by the University of Macao.
文摘Escalating competition within aquatic environments,particularly in oceans,underscores the imperative for innovative solutions in underwater operations.These solutions necessitate the development of intelligent underwater equipment,with robotic fish emerging as a promising contender.1 Leveraging advancements in robotics and artificial intelligence,robotic fish offer a suite of advantages that position them as transformative assets in underwater exploration and operations.Robotic fish are autonomous robots designed based on biomimetics principles that mimic the appearance of fish and can autonomously swim and perform specific tasks in water.
基金partially supported by the General Research Funds from the Research Grants Council of the Hong Kong Special Administrative Region(HKSAR),China(Project Nos.:PolyU 15221322 and PolyU 15206824)Mainland-Hong Kong Joint Funding Scheme(MHKJFS)from Innovation and Technology Commission(ITC)of the Government of HKSAR(Project No.:MHP/051/22)+2 种基金The Special Funding for Jiangsu Province Innovation Support Program under Grant(BZ2023058)The authors would also like to express their sincere gratitude to the support from the State Key Laboratories in Hong Kong from the ITC of the Government of HKSARthe Research and Innovation Office of The Hong Kong Polytechnic University.
文摘Field-assisted diamond cutting technology is a significant machining method that utilizes external energy fields to enhance the manufacturing performance.However,aimed the emergence of advanced high-performance materials,traditional single-field-assisted machining struggles to meet stringent precision requirements.Therefore,this study introduces an innovative and unique multi-energy field-assisted ultra-precision machining technology,in-situ laser-magnetic dual-field assisted diamond cutting(LMDFDC),to transcend the limitations of conventional single-field-assisted cutting methods and advance the machinability of challenging materials,notably the multi-principal-element high-entropy alloy(HEA).To elucidate the fundamental science questions of“what occurs,what changes,and what improves”in this work,the phenomenological behaviors of the dual-field coupling interaction are systematically investigated through advanced characterization techniques,spanning macroscopic surface integrity to microscopic atomic arrangement.This comprehensive study encompasses integrated analyses of four machining techniques for HEA workpiece,namely dual-energy field,two single-energy fields,and no-energy field.The research results indicate that the dual-field coupling effect demonstrates a leap in manufacturing performance through thermo-magneto-mechanical multi-physical synergistic interactions,primarily manifested in improved surface quality,reduced subsurface damage,suppressed diamond tool wear,and enhanced material removal stability.The significance of in-situ LMDFDC technology resides in propelling frontier academic developments in multi-physics coupled manufacturing theories while uncovering innovative machining approaches for next-generation high-performance materials.
基金financial supports from Young Scientist Fund of National Natural Science Foundation of China(Project No.52205498/K-ZGFT)the State Key Laboratory in Hong Kong from the Innovation and Technology Commission(ITC)of the Government of the Hong Kong Special Administrative Region(HKSAR),China+2 种基金the General Research Fund(GRF)of the Research Grants Council(RGC)of the Hong Kong Special Administrative Region(HKSAR),China(Project No.PolyU 15220724)the Shenzhen Key Technology Breakthrough Project(No.Z2022N074)Shenzhen Engineering Research Center for Semiconductor-specific Equipment and the Research Committee of The Hong Kong Polytechnic University(Project code:RKWR).
文摘Ultraprecision machining of titanium alloy(Ti-6Al-4V)remains challenging due to its low thermal conductivity,pronounced elastic recovery,and tool-workpiece adhesion,all of which degrade surface integrity and accelerate tool wear.This study systematically investigates the effect of a weak magnetic field(~0.015 T)on the single-point diamond turning and microgroove machining of Ti-6Al-4V flat surfaces,microgroove arrays,and microstructures.Four machining conditions were designed to decouple the magnetic field effect:no field(nM-nM),field applied only during microgroove cutting(nM-M),field applied only during finish turning(M-nM),and field applied throughout(M-M).Theoretical analyses and experiments have demonstrated that the rotation of the conductive titanium alloy within a magnetic field induces eddy currents,generating Lorentz damping,which suppresses vibrations in Y/Z directions,enhances cutting stability,and improves surface finish.The results showed that magnetic-field assistance significantly reduces both the principal cutting forces and noise levels,and that performance under M-nM conditions surpasses that under nM-M conditions,suggesting that the finishcutting process exerts a stronger influence on the quality of microgroove machining.Microstructures machined under M-M conditions exhibit exceptional dimensional accuracy and uniformity,with groove depths approaching a nominal value of 4μm(reaching~3.98μm under the M-M conditions)and minimal burrs or microcracks forming at boundaries.The findings enhance the understanding of the magnetic field-assisted ultraprecision cutting of titanium alloys,enabling the manufacturing of high-quality micro/nanostructures for applications in aerospace,biomedicine,and optical components.
基金The work described in this paper was jointly supported by the Research Committee(Project No.G-YBLE)State Key Laboratory of Ultra-precision Machining Technology(Project No.RUWB)of the Hong Kong Polytechnic University.
文摘In this study,surface modification of monocrystalline silicon with two doses of hydrogen ion implantation and the plunge cutting process were conducted to explore the influence of hydrogen ions on the cutting behavior of silicon.The results show that ion implantation is capable of deteriorating or improving the machinability of silicon,depending on the implantation dose.More cleavages and a reduction of critical depth of cut(CDoC)were observed for the silicon with a low implantation dose in the cutting direction of<100>in comparison to bare silicon,while no cleavage and an increase of CDoC were achieved after implantation with a high dose in the same cutting direction.Besides,the ductile cutting and thrust forces of the silicon with the low dose are larger than the bare silicon,but the forces are significantly reduced for the silicon after the high dose of implantation.The variation of the cutting forces is due to the different required stresses to overcome ductile and fracture deformation of silicon.
基金supported by the State Key Laboratories in Hong Kong,China,from the Innovation and Technology Commission(project code:BBR3)of the Government of the Hong Kong Special Administrative Region,Chinathe Research Office(project codes:BBXM and BBX)of The Hong Kong Polytechnic University,China+1 种基金the Project of Strategic Importance(project codes:1-ZE0G and SBBD)of The Hong Kong Polytechnic University,Chinaand the Research Committee(project code:RMAC)of The Hong Kong Polytechnic University,China。
文摘Additive manufacturing,particularly 3D printing,has revolutionized the manufacturing industry by allowing the production of complex and intricate parts at a lower cost and with greater efficiency.However,3D-printed parts frequently require post-processing or integration with other machining technologies to achieve the desired surface finish,accuracy,and mechanical properties.Ultra-precision machining(UPM)is a potential machining technology that addresses these challenges by enabling high surface quality,accuracy,and repeatability in 3D-printed components.This study provides an overview of the current state of UPM for 3D printing,including the current UPM and 3D printing stages,and the application of UPM to 3D printing.Following the presentation of current stage perspectives,this study presents a detailed discussion of the benefits of combining UPM with 3D printing and the opportunities for leveraging UPM on 3D printing or supporting each other.In particular,future opportunities focus on cutting tools manufactured via 3D printing for UPM,UPM of 3D-printed components for real-world applications,and post-machining of 3D-printed components.Finally,future prospects for integrating the two advanced manufacturing technologies into potential industries are discussed.This study concludes that UPM is a promising technology for 3D-printed components,exhibiting the potential to improve the functionality and performance of 3D-printed products in various applications.It also discusses how UPM and 3D printing can complement each other.
