Pub Date : 2024-12-26DOI: 10.1016/j.precisioneng.2024.12.010
Ping Zhang , Shunxiang Wang , Junbao Zhang , Tengfei Zhang , Guohong Li
This study investigates the wear mechanisms and grain refinement patterns of CoCrFeNiAlX series high-entropy alloy-coated tools during the micro-cutting of TC4 titanium alloy. Three coatings were selected: CoCrFeNiAl (Al1), CoCrFeNiAl0.6 (Al0.6), and CoCrFeNi (Al0). Using DEFORM-3D for three-dimensional cutting simulations, the effects of coating type and thickness on tool wear and grain refinement in the cutting deformation zone were analyzed. Results show that at a coating thickness of 10 μm, all types of coated tools exhibited minimal wear depth. Al0.6 coating was significantly affected by thickness, with wear depth increasing by up to 10 %. Dual-layer coatings performed better in reducing wear and maintained good wear resistance even at higher thicknesses, whereas single-layer coatings showed a marked increase in wear depth and rate with increased thickness. As coating thickness increased, the number of dynamic recrystallization (DRX) grains at location P2 decreased for single-layer coated tools. Dual-layer coated tools showed stable DRX numbers, fluctuating between 400 and 600 at P2. Compared to single-layer coatings, dual-layer coatings exhibited higher DRX grain counts across all cutting deformation zones, especially in the third deformation zone, demonstrating superior mechanical properties and recrystallization effects. Dual-layer coated tools also displayed good stability with minimal grain size variation, with Al1 as the inner layer contributing to more stable grain sizes. The Al0.6+Al1 coating experienced significant grain size growth in the third deformation zone due to stress concentration.
{"title":"Study on the wear mechanism of high-entropy alloy coated tools and grain evolution in micro-cutting of TC4 titanium alloy","authors":"Ping Zhang , Shunxiang Wang , Junbao Zhang , Tengfei Zhang , Guohong Li","doi":"10.1016/j.precisioneng.2024.12.010","DOIUrl":"10.1016/j.precisioneng.2024.12.010","url":null,"abstract":"<div><div>This study investigates the wear mechanisms and grain refinement patterns of CoCrFeNiAlX series high-entropy alloy-coated tools during the micro-cutting of TC4 titanium alloy. Three coatings were selected: CoCrFeNiAl (Al1), CoCrFeNiAl0.6 (Al0.6), and CoCrFeNi (Al0). Using DEFORM-3D for three-dimensional cutting simulations, the effects of coating type and thickness on tool wear and grain refinement in the cutting deformation zone were analyzed. Results show that at a coating thickness of 10 μm, all types of coated tools exhibited minimal wear depth. Al0.6 coating was significantly affected by thickness, with wear depth increasing by up to 10 %. Dual-layer coatings performed better in reducing wear and maintained good wear resistance even at higher thicknesses, whereas single-layer coatings showed a marked increase in wear depth and rate with increased thickness. As coating thickness increased, the number of dynamic recrystallization (DRX) grains at location P2 decreased for single-layer coated tools. Dual-layer coated tools showed stable DRX numbers, fluctuating between 400 and 600 at P2. Compared to single-layer coatings, dual-layer coatings exhibited higher DRX grain counts across all cutting deformation zones, especially in the third deformation zone, demonstrating superior mechanical properties and recrystallization effects. Dual-layer coated tools also displayed good stability with minimal grain size variation, with Al1 as the inner layer contributing to more stable grain sizes. The Al0.6+Al1 coating experienced significant grain size growth in the third deformation zone due to stress concentration.</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"92 ","pages":"Pages 253-264"},"PeriodicalIF":3.5,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-25DOI: 10.1016/j.precisioneng.2024.12.014
Aalim M. Mustafa, Hussam Muhamedsalih, Dawei Tang, Prashant Kumar, Liam Blunt, Jane Jiang
Optical metrology plays a vital role in a wide range of research fields and for inspection in manufacturing industries. At present, the market offers a variety of optical metrology instruments, such as interferometers, confocal microscopes, and focus variation (FV) instruments. Although interferometers have the highest precision among optical metrology instruments, they are very sensitive to vibrations/environmental disturbances. On the other hand, focus variation technology is widely recognised for its robustness to vibrations (compared to interferometers), but so far, there is no study in place investigating the vibration frequency and amplitude limits within which focus variation instruments operate optimally in the presence of vibrations. To our knowledge, this article is the first study that aims to estimate quantitatively the immunity of focus variation instruments to vibration. This paper presents theoretical simulations to investigate how vibrations affect the FV principle of evaluating the best-focused images to calculate surface topography. The simulations were verified with practical results from an experimental FV setup built in the lab, and the two results match very well. Afterwards, vibration experiments were performed using the state-of-the-art focus variation instrument, Alicona InfiniteFocus G5, to measure the surface roughness of the Microusurf 334 comparator from Rubert & Co. LTD under vibrations induced by the P-840.2 piezoelectric actuator from Physik Instrumente (PI). The experiments were performed at different frequencies by incrementally changing the vibration amplitudes, pre-planned as a function of the depth of field (DoF) of each magnification lens (10x to 100x). It is observed that the FV system generates 100 % “bad-data” when the vibration amplitude exceeds three times the DoF of the used objective lens at low frequencies (i.e. as early as 5 Hz).
{"title":"Investigation of focus variation microscopy immunity to vibrations","authors":"Aalim M. Mustafa, Hussam Muhamedsalih, Dawei Tang, Prashant Kumar, Liam Blunt, Jane Jiang","doi":"10.1016/j.precisioneng.2024.12.014","DOIUrl":"10.1016/j.precisioneng.2024.12.014","url":null,"abstract":"<div><div>Optical metrology plays a vital role in a wide range of research fields and for inspection in manufacturing industries. At present, the market offers a variety of optical metrology instruments, such as interferometers, confocal microscopes, and focus variation (FV) instruments. Although interferometers have the highest precision among optical metrology instruments, they are very sensitive to vibrations/environmental disturbances. On the other hand, focus variation technology is widely recognised for its robustness to vibrations (compared to interferometers), but so far, there is no study in place investigating the vibration frequency and amplitude limits within which focus variation instruments operate optimally in the presence of vibrations. To our knowledge, this article is the first study that aims to estimate quantitatively the immunity of focus variation instruments to vibration. This paper presents theoretical simulations to investigate how vibrations affect the FV principle of evaluating the best-focused images to calculate surface topography. The simulations were verified with practical results from an experimental FV setup built in the lab, and the two results match very well. Afterwards, vibration experiments were performed using the state-of-the-art focus variation instrument, Alicona InfiniteFocus G5, to measure the surface roughness of the Microusurf 334 comparator from Rubert & Co. LTD under vibrations induced by the P-840.2 piezoelectric actuator from Physik Instrumente (PI). The experiments were performed at different frequencies by incrementally changing the vibration amplitudes, pre-planned as a function of the depth of field (DoF) of each magnification lens (10x to 100x). It is observed that the FV system generates 100 % “bad-data” when the vibration amplitude exceeds three times the DoF of the used objective lens at low frequencies (i.e. as early as 5 Hz).</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"93 ","pages":"Pages 87-98"},"PeriodicalIF":3.5,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143287496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-24DOI: 10.1016/j.precisioneng.2024.12.015
H. Nozato, W. Kokuyama, T. Shimoda, H. Inaba
In this study, we propose a primary calibration method for laser Doppler vibrometers using an independent reference heterodyne laser interferometer and electro-optical modulator up to 1 MHz, and demonstrate its performance under the measurement uncertainties of velocity sensitivity and phase shift at different frequencies. To validate the proposed method, we compared its results with the comparison calibration results of a back-to-back accelerometer. Consequently, we confirmed the reliability of the proposed primary calibration method within the expanded uncertainty range.
{"title":"Primary calibration method for laser Doppler vibrometers using electro-optical modulator","authors":"H. Nozato, W. Kokuyama, T. Shimoda, H. Inaba","doi":"10.1016/j.precisioneng.2024.12.015","DOIUrl":"10.1016/j.precisioneng.2024.12.015","url":null,"abstract":"<div><div>In this study, we propose a primary calibration method for laser Doppler vibrometers using an independent reference heterodyne laser interferometer and electro-optical modulator up to 1 MHz, and demonstrate its performance under the measurement uncertainties of velocity sensitivity and phase shift at different frequencies. To validate the proposed method, we compared its results with the comparison calibration results of a back-to-back accelerometer. Consequently, we confirmed the reliability of the proposed primary calibration method within the expanded uncertainty range.</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"93 ","pages":"Pages 204-215"},"PeriodicalIF":3.5,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143287499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-21DOI: 10.1016/j.precisioneng.2024.12.011
Kai Feng, Guoqing Wang, Chenhui An, Rui Chen, Wenjun Li, Shuai Huang, Jiqiang Jiang
Pocketed orifice-restrictor aerostatic bearings (PORABs) are widely used in ultra-precision machining, metrology, and semiconductor manufacturing. However, the pocket limits further improvement in load capacity and stiffness. The complex vortices within the pocket can induce micro-vibration of aerostatic bearings, which is harmful to the positioning accuracy of state-of-the-art equipment. This contradicts the requirements of state-of-the-art equipment for greater load capacity, stiffness, and stability. A novel biomimetic micro-groove aerostatic bearings (MGABs) inspired by Populus euphratica veins is proposed. The design of the micro-groove provides a transmission channel for the high-pressure air near the orifice. Numerical results, while maintaining the same dead volume, indicate that the high-pressure area of the MGABs covers most of the bearing surface compared to the PORABs. Among the MGABs, the dentate fan-shaped bearing (DFS-B) has a more uniform and larger high-pressure area. Theoretical results indicate that the maximum load capacity of DFS-B increased by 139.82 % and maximum stiffness increased by 484.62 % compared to the PORABs while maintaining a relatively lower maximum mass flow rate. Additionally, the flow field characteristics results show that vortices are difficult to form in the DFS-B. The PORABs and MGABs are manufactured using ultra-precision machining and laser technology. Static and dynamic test-beds are constructed to test the bearings. The experimental results validated the effectiveness of the solution model and demonstrated that the MGABs are superior to PORABs in load capacity, stiffness, and stability.
{"title":"Design and analysis of biomimetic micro-groove aerostatic bearing inspired by Populus euphratica veins for enhanced load capacity and stiffness","authors":"Kai Feng, Guoqing Wang, Chenhui An, Rui Chen, Wenjun Li, Shuai Huang, Jiqiang Jiang","doi":"10.1016/j.precisioneng.2024.12.011","DOIUrl":"10.1016/j.precisioneng.2024.12.011","url":null,"abstract":"<div><div>Pocketed orifice-restrictor aerostatic bearings (PORABs) are widely used in ultra-precision machining, metrology, and semiconductor manufacturing. However, the pocket limits further improvement in load capacity and stiffness. The complex vortices within the pocket can induce micro-vibration of aerostatic bearings, which is harmful to the positioning accuracy of state-of-the-art equipment. This contradicts the requirements of state-of-the-art equipment for greater load capacity, stiffness, and stability. A novel biomimetic micro-groove aerostatic bearings (MGABs) inspired by Populus euphratica veins is proposed. The design of the micro-groove provides a transmission channel for the high-pressure air near the orifice. Numerical results, while maintaining the same dead volume, indicate that the high-pressure area of the MGABs covers most of the bearing surface compared to the PORABs. Among the MGABs, the dentate fan-shaped bearing (DFS-B) has a more uniform and larger high-pressure area. Theoretical results indicate that the maximum load capacity of DFS-B increased by 139.82 % and maximum stiffness increased by 484.62 % compared to the PORABs while maintaining a relatively lower maximum mass flow rate. Additionally, the flow field characteristics results show that vortices are difficult to form in the DFS-B. The PORABs and MGABs are manufactured using ultra-precision machining and laser technology. Static and dynamic test-beds are constructed to test the bearings. The experimental results validated the effectiveness of the solution model and demonstrated that the MGABs are superior to PORABs in load capacity, stiffness, and stability.</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"93 ","pages":"Pages 18-36"},"PeriodicalIF":3.5,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143286919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-12DOI: 10.1016/j.precisioneng.2024.11.014
Peng Shi, Xiaomeng Tong, Hongquan Qu, Maolin Cai
Contour parallel toolpaths are the most common machining strategies for 2.5D features. To enhance the machining efficiency, different cutting paths for various tool combinations should be considered. However, existing algorithms have paid limited attention to multi-tool cutting, which is nevertheless an industrial practice in roughening and finishing. This paper proposes a rapid generation method for contour parallel toolpaths based on an accurate two-dimensional discrete medial-axis transform (MAT) for complex closed cavities. The accurate discrete MAT was refined using the Delaunay triangulation (DT) method. According to the definition of MAT, the calculated discrete medial axis (MA) points are adjusted to obtain accurate MA points by iterative method. The accurate discrete MAT obtained served as the basis for the toolpath generation. Contour parallel toolpaths can be rapidly generated by applying the discrete MAT and the proposed toolpath generation method. The resulting toolpaths have been validated to closely match the cutting path obtained through commercial software calculations, which require much higher computational efforts. The proposed method introduces a novel accurate discrete medial axis calculation method and enables the rapid computation of multi-tool combination cutting paths., which is more suitable in toolpath generation, cutting time prediction and toolset optimization in practice.
{"title":"Rapid generation of contour parallel toolpaths for 2.5D closed cavity based on accurate discrete medial axis transform","authors":"Peng Shi, Xiaomeng Tong, Hongquan Qu, Maolin Cai","doi":"10.1016/j.precisioneng.2024.11.014","DOIUrl":"10.1016/j.precisioneng.2024.11.014","url":null,"abstract":"<div><div>Contour parallel toolpaths are the most common machining strategies for 2.5D features. To enhance the machining efficiency, different cutting paths for various tool combinations should be considered. However, existing algorithms have paid limited attention to multi-tool cutting, which is nevertheless an industrial practice in roughening and finishing. This paper proposes a rapid generation method for contour parallel toolpaths based on an accurate two-dimensional discrete medial-axis transform (MAT) for complex closed cavities. The accurate discrete MAT was refined using the Delaunay triangulation (DT) method. According to the definition of MAT, the calculated discrete medial axis (MA) points are adjusted to obtain accurate MA points by iterative method. The accurate discrete MAT obtained served as the basis for the toolpath generation. Contour parallel toolpaths can be rapidly generated by applying the discrete MAT and the proposed toolpath generation method. The resulting toolpaths have been validated to closely match the cutting path obtained through commercial software calculations, which require much higher computational efforts. The proposed method introduces a novel accurate discrete medial axis calculation method and enables the rapid computation of multi-tool combination cutting paths., which is more suitable in toolpath generation, cutting time prediction and toolset optimization in practice.</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"92 ","pages":"Pages 231-252"},"PeriodicalIF":3.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-12DOI: 10.1016/j.precisioneng.2024.12.008
Liangzhu Yuan , Jinying Li , Yue Fan , Jianliang Shi , Yongmei Huang
High-precision pointing is crucial in evaluating the effectiveness of beam control technology. However, devices utilizing compact rotational Risley prisms (RRP) face a challenge in balancing field-of-view (FOV) and pointing accuracy. This study aims to develop a beam pointing model for RRP and enhance pointing accuracy through error calibration using the system identification method. Moreover, the current two-step inverse solution method is inadequate when the beam deflection model includes the prism's tilt error. To overcome this limitation, this study proposes a stochastic parallel gradient descent (SPGD) inverse solution method to further improve the system's pointing accuracy. A RRP system with a FOV of was constructed for experimentation. The results indicate the pointing accuracy is 2.8 arcsec, the angular dynamic range is 46 dB, and the root-mean-square errors (RMSE) in the x- and y-directions are 1.2 arcsec and 0.9 arcsec, respectively. This device exhibits the highest angular dynamic range among existing RRP devices.
{"title":"Enhancing pointing accuracy in Risley prisms through error calibration and stochastic parallel gradient descent inverse solution method","authors":"Liangzhu Yuan , Jinying Li , Yue Fan , Jianliang Shi , Yongmei Huang","doi":"10.1016/j.precisioneng.2024.12.008","DOIUrl":"10.1016/j.precisioneng.2024.12.008","url":null,"abstract":"<div><div>High-precision pointing is crucial in evaluating the effectiveness of beam control technology. However, devices utilizing compact rotational Risley prisms (RRP) face a challenge in balancing field-of-view (FOV) and pointing accuracy. This study aims to develop a beam pointing model for RRP and enhance pointing accuracy through error calibration using the system identification method. Moreover, the current two-step inverse solution method is inadequate when the beam deflection model includes the prism's tilt error. To overcome this limitation, this study proposes a stochastic parallel gradient descent (SPGD) inverse solution method to further improve the system's pointing accuracy. A RRP system with a FOV of <span><math><mrow><mo>±</mo><msup><mn>15</mn><mo>∘</mo></msup></mrow></math></span> was constructed for experimentation. The results indicate the pointing accuracy is 2.8 arcsec, the angular dynamic range is 46 dB, and the root-mean-square errors (RMSE) in the x- and y-directions are 1.2 arcsec and 0.9 arcsec, respectively. This device exhibits the highest angular dynamic range among existing RRP devices.</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"93 ","pages":"Pages 37-45"},"PeriodicalIF":3.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143286918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-09DOI: 10.1016/j.precisioneng.2024.12.007
Paloma Sirvent , Ana Lozano , Miguel A. Garrido-Maneiro , Pedro Poza , Rordolpho F. Vaz , Vicente Albaladejo-Fuentes , Irene G. Cano
Additive manufacturing, and particularly the cold spray technology for additive manufacturing (CSAM), is fast becoming a key technology to produce components in an efficient and environmentally friendly manner. This method usually requires a final rectification to generate specific surface topographies. The novelty of this paper is related to the capabilities of the CSAM technique to control the surface topography of the samples. Thus, this work investigates the topography of CSAM samples and its correlation with the processing parameters. Pure Al and Ti samples were manufactured following two different deposition strategies: traditional and metal knitting. This last strategy constitutes a promising alternative for CSAM to obtain near-net-final shape components. The topography was analyzed by confocal microscopy considering the form, waviness, and roughness components. Moreover, the microstructure and mechanical properties of the samples were also investigated in order to assure reliable freestanding CSAM deposits. Results showed that the waviness was controlled by the spraying line spacing, and that the waviness and roughness profiles of the metal knitting samples presented the largest wavelengths regardless the material. The metal knitting method generated samples with higher thickness and porosity than the traditional strategy, while the mechanical properties at the local scale were not varied. The study highlights the CSAM technology potential for controlling the deposit’s surface topography.
{"title":"Surface topography analysis in cold spray additive manufacturing","authors":"Paloma Sirvent , Ana Lozano , Miguel A. Garrido-Maneiro , Pedro Poza , Rordolpho F. Vaz , Vicente Albaladejo-Fuentes , Irene G. Cano","doi":"10.1016/j.precisioneng.2024.12.007","DOIUrl":"10.1016/j.precisioneng.2024.12.007","url":null,"abstract":"<div><div>Additive manufacturing, and particularly the cold spray technology for additive manufacturing (CSAM), is fast becoming a key technology to produce components in an efficient and environmentally friendly manner. This method usually requires a final rectification to generate specific surface topographies. The novelty of this paper is related to the capabilities of the CSAM technique to control the surface topography of the samples. Thus, this work investigates the topography of CSAM samples and its correlation with the processing parameters. Pure Al and Ti samples were manufactured following two different deposition strategies: traditional and metal knitting. This last strategy constitutes a promising alternative for CSAM to obtain near-net-final shape components. The topography was analyzed by confocal microscopy considering the form, waviness, and roughness components. Moreover, the microstructure and mechanical properties of the samples were also investigated in order to assure reliable freestanding CSAM deposits. Results showed that the waviness was controlled by the spraying line spacing, and that the waviness and roughness profiles of the metal knitting samples presented the largest wavelengths regardless the material. The metal knitting method generated samples with higher thickness and porosity than the traditional strategy, while the mechanical properties at the local scale were not varied. The study highlights the CSAM technology potential for controlling the deposit’s surface topography.</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"92 ","pages":"Pages 207-218"},"PeriodicalIF":3.5,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-06DOI: 10.1016/j.precisioneng.2024.12.006
Juan Chen , Changlin Liu , Hao Liu , Bi Zhang , Suet To
Ultra-high-speed machining offers significant potential to enhance material removal efficiency and reduce subsurface damage in metals. However, the interplay between machining temperature and speed on dislocation evolution and subsurface damage remains inadequately understood. This study employs molecular dynamics simulations to investigate surface and subsurface deformation mechanisms in iron across various machining speeds. Results indicate that increased machining speed improves material removal efficiency. The high strain zone concentrates near the machined surface and decreases with depth, while higher machining speeds further confine shear strain to a smaller region. Specifically, the decreased dislocation length at high machining speed indicates a deformation mechanism shift dominated by the strain rate effect. Additionally, subsurface damage depth decreases with higher speeds due to reduced shear strain penetration and enhanced stress relaxation. These findings contribute to the development of low-damage machining techniques for iron and other difficult-to-machine metals within a wide speed range.
{"title":"Atomic insight into the speed effect on deformation mechanisms in nano-scratching of monocrystalline iron","authors":"Juan Chen , Changlin Liu , Hao Liu , Bi Zhang , Suet To","doi":"10.1016/j.precisioneng.2024.12.006","DOIUrl":"10.1016/j.precisioneng.2024.12.006","url":null,"abstract":"<div><div>Ultra-high-speed machining offers significant potential to enhance material removal efficiency and reduce subsurface damage in metals. However, the interplay between machining temperature and speed on dislocation evolution and subsurface damage remains inadequately understood. This study employs molecular dynamics simulations to investigate surface and subsurface deformation mechanisms in iron across various machining speeds. Results indicate that increased machining speed improves material removal efficiency. The high strain zone concentrates near the machined surface and decreases with depth, while higher machining speeds further confine shear strain to a smaller region. Specifically, the decreased dislocation length at high machining speed indicates a deformation mechanism shift dominated by the strain rate effect. Additionally, subsurface damage depth decreases with higher speeds due to reduced shear strain penetration and enhanced stress relaxation. These findings contribute to the development of low-damage machining techniques for iron and other difficult-to-machine metals within a wide speed range.</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"92 ","pages":"Pages 219-230"},"PeriodicalIF":3.5,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-06DOI: 10.1016/j.precisioneng.2024.12.005
Xinyu Chen , ZiHui Zhu , LiMin Zhu , Zhiwei Zhu
This paper presents an innovative magnetorheological (MR) fabrication method for directly generating precision miniature glass optics without the need of precision grinding. In this method, the optimized rotating small ring-shaped permanent-magnet tool (PMT) enhanced the viscosity of the MR slurry with abrasives inside the working gap between the workpiece material and PMT, thereby achieving the non-contact removal of the workpiece materials. Through a combination of theoretical analysis and experimental tests, the PMT with axial magnetization has been selected to generate a high-performance Gaussian-like tool influence function. The effects of the working gap widths, spindle speeds, and dwell time on the material removal behavior were systematically studied through a self-developed three-axis MR fabrication system. Accordingly, a gap width of 0.4 mm and a spindle speed of 800 rpm were recommended to balance the material removal rate and the alignment complexity. By precisely controlling the dwell time, ultra-smooth surfaces with form errors of around 21.538 nm, 101.043 nm, and 396.170 nm (rms) were achieved for fabricating the planar, spherical, and freeform surfaces on flat K9 glasses, respectively. The results demonstrate the effectiveness of the proposed MR fabrication method for the low-cost fabrication of miniature optics with complex shapes.
{"title":"Low-cost and precise magnetorheological fabrication of miniature glass optics","authors":"Xinyu Chen , ZiHui Zhu , LiMin Zhu , Zhiwei Zhu","doi":"10.1016/j.precisioneng.2024.12.005","DOIUrl":"10.1016/j.precisioneng.2024.12.005","url":null,"abstract":"<div><div>This paper presents an innovative magnetorheological (MR) fabrication method for directly generating precision miniature glass optics without the need of precision grinding. In this method, the optimized rotating small ring-shaped permanent-magnet tool (PMT) enhanced the viscosity of the MR slurry with abrasives inside the working gap between the workpiece material and PMT, thereby achieving the non-contact removal of the workpiece materials. Through a combination of theoretical analysis and experimental tests, the PMT with axial magnetization has been selected to generate a high-performance Gaussian-like tool influence function. The effects of the working gap widths, spindle speeds, and dwell time on the material removal behavior were systematically studied through a self-developed three-axis MR fabrication system. Accordingly, a gap width of 0.4 mm and a spindle speed of 800 rpm were recommended to balance the material removal rate and the alignment complexity. By precisely controlling the dwell time, ultra-smooth surfaces with form errors of around 21.538 nm, 101.043 nm, and 396.170 nm (rms) were achieved for fabricating the planar, spherical, and freeform surfaces on flat K9 glasses, respectively. The results demonstrate the effectiveness of the proposed MR fabrication method for the low-cost fabrication of miniature optics with complex shapes.</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"92 ","pages":"Pages 179-190"},"PeriodicalIF":3.5,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-04DOI: 10.1016/j.precisioneng.2024.12.004
Chenchun Shi , Xiaokang Zhang , Yicheng Wu , Jinbang Li , Wei Wu , Chi Fai Cheung , Zhenzhong Wang , Chunjin Wang
Optical freeform surfaces (OFS) have been extensively employed as core components in advanced optical systems for their excellent performances. However, the surface complexity and the high surface accuracy do impose challenges to the processing of OFS, especially the surface form maintaining or control during polishing. As one of the promising ultra-precision machining technologies to fabricate OFS, the flexible ball-end tool (FBET) polishing becomes available due to its attractive technical advantages. Nevertheless, there are still lack of more comprehensive insights on material removal mechanisms for FBET polishing incorporating the curvature effect, particularly from a microscopic scale, which is of great significance to determine the surface quality and form control in ultra-precision polishing process. In this paper, different from those published macro-scale Preston law-based models, a micro-scale material removal model is developed based on the mutual interaction of the slurry, polishing pad and curved workpiece among the FBET polishing interfaces with micro-contact theory and tribology theory, wherein various parameters embodied in FBET polishing are formulated quantitatively, such as slurry characteristics, pad properties, tool features, processing conditions, as well as workpiece curvature effect. The FBET is designed and adopted to conduct the spot polishing experiments within the concave curvature radius range from 75 mm to 225 mm, wherein the curvature radius range from 225 mm to 800 mm is theoretically chosen as an extension of this research. The predicted results agree well with the experimentally measured section profiles of polishing spots, thereby demonstrating the correctness and effectiveness of the proposed model. Furthermore, the effective relative velocity U together with the separation gap d between reference plane and workpiece surface are known as the two key parameters to account for the material removal mechanisms, and the latter is figured out to be the sensitive one to the curvature effect rather than the former. Through the analysis of key parameters, the established model is capable of helping to strengthen the understanding of material removal mechanisms for FBET polishing with the consideration of curvature effect, addressing those cannot be interpreted by the classical Preston equation previously, which is meaningful for precision control of material removal during polishing of OFS.
{"title":"Micro-scale modeling and analysis on material removal mechanisms for flexible ball-end tool polishing incorporating the curvature effect","authors":"Chenchun Shi , Xiaokang Zhang , Yicheng Wu , Jinbang Li , Wei Wu , Chi Fai Cheung , Zhenzhong Wang , Chunjin Wang","doi":"10.1016/j.precisioneng.2024.12.004","DOIUrl":"10.1016/j.precisioneng.2024.12.004","url":null,"abstract":"<div><div>Optical freeform surfaces (OFS) have been extensively employed as core components in advanced optical systems for their excellent performances. However, the surface complexity and the high surface accuracy do impose challenges to the processing of OFS, especially the surface form maintaining or control during polishing. As one of the promising ultra-precision machining technologies to fabricate OFS, the flexible ball-end tool (FBET) polishing becomes available due to its attractive technical advantages. Nevertheless, there are still lack of more comprehensive insights on material removal mechanisms for FBET polishing incorporating the curvature effect, particularly from a microscopic scale, which is of great significance to determine the surface quality and form control in ultra-precision polishing process. In this paper, different from those published macro-scale Preston law-based models, a micro-scale material removal model is developed based on the mutual interaction of the slurry, polishing pad and curved workpiece among the FBET polishing interfaces with micro-contact theory and tribology theory, wherein various parameters embodied in FBET polishing are formulated quantitatively, such as slurry characteristics, pad properties, tool features, processing conditions, as well as workpiece curvature effect. The FBET is designed and adopted to conduct the spot polishing experiments within the concave curvature radius range from 75 mm to 225 mm, wherein the curvature radius range from 225 mm to 800 mm is theoretically chosen as an extension of this research. The predicted results agree well with the experimentally measured section profiles of polishing spots, thereby demonstrating the correctness and effectiveness of the proposed model. Furthermore, the effective relative velocity <em>U</em> together with the separation gap <em>d</em> between reference plane and workpiece surface are known as the two key parameters to account for the material removal mechanisms, and the latter is figured out to be the sensitive one to the curvature effect rather than the former. Through the analysis of key parameters, the established model is capable of helping to strengthen the understanding of material removal mechanisms for FBET polishing with the consideration of curvature effect, addressing those cannot be interpreted by the classical Preston equation previously, which is meaningful for precision control of material removal during polishing of OFS.</div></div>","PeriodicalId":54589,"journal":{"name":"Precision Engineering-Journal of the International Societies for Precision Engineering and Nanotechnology","volume":"92 ","pages":"Pages 191-206"},"PeriodicalIF":3.5,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号