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Picosecond fiber laser was subjected on surface of ductile cast iron to induce graphene-like micro-texture array and enhance the tribological properties. The size of the dimples was regulated in the range of 5 μm–110 μm. The in-situ fabrication process was carried out on the workpiece surface in parallel manner and the scanning speed can be up to 3 m/s. The formation mechanism of graphene-like structure was analyzed. The tribological properties of the textured samples were investigated using a ball-on-disk tribometer. The results showed that the laser textured samples exhibit low coefficient of friction and the anti-wear properties were improved significantly. The textured sample showed no distinct wear pit, while the non-textured sample showed typical wear pit with depth up to 15 μm. Volume wear rate was reduced by 69.6 ± 6.9%. The graphene-like micro-texture array conducted by picosecond fiber laser scanning will not change the material isotropic, and the improved tribological properties are attributed to the combined effects of the increased surface hardness, improved heat dispersion property and entrapment of wear debris.
Zhiwen Wang; Weicheng Liu; Wei Yuan; Jianchen Cong; Prakash Chander; Linda Yongling Wu; Hongyu Zheng. The effect of laser in-situ induced graphene-like micro-texture on the friction and wear properties of ductile cast iron. Journal of Materials Research and Technology 2021, 12, 2407 -2413.
AMA StyleZhiwen Wang, Weicheng Liu, Wei Yuan, Jianchen Cong, Prakash Chander, Linda Yongling Wu, Hongyu Zheng. The effect of laser in-situ induced graphene-like micro-texture on the friction and wear properties of ductile cast iron. Journal of Materials Research and Technology. 2021; 12 ():2407-2413.
Chicago/Turabian StyleZhiwen Wang; Weicheng Liu; Wei Yuan; Jianchen Cong; Prakash Chander; Linda Yongling Wu; Hongyu Zheng. 2021. "The effect of laser in-situ induced graphene-like micro-texture on the friction and wear properties of ductile cast iron." Journal of Materials Research and Technology 12, no. : 2407-2413.
It is indicated that a certain RGB color can be obtained by specific processing parameters in Laser Color Marking (LCM). However, these parameters do not necessarily provide the same color in different laser systems. In most of the conducted studies on LCM, the focus is on the oxide layer formation mechanism, reflectance spectra, composition, and thickness of the oxide layer, which are ultimately controlled by various factors such as laser processing parameters, sample substrate properties, and ambient conditions. However, there is a lack of study on the quantitative relationship between processing parameters (as the main influential factor) and the produced RGB color in LCM. In this work, for the first time, we propose a method to quantitatively match the processing parameters and the RGB colors in LCM using the artificial neural network (ANN). In this regard, two models have been developed based on experimental data to predict the resultant RGB color and the proper processing parameters for a desired color, respectively. The results show that the ANN has a superior ability to model the behavior of LCM in the fabrication of RGB colors in different laser systems. It is demonstrated that the ANN model can be employed to improve the color consistency and repeatability in LCM without the need of trial and error.
Ali Naderi Bakhtiyari; Zhiwen Wang; Hongyu Zheng. Feasibility of artificial neural network on modeling laser-induced colors on stainless steel. Journal of Manufacturing Processes 2021, 65, 471 -477.
AMA StyleAli Naderi Bakhtiyari, Zhiwen Wang, Hongyu Zheng. Feasibility of artificial neural network on modeling laser-induced colors on stainless steel. Journal of Manufacturing Processes. 2021; 65 ():471-477.
Chicago/Turabian StyleAli Naderi Bakhtiyari; Zhiwen Wang; Hongyu Zheng. 2021. "Feasibility of artificial neural network on modeling laser-induced colors on stainless steel." Journal of Manufacturing Processes 65, no. : 471-477.
In the present research work, an effort has been made to explore the potential of using the adhesive tapes while drilling CFRPs. The input parameters, such as drill bit diameter, point angle, Scotch tape layers, spindle speed, and feed rate have been studied in response to thrust force, torque, circularity, diameter error, surface roughness, and delamination occurring during drilling. It has been found that the increase in point angle increased the delamination, while increase in Scotch tape layers reduced delamination. The surface roughness decreased with the increase in drill diameter and point angle, while it increased with the speed, feed rate, and tape layer. The best low roughness was obtained at 6 mm diameter, 130° point angle, 0.11 mm/rev feed rate, and 2250 rpm speed at three layers of Scotch tape. The circularity error initially increased with drill bit diameter and point angle, but then decreased sharply with further increase in the drill bit diameter. Further, the circularity error has non-linear behavior with the speed, feed rate, and tape layer. Low circularity error has been obtained at 4 mm diameter, 118° point angle, 0.1 mm/rev feed rate, and 2500 RPM speed at three layers of Scotch tape. The low diameter error has been obtained at 6 mm diameter, 130° point angle, 0.12 mm/rev feed rate, and 2500 rpm speed at three layer Scotch tape. From the optical micro-graphs of drilled holes, it has been found that the point angle is one of the most effective process parameters that significantly affects the delamination mechanism, followed by Scotch tape layers as compared to other parameters such as drill bit diameter, spindle speed, and feed rate.
Chander Prakash; Alokesh Pramanik; Animesh Basak; Yu Dong; Sujan Debnath; Subramaniam Shankar; Sunpreet Singh; Linda Wu; Hongyu Zheng. Investigating the Efficacy of Adhesive Tape for Drilling Carbon Fibre Reinforced Polymers. Materials 2021, 14, 1699 .
AMA StyleChander Prakash, Alokesh Pramanik, Animesh Basak, Yu Dong, Sujan Debnath, Subramaniam Shankar, Sunpreet Singh, Linda Wu, Hongyu Zheng. Investigating the Efficacy of Adhesive Tape for Drilling Carbon Fibre Reinforced Polymers. Materials. 2021; 14 (7):1699.
Chicago/Turabian StyleChander Prakash; Alokesh Pramanik; Animesh Basak; Yu Dong; Sujan Debnath; Subramaniam Shankar; Sunpreet Singh; Linda Wu; Hongyu Zheng. 2021. "Investigating the Efficacy of Adhesive Tape for Drilling Carbon Fibre Reinforced Polymers." Materials 14, no. 7: 1699.
Laser direct fabrication of metallic mesh is a very promising structure for the next-generation transparent electrodes due to its outstanding optical and electrical properties. However, photoelectric properties and morphologies of the metallic mesh electrodes are not excellent after Gaussian pulse laser writing technology, which largely restricts the development of laser direct ablation process for the fabrication of high-quality transparent electrodes. In this study, we present newly developed copper mesh transparent electrode by spatially modulated one-step top-flat square nanosecond laser direct writing ablation of Cu film under ambient conditions. The copper square shaped electrode without outward radial mass transfer of molten metal, and no structural deformation and damage on the edge of metallic meshes. The clean square shaped of copper meshes structure not only shows high optical transparency in visual region and excellent a filtration in NIR regions, but also presents electrothermogenic of conductive copper mesh. In addition, the clean square shaped of copper mesh electrode on glass was demonstrated enhanced thermal shielding efficiency and defrost test as the smart windows.
Qingwei Zhang; Donglin Huang; Dongfeng Qi; Wenju Zhou; Letian Wang; Zifeng Zhang; Songyan Chen; Shixun Dai; Hongyu Zheng. Mask-free patterning of Cu mesh as smart windows by spatially modulated nanosecond laser pulses. Optics & Laser Technology 2021, 140, 107056 .
AMA StyleQingwei Zhang, Donglin Huang, Dongfeng Qi, Wenju Zhou, Letian Wang, Zifeng Zhang, Songyan Chen, Shixun Dai, Hongyu Zheng. Mask-free patterning of Cu mesh as smart windows by spatially modulated nanosecond laser pulses. Optics & Laser Technology. 2021; 140 ():107056.
Chicago/Turabian StyleQingwei Zhang; Donglin Huang; Dongfeng Qi; Wenju Zhou; Letian Wang; Zifeng Zhang; Songyan Chen; Shixun Dai; Hongyu Zheng. 2021. "Mask-free patterning of Cu mesh as smart windows by spatially modulated nanosecond laser pulses." Optics & Laser Technology 140, no. : 107056.
Amid bone grinding, a part of the hard tissue (i.e. bone) is usually removed to gain clearer operative excess to the tumours present beneath the bone. The tool wear and tool loading influence the thermal as well as mechanical conditions of surgery. The rise in temperature during osteotomy may cause severe consequence like thermogenesis and damage to optic nerves, cervical, and sciatic nerves. Therefore, the present study has been carried out to investigate the burr wear with different shaped grinding burrs. The burr wear is characterized in terms of burr loading, dislodging and fracture in abrasives. The burr loading is further quantified on the amount of bone adhered over the surface of the burr. The results of surface characterization revealed that minimum wear occurred in case of convex shape burr whereas cylindrical burr caused the highest wear in terms of abrasive fragmentation, dislodging, and wear flats. The minimum percentage of weight reduction observed with the convex burr i.e., 1.68% including 0.4196 g weight of dislodged abrasive (Wab) and corresponding burr loading is observed as 0.1464 g. The maximum burr loading was seen in the case of the spherical burr (Wb) i.e. 0.5907 g.
Atul Babbar; Vivek Jain; Dheeraj Gupta; Deepak Agrawal; Chander Prakash; Sunpreet Singh; Linda Yongling Wu; H.Y. Zheng; Grzegorz Królczyk; Marta Bogdan-Chudy. Experimental analysis of wear and multi-shape burr loading during neurosurgical bone grinding. Journal of Materials Research and Technology 2021, 12, 15 -28.
AMA StyleAtul Babbar, Vivek Jain, Dheeraj Gupta, Deepak Agrawal, Chander Prakash, Sunpreet Singh, Linda Yongling Wu, H.Y. Zheng, Grzegorz Królczyk, Marta Bogdan-Chudy. Experimental analysis of wear and multi-shape burr loading during neurosurgical bone grinding. Journal of Materials Research and Technology. 2021; 12 ():15-28.
Chicago/Turabian StyleAtul Babbar; Vivek Jain; Dheeraj Gupta; Deepak Agrawal; Chander Prakash; Sunpreet Singh; Linda Yongling Wu; H.Y. Zheng; Grzegorz Królczyk; Marta Bogdan-Chudy. 2021. "Experimental analysis of wear and multi-shape burr loading during neurosurgical bone grinding." Journal of Materials Research and Technology 12, no. : 15-28.
Investigation of the selective laser melting (SLM) process, using finite element method, to understand the influences of laser power and scanning speed on the heat flow and melt-pool dimensions is a challenging task. Most of the existing studies are focused on the study of thin layer thickness and comparative study of same materials under different manufacturing conditions. The present work is focused on comparative analysis of thermal cycles and complex melt-pool behavior of a high layer thickness multi-layer laser additive manufacturing (LAM) of pure Titanium (Ti) and Inconel 718. A transient 3D finite-element model is developed to perform a quantitative comparative study on two materials to examine the temperature distribution and disparities in melt-pool behaviours under similar processing conditions. It is observed that the layers are properly melted and sintered for the considered process parameters. The temperature and melt-pool increases as laser power move in the same layer and when new layers are added. The same is observed when the laser power increases, and opposite is observed for increasing scanning speed while keeping other parameters constant. It is also found that Inconel 718 alloy has a higher maximum temperature than Ti material for the same process parameter and hence higher melt-pool dimensions.
Sapam Ningthemba Singh; Sohini Chowdhury; Yadaiah Nirsanametla; Anil Kumar Deepati; Chander Prakash; Sunpreet Singh; Linda Yongling Wu; Hongyu Y. Zheng; Catalin Pruncu. A Comparative Analysis of Laser Additive Manufacturing of High Layer Thickness Pure Ti and Inconel 718 Alloy Materials Using Finite Element Method. Materials 2021, 14, 876 .
AMA StyleSapam Ningthemba Singh, Sohini Chowdhury, Yadaiah Nirsanametla, Anil Kumar Deepati, Chander Prakash, Sunpreet Singh, Linda Yongling Wu, Hongyu Y. Zheng, Catalin Pruncu. A Comparative Analysis of Laser Additive Manufacturing of High Layer Thickness Pure Ti and Inconel 718 Alloy Materials Using Finite Element Method. Materials. 2021; 14 (4):876.
Chicago/Turabian StyleSapam Ningthemba Singh; Sohini Chowdhury; Yadaiah Nirsanametla; Anil Kumar Deepati; Chander Prakash; Sunpreet Singh; Linda Yongling Wu; Hongyu Y. Zheng; Catalin Pruncu. 2021. "A Comparative Analysis of Laser Additive Manufacturing of High Layer Thickness Pure Ti and Inconel 718 Alloy Materials Using Finite Element Method." Materials 14, no. 4: 876.
This study describes the effect of magnetorheological fluid assisted magnetic abrasive finishing (MRAF) process on the surface topography of fine finished high strength biomedical grade β-phase Ti–Nb–Ta–Zr (β-TNTZ) alloy for orthopedic applications. β-type Ti–35Nb–7Ta–5Zr alloy exhibit high strength, better corrosion resistance and excellent bioactivity in comparison with Ti–6Al–4V alloy. The topographic features of finished surfaces (including surface roughness, skewness, and kurtosis), percentage change in surface roughness, and material removal have been studied to understand the influence of MRAF processing parameters, such as carbonyl iron particles proportion, diamond abrasive particles proportion, rotational speed of the abrasive tool, and work gap between workpiece and abrasive tool. Furthermore, MRAF finishing has been conducted using raster and spiral strategies. The topographic characteristics of the finished surfaces have been measured using a noncontact three-dimensional Surface Profilometer and atomic force microscopy. The results of the study showed that all the input process parameters have strongly influenced the surface characteristics in both quantitative (material removal) and qualitative measures (Surface roughness). The β-TNTZ have possed excellent bio-mechanical properties such as high compressive strength (1195 MPa), micro-hardness (515 HV), corrosion resistance, and excellent bioactivity. The best optimal condition to obtain lowest SR (9 nm) and highest MR (65 mg) was obtained in the case of rater path finishing strategy at CIP – 40%vol., Dv – 3.5%vol., Nt – 900 rpm, and Gp – 1 mm. The maximum percentage change in surface roughness (%ΔRa) was measured around 97.68% and 93.27% in raster and spiral path strategy, respectively. The minimum surface finish ranging about 9 nm has been achieved through the MRAF process. Further, the raster path strategy has been found more effective in producing negative skewness (Ssk), kurtosis (Sku) value less than 3, and minimum number of peaks density (Spd). The overall results of the study suggested that MRAF of β-TNTZ alloy is a good solution for obtaining fine-finished orthopedic devices while sustaining their tribological and wear properties.
Chander Prakash; Sunpreet Singh; Alokesh Pramanik; Animesk Basak; Grzegorz Królczyk; Marta Bogdan-Chudy; Yongling Linda Wu; H.Y. Zheng. Experimental investigation into nano-finishing of β-TNTZ alloy using magnetorheological fluid magnetic abrasive finishing process for orthopedic applications. Journal of Materials Research and Technology 2021, 11, 600 -617.
AMA StyleChander Prakash, Sunpreet Singh, Alokesh Pramanik, Animesk Basak, Grzegorz Królczyk, Marta Bogdan-Chudy, Yongling Linda Wu, H.Y. Zheng. Experimental investigation into nano-finishing of β-TNTZ alloy using magnetorheological fluid magnetic abrasive finishing process for orthopedic applications. Journal of Materials Research and Technology. 2021; 11 ():600-617.
Chicago/Turabian StyleChander Prakash; Sunpreet Singh; Alokesh Pramanik; Animesk Basak; Grzegorz Królczyk; Marta Bogdan-Chudy; Yongling Linda Wu; H.Y. Zheng. 2021. "Experimental investigation into nano-finishing of β-TNTZ alloy using magnetorheological fluid magnetic abrasive finishing process for orthopedic applications." Journal of Materials Research and Technology 11, no. : 600-617.
Laser-induced graphene (LIG) is an emerging technique for producing few-layer graphene or graphene-like material that has recently received increasing attention, due to its unique advantages. Subsequently, a variety of lasers and materials have been used to fabricate LIG using this technique. However, there is a lack of understanding of how different lasers (wavelengths) perform differently in the LIG conversion process. In this study, the produced LIG on polyimide (PI) under a locally water-cooled condition using a 10.6 μm CO2 infrared laser and a 355 nm ultraviolet (UV) laser are compared. The experimental investigations reveal that under the same UV and CO2 laser fluence, the ablation of PI show different results. Surface morphologies with micron-sized and nanometer pores were formed by the UV laser under different laser fluences, whereas micron-sized pores and sheet structure with fewer pores were produced by the CO2 laser. Energy dispersive spectrometry and three-dimensional topography characterization indicate that the photochemical effects were also involved in the LIG conversion with UV laser irradiation. It is also observed through experiments that the photothermal effect contributed to the formation of LIG under both lasers, and the LIG formed on PI substrates by the CO2 laser showed better quality and fewer layers.
Liyong Wang; Zhiwen Wang; Ali Bakhtiyari; Hongyu Zheng. A Comparative Study of Laser-Induced Graphene by CO2 Infrared Laser and 355 nm Ultraviolet (UV) Laser. Micromachines 2020, 11, 1094 .
AMA StyleLiyong Wang, Zhiwen Wang, Ali Bakhtiyari, Hongyu Zheng. A Comparative Study of Laser-Induced Graphene by CO2 Infrared Laser and 355 nm Ultraviolet (UV) Laser. Micromachines. 2020; 11 (12):1094.
Chicago/Turabian StyleLiyong Wang; Zhiwen Wang; Ali Bakhtiyari; Hongyu Zheng. 2020. "A Comparative Study of Laser-Induced Graphene by CO2 Infrared Laser and 355 nm Ultraviolet (UV) Laser." Micromachines 11, no. 12: 1094.
Laser beam machining (LBM) as an efficient tool for material removal has attracted the attention of manufacturing industries. Accordingly, there is a great motivation in the modeling and optimization of this non-conventional machining process. In this paper, the focus is on the most common LBM process, including cutting, grooving, turning, milling, and drilling. The development of an accurate model between the input and output variables of the LBM process is difficult and complex due to the non-linear behavior of the process under various conditions. In the case of LBM, the input variables are system, material, and process parameters, and the output variables are the quality characteristics of laser machined workpiece, including geometry characteristics, metallurgical characteristics, surface roughness, and material removal rate (MRR). Recently, among computational methods, artificial intelligence (AI) has been studied by scientists as a pioneer in the field of modeling and optimizing quality features of LBM. AI techniques utilize the empirical findings and existing knowledge for modeling, optimization, monitoring, and controlling of the LBM process. In this paper, the applications of AI techniques, including artificial neural network (ANN), fuzzy logic (FL), metaheuristic optimization algorithms, and hybrid approaches in modeling and optimization of the quality characteristics of LBM are reviewed. It is shown that AI techniques are successfully capable of predicting and improving the features of the laser machined workpiece. It is also demonstrated that AI can be used as a powerful tool to obtain a comprehensive model and optimal setting parameters of LBM. In addition, according to the potential and capability of AI techniques, several ideas have been offered for future studies.
Ali Naderi Bakhtiyari; Zhiwen Wang; Liyong Wang; Hongyu Zheng. A review on applications of artificial intelligence in modeling and optimization of laser beam machining. Optics & Laser Technology 2020, 135, 106721 .
AMA StyleAli Naderi Bakhtiyari, Zhiwen Wang, Liyong Wang, Hongyu Zheng. A review on applications of artificial intelligence in modeling and optimization of laser beam machining. Optics & Laser Technology. 2020; 135 ():106721.
Chicago/Turabian StyleAli Naderi Bakhtiyari; Zhiwen Wang; Liyong Wang; Hongyu Zheng. 2020. "A review on applications of artificial intelligence in modeling and optimization of laser beam machining." Optics & Laser Technology 135, no. : 106721.
This paper focusses on understanding laser-NBR rubber interactions in particular the effect of laser wavelength and pulse width on material removal and thermal damage. Three lasers with wavelengths at 355 nm, 795 nm and 1064 nm and pulse duration at 30 ns, 10 ps and 130 fs, respectively, have been investigated for their optical absorption, heat conduction and their material removal mechanisms in high aspect ratio drilling of NBR rubber. It is interesting to find that under certain conditions, the ultrashort pulse lasers (both the femtosecond and picosecond lasers) did not lead to better results than the nanosecond UV laser in drilling hole profile (straightness and thermal damage), aspect ratio and amount of the ablated material re-deposition on the substrate surfaces. The results implied that there is heat conduction and thermal damage even with ultrashort laser pulses when the processing conditions are not appropriate. Firing laser pulses intermittently was shown to reduce thermal accumulation. Experimental studies showed that the 355-nm Nd:YAG laser (UV laser) achieved higher material removal rate with high aspect ratio as compared to the ultrashort laser pulses in drilling the NBR substrates.
Juan Carlos Hernandez-Castaneda; Hui Guang Lim; Yin Chi Wan; Hongyu Zheng. An experimental investigation of laser drilling nitrile butadine (NBR) rubber. The International Journal of Advanced Manufacturing Technology 2020, 108, 1139 -1152.
AMA StyleJuan Carlos Hernandez-Castaneda, Hui Guang Lim, Yin Chi Wan, Hongyu Zheng. An experimental investigation of laser drilling nitrile butadine (NBR) rubber. The International Journal of Advanced Manufacturing Technology. 2020; 108 (4):1139-1152.
Chicago/Turabian StyleJuan Carlos Hernandez-Castaneda; Hui Guang Lim; Yin Chi Wan; Hongyu Zheng. 2020. "An experimental investigation of laser drilling nitrile butadine (NBR) rubber." The International Journal of Advanced Manufacturing Technology 108, no. 4: 1139-1152.
This study explores the feasibility of different laser systems to sinter screen-printed lines from nonconductive copper nanoparticles (Cu NPs) on polyethylene terephthalate polymer film. These materials are commonly used in manufacturing functional printed electronics for large-area applications. Here, optical and thermal characterization of the materials is conducted to identify suitable laser sources and process conditions. Direct diode (808 nm), Nd:YAG (1064 nm and second harmonic of 532 nm), and ytterbium fiber (1070 nm) lasers are explored. Optimal parameters for sintering the Cu NPs are identified for each laser system, which targets low resistivity and high processing speed. Finally, the quality of the sintered tracks is quantified, and the laser sintering mechanisms observed under different wavelengths are analyzed. Practical considerations are discussed to improve the laser sintering process of Cu NPs.
Juan Carlos Hernandez-Castaneda; Boon Keng Lok; Hongyu Zheng. Laser sintering of Cu nanoparticles on PET polymer substrate for printed electronics at different wavelengths and process conditions. Frontiers of Mechanical Engineering 2019, 15, 303 -318.
AMA StyleJuan Carlos Hernandez-Castaneda, Boon Keng Lok, Hongyu Zheng. Laser sintering of Cu nanoparticles on PET polymer substrate for printed electronics at different wavelengths and process conditions. Frontiers of Mechanical Engineering. 2019; 15 (2):303-318.
Chicago/Turabian StyleJuan Carlos Hernandez-Castaneda; Boon Keng Lok; Hongyu Zheng. 2019. "Laser sintering of Cu nanoparticles on PET polymer substrate for printed electronics at different wavelengths and process conditions." Frontiers of Mechanical Engineering 15, no. 2: 303-318.
Weight reduction of parts is of great importance in automotive and aerospace industries. Laser direct joining of dissimilar materials had been investigated previously to obtain lightweight characteristics and keep the local excellent plasticity and mechanical property. In the present work, the authors adopt the hybrid laser joining method to bond Ti6Al4V and polyamide (PA66). Laser texturing pretreatment is performed on the Ti6Al4V surface prior to the laser joining process. Oblique microgrooves with the depth ranging from 100 to 550 μm are designed and fabricated on Ti6Al4V surfaces to improve the bonding strength between Ti6Al4V and polyamide. Single lap shear tests are carried out after the laser joining process. The highest breaking force of laser joined Ti6Al4V-PA66 joints reaches around 942 N, which is high up to more than 90% of base PA66 breaking force (1043 N) and about 4.9 times of the joints with a smooth Ti6Al4V surface (194 N). The great enhancement of breaking force of the joints is attributed to the strong mechanical bonding quality between PA66 and surface-textured Ti6Al4V. The employed hybrid laser joining method shows great potential in manufacturing industries.Weight reduction of parts is of great importance in automotive and aerospace industries. Laser direct joining of dissimilar materials had been investigated previously to obtain lightweight characteristics and keep the local excellent plasticity and mechanical property. In the present work, the authors adopt the hybrid laser joining method to bond Ti6Al4V and polyamide (PA66). Laser texturing pretreatment is performed on the Ti6Al4V surface prior to the laser joining process. Oblique microgrooves with the depth ranging from 100 to 550 μm are designed and fabricated on Ti6Al4V surfaces to improve the bonding strength between Ti6Al4V and polyamide. Single lap shear tests are carried out after the laser joining process. The highest breaking force of laser joined Ti6Al4V-PA66 joints reaches around 942 N, which is high up to more than 90% of base PA66 breaking force (1043 N) and about 4.9 times of the joints with a smooth Ti6Al4V surface (194 N). The great enhancement of breaking force of the joints is attribut...
Haipeng Wang; Wenhe Feng; Zhen Zhang; Yingchun Guan; Hongyu Zheng. Hybrid laser technique for joining of polymer and titanium alloy. Journal of Laser Applications 2019, 31, 042017 .
AMA StyleHaipeng Wang, Wenhe Feng, Zhen Zhang, Yingchun Guan, Hongyu Zheng. Hybrid laser technique for joining of polymer and titanium alloy. Journal of Laser Applications. 2019; 31 (4):042017.
Chicago/Turabian StyleHaipeng Wang; Wenhe Feng; Zhen Zhang; Yingchun Guan; Hongyu Zheng. 2019. "Hybrid laser technique for joining of polymer and titanium alloy." Journal of Laser Applications 31, no. 4: 042017.
We propose a method to use laser to pattern a 6.6 μm-thick Ag back electrode layer on electroluminescence (EL) film to electrically isolate designated regions towards the functionality of selective lighting. The laser processing system employs a 20 W, 1064 nm wavelength, nanosecond-pulsed, master oscillator power amplifier (MOPA) fibre laser as the laser source. A dynamic focusing configuration is adopted as a replacement of conventional telecentric lens setup for beam focusing and delivery, with a focal spot size of 33 μm and a speed as high as 3 m/s. The effects of processing parameters on ablated channel width, depth, quality, elemental composition and electrical isolation are investigated. It is found that a higher deposited laser energy causes kerf width and depth, as well as isolation reproducibility to increase, at a cost of increased chance of damage to surrounding electrode and substrate layer. Based on the findings, a processing recipe is established to isolate Ag electrode by producing channels as narrow as (41.3 ± 0.8) μm without introducing collateral damage to the film. Using selected parameter combinations from the processing window, the uniformity of laser ablation over a 300 × 200 mm2 scanning area is examined. Finally, using the raster scanning method, selective lighting over a designated area of 295 × 180 mm2 is demonstrated.
Wenhe Feng; Ju Nie Tey; Yin Chi Wan; Xuechuan Shan; Hongyu Zheng. Laser patterning of printed silver for selective lighting of electroluminescence film. Journal of Manufacturing Processes 2019, 38, 445 -452.
AMA StyleWenhe Feng, Ju Nie Tey, Yin Chi Wan, Xuechuan Shan, Hongyu Zheng. Laser patterning of printed silver for selective lighting of electroluminescence film. Journal of Manufacturing Processes. 2019; 38 ():445-452.
Chicago/Turabian StyleWenhe Feng; Ju Nie Tey; Yin Chi Wan; Xuechuan Shan; Hongyu Zheng. 2019. "Laser patterning of printed silver for selective lighting of electroluminescence film." Journal of Manufacturing Processes 38, no. : 445-452.
Additive manufacturing (AM) has become more prominent in leading industries. Recently, there have been intense efforts to achieve a fully functional 3D structural electronic device by integrating conductive structures into AM parts. Here, we introduce a simple approach to creating a conductive layer on a polymer AM part by CO2 laser processing. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy were employed to analyze laser-induced modifications in surface morphology and surface chemistry. The results suggest that conductive porous graphene was obtained from the AM-produced carbon precursor after the CO2 laser scanning. At a laser power of 4.5 W, the lowest sheet resistance of 15.9 Ω/sq was obtained, indicating the excellent electrical conductivity of the laser-induced graphene (LIG). The conductive graphene on the AM parts could serve as an electrical interconnection and shows a potential for the manufacturing of electronics components. An interdigital electrode capacitor was written on the AM parts to demonstrate the capability of LIG. Cyclic voltammetry, galvanostatic charge-discharge, and cyclability testing demonstrated good electrochemical performance of the LIG capacitor. These findings may create opportunities for the integration of laser direct writing electronic and additive manufacturing.
Lishi Jiao; Zhong Yang Chua; Seung Ki Moon; Jie Song; Guijun Bi; Hongyu Zheng; Byunghoon Lee; Jamyeong Koo. Laser-Induced Graphene on Additive Manufacturing Parts. Nanomaterials 2019, 9, 90 .
AMA StyleLishi Jiao, Zhong Yang Chua, Seung Ki Moon, Jie Song, Guijun Bi, Hongyu Zheng, Byunghoon Lee, Jamyeong Koo. Laser-Induced Graphene on Additive Manufacturing Parts. Nanomaterials. 2019; 9 (1):90.
Chicago/Turabian StyleLishi Jiao; Zhong Yang Chua; Seung Ki Moon; Jie Song; Guijun Bi; Hongyu Zheng; Byunghoon Lee; Jamyeong Koo. 2019. "Laser-Induced Graphene on Additive Manufacturing Parts." Nanomaterials 9, no. 1: 90.
The short pulse duration of a picosecond laser (ps) leads to high peak power and ablates materials with much reduced thermal effects. Commercial ps lasers generate high-repetition-rate pulses and become more accepted as a major tool for material removal applications. However, most of the commercial ps lasers emit pulses at infrared (IR) wavelengths with photon energy close to the Si band gap energy of 1.1 eV. The corresponding optical absorption coefficient is low. To improve the laser beam absorption in Si, several methods have been investigated. For instance, it is reported that the material removal efficiency has been improved by raising the substrate temperatures during laser drilling due to the enhancement of the Si absorption coefficient. However, such approach may result in reduction in machining accuracy due to thermal expansion of the substrate. In this paper, we propose a new method by applying a direct current (DC) across a silicon substrate during the ps laser drilling process. The externally applied voltage potential would lead to more aligned movement of free electrons and therefore increase electrical current flow in the silicon substrate. The hypothesis of this study is that more free electrons are made available in the Si substrate for collisions with the laser photons, which increases the Si absorption coefficient of the laser beam. It was found that the material removal is markedly improved with the assistance of the electrical current flow. The entrance hole diameter increased by 14% and the exit hole diameter increased by 90% when the current in the Si substrate was subjected to a fixed current of 0.5 A. However, a larger amount of material debris covering an enlarged surface area was observed under the applied DC voltage. The possible reasons for such observations are discussed based on the enhanced laser energy absorption as the result of the presence of electrical current in the Si substrate.
Lishi Jiao; Hongyu Zheng; Yilei Zhang; Eddie Yin Kwee Ng. Picosecond laser drilling of silicon with applied voltage. SN Applied Sciences 2018, 1, 80 .
AMA StyleLishi Jiao, Hongyu Zheng, Yilei Zhang, Eddie Yin Kwee Ng. Picosecond laser drilling of silicon with applied voltage. SN Applied Sciences. 2018; 1 (1):80.
Chicago/Turabian StyleLishi Jiao; Hongyu Zheng; Yilei Zhang; Eddie Yin Kwee Ng. 2018. "Picosecond laser drilling of silicon with applied voltage." SN Applied Sciences 1, no. 1: 80.
We investigate the effect of micro/nano hybrid structures in cemented tungsten carbide with a focus on optical absorption enhancement. Distinct micro/nano hybrid structures, including regular LIPSS, semi-continuous nano-bumps and nanoscale to microscale protrusions, were induced on WC-Co alloy by picosecond laser irradiation, and reflectance performances of these controllable hybrid structures were compared. We provide insight into mechanisms responsible for protrusion formation by associating hydrodynamic instabilities of molten materials during laser irradiation. Spectral reflectance measurement reveals significant reduction of optical reflectance at laser-treated surfaces in visible wavelength range. The laser induced hybrid structures on WC-Co alloy show potential applications for solar photo-thermal conversion. Investigations of morphology evolution and reflectance performance pave the way for functional surface design via surface structuring process.
H.P. Wang; Y.C. Guan; Hongyu Zheng; M.H. Hong. Controllable fabrication of metallic micro/nano hybrid structuring surface for antireflection by picosecond laser direct writing. Applied Surface Science 2018, 471, 347 -354.
AMA StyleH.P. Wang, Y.C. Guan, Hongyu Zheng, M.H. Hong. Controllable fabrication of metallic micro/nano hybrid structuring surface for antireflection by picosecond laser direct writing. Applied Surface Science. 2018; 471 ():347-354.
Chicago/Turabian StyleH.P. Wang; Y.C. Guan; Hongyu Zheng; M.H. Hong. 2018. "Controllable fabrication of metallic micro/nano hybrid structuring surface for antireflection by picosecond laser direct writing." Applied Surface Science 471, no. : 347-354.
Laser machining in the nanosecond pulse regime utilises the heat induced by laser irradiation to ablate solid material, however the heat-driven ablation is very often accompanied with adverse effects such as oxidation, debris recast and burr formation. An effective technique invented to minimise these effects was underwater laser machining. In this study, we present a multi-scan laser machining process on a copper sample immersed under flowing water with a secured upper surface. The results show that channels with smaller heat affected zone (HAZ), less debris recast and minimal burr can be produced by this process. By applying multi-scan machining, channels with up to 275 µm depth, 13–22° taper angle and 1.30–6.95 µm roughness Sa were produced. Moreover, empirical models relating the processing parameters to channels’ characteristics were derived using polynomial regression (PR) analysis and a machine learning algorithm, Gaussian process regression (GPR), after which their performances in the prediction of the channels’ characteristics were validated.
Wenhe Feng; Jiang Guo; Wenjin Yan; Yin Chi Wan; Hongyu Zheng. Deep channel fabrication on copper by multi-scan underwater laser machining. Optics & Laser Technology 2018, 111, 653 -663.
AMA StyleWenhe Feng, Jiang Guo, Wenjin Yan, Yin Chi Wan, Hongyu Zheng. Deep channel fabrication on copper by multi-scan underwater laser machining. Optics & Laser Technology. 2018; 111 ():653-663.
Chicago/Turabian StyleWenhe Feng; Jiang Guo; Wenjin Yan; Yin Chi Wan; Hongyu Zheng. 2018. "Deep channel fabrication on copper by multi-scan underwater laser machining." Optics & Laser Technology 111, no. : 653-663.
In this investigation, a picosecond laser was employed to fabricate surface textures on a Stavax steel substrate, which is a key material for mold fabrication in the manufacturing of various polymer products. Three main types of surface textures were fabricated on a Stavax steel substrate: periodic sub-micron ripples, a hierarchical two-dimensional array of micro-bumps, and micro-pits with nano-ripples. The wettability of the laser-textured Stavax steel surface was converted from its original hydrophilicity into hydrophobicity and even super-hydrophobicity after exposure to air. The results clearly show that this super-hydrophobicity is mainly due to the surface textures. The ultrafast laser-induced catalytic effect may play a secondary role in modifying the surface chemistry so as to lower the surface energy. The laser-induced surface textures on the metal mold substrates were then replicated onto polypropylene substrates via the polymer injection molding process. The surface wettability of the molded polypropylene was found to be changed from the original hydrophilicity to super-hydrophobicity. This developed process holds the potential to improve the performance of fabricated plastic products in terms of wettability control and easy cleaning.
Xincai Wang; Hongyu Zheng; Yinchi Wan; Wenhe Feng; Yee Cheong Lam. Picosecond Laser Surface Texturing of a Stavax Steel Substrate for Wettability Control. Engineering 2018, 4, 816 -821.
AMA StyleXincai Wang, Hongyu Zheng, Yinchi Wan, Wenhe Feng, Yee Cheong Lam. Picosecond Laser Surface Texturing of a Stavax Steel Substrate for Wettability Control. Engineering. 2018; 4 (6):816-821.
Chicago/Turabian StyleXincai Wang; Hongyu Zheng; Yinchi Wan; Wenhe Feng; Yee Cheong Lam. 2018. "Picosecond Laser Surface Texturing of a Stavax Steel Substrate for Wettability Control." Engineering 4, no. 6: 816-821.
Optimization for heat dissipation plays a significant role in energy saving and high-efficiency utilizing of integrated electronics. In this paper, we present a study of micro structuring on polymer-based flexible substrate coupled with aluminum-alloy heat sink. The heat dissipation performance was investigated by temperature evolution of a heat sink under natural convection by infrared (IR) camera, and results showed that the heat dissipation enhancement could be up to 25%. Moreover, the heat dissipation performance of a typical heat sink in terms of light-emitting diode (LED) hip was investigated via both thermal transient measurement and the finite element analysis (FEA). The maximum LED chip temperature of the laser-textured heat sink was approximately 22.4% lower than that of the as-received heat sink. We propose that these properties accompanied with the simplicity of fabrication make laser surface texturing a promising candidate for on-chip thermal management applications in electronics.
Libin Lu; Zhen Zhang; Yingchun Guan; Hongyu Zheng. Enhancement of Heat Dissipation by Laser Micro Structuring for LED Module. Polymers 2018, 10, 886 .
AMA StyleLibin Lu, Zhen Zhang, Yingchun Guan, Hongyu Zheng. Enhancement of Heat Dissipation by Laser Micro Structuring for LED Module. Polymers. 2018; 10 (8):886.
Chicago/Turabian StyleLibin Lu; Zhen Zhang; Yingchun Guan; Hongyu Zheng. 2018. "Enhancement of Heat Dissipation by Laser Micro Structuring for LED Module." Polymers 10, no. 8: 886.
With the recent expansion of additive manufacturing (AM) in industries, there is an intense need to improve the surface quality of AM parts. A functional surface with extreme wettability would explore the application of AM in medical implants and microfluid. In this research, we propose to superimpose the femtosecond (fs) laser induced period surface structures (LIPSS) in the nanoscale onto AM part surfaces with the micro structures that are fabricated in the AM process. A hierarchical structure that has a similar morphology to a lotus leaf surface is obtained by combining the advantages of liquid assisting fs laser processing and AM. A water contact angle (WCA) of 150° is suggested so that a super hydrophobic surface is achieved. The scanning electron microscopy (SEM) images and X-ray photoelectron spectroscopy (XPS) analysis indicate that both hierarchical structures and higher carbon content in the laser processed area are responsible for the super hydrophobicity.
Lishi Jiao; Zhong Yang Chua; Seung Ki Moon; Jie Song; Guijun Bi; Hongyu Zheng. Femtosecond Laser Produced Hydrophobic Hierarchical Structures on Additive Manufacturing Parts. Nanomaterials 2018, 8, 601 .
AMA StyleLishi Jiao, Zhong Yang Chua, Seung Ki Moon, Jie Song, Guijun Bi, Hongyu Zheng. Femtosecond Laser Produced Hydrophobic Hierarchical Structures on Additive Manufacturing Parts. Nanomaterials. 2018; 8 (8):601.
Chicago/Turabian StyleLishi Jiao; Zhong Yang Chua; Seung Ki Moon; Jie Song; Guijun Bi; Hongyu Zheng. 2018. "Femtosecond Laser Produced Hydrophobic Hierarchical Structures on Additive Manufacturing Parts." Nanomaterials 8, no. 8: 601.