scholarly journals Simulation of the ductile machining mode of silicon

Author(s):  
Hagen Klippel ◽  
Stefan Süssmaier ◽  
Matthias Röthlin ◽  
Mohamadreza Afrasiabi ◽  
Uygar Pala ◽  
...  

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.

2021 ◽  
Author(s):  
Hagen Klippel ◽  
Stefan Süssmaier ◽  
Matthias Röthlin ◽  
Mohamadreza Afrasiabi ◽  
Uygar Pala ◽  
...  

Abstract Diamond 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, thesurface is damaged during sawing. The extent of the damage depends primarily on the material removal mode. Undercertain conditions the generally brittle material can be machined in ductile mode, whereby considerably fewer cracksoccur in the surface than with brittle material removal. In the presented paper a numerical model is developed in orderto support the optimization of the machining process regarding the transition between ductile and brittle materialremoval. The simulations are performed with an GPUaccelerated in–house developed code using mesh-free methodswhich easily handle large deformations while classic methods like FEM would require intensive remeshing. Thesimulation results are compared with results obtained from single grain scratch experiments.


2010 ◽  
Vol 431-432 ◽  
pp. 265-268 ◽  
Author(s):  
Yu Fei Gao ◽  
Pei Qi Ge

Based on reciprocating electroplated diamond wire saw (REDWS) slicing experiments, a study on REDWS machining brittle-ductile transition of single crystal silicon was introduced. The machined surfaces and chips were observed by using Scanning Electron Microscope (SEM), and some experimental evidences of the change of material removal mode had been obtained. The experimental results indicate there is a close relationship between material removal mode and the ratio r value of ingot feed speed and wire speed, through controlling and adjusting the r value, the material removal mode can be complete brittle, partial ductile and near-ductile removal.


2006 ◽  
Vol 532-533 ◽  
pp. 436-439 ◽  
Author(s):  
Hui Huang ◽  
Xi Peng Xu

Diamond wire sawing has been used for many applications in stone industries and civil engineering several decades ago. The wear of bead is a major factor that affects wire-sawing performance in machining process. In this paper, seven diamond wires with different matrix system and different structures are taken from the factory. The diameters in the front, middle and end of bead along the moving direction of diamond wire, are measured respectively. The wear of diamond grits is also observed using a digital video microscope system. It is show that the wear of bead varies along the moving direction of diamond wire. The wear in the front of bead is greater than the others. The diameter gaps are associated with the type of matrix and the wear of diamond grits. The diameter gaps keep constant in the smooth sawing process.


2015 ◽  
Vol 656-657 ◽  
pp. 450-455 ◽  
Author(s):  
Rong Hwei Yeh ◽  
H.Y. Chen ◽  
Cheng Kuo Lee ◽  
A.H. Tan

A production-scale multiwire saw machine and 4 inch sapphire ingots were used in this study. The diamond wire used in the study had a core diameter of 0.1mm with an attached diamond particle size of 8–12μm. This study uses the Taguchi method and Grey relational analysis on the key diamond wire parameters which are electroplated nickel layer thickness, diamond wire tension, diamond wire speed and sapphire ingot feed rate, in order to simultaneously optimize the cutting performance in the diamond wire sawing of sapphire ingots. Based on the analysis, the nickel layer thickness and wire speed are the first and second most significant factors with 31.7 and 29.9% effects on cutting performances. The optimal control factors were then simultaneously evaluated for Ra, material removal rate, diamond wire wear rate and TTV and were found at optimization to be 14 μm nickel layer thickness, 15NT wire tension, 800m/min wire speed and 0.2mm/min feed rate, respectively. Compared with current standard condition, this improved process obtained from the optimization of diamond wire electroplated nickel layer thickness and saw machine parameters in the diamond wire sawing of sapphire ingots can achieve a 33% lower Ra, a 20% lower diamond wear rate, a 13% lower TTV and a 20% higher material removal rate, simultaneously.


2007 ◽  
Vol 24-25 ◽  
pp. 201-210
Author(s):  
Yan Li ◽  
Hang Gao ◽  
Ren Ke Kang

Cd1−xZnxTe (CZT) is an excellent ternary compound semiconductor. CZT is the most suitable substrate material for Hg1−yCdyTe epitaxial growth and can make the detector itself. The researchers have done a lot of works on the hard and brittle material removal mechanism in lapping process. however, no published articles are available regarding the removal mechanism and the abrasives embedding mechanism of the soft and brittle material in lapping progress .and there is its own characteristic if the hard abrasives machining the soft and brittle material in lapping progress, the objective of this paper is to build the physical model ,and divide the abrasive into four kinds of abrasives , they are two-body abrasive ,three-body abrasive ,embedded abrasive and small abrasive, and the authors analyze the effects on the material surface of the above abrasives. At last, design series of experiments, through analyzing the results and observe the surface morphology, the authors prove that the physical model is correct.


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