Pub Date : 2020-12-21DOI: 10.1177/2516598420980404
Mahavir Singh, V. Jain, J. Ramkumar
The present work discusses micro-texturing on flat and cylindrical surfaces using the electric-discharge micromachining (EDMM) process. The arrays of micro-dimples are generated on flat Ti-6Al-4V surfaces using a block–electric discharge grinding (block-EDG)–fabricated microtools of an average diameter of 148 µm and 105 µm. Large-area surface texturing on flat Ti-6Al-4V and aluminium surfaces are performed to analyse the variation in water contact angle with varying depths of dimples. Adopting the electric discharge–milling (ED-milling) strategy, micro-pillars of dimensions 242 µm × 166 µm × 50 µm are machined on flat Ti-6Al-4V surfaces. The EDMM process for non-flat surfaces, such as curved (internal and external), spherical and freeform surfaces, is receiving attention in various applications. Machining of the aforementioned surfaces using the EDMM process appears to be problematic, due to the continuous change in curvature, which results in the subsequent spark gap variation. In the present work, processing of cylindrical surfaces for micro-features generation, such as micro-dimple arrays, has been attempted. Arrays of micro-dimples are machined on copper and Ti-6Al-4V cylindrical surfaces. A precise indexing setup is fabricated to hold and index the workpiece at the desired angular positions. Unlike machining on flat surfaces, the relative dimensions of the tool and the workpiece’s curvature result in non-uniform wear at the tool’s end cross-section. Owing to this non-uniform wear of tool electrode caused by the curvature effect of the workpiece, the formation of a microscopic bump/spike is observed on the dimple’s bottom. The depth of the dimple up to which the entire bottom surface of the tool is not exposed to the sparks is defined as its critical depth. For a combination of a tool and a workpiece of diameters 500 µm and 5 mm, respectively, the critical depth of the dimple is found to be 12.53 µm. However, the critical depth increases with a decrease in workpiece diameter, provided the diameter of the tool is constant.
{"title":"Micro-texturing on flat and cylindrical surfaces using electric discharge micromachining","authors":"Mahavir Singh, V. Jain, J. Ramkumar","doi":"10.1177/2516598420980404","DOIUrl":"https://doi.org/10.1177/2516598420980404","url":null,"abstract":"The present work discusses micro-texturing on flat and cylindrical surfaces using the electric-discharge micromachining (EDMM) process. The arrays of micro-dimples are generated on flat Ti-6Al-4V surfaces using a block–electric discharge grinding (block-EDG)–fabricated microtools of an average diameter of 148 µm and 105 µm. Large-area surface texturing on flat Ti-6Al-4V and aluminium surfaces are performed to analyse the variation in water contact angle with varying depths of dimples. Adopting the electric discharge–milling (ED-milling) strategy, micro-pillars of dimensions 242 µm × 166 µm × 50 µm are machined on flat Ti-6Al-4V surfaces. The EDMM process for non-flat surfaces, such as curved (internal and external), spherical and freeform surfaces, is receiving attention in various applications. Machining of the aforementioned surfaces using the EDMM process appears to be problematic, due to the continuous change in curvature, which results in the subsequent spark gap variation. In the present work, processing of cylindrical surfaces for micro-features generation, such as micro-dimple arrays, has been attempted. Arrays of micro-dimples are machined on copper and Ti-6Al-4V cylindrical surfaces. A precise indexing setup is fabricated to hold and index the workpiece at the desired angular positions. Unlike machining on flat surfaces, the relative dimensions of the tool and the workpiece’s curvature result in non-uniform wear at the tool’s end cross-section. Owing to this non-uniform wear of tool electrode caused by the curvature effect of the workpiece, the formation of a microscopic bump/spike is observed on the dimple’s bottom. The depth of the dimple up to which the entire bottom surface of the tool is not exposed to the sparks is defined as its critical depth. For a combination of a tool and a workpiece of diameters 500 µm and 5 mm, respectively, the critical depth of the dimple is found to be 12.53 µm. However, the critical depth increases with a decrease in workpiece diameter, provided the diameter of the tool is constant.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127704810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-11DOI: 10.1177/2516598420965338
RamaGopal V. Sarepaka, Sivasakthi Balan, Somaiah Doodala, R. Panwar, D. R. Kotaria
In multiple applications of advanced instrumentation, single-point diamond turning (SPDT) is a popular and effective process to generate novel surfaces with nanometric surface roughness and sub-micron surface irregularities, albeit at a high cost. In SPDT, precision diamond tooling contributes significantly to the process cost escalation. Hence, for SPDT, it is vital to have an optimal precision diamond tool deployment. In this article, details of comprehensive precision diamond tool selection and tool characterization are discussed. Three makes of selected ultra-precision diamond (UPD) tools and standard diamond tools (of a global make), designated as CFT, are considered for this study. In this tool bench-marking exercise, the fabrication of Cu–Be alloy predesigned precision components (PDPCs) of a critical geometry is selected. UPD and CFT tools are deployed to fabricate (under similar machining-metrology conditions) the PDPCs. These diamond tools are evaluated in terms of the quality parameters (variation in radius of curvature, form error, and surface roughness) of the workpieces. Further, to explore the progressive wear of these tools, multiple machining cycles are conducted on these workpieces, and their quality parameters are analyzed. Thus, the precision diamond tools of three makes are benchmarked against the CFT tool. Based on the final outcome of this analysis, suitable recommendations are provided to precision diamond tool manufacturers to improve their product in terms of performance and optimized costs to meet the ever-growing tooling demands of the SPDT community.
{"title":"Study, analysis, and characterization of ultra-precision diamond tools for single-point diamond turning","authors":"RamaGopal V. Sarepaka, Sivasakthi Balan, Somaiah Doodala, R. Panwar, D. R. Kotaria","doi":"10.1177/2516598420965338","DOIUrl":"https://doi.org/10.1177/2516598420965338","url":null,"abstract":"In multiple applications of advanced instrumentation, single-point diamond turning (SPDT) is a popular and effective process to generate novel surfaces with nanometric surface roughness and sub-micron surface irregularities, albeit at a high cost. In SPDT, precision diamond tooling contributes significantly to the process cost escalation. Hence, for SPDT, it is vital to have an optimal precision diamond tool deployment. In this article, details of comprehensive precision diamond tool selection and tool characterization are discussed. Three makes of selected ultra-precision diamond (UPD) tools and standard diamond tools (of a global make), designated as CFT, are considered for this study. In this tool bench-marking exercise, the fabrication of Cu–Be alloy predesigned precision components (PDPCs) of a critical geometry is selected. UPD and CFT tools are deployed to fabricate (under similar machining-metrology conditions) the PDPCs. These diamond tools are evaluated in terms of the quality parameters (variation in radius of curvature, form error, and surface roughness) of the workpieces. Further, to explore the progressive wear of these tools, multiple machining cycles are conducted on these workpieces, and their quality parameters are analyzed. Thus, the precision diamond tools of three makes are benchmarked against the CFT tool. Based on the final outcome of this analysis, suitable recommendations are provided to precision diamond tool manufacturers to improve their product in terms of performance and optimized costs to meet the ever-growing tooling demands of the SPDT community.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128171392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-05DOI: 10.1177/2516598420963996
Prabhat Ranjan, Anuj Sharma, R. Balasubramaniam
In this work, the atomic mechanism of chemical treatment on diamond-turned aluminium surface due to aqueous H2O2 is investigated using a reactive molecular dynamics simulation (R-MDS). This study is carried out to understand the mechanism of surface quality improvement of a diamond-turned aluminium workpiece due to chemical treatment. Surface quality improvement is focused to analyse the effect of chemical treatment process for improving surface finish, reflectance and chemical stability of the workpiece. It is observed that the diamond-turned surface contains a higher cohesive energy as compared to atomically smooth surfaces. Chemical treatment does more material removal on nano-peaks with respect to the smooth surface, and this helps to reduce the cohesive energy as low as naturally possible. By applying this treatment, the optical quality of the workpiece gets enhanced drastically. R-MDS also reveals that the nano-peaks of diamond turn machining (DTM) surface can further improve surface finish by using the chemical treatment process, and the same is validated by experiments. Experimental data also support that due to the reduction of surface roughness, reflectance increases in a broad band of wavelength. The present work shows that material removal from the nano-peaks of workpiece occurs due to the oxygen radicals generated from H2O2, which raise the local temperature, followed by temperature-assisted chemical reaction. When most of the nano-peak atoms are removed, further material removal stops. Experimental results also support the mechanism of such process of chemical treatment. Hence, the diamond turned surface can be further improved beyond the capability of the diamond turning process to cater the need for optics and astronomical mirror at-least one step ahead in the domain of ultra-precision manufacturing.
{"title":"Improvement in surface quality of diamond-turned aluminium substrate by using hydrogen peroxide: a molecular dynamics simulation study","authors":"Prabhat Ranjan, Anuj Sharma, R. Balasubramaniam","doi":"10.1177/2516598420963996","DOIUrl":"https://doi.org/10.1177/2516598420963996","url":null,"abstract":"In this work, the atomic mechanism of chemical treatment on diamond-turned aluminium surface due to aqueous H2O2 is investigated using a reactive molecular dynamics simulation (R-MDS). This study is carried out to understand the mechanism of surface quality improvement of a diamond-turned aluminium workpiece due to chemical treatment. Surface quality improvement is focused to analyse the effect of chemical treatment process for improving surface finish, reflectance and chemical stability of the workpiece. It is observed that the diamond-turned surface contains a higher cohesive energy as compared to atomically smooth surfaces. Chemical treatment does more material removal on nano-peaks with respect to the smooth surface, and this helps to reduce the cohesive energy as low as naturally possible. By applying this treatment, the optical quality of the workpiece gets enhanced drastically. R-MDS also reveals that the nano-peaks of diamond turn machining (DTM) surface can further improve surface finish by using the chemical treatment process, and the same is validated by experiments. Experimental data also support that due to the reduction of surface roughness, reflectance increases in a broad band of wavelength. The present work shows that material removal from the nano-peaks of workpiece occurs due to the oxygen radicals generated from H2O2, which raise the local temperature, followed by temperature-assisted chemical reaction. When most of the nano-peak atoms are removed, further material removal stops. Experimental results also support the mechanism of such process of chemical treatment. Hence, the diamond turned surface can be further improved beyond the capability of the diamond turning process to cater the need for optics and astronomical mirror at-least one step ahead in the domain of ultra-precision manufacturing.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129975890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-01DOI: 10.1177/2516598420931013
Ankit Bairwa, A. Reddy, Gurmeet Singh
Metal granshot is a process that is used to convert metal lumps or scraps into metal grains of uniform sizes and shapes. The concept of metal granulation is based on the heat difference between melting and pouring medium. The commercial uses of metal granules are jewelry making and spray coating of costly metals such as silver, gold, and platinum. The basic aim of the silver granshot process is to get uniform size, shape, and maximum yield of silver metal granules. During processing, the metal gets superheated within vacuum up to viscosity more than 2.2 cP flow out of the minimum diameter orifice and allow to drop in the coolant with high pressurized argon gas. The present study focuses on the granulation of silver and tries to achieve the maximum yield of metal. The shape and size of the granules produced were observed using scanning electron microscopy and the results show that the average diameters of granules are between 1.2 mm and 3.8 mm. Yield is also considered as an important factor for granulation of valuable metals like silver, and after experimentation successfully achieved the 99.9 percent yield. The granulation process of silver will help to ease the trading of metal in the jewelry industry.
{"title":"Feasibility analysis for granulation of silver using Granshot method","authors":"Ankit Bairwa, A. Reddy, Gurmeet Singh","doi":"10.1177/2516598420931013","DOIUrl":"https://doi.org/10.1177/2516598420931013","url":null,"abstract":"Metal granshot is a process that is used to convert metal lumps or scraps into metal grains of uniform sizes and shapes. The concept of metal granulation is based on the heat difference between melting and pouring medium. The commercial uses of metal granules are jewelry making and spray coating of costly metals such as silver, gold, and platinum. The basic aim of the silver granshot process is to get uniform size, shape, and maximum yield of silver metal granules. During processing, the metal gets superheated within vacuum up to viscosity more than 2.2 cP flow out of the minimum diameter orifice and allow to drop in the coolant with high pressurized argon gas. The present study focuses on the granulation of silver and tries to achieve the maximum yield of metal. The shape and size of the granules produced were observed using scanning electron microscopy and the results show that the average diameters of granules are between 1.2 mm and 3.8 mm. Yield is also considered as an important factor for granulation of valuable metals like silver, and after experimentation successfully achieved the 99.9 percent yield. The granulation process of silver will help to ease the trading of metal in the jewelry industry.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"210 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125358747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-01DOI: 10.1177/2516598420965319
Shreyansh Tatiya, Mohit Pandey, S. Bhattacharya
Nanomaterials have already contributed to many innovative products in the consumer markets. Constant efforts are directed at attaining unique morphologies and reduction in size. Exponential growth in research is thus involved in the synthesis of the novel nanomaterials. Boron and its compounds with distinct functional and structural properties find extensive usage in a variety of fields ranging from nuclear technology to electronics, ceramics, etc. Also, due to their non-toxicity, they are considered an attractive intermediate in the healthcare and cosmetic industry. The majority of reviews on boron and its compounds are focused on morphologies and the structure of the boron compound obtained. Here, we offer a comprehensive review of the unique properties of the major boron compounds: boron carbide (B4C), boron nitride (BN), and heterostructures with metals and organic compounds. In each section, we also describe the subsequent synthesis routes and the challenges associated with them. We have also summarized the various morphologies and shapes reported to be associated with boron and its compounds. In recent years, however, primary research on boron nanoparticle (BNP) has focused on non-toxic/greener and energy-efficient synthesis routes. The usage and production of pure BNPs in the industry are very scarce and are often associated with nanoclusters of boron and other elements. The intricate structural design and low purity of the nanoproducts formed make BNP synthesis challenging. Thus, in the last section, we summarize the challenges and outlook of the current research with future prospects in the area of BNP research.
{"title":"Nanoparticles containing boron and its compounds—synthesis and applications: A review","authors":"Shreyansh Tatiya, Mohit Pandey, S. Bhattacharya","doi":"10.1177/2516598420965319","DOIUrl":"https://doi.org/10.1177/2516598420965319","url":null,"abstract":"Nanomaterials have already contributed to many innovative products in the consumer markets. Constant efforts are directed at attaining unique morphologies and reduction in size. Exponential growth in research is thus involved in the synthesis of the novel nanomaterials. Boron and its compounds with distinct functional and structural properties find extensive usage in a variety of fields ranging from nuclear technology to electronics, ceramics, etc. Also, due to their non-toxicity, they are considered an attractive intermediate in the healthcare and cosmetic industry. The majority of reviews on boron and its compounds are focused on morphologies and the structure of the boron compound obtained. Here, we offer a comprehensive review of the unique properties of the major boron compounds: boron carbide (B4C), boron nitride (BN), and heterostructures with metals and organic compounds. In each section, we also describe the subsequent synthesis routes and the challenges associated with them. We have also summarized the various morphologies and shapes reported to be associated with boron and its compounds. In recent years, however, primary research on boron nanoparticle (BNP) has focused on non-toxic/greener and energy-efficient synthesis routes. The usage and production of pure BNPs in the industry are very scarce and are often associated with nanoclusters of boron and other elements. The intricate structural design and low purity of the nanoproducts formed make BNP synthesis challenging. Thus, in the last section, we summarize the challenges and outlook of the current research with future prospects in the area of BNP research.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114091371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-01DOI: 10.1177/2516598420964049
S. Shinde, R. Lekurwale
The flexural bearing or the flexural cartridge allows very nano-meter axial displacement movement, which is frictionless and noiseless. The repeatability of the mechanism obtained is achieved by bending of the load element. The bearing can operate under stringent conditions such as vacuum, elevated temperatures (0–40 °C), and moist conditions. Hence, due to these indigenous properties, these bearings are observed in applications such as linear bearing of linear compressor, flexural bearing electromagnetic linear actuator, and parasitic error-free mechanism. The endorsed capability of obtaining high-level positional accuracy along with repeatability leads to design and development of low-cost flexural cartridge for micro-drilling spindle head. This flexural cartridge provides a linear guideway while feeding inside the test specimen (in micro-drilling operation). The designed head dampens and nullifies the force, acting on the shaft carrying the micro-tool. The designed spindle head carrying the three-leg spiral flexural stack is assembled on the designed machine tool. The run out measured on the spindle shaft is 50 µm. Four test specimens, namely aluminum, brass, acrylic and mild steel, are drilled by three drills of diameter 1 mm, 0.8 mm, and 0.5 mm each. The main objective of the article is to understand the differential analysis of diameter enlargement and circularity between the experimental method and the numerical method. The answers predicted by the experimental method may have second possible value as it depends upon judgment of inscribing the circle/points in the computer-aided design (CAD) environment. This ambiguity is excluded by the MATLAB code, which gives one specific answer. The maximum difference in diameter enlargement for aluminum, brass, acrylic, and mild steel specimens are 3.8 µm, 11 µm, 24.6 µm, and 16.1 µm, respectively, whereas the maximum difference in circularity for the same specimens is 11.8 µm, 1.3 µm, 8.2 µm, and 16.8 µm, respectively. This difference is termed as the |error|.
{"title":"Experimental and numerical investigation of difference in diameter enlargement and circularity of micro-holes drilled by flexural spindle head","authors":"S. Shinde, R. Lekurwale","doi":"10.1177/2516598420964049","DOIUrl":"https://doi.org/10.1177/2516598420964049","url":null,"abstract":"The flexural bearing or the flexural cartridge allows very nano-meter axial displacement movement, which is frictionless and noiseless. The repeatability of the mechanism obtained is achieved by bending of the load element. The bearing can operate under stringent conditions such as vacuum, elevated temperatures (0–40 °C), and moist conditions. Hence, due to these indigenous properties, these bearings are observed in applications such as linear bearing of linear compressor, flexural bearing electromagnetic linear actuator, and parasitic error-free mechanism. The endorsed capability of obtaining high-level positional accuracy along with repeatability leads to design and development of low-cost flexural cartridge for micro-drilling spindle head. This flexural cartridge provides a linear guideway while feeding inside the test specimen (in micro-drilling operation). The designed head dampens and nullifies the force, acting on the shaft carrying the micro-tool. The designed spindle head carrying the three-leg spiral flexural stack is assembled on the designed machine tool. The run out measured on the spindle shaft is 50 µm. Four test specimens, namely aluminum, brass, acrylic and mild steel, are drilled by three drills of diameter 1 mm, 0.8 mm, and 0.5 mm each. The main objective of the article is to understand the differential analysis of diameter enlargement and circularity between the experimental method and the numerical method. The answers predicted by the experimental method may have second possible value as it depends upon judgment of inscribing the circle/points in the computer-aided design (CAD) environment. This ambiguity is excluded by the MATLAB code, which gives one specific answer. The maximum difference in diameter enlargement for aluminum, brass, acrylic, and mild steel specimens are 3.8 µm, 11 µm, 24.6 µm, and 16.1 µm, respectively, whereas the maximum difference in circularity for the same specimens is 11.8 µm, 1.3 µm, 8.2 µm, and 16.8 µm, respectively. This difference is termed as the |error|.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131040213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-12DOI: 10.1177/2516598420939745
I. Singh, G. S, T. N. Reddy, P. Vinod
This research aims to establish a methodology for machining of toric lenses, using fast tool servo-assisted single point diamond turning and to assess the generated surface for its characteristics. Using the established mathematical model, toric surface is explained to understand the geometry and to generate the parameters required for fast tool servo machining. A toric surface with a major diameter of 18.93 mm and a minor diameter of 15.12 mm has been cut on the intelligent ultra-precision turning machine (iUPTM). The surface profile and surface roughness were measured. After analysing the measurement data of the machined surface, on two perpendicular axes of the toric lens, form accuracy of 0.49 µm peak-to-valley (PV), and surface roughness of 12 nm in Ra, 4–8 nm in Sa are obtained. From the experimental results obtained, it can be concluded that the proposed method is a reasonable alternative for manufacturing toric lens mould.
{"title":"Freeform machining of ophthalmic toric lens mould using fast tool servo-assisted ultra-precision diamond turning process","authors":"I. Singh, G. S, T. N. Reddy, P. Vinod","doi":"10.1177/2516598420939745","DOIUrl":"https://doi.org/10.1177/2516598420939745","url":null,"abstract":"This research aims to establish a methodology for machining of toric lenses, using fast tool servo-assisted single point diamond turning and to assess the generated surface for its characteristics. Using the established mathematical model, toric surface is explained to understand the geometry and to generate the parameters required for fast tool servo machining. A toric surface with a major diameter of 18.93 mm and a minor diameter of 15.12 mm has been cut on the intelligent ultra-precision turning machine (iUPTM). The surface profile and surface roughness were measured. After analysing the measurement data of the machined surface, on two perpendicular axes of the toric lens, form accuracy of 0.49 µm peak-to-valley (PV), and surface roughness of 12 nm in Ra, 4–8 nm in Sa are obtained. From the experimental results obtained, it can be concluded that the proposed method is a reasonable alternative for manufacturing toric lens mould.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128775688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-12DOI: 10.1177/2516598420936131
Arvind Shivaji Shirale, S. Sahu, S. Patel, J. Ramkumar, S. Shekhar
In the present work, an analytical model is proposed to predict the cutting forces in elliptical vibration cutting (EVC). In general, cutting force in metal cutting is a function of the shear angle (φ) and shear strength (τ) of the material. However, these parameters vary dynamically over a cutting cycle of EVC. In this work, the shear angle has been modelled based on the plasticity theory of maximum shear stress criteria. For transient shear strength prediction, the Johnson–Cook model is used. This model predicts shear strength for time-varying strain and strain rate in EVC. The obtained analytical results of cutting forces were compared with experimental results published in the literature and found to be in good agreement (within 12% error) with them. Based on the proposed model, the cutting forces can be modelled as a function of cutting process parameters (depth of cut, cutting velocity), tool parameter (rake angle), physical and thermo-mechanical properties for different materials, without any experimental inputs from EVC.
{"title":"An analytical modelling of cutting forces in orthogonal elliptical vibration cutting","authors":"Arvind Shivaji Shirale, S. Sahu, S. Patel, J. Ramkumar, S. Shekhar","doi":"10.1177/2516598420936131","DOIUrl":"https://doi.org/10.1177/2516598420936131","url":null,"abstract":"In the present work, an analytical model is proposed to predict the cutting forces in elliptical vibration cutting (EVC). In general, cutting force in metal cutting is a function of the shear angle (φ) and shear strength (τ) of the material. However, these parameters vary dynamically over a cutting cycle of EVC. In this work, the shear angle has been modelled based on the plasticity theory of maximum shear stress criteria. For transient shear strength prediction, the Johnson–Cook model is used. This model predicts shear strength for time-varying strain and strain rate in EVC. The obtained analytical results of cutting forces were compared with experimental results published in the literature and found to be in good agreement (within 12% error) with them. Based on the proposed model, the cutting forces can be modelled as a function of cutting process parameters (depth of cut, cutting velocity), tool parameter (rake angle), physical and thermo-mechanical properties for different materials, without any experimental inputs from EVC.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130054373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-12DOI: 10.1177/2516598420941728
K. Mahajan, R. Pawade
Single-point diamond turning (SPDT) is an emerging process for achieving nanometric surface finish, required in various optical devices made from metals like aluminum, copper, and nonmetals like polymers. The optical devices are manufactured in different shapes and profiles, preferably flat and curved surfaces. During the manufacturing of optical devices, controllable and noncontrollable parameters affect the desired surface finish. In this article, controllable machining parameters such as the incremental distance of X slide, feed rate, spindle speed, and depth of cut are selected to study their effect on surface finish and vibration generation of the curved surface. The chosen workpiece material is polymethylmethacrylate (PMMA). Design of experiment (DoE) is used to find out the optimum parameters of surface finish and infeed vibration responses. According to the Taguchi and analysis of Variance (ANOVA) analysis, the feed rate is the most influencing parameter for surface roughness, and incremental distance is for infeed vibration. A confirmation test is carried out to verify the experimental responses with a mathematical regression model, and it shows a close difference within 2.7 percent. Further, minimum surface roughness is perceived as 12.4 nm, corresponding to an infeed vibration amplitude of 4.9 µm/s2, which is signified at a lower frequency.
{"title":"Effect of machining parameters and vibration on polymethylmethacrylate curved surface in single-point diamond turning","authors":"K. Mahajan, R. Pawade","doi":"10.1177/2516598420941728","DOIUrl":"https://doi.org/10.1177/2516598420941728","url":null,"abstract":"Single-point diamond turning (SPDT) is an emerging process for achieving nanometric surface finish, required in various optical devices made from metals like aluminum, copper, and nonmetals like polymers. The optical devices are manufactured in different shapes and profiles, preferably flat and curved surfaces. During the manufacturing of optical devices, controllable and noncontrollable parameters affect the desired surface finish. In this article, controllable machining parameters such as the incremental distance of X slide, feed rate, spindle speed, and depth of cut are selected to study their effect on surface finish and vibration generation of the curved surface. The chosen workpiece material is polymethylmethacrylate (PMMA). Design of experiment (DoE) is used to find out the optimum parameters of surface finish and infeed vibration responses. According to the Taguchi and analysis of Variance (ANOVA) analysis, the feed rate is the most influencing parameter for surface roughness, and incremental distance is for infeed vibration. A confirmation test is carried out to verify the experimental responses with a mathematical regression model, and it shows a close difference within 2.7 percent. Further, minimum surface roughness is perceived as 12.4 nm, corresponding to an infeed vibration amplitude of 4.9 µm/s2, which is signified at a lower frequency.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125580617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-05DOI: 10.1177/2516598420938495
V. Mishra, Rohit Sharma, K. Mahajan, J. Kumar, Neha Khatri, Anikate Gupta, H. Garg, V. Karar, R. Pawade, RamaGopal V. Sarepaka
Optical plastic lenses are progressively substituting glass optics due to their lightweight and low costs. Polycarbonate (PC) is considered as one of the leading optical materials due to its good mechanical and optical properties. Ultra-precision machining is the most suited process to develop PC optical components. Nevertheless, ultra-precision machining is considered as one of the deterministic processes to ensure the surface quality required for optical components. However, it is important to understand the behavior of the material during each stage of manufacturing. PC offers many challenges during its processing to achieve the nanometric finish and sub-micron form accuracies. In this article, the various issues of PC machining are discussed through experimental investigations. The effect of machining variables, that is, machining parameters, cutting temperature, and vacuum clamping on surface quality is studied. The results show the importance of the selection of optimum conditions for machining PC with good surface quality. The PC optical component is developed with surface finish (Ra) 18.1 nm and profile accuracies (Pv) of 0.116 µm. The study is helpful to understand the various issues involved in PC machining and hence to minimize their effects on surface quality.
{"title":"Experimental investigations on ultra-precision machining of polycarbonate and related issues","authors":"V. Mishra, Rohit Sharma, K. Mahajan, J. Kumar, Neha Khatri, Anikate Gupta, H. Garg, V. Karar, R. Pawade, RamaGopal V. Sarepaka","doi":"10.1177/2516598420938495","DOIUrl":"https://doi.org/10.1177/2516598420938495","url":null,"abstract":"Optical plastic lenses are progressively substituting glass optics due to their lightweight and low costs. Polycarbonate (PC) is considered as one of the leading optical materials due to its good mechanical and optical properties. Ultra-precision machining is the most suited process to develop PC optical components. Nevertheless, ultra-precision machining is considered as one of the deterministic processes to ensure the surface quality required for optical components. However, it is important to understand the behavior of the material during each stage of manufacturing. PC offers many challenges during its processing to achieve the nanometric finish and sub-micron form accuracies. In this article, the various issues of PC machining are discussed through experimental investigations. The effect of machining variables, that is, machining parameters, cutting temperature, and vacuum clamping on surface quality is studied. The results show the importance of the selection of optimum conditions for machining PC with good surface quality. The PC optical component is developed with surface finish (Ra) 18.1 nm and profile accuracies (Pv) of 0.116 µm. The study is helpful to understand the various issues involved in PC machining and hence to minimize their effects on surface quality.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114970336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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