Pub Date : 2023-06-02DOI: 10.1177/25165984231172007
Gaganpreet Singh, Bhawandeep Sharma, R. Kumar, J. Ramkumar, S. A. Ramakrishna
In this article, an analytical study of the effect of the shape and size of the mask on the machining quality of complex shapes has been carried out. For this study, we considered square and circular masks of varying sizes with varying overlap for the machining of square, inclined, and circular features. Mask size varied from 1 to 20 mm, while overlap varied from 10% to 90%. The machining quality of the aforementioned features was evaluated by studying the unmachined area “An” (in the machining zone) and the machining time “Tm.” For machining a similar feature, it was observed that the square mask performed much better than the circular mask in minimizing the machining time. However, the circular mask is much more suitable for minimizing the unmachined area. For validation, the experiment was conducted to machine the inclined lines with square and circular shape masks with varying overlap percentages. The experimental results were found to be in good agreement with the analytically obtained results, with an error of 2.5%. This study is relevant for the industrial-scale manufacturing of complicated features using the mask projection approach in laser machining.
{"title":"Analytical study for the selection of mask size and shape for obtaining high machining quality of complex features","authors":"Gaganpreet Singh, Bhawandeep Sharma, R. Kumar, J. Ramkumar, S. A. Ramakrishna","doi":"10.1177/25165984231172007","DOIUrl":"https://doi.org/10.1177/25165984231172007","url":null,"abstract":"In this article, an analytical study of the effect of the shape and size of the mask on the machining quality of complex shapes has been carried out. For this study, we considered square and circular masks of varying sizes with varying overlap for the machining of square, inclined, and circular features. Mask size varied from 1 to 20 mm, while overlap varied from 10% to 90%. The machining quality of the aforementioned features was evaluated by studying the unmachined area “An” (in the machining zone) and the machining time “Tm.” For machining a similar feature, it was observed that the square mask performed much better than the circular mask in minimizing the machining time. However, the circular mask is much more suitable for minimizing the unmachined area. For validation, the experiment was conducted to machine the inclined lines with square and circular shape masks with varying overlap percentages. The experimental results were found to be in good agreement with the analytically obtained results, with an error of 2.5%. This study is relevant for the industrial-scale manufacturing of complicated features using the mask projection approach in laser machining.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122389350","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 : 2023-02-10DOI: 10.1177/25165984231151303
Naresh Besekar, B. Bhattacharyya
Nitinol shape memory alloy (SMA) has outstanding chemical and mechanical properties which make the machining of Nitinol SMA more difficult than other materials due to super-elasticity and multiphase transformation. Wire electrochemical machining (WECM) is a nontraditional process, which removes conductive material through anodic dissolution despite of material’s properties. In this paper, the mathematical model is presented for slit width calculation for the influence of different parameters using vibration-assisted nozzle jet flushing. In this experimental investigation, the effect of prominent energy input parameters on wire feed rate to achieve better homogeneity, machining accuracy, and surface quality with a 300 µm thick sheet of Nitinol SMA micro-slits has been presented using an in-house developed WECM set-up. Experimental results revealed that the wire feed rate and surface roughness drastically increases with an increase in the most influencing energy input parameter, that is, pulse voltage with minimum average surface roughness (Ra) of 0.1076 µm and 123.60 µm average slit width at 7 V pulse voltage. Finally, the curved complex micro-feature of a 120 µm thick sheet of Nitinol SMA was fabricated successfully with a 137.795 µm average slit width under the controlled process parameter combination using WECM.
{"title":"Influence of energy input parameters on wire feed rate and surface characteristics during WECM of Nitinol SMA","authors":"Naresh Besekar, B. Bhattacharyya","doi":"10.1177/25165984231151303","DOIUrl":"https://doi.org/10.1177/25165984231151303","url":null,"abstract":"Nitinol shape memory alloy (SMA) has outstanding chemical and mechanical properties which make the machining of Nitinol SMA more difficult than other materials due to super-elasticity and multiphase transformation. Wire electrochemical machining (WECM) is a nontraditional process, which removes conductive material through anodic dissolution despite of material’s properties. In this paper, the mathematical model is presented for slit width calculation for the influence of different parameters using vibration-assisted nozzle jet flushing. In this experimental investigation, the effect of prominent energy input parameters on wire feed rate to achieve better homogeneity, machining accuracy, and surface quality with a 300 µm thick sheet of Nitinol SMA micro-slits has been presented using an in-house developed WECM set-up. Experimental results revealed that the wire feed rate and surface roughness drastically increases with an increase in the most influencing energy input parameter, that is, pulse voltage with minimum average surface roughness (Ra) of 0.1076 µm and 123.60 µm average slit width at 7 V pulse voltage. Finally, the curved complex micro-feature of a 120 µm thick sheet of Nitinol SMA was fabricated successfully with a 137.795 µm average slit width under the controlled process parameter combination using WECM.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116703451","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 : 2023-02-07DOI: 10.1177/25165984231151745
Jibin Boban, Afzaal Ahmed
Selective laser melting (SLM) of titanium–aluminium (TiAl) alloy components has gained significant attention in the modern industrial world. The flexibility of the SLM process in producing complex shapes with minimum utilization of material and energy makes it dominant over other manufacturing techniques. As aerospace and biomedical industries demand complex-shaped TiAl alloy components, part fabrication using SLM becomes the ultimate solution. However, the unacceptable level of surface integrity and anisotropic behavior of SLM components demand post processing operations such as laser polishing, chemical polishing, and conventional polishing methods. In this study, a recently developed polishing method called wire electrical discharge polishing (WEDP) is performed on TiAl alloys for obtaining a smooth and defect-free surface. This study aims to investigate the micro-layer modification occurring to the WEDP-processed surface in detail. The experimental results establish the effectiveness of WEDP method in terms of improved surface integrity. The surface finish (Sa) got enhanced by ~88% after WEDP processing. In addition, the thickness of recast layer formed by WEDP was found to be minimum. Moreover, post-processing of TiAl alloy resulted in better surface morphology specifically at lower settings of peak current. It is noteworthy that the migration of wire material was minimum with zinc-coated brass electrode compared to the normal brass electrode. Hence, coated wire electrodes are recommended for WEDP process. In short, an excellent surface integrity can be achieved using WEDP process through favorable surface modification aided by lower peak current and coated wire electrodes. Furthermore, less electrode wear observed in WEDP process enables the deployment of lower feed rates leading to minimal electrode consumption.
{"title":"Finishing the surface micro-layer of additively manufactured TiAl alloy using electro-thermal discharge assisted post-processing","authors":"Jibin Boban, Afzaal Ahmed","doi":"10.1177/25165984231151745","DOIUrl":"https://doi.org/10.1177/25165984231151745","url":null,"abstract":"Selective laser melting (SLM) of titanium–aluminium (TiAl) alloy components has gained significant attention in the modern industrial world. The flexibility of the SLM process in producing complex shapes with minimum utilization of material and energy makes it dominant over other manufacturing techniques. As aerospace and biomedical industries demand complex-shaped TiAl alloy components, part fabrication using SLM becomes the ultimate solution. However, the unacceptable level of surface integrity and anisotropic behavior of SLM components demand post processing operations such as laser polishing, chemical polishing, and conventional polishing methods. In this study, a recently developed polishing method called wire electrical discharge polishing (WEDP) is performed on TiAl alloys for obtaining a smooth and defect-free surface. This study aims to investigate the micro-layer modification occurring to the WEDP-processed surface in detail. The experimental results establish the effectiveness of WEDP method in terms of improved surface integrity. The surface finish (Sa) got enhanced by ~88% after WEDP processing. In addition, the thickness of recast layer formed by WEDP was found to be minimum. Moreover, post-processing of TiAl alloy resulted in better surface morphology specifically at lower settings of peak current. It is noteworthy that the migration of wire material was minimum with zinc-coated brass electrode compared to the normal brass electrode. Hence, coated wire electrodes are recommended for WEDP process. In short, an excellent surface integrity can be achieved using WEDP process through favorable surface modification aided by lower peak current and coated wire electrodes. Furthermore, less electrode wear observed in WEDP process enables the deployment of lower feed rates leading to minimal electrode consumption.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129219042","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 : 2023-01-24DOI: 10.1177/25165984221148564
P. Pandit, G. Samuel
Compared to the traditional machining and finishing process, a hybrid technique consisting of mechanical micro-milling and electropolishing is advantageous in maintaining dimensional accuracy and fine surface quality without compromising the form. This is a cost-effective, less tedious technique that can fabricate high-quality masters for microfluidic devices. P20-die steel masters are fabricated to evaluate the method with this technique. The dimensional accuracy and surface quality of the masters are studied. It is found that the peak-to-valley surface roughness (Rt) of the masters is reduced by 50%. These die steel masters are then used to make polydimethylsiloxane (PDMS)-based microfluidic devices that could be used for particle separation. As biofouling and bacterial growth are undesirable in most of the microfluidic devices, the fabricated PDMS devices are tested for bacterial growth and adhesion. The growth of DH5α Escherichia coli bacteria in the devices fabricated using the electropolished masters is evaluated. Bacterial growth and adhesion are monitored for 0, 4 and 12 h, and it is found that the growth and adhesion in these devices are reduced by 15–20% and 40–50%, respectively, compared to the devices produced using non-electropolished masters. Enumeration of the bacterial cells in the samples flown is carried out by evaluating the optical density of the sample fluids by UV-visible spectroscopy and quantifying the bacterial cells using the McFarland 0.5 standard.
{"title":"Hybrid machining of P20 die steel masters for the development of polymer-based microfluidic devices to study the effect of surface roughness on bacterial activity","authors":"P. Pandit, G. Samuel","doi":"10.1177/25165984221148564","DOIUrl":"https://doi.org/10.1177/25165984221148564","url":null,"abstract":"Compared to the traditional machining and finishing process, a hybrid technique consisting of mechanical micro-milling and electropolishing is advantageous in maintaining dimensional accuracy and fine surface quality without compromising the form. This is a cost-effective, less tedious technique that can fabricate high-quality masters for microfluidic devices. P20-die steel masters are fabricated to evaluate the method with this technique. The dimensional accuracy and surface quality of the masters are studied. It is found that the peak-to-valley surface roughness (Rt) of the masters is reduced by 50%. These die steel masters are then used to make polydimethylsiloxane (PDMS)-based microfluidic devices that could be used for particle separation. As biofouling and bacterial growth are undesirable in most of the microfluidic devices, the fabricated PDMS devices are tested for bacterial growth and adhesion. The growth of DH5α Escherichia coli bacteria in the devices fabricated using the electropolished masters is evaluated. Bacterial growth and adhesion are monitored for 0, 4 and 12 h, and it is found that the growth and adhesion in these devices are reduced by 15–20% and 40–50%, respectively, compared to the devices produced using non-electropolished masters. Enumeration of the bacterial cells in the samples flown is carried out by evaluating the optical density of the sample fluids by UV-visible spectroscopy and quantifying the bacterial cells using the McFarland 0.5 standard.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133069918","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 : 2023-01-11DOI: 10.1177/25165984221143866
Poonam Chauhan, Aditya Kumar
This work demonstrates the maximum spreading behavior of water droplets on prepared surfaces: superhydrophilic (etched), hydrophilic (inherent nature), hydrophobic (treated with hexadecyltrimethoxysilane (HDTMS), and superhydrophobic (etched and HDTMS treated). Here, a simple chemical etching and immersion approach were used to modify the surfaces. Altering one surface property to the next shows a significant variation in the wetting behavior. The change in the wettability of the aluminium surface depends on its surface roughness and surface chemistry. The wettability of the fabricated surfaces was determined via water contact angle (WCA) measurement using a goniometer. A field emission scanning electron microscope (FESEM) and a 3-D optical non-contact profilometer were used to analyze the surface morphology and surface roughness of all manufactured surfaces, respectively. Additional features such as the droplet dynamics property of all surfaces were studied in detail. Finally, the experimental results for the maximum spreading factor were compared to the existing model.
{"title":"Maximum spreading behavior of a water droplet on the aluminium surfaces with different wettabilities","authors":"Poonam Chauhan, Aditya Kumar","doi":"10.1177/25165984221143866","DOIUrl":"https://doi.org/10.1177/25165984221143866","url":null,"abstract":"This work demonstrates the maximum spreading behavior of water droplets on prepared surfaces: superhydrophilic (etched), hydrophilic (inherent nature), hydrophobic (treated with hexadecyltrimethoxysilane (HDTMS), and superhydrophobic (etched and HDTMS treated). Here, a simple chemical etching and immersion approach were used to modify the surfaces. Altering one surface property to the next shows a significant variation in the wetting behavior. The change in the wettability of the aluminium surface depends on its surface roughness and surface chemistry. The wettability of the fabricated surfaces was determined via water contact angle (WCA) measurement using a goniometer. A field emission scanning electron microscope (FESEM) and a 3-D optical non-contact profilometer were used to analyze the surface morphology and surface roughness of all manufactured surfaces, respectively. Additional features such as the droplet dynamics property of all surfaces were studied in detail. Finally, the experimental results for the maximum spreading factor were compared to the existing model.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"197 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129674740","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 : 2022-12-19DOI: 10.1177/25165984221139615
Anu Tomy, S. Hiremath
Titanium is extensively utilized in aerospace and medical scenarios owing to its outstanding mechanical properties and corrosion resistance. Conventional machining of titanium alloys is challenging because of its innate characteristics like hardness, lofty reactivity, modest thermal conductivity and elastic modulus. Therefore, an attempt has been made to study the ease with which titanium alloy (Ti-6Al-4V) can be machined using abrasive jet machining (AJM). Machining of holes in Ti-6Al-4V was executed by incorporating a group of input parameters—air pressure, abrasive grit size and standoff distance. The output responses such as material removal rate (MRR), circularity, radial overcut (ROC) and taper angle (TA) are chosen for the evaluation of the experiment. The machining parameters are optimized for higher MRR (case 1) and for lower ROC and TA (case 2) using multi-objective grey relational analysis to choose a moderate course among the output parameters.
{"title":"An experimental investigation and multi-objective optimization of abrasive jet machining on Ti-6Al-4V ELI bio-material","authors":"Anu Tomy, S. Hiremath","doi":"10.1177/25165984221139615","DOIUrl":"https://doi.org/10.1177/25165984221139615","url":null,"abstract":"Titanium is extensively utilized in aerospace and medical scenarios owing to its outstanding mechanical properties and corrosion resistance. Conventional machining of titanium alloys is challenging because of its innate characteristics like hardness, lofty reactivity, modest thermal conductivity and elastic modulus. Therefore, an attempt has been made to study the ease with which titanium alloy (Ti-6Al-4V) can be machined using abrasive jet machining (AJM). Machining of holes in Ti-6Al-4V was executed by incorporating a group of input parameters—air pressure, abrasive grit size and standoff distance. The output responses such as material removal rate (MRR), circularity, radial overcut (ROC) and taper angle (TA) are chosen for the evaluation of the experiment. The machining parameters are optimized for higher MRR (case 1) and for lower ROC and TA (case 2) using multi-objective grey relational analysis to choose a moderate course among the output parameters.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"35 12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131696124","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 : 2022-12-09DOI: 10.1177/25165984221136706
N. Dancholvichit, S. Salapaka, S. Kapoor
Drawing velocity is essential in the manufacturing of the multi-facet bulk metallic glass (BMG) knife edges used in corneal surgery since it is one of the factors that can determine good blade profiles in the thermoplastic forming process. The goal of this article is to determine and regulate drawing velocity based on the viscoelastic filament stretching and knowledge of the thermoplastic forming map of BMG. The generation of drawing velocity profile is done in two stages: the initial transient stage before the extensional viscosity stage is fully developed, and the extensional viscosity stage. The controller based on the system identification of the testbed is then optimized from the requirements of the drawing velocity and its implementation feasibility. The control objectives of regulation performance and robustness to modeling uncertainties are posed and solved in an optimal control (H∞) framework. The proposed controller shows an improvement over other controllers including proportional-integral-derivative controllers in terms of robustness to uncertainties and tracking performance. BMG samples processed from this study result in good quality with improvement of 20% and 54% in X–Y ( 2.2 ± 0.1 µm) and X–Z ( 1.3 ± 0.1 µm) straightness and 25% more consistent edge radii ( 46 ± 3 nm).
{"title":"Thermoplastic micro-forming process of bulk metallic glass surgical blades using drawing velocity regulation","authors":"N. Dancholvichit, S. Salapaka, S. Kapoor","doi":"10.1177/25165984221136706","DOIUrl":"https://doi.org/10.1177/25165984221136706","url":null,"abstract":"Drawing velocity is essential in the manufacturing of the multi-facet bulk metallic glass (BMG) knife edges used in corneal surgery since it is one of the factors that can determine good blade profiles in the thermoplastic forming process. The goal of this article is to determine and regulate drawing velocity based on the viscoelastic filament stretching and knowledge of the thermoplastic forming map of BMG. The generation of drawing velocity profile is done in two stages: the initial transient stage before the extensional viscosity stage is fully developed, and the extensional viscosity stage. The controller based on the system identification of the testbed is then optimized from the requirements of the drawing velocity and its implementation feasibility. The control objectives of regulation performance and robustness to modeling uncertainties are posed and solved in an optimal control (H∞) framework. The proposed controller shows an improvement over other controllers including proportional-integral-derivative controllers in terms of robustness to uncertainties and tracking performance. BMG samples processed from this study result in good quality with improvement of 20% and 54% in X–Y ( 2.2 ± 0.1 µm) and X–Z ( 1.3 ± 0.1 µm) straightness and 25% more consistent edge radii ( 46 ± 3 nm).","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114889226","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 : 2022-11-28DOI: 10.1177/25165984221135713
P. P, S. Hiremath
Nickel-based superalloy Inconel 625 is considered a hard-to-cut material due to characteristics such as high hardness, strain hardening behavior, and affinity with tool materials. It is challenging to machine through micro-holes of less than Ø 500 µm with the desired quality on Inconel 625 using the mechanical micro-drilling (MMD) process under dry conditions. The machining parameters must be selected optimally to enhance hole quality and to avoid frequent drill breakages. In this study, through micro-holes are machined on Inconel 625 by the MMD process using solid carbide micro-drills under dry conditions using a peck drilling strategy. Experiments are carried out by varying machining parameters such as spindle speed (8000 rpm, 11000 rpm, and 14000 rpm), feed (5 µm/rev, 7.5 µm/rev, and 10 µm/rev), and drill diameter (Ø 300 µm, Ø 400 µm, and Ø 500 µm) at three levels based on full factorial design. Thrust force and hole quality features such as exit burr height, radial overcut, and taper angle are measured as output responses. The mean effect plots are used to study the influence of machining parameters on output responses. The drill diameter had a significant effect on thrust force and radial overcut. Whereas feed and spindle speed had a major influence on exit burr height and taper angle, respectively. Finally, multi-response optimization is carried out using the grey fuzzy logic method, and an optimal machining parameter setting for multiple responses is ascertained.
{"title":"Mechanical peck drilling of Inconel 625: Parametric analysis and grey fuzzy logic based multi-response optimization","authors":"P. P, S. Hiremath","doi":"10.1177/25165984221135713","DOIUrl":"https://doi.org/10.1177/25165984221135713","url":null,"abstract":"Nickel-based superalloy Inconel 625 is considered a hard-to-cut material due to characteristics such as high hardness, strain hardening behavior, and affinity with tool materials. It is challenging to machine through micro-holes of less than Ø 500 µm with the desired quality on Inconel 625 using the mechanical micro-drilling (MMD) process under dry conditions. The machining parameters must be selected optimally to enhance hole quality and to avoid frequent drill breakages. In this study, through micro-holes are machined on Inconel 625 by the MMD process using solid carbide micro-drills under dry conditions using a peck drilling strategy. Experiments are carried out by varying machining parameters such as spindle speed (8000 rpm, 11000 rpm, and 14000 rpm), feed (5 µm/rev, 7.5 µm/rev, and 10 µm/rev), and drill diameter (Ø 300 µm, Ø 400 µm, and Ø 500 µm) at three levels based on full factorial design. Thrust force and hole quality features such as exit burr height, radial overcut, and taper angle are measured as output responses. The mean effect plots are used to study the influence of machining parameters on output responses. The drill diameter had a significant effect on thrust force and radial overcut. Whereas feed and spindle speed had a major influence on exit burr height and taper angle, respectively. Finally, multi-response optimization is carried out using the grey fuzzy logic method, and an optimal machining parameter setting for multiple responses is ascertained.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128436767","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 : 2022-11-24DOI: 10.1177/25165984221129958
Pinal Rana, D. P. Khatri, A. Kottantharayil, D. Marla
In this work, a nanosecond green laser (532 nm) is used to generate narrow openings by removing an ultra-thin (85 nm) SiN x layer that is coated on a silicon substrate for application in the fabrication of Passivated Emitter and Rear Contact (PERC) solar cells. An experimental analysis is presented to identify the optimal range of laser parameters for an efficient ablation with minimal damage to the silicon substrate. The ablated samples were characterized using a 3D profilometer to obtain the surface profiles and scanning electron microscope imaging to observe the surface quality. Further, energy-dispersive X-ray line analysis and atom probe tomography were performed to evaluate the nitrogen content on the surface and along the depth, respectively. The experimental results suggest that the SiN x layer starts to ablate only above a threshold laser fluence of 1.4 J/cm2, while the surface bulged out for laser fluence slightly below the ablation threshold. The central part of the ablated region was clean with a negligible nitrogen concentration at the surface, about ∼0.03% at a fluence of 2.4 J/cm2. Nitrogen concentration reduces continuously and almost becomes zero at 80 nm depth, suggesting complete ablation of the SiN x layer for establishing electrical contacts. The ablation width was close to the laser spot diameter only at lower values of the laser fluence. The lowest value of ablation depth was about 180 nm, suggesting that only about 95 nm layer of the silicon is ablated. The study demonstrates that nanosecond laser ablation is a potential technique for ablation of the SiN x layer of PERC solar cells but requires choosing the optimal parameters.
在这项工作中，使用纳秒绿色激光(532 nm)去除涂在硅衬底上的超薄(85 nm) SiN x层来产生狭窄的开口，该层用于制造钝化发射极和后接触(PERC)太阳能电池。通过实验分析，确定了在对硅衬底损伤最小的情况下进行有效烧蚀的最佳激光参数范围。利用三维轮廓仪对烧蚀后的样品进行了表征，获得了表面轮廓，并用扫描电镜成像观察了表面质量。此外，利用能量色散x射线线分析和原子探针层析成像分别评估了表面和深度上的氮含量。实验结果表明，当激光辐照强度为1.4 J/cm2时，sinx层才开始烧蚀，而当激光辐照强度略低于烧蚀阈值时，表面会凸出。烧蚀区域的中心部分是干净的，表面的氮浓度可以忽略不计，在2.4 J/cm2的影响下，约为0.03%。氮浓度持续下降，在80nm深度时几乎为零，表明为了建立电接触，sinx层已经完全烧蚀。只有在较低的激光通量下，烧蚀宽度才接近光斑直径。烧蚀深度最小值约为180 nm，表明仅烧蚀了约95 nm的硅层。研究表明，纳秒激光烧蚀是一种有潜力的烧蚀PERC太阳能电池sinx层的技术，但需要选择最佳参数。
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Pub Date : 2022-11-19DOI: 10.1177/25165984221135047
V. V. Vanmore, U. Dabade
In non-traditional machining, micro-abrasive jet machining (MAJM) is a cost-effective machining process. MAJM has been used for fabricating electronic devices and microfluidic channels. This work has made an effort to utilize MAJM for glass. A new design and fabrication of the Laval type of nozzle have been proposed to improve machining accuracy. A nozzle is conceived to ensure specific characteristics of the mixture (compressed air and abrasive particles) pass through it. The abrasive particle force is converted to kinetic energy, increasing the mixture’s velocity. The cross-sectional area of the nozzle can be circular, rectangular, square, or oval. A circular cross-sectional nozzle has been developed for high velocity, precise etching, and patterning on difficult-to-machine materials such as steel alloys. A circular cross-sectional micro-nozzle with a large aspect ratio is proposed, and the flow characteristics and cutting performance are examined precisely by the experiment. Efforts are being made to make machining processes sustainable, productive, and efficient. Here, the Taguchi-grey relational analysis integration approach has been used to analyze the machining parameters such as air pressure, stand-off distance, and abrasive mesh size (AMS). The top hole diameter, bottom hole diameter, material removal rate, and radial overcut are the response variables in this investigation. Analysis of variance (ANOVA) results showed that the AMS was the most efficient parameter, which followed the processing condition on the total input of the multi-purpose function. The reported optimized process parameters are air pressure of 8 bar, stand-off distance of 2 mm, and AMS mix (50%+100%) micron, which significantly affects the top and bottom micro-hole diameters.
在非传统加工中，微磨料射流加工(MAJM)是一种经济高效的加工工艺。MAJM已被用于制造电子器件和微流体通道。这项工作为利用MAJM制造玻璃做出了努力。为了提高加工精度，提出了一种新的拉瓦尔型喷嘴的设计和制造方法。喷嘴的设计是为了确保混合物的特定特性(压缩空气和磨料颗粒)通过它。磨料颗粒的力转化为动能，增加了混合物的速度。喷嘴的横截面积可以是圆形、矩形、方形或椭圆形。一种用于高速、精确刻蚀和在难以加工的材料(如钢合金)上刻蚀的圆形截面喷嘴已经被开发出来。提出了一种大展弦比圆形截面微喷嘴，并通过实验对其流动特性和切削性能进行了精确检验。人们正在努力使机械加工过程可持续、高产和高效。在这里，田口灰关联分析集成方法已被用于分析加工参数，如空气压力，隔离距离，磨料孔径(AMS)。顶孔直径、底孔直径、材料去除率和径向过切量是本研究的响应变量。方差分析(ANOVA)结果表明，AMS是最有效的参数，它遵循了多用途函数总输入的处理条件。优化后的工艺参数为:气压为8 bar，隔离距离为2 mm, AMS掺量(50%+100%)微米，对顶、底微孔直径影响显著。
{"title":"Multi-criteria optimization of micro-hole on glass using developed µ-abrasive jet machine set-up","authors":"V. V. Vanmore, U. Dabade","doi":"10.1177/25165984221135047","DOIUrl":"https://doi.org/10.1177/25165984221135047","url":null,"abstract":"In non-traditional machining, micro-abrasive jet machining (MAJM) is a cost-effective machining process. MAJM has been used for fabricating electronic devices and microfluidic channels. This work has made an effort to utilize MAJM for glass. A new design and fabrication of the Laval type of nozzle have been proposed to improve machining accuracy. A nozzle is conceived to ensure specific characteristics of the mixture (compressed air and abrasive particles) pass through it. The abrasive particle force is converted to kinetic energy, increasing the mixture’s velocity. The cross-sectional area of the nozzle can be circular, rectangular, square, or oval. A circular cross-sectional nozzle has been developed for high velocity, precise etching, and patterning on difficult-to-machine materials such as steel alloys. A circular cross-sectional micro-nozzle with a large aspect ratio is proposed, and the flow characteristics and cutting performance are examined precisely by the experiment. Efforts are being made to make machining processes sustainable, productive, and efficient. Here, the Taguchi-grey relational analysis integration approach has been used to analyze the machining parameters such as air pressure, stand-off distance, and abrasive mesh size (AMS). The top hole diameter, bottom hole diameter, material removal rate, and radial overcut are the response variables in this investigation. Analysis of variance (ANOVA) results showed that the AMS was the most efficient parameter, which followed the processing condition on the total input of the multi-purpose function. The reported optimized process parameters are air pressure of 8 bar, stand-off distance of 2 mm, and AMS mix (50%+100%) micron, which significantly affects the top and bottom micro-hole diameters.","PeriodicalId":129806,"journal":{"name":"Journal of Micromanufacturing","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114236001","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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