The effect of cut depth and distribution for abrasives on wafer surface morphology in diamond wire sawing of PV polycrystalline silicon

2019 ◽  
Vol 91 ◽  
pp. 316-326 ◽  
Author(s):  
Xinying Li ◽  
Yufei Gao ◽  
Peiqi Ge ◽  
Lei Zhang ◽  
Wenbo Bi
Keyword(s):  
Surface Morphology ◽  
Polycrystalline Silicon ◽  
Wafer Surface ◽  
Diamond Wire ◽  
Diamond Wire Sawing ◽  
Cut Depth

Three-dimensional topography simulation research of diamond-wire sawing based on MATLAB

2019 ◽  
Vol 72 (3) ◽  
pp. 325-331
Author(s):  
Ligang Zhao ◽  
Guofeng Xia ◽  
Yuhu Shi ◽  
Aisheng Wu
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Feed Speed ◽  
Machining Parameters ◽  
Content Type ◽  
Diamond Wire ◽  
Wire Saw ◽  
Diamond Wire Sawing

Purpose The purpose of this paper is to study the influence of the processing parameters of diamond wire sawing on surface morphology and roughness. Design/methodology/approach First, a wire saw cutting model is established to determine the positional relationship between a wire saw and the machined surface of the workpiece, and the abrasive grain cutting trajectory is generated. Through the data processing of the cutting trajectory, the simulation of the three-dimensional surface topography of the slice and the calculation of the surface roughness are realized by using the GUI programming of MATLAB. Finally, different surface roughness values are obtained by changing the machining parameters (saw wire speed and workpiece feed speed). Findings The conclusion is that the surface roughness of the slice is larger when the feed speed is higher and smaller when the linear speed is higher. Originality/value Diamond wire saw cutting is the first process of chip processing, and its efficiency and quality have an important impact on subsequent processing. This paper will focus on the influence of the sawing wire cutting processing parameters (sawing wire speed and workpiece feed speed) on the surface roughness to optimize the processing parameters and obtain smaller surface roughness values. Through MATLAB three-dimensional simulation, the surface morphology can be observed more intuitively, which provides a theoretical basis for improving the processing quality.

scholarly journals Simulation of the ductile machining mode of silicon

2021 ◽  
Author(s):  
Hagen Klippel ◽  
Stefan Süssmaier ◽  
Matthias Röthlin ◽  
Mohamadreza Afrasiabi ◽  
Uygar Pala ◽  
...  
Keyword(s):  
Brittle Material ◽  
Material Removal ◽  
Machining Process ◽  
Ductile Material ◽  
Diamond Wire ◽  
Ductile Machining ◽  
Mesh Free ◽  
Diamond Wire Sawing ◽  
Material Removal Mode ◽  
Brittle Material Removal

AbstractDiamond wire sawing has been developed to reduce the cutting loss when cutting silicon wafers from ingots. The surface of silicon solar cells must be flawless in order to achieve the highest possible efficiency. However, the surface is damaged during sawing. The extent of the damage depends primarily on the material removal mode. Under certain conditions, the generally brittle material can be machined in ductile mode, whereby considerably fewer cracks occur in the surface than with brittle material removal. In the presented paper, a numerical model is developed in order to support the optimisation of the machining process regarding the transition between ductile and brittle material removal. The simulations are performed with an GPU-accelerated in-house developed code using mesh-free methods which easily handle large deformations while classic methods like FEM would require intensive remeshing. The Johnson-Cook flow stress model is implemented and used to evaluate the applicability of a model for ductile material behaviour in the transition zone between ductile and brittle removal mode. The simulation results are compared with results obtained from single grain scratch experiments using a real, non-idealised grain geometry as present in the diamond wire sawing process.

Surface integrity of quenched steel 1045 machined by CBN grinding wheel and SiC grinding wheel

2017 ◽  
Vol 8 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Kankan Ji ◽  
Xingquan Zhang ◽  
Shubao Yang ◽  
Liping Shi ◽  
Shiyi Wang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Compressive Stress ◽  
Surface Integrity ◽  
Grinding Wheel ◽  
Micro Hardness ◽  
Content Type ◽  
Quenched Steel ◽  
Cut Depth ◽  
Cbn Grinding Wheel

Purpose The purpose of this paper is to evaluate surface integrity of quenched steel 1045 ground drily by the brazed cubic boron nitride (CBN) grinding wheel and the black SiC wheel, respectively. Surface integrity, including surface roughness, sub-surface hardness, residual stresses and surface morphology, was investigated in detail, and the surface quality of samples ground by two grinding wheels was compared. Design/methodology/approach In the present work, surface integrity of quenched steel 1045 machined by the CBN grinding wheel and the SiC wheel was investigated systematically. All the specimens were machined with a single pass in the down-cutting mode of dry condition. Surface morphology of the ground specimen was observed by using OLYMPUS BX51M optical microscopy. Surface roughness of seven points was measured by using a surface roughness tester at a cut-off length of 1.8 mm and the measurement traces were perpendicular to the grinding direction. Sub-surface micro-hardness was measured by using HVS-1000 digital micro-hardness tester after the cross-section surface was polished. The residual stress was tested by using X-350A X-ray stress analyzer. Findings When the cut depth is increased from 0.01 to 0.07 mm, the steel surface machined by the CBN wheel remains clear grinding mark, lower roughness, higher micro-hardness and higher magnitude of compressive stress and fine microstructure, while the surface machined by the SiC grinding wheel becomes worse with increasing of cut depth. The value of micro-hardness decreases, and the surface roughness increases, and the surface compressive stress turns into tensile stress. Some micro-cracks and voids occur when the sample is processed by the SiC grinding wheel with cut depth 0.07 mm. Originality/value In this paper, the specimens of quenched steel 1045 were machined by the CBN grinding wheel and the SiC wheel with various cutting depths. The processing quality resulted from the CBN grinding wheel is better than that resulted from the SiC grinding wheel.

scholarly journals Surface Morphology of Single and Multi-Layer Silicon Nitride Dielectric Nano-Coatings on Silicon Dioxide and Polycrystalline Silicon

2019 ◽  
Vol 26 (1) ◽  
pp. 25-29
Author(s):  
Liga AVOTINA ◽  
Elina PAJUSTE ◽  
Marina ROMANOVA ◽  
Gennady ENICHEK ◽  
Aleksandrs ZASLAVSKIS ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Surface Morphology ◽  
Polycrystalline Silicon ◽  
Chemical Vapour ◽  
Attenuated Total Reflection ◽  
Infrared Spectrometry ◽  
Chemical Bonds ◽  
Force Microscopy ◽  
Atomic Force ◽  
Pressure Chemical

Silicon nitride (Si3N4) in a form of single and multi-layer nanofilms is proposed to be used as a dielectric layer in nanocapacitors for operation in harsh environmental conditions. Characterization of surface morphology, roughness and chemical bonds of the Si3N4 coatings has an important role in production process as the surface morphology affects the contact surface with other components of the produced device. Si3N4 was synthesized by using low pressure chemical vapour deposition method and depositing single and multi-layer (3 – 5 layers) nanofilms on SiO2 and polycrystalline silicon (PolySi). The total thickness of the synthesized nanofilms was 20 – 60 nm. Surface morphology was investigated by means of scanning electron microscopy (SEM) and atomic force microscopy (AFM). Chemical bonds in the layers were identified by means of Fourier transform infrared spectrometry, attenuated total reflection (FTIR-ATR) method. (From the SEM and AFM images it was estimated that both single and multi-layer coatings are deposited homogenously. Si-N breathing and stretching modes are observed in FTIR spectra and the surface morphology is highly dependent on PolySi, therefore suggesting the decrease of the roughness of the bottom electrode for use in the nanocapacitors.

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