scholarly journals Influence of Surface State in Micro-Welding of Copper by Nd:YAG Laser

2018 ◽  
Vol 8 (12) ◽  
pp. 2364 ◽  
Author(s):  
Martin Maina ◽  
Yasuhiro Okamoto ◽  
Reiki Inoue ◽  
Shin-ichi Nakashiba ◽  
Akira Okada ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface State ◽  
Nd:Yag Laser ◽  
Absorption Rate ◽  
Processing Condition ◽  
Energy Utilization ◽  
Surface Shape ◽  
Deep Penetration ◽  
Welding Quality ◽  
Enhanced Absorption

Laser welding of copper is characterized by low and unstable light absorption around 1000 nm wavelength. Combination of high thermal conductivity and low melting point makes it difficult to obtain good welding quality and leads to low energy utilization. To improve efficiency and welding quality, a technique to enhance process stability using 1064 nm wavelength Nd:YAG laser has been proposed, and absorption rate and molten volume in laser micro-welding were discussed. Since the surface state of specimen affects absorption phenomena, effects of surface shape and surface roughness were investigated. Absorption rate and molten volume were increased by creating appropriate concave holes and by controlled surface roughness. Stable micro-welding process with deep penetration and good surface quality was achieved for transitional processing condition between heat conduction and keyhole welding, by enhanced absorption rate.

Effects analysis of processing factors on surface quality in optical grinding using ɛ-support vector regression

2015 ◽  
Vol 229 (18) ◽  
pp. 3449-3458 ◽  
Author(s):  
Dongxu Zhang ◽  
Ping Yang ◽  
Yanting Zhang ◽  
Guo Bi ◽  
Yinbiao Guo
Keyword(s):  
Experimental Data ◽  
Surface Roughness ◽  
Support Vector Regression ◽  
Surface Quality ◽  
Processing Condition ◽  
Surface Shape ◽  
Support Vector ◽  
Technological Parameters ◽  
Effect Factor ◽  
Processing Factors

The aim of this study was to quantitatively analyze the effects of the processing factors on the surface quality in precision optical grinding. A novel identifying model which incorporates an effect factor is proposed based on ɛ-support vector regression ( ɛ-SVR). Experiments were designed and performed to investigate the effects of the processing factors comprising the technological parameters and processing condition factors on the surface quality, and the experimental data were used to train the ɛ-SVR. Subsequently, the values of effect factor were solved to quantify the effects of the respective processing factors on the surface quality. Further experiments were performed to verify the effectiveness of effect factor. ɛ-SVRs of which the input vectors were multiplied and not multiplied by effect factor were respectively used to predict the surface quality including the surface roughness and surface shape peak–valley value. The values calculated by ɛ-SVR using effect factor were found to be much more accurate than those calculated without using effect factor. The results confirmed the effectiveness of identifying model for precision optical grinding.

Videooptical Surface Shape and Integrity Estimation in Robots Machining

2013 ◽  
Vol 332 ◽  
pp. 270-275 ◽  
Author(s):  
Tadeusz Mikolajczyk
Keyword(s):  
Surface Roughness ◽  
Industrial Robot ◽  
Surface Shape ◽  
Engineering System ◽  
Machined Surface ◽  
Reflectivity Method ◽  
Machining System ◽  
Grinding Tool ◽  
Smart Machining ◽  
Usb Camera

Paper shows system to surface shape and quality control in machining using industrial robot. To surface control videooptical methods were used. Surface shape was controlled using the special reverse engineering system. To surface roughness measure machined surface reflectivity method was used. Used own constructions non contact system was equipped with red laser light and USB camera. Wrist of robot was equipped with grinding tool. In paper shows some algorithms of presented processes. Shown too examples of experiments results in surface roughness measure in start end of grinding process. First trials of presented system shows possibility to build smart machining system for finishing of surface with unknown shape.

Surface Roughness and Electrical Resistivity of High-purity Zinc Irradiated with Nd:YAG Laser Pulses

2015 ◽  
Vol 2 (10) ◽  
pp. 5587-5591 ◽  
Author(s):  
M.Z. Butt ◽  
Dilawar Ali ◽  
M. Usman Tanveer ◽  
S. Naseem
Keyword(s):  
Surface Roughness ◽  
Electrical Resistivity ◽  
High Purity ◽  
Nd:Yag Laser ◽  
Laser Pulses

Gate Dielectric Dependent on Pentacene Growth and Electrical Stability in OTFTs

2006 ◽  
Vol 965 ◽  
Author(s):  
Kim Chang Su ◽  
Jo Sung Jin ◽  
Lee Sung Won ◽  
Baik Hong Koo
Keyword(s):  
Surface Roughness ◽  
Surface Energy ◽  
Functional Groups ◽  
Surface State ◽  
Spin Coating ◽  
Gate Dielectric ◽  
Gate Dielectrics ◽  
Dielectric Surface ◽  
Electrical Stability ◽  
Oh Groups

ABSTRACTWe report on the effects of modifying the gate dielectrics by spin coating of HMDS, PVP and PVA which cause different surface energy and surface roughness owing to the different functional groups. In changing the surface state with applying various surface treatments, I-V and C-V measurements of the OTFTs were performed. The PVP-coated OTFTs, which has smoother and lesser amount of OH-groups on the gate dielectric surface, showed enhanced pentacene growth and nearly free hysteresis behavior than that of the HMDS and PVA-coated OTFTs.

Experimental investigations of nanosecond-pulsed Nd:YAG laser beam micromachining on 304 stainless steel

2018 ◽  
Vol 1 (1) ◽  
pp. 62-75 ◽  
Author(s):  
Rasmi Ranjan Behera ◽  
Mamilla Ravi Sankar ◽  
Prahlad Kumar Baruah ◽  
Ashwini Kumar Sharma ◽  
Alika Khare
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Laser Beam ◽  
Nd:Yag Laser ◽  
Research Work ◽  
Scanning Speed ◽  
304 Stainless Steel ◽  
Experimental Investigations ◽  
Micro Channel ◽  
Micro Channels

The demand for miniaturized components is increasing day by day as their application varies from industry to industry such as biomedical, micro-electro-mechanical system and aerospace. In the present research work, high-quality micro-channels are fabricated on 304 stainless steel by laser beam micromachining process with nanosecond Nd:YAG laser. The laser pulse energy (LPE), scanning speed (SS) and scanning pass number (SP No.) are used as the process parameters, whereas the depth and width of the kerf as well as the surface roughness are used to characterize the micro-channels. It is found that the kerf depth, width and surface roughness decrease with increase in the SS. The kerf depth sharply increases with increase in the SP No. The kerf width is minimum at 30 mJ LPE, 400 µm s‒1 SS and 10 SP No. The minimum surface roughness is observed at 30 mJ LPE, 500 µm s‒1 SS and 10 SP No. The oxygen content is found to gradually decrease with the distance from the centre of the micro-channel. Based on the experimental results, optimized input parameters can be offered to control the micro-channel dimensions and improve their surface finish effectively on stainless steel.

scholarly journals Effects of Different Laser Treatments on Some Properties of the Zirconia-Porcelain Interface

2021 ◽  
Vol 12 ◽  
pp. e2-e2
Author(s):  
Abdulsatar M Abdulsatar ◽  
Basima M A Hussein ◽  
Ali M Mahmood
Keyword(s):  
Surface Roughness ◽  
Bond Strength ◽  
Surface Treatment ◽  
Co2 Laser ◽  
Nd:Yag Laser ◽  
Light Microscope ◽  
Shear Bond Strength ◽  
Control Group ◽  
Fractional Co2 Laser ◽  
Laser Treatments

Introduction: This study was performed to compare the effect of Fractional CO2 laser or Q switched Nd:YAG laser of surface treatment on the shear bond strength of zirconia-porcelain interface. Methods: Fractional CO2 laser at 30 W, 2 ms, time interval 1 ms, distance between spots 0.3 mm, and number of scans is (4) or Q switched Nd:YAG laser at 30 J/mm2 and 10 Hz were used to assess the shear bond strength of zirconia to porcelain. Pre-sintered zirconia specimens were divided into three groups (n = 10) according to the surface treatment technique used: (a) untreated (Control) group; (b) CO2 group; (c) Nd:YAG group. All samples were then sintered and veneered with porcelain according to the manufacturer’s instructions. Surface morphology was examined using a light microscope, the surface roughness test was done by the atomic force microscope (AFM), and the shear bond strength (SBS) test was done by a universal testing machine. After debonding following shear bond test, zirconia surfaces were examined under a light microscope to determine their fracture mode. Results: The Results of this study showed that the lowest SBS was recorded in the control group, and the highest SBS recorded in the Fractional CO2 group, followed by the Q switched Nd:YAG laser group, as well as an increase in surface roughness and change in the morphology and mode of failure in the experimental groups . Conclusion: This study shows that Fractional CO2 laser and Q switched Nd:YAG laser treatments significantly increase the bond strength than untreated zirconia .

scholarly journals Evaluation of Surface Roughness of a Ni-Cr Alloy Treated With the Nd/YAG Laser and the Sandblast Technique

2021 ◽  
Vol 12 (1) ◽  
pp. e69-e69
Author(s):  
Elnaz Moslehifard ◽  
Mir Mahdi Seyyedashrafi ◽  
Nasim Khosronejad
Keyword(s):  
Surface Roughness ◽  
Nd:Yag Laser ◽  
Study Groups ◽  
Spot Size ◽  
Chromium Alloy ◽  
Air Abrasion ◽  
Average Roughness ◽  
Average Value ◽  
Nickel Chromium ◽  
Group B

Introduction: This study was to assess the effect of various output parameters of laser treatment on roughening the surface of a commercial nickel-chromium (Ni-Cr) alloy as compared to the sandblasting technique. Materials and Methods: Ninety-six disk-shaped (5 mm diameter and 2 mm thickness) specimens in total were made of a nickel-chromium alloy by using the lost-wax technique. Air-abrasion surface treatment was used for sixteen specimens. Specimens were divided into six groups; one of them was sandblasted and the rest were irradiated by different Nd:YAG laser output parameters as follows: Group A: energy: 122 mJ, frequency: 20 Hz, irradiation duration: 20 seconds, spot size: 1.5 mm; Group B: energy: 122 mJ, frequency: 20 Hz, irradiation duration: 20 seconds, spot size: 3.5 mm; Group C: energy: 122 mJ, frequency: 10 Hz, irradiation duration: 20 seconds, spot size: 3.5 mm; Group D: energy: 102 mJ, frequency: 10 Hz, irradiation duration: 20 seconds, spot size: 3 mm; Group E: energy: 102 mJ, frequency: 20 Hz, irradiation duration: 20 seconds, spot size: 3 mm. The surface roughness of all surface-treated specimens was evaluated by using a profilometer, and their average roughness (Ra) was calculated. The average value of each group was analyzed by t test and one-way ANOVA (SPSS 17). Results: Significant differences (P<0.05) were observed between the study groups. The highest Ra was achieved for the sandblasted group. The Ra value in group C was the highest value among the laser-etched groups. Conclusion: Based on the results, Nd:YAG laser irradiation increases surface roughness, but it is not as efficient as the sandblasting method as a gold standard.

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