China
Africa
Explore chapters and articles related to this topic
Optimization of Surface Roughness in Slicing Process of Silicon Ingots
Published in Levent Aydin, H Seçil Artem, Selda Oterkus, Designing Engineering Structures Using Stochastic Optimization Methods, 2020
Savas Ozturk, Nilay Kucukdogan, Levent Aydin, Ayşe Seyhan
The quality of Si wafers (within a certain amount of dopant) used in solar cells and electronic devices is directly related to the morphological properties of the surface. Between the Si wafer production stages, most of the surface damage occurs in slicing with a wire saw. In this process, abrasive particles on the cutting surfaces cause abrasion damage. Furthermore, wave-like wear marks are formed on the cutting surface during the back and forth of the cutting wire. The surface roughness value Ra can be defined as the arithmetic mean of the absolute values of the profile deviations from the mean line, which is determined by surface roughness measurement techniques. The mathematical expression of Ra can be expressed as in Equation 8.1. ()Ra=1n∑i=1n|yi|
Photovoltaics
Published in Wolfgang Palz, The Triumph of the Sun in 2000–2020, 2019
Another challenge is the cutting of the silicon blocks, be they single-crystalline or multi-crystalline, into wafers. In particular, for solar cells, they must be the thinnest possible, between 150 and 200 microns. To this end, a new device was developed keeping the “kerf” loss, the powder loss during sawing to a minimum. It is the wire saw. A diamond cutting wire saw was developed by Charles Hauser in Switzerland with the support of inter alia Guy Smekens from the company ENE in Brussels and Photowatt in France. Hauser started as a consultant to Solarex and had achieved in 1986 his first multi-wire saw. He created the company HCT Shaping Systems and was able to sell it in 2007 to Applied Materials for $475 million. Later, the know-how was transferred to China. Currently Swiss company Meyer Burger is one of the leaders in wire sawing.
Photovoltaics
Published in Wolfgang Palz, The Triumph of the Sun, 2018
Another challenge is the cutting of the silicon blocks, be they single-crystalline or multi-crystalline, into wafers. In particular, for solar cells, they must be the thinnest possible, between 150 and 200 microns. To this end, a new device was developed keeping the “kerf” loss, the powder loss during sawing to a minimum. It is the wire saw. A diamond cutting wire saw was developed by Charles Hauser in Switzerland with the support of inter alia Guy Smekens from the company ENE in Brussels and Photowatt in France. Hauser started as a consultant to Solarex and had achieved in 1986 his first multi-wire saw. He created the company HCT Shaping Systems and was able to sell it in 2007 to Applied Materials for $475 million. Later, the know-how was transferred to China. Currently Swiss company Meyer Burger is one of the leaders in wire sawing.
Validation and Optimization of Activity Estimates of the FiR 1 TRIGA Research Reactor Biological Shield Concrete
Published in Nuclear Science and Engineering, 2022
Antti Räty, Merja Tanhua-Tyrkkö, Petri Kotiluoto, Tommi Kekki
Figure 16 compares the final results with the earlier calculated estimate4 of the activated area. As seen from Fig. 16, the radius of the activated area is smaller than the half-width of the steel shadow shield. However, the concrete around the beam tubes will be removed using a diamond wire saw. Cutting steel with this technique is significantly slower than cutting concrete. Therefore, the optimal compromise was to scale the cutting scheme such that the steel shadow shields are kept inside the concrete blocks. Nevertheless, the concrete block half-width can still be reduced by around 100 mm, which practically means around 5 tons less low-level active waste compared to the earlier estimates using the conservative activation calculations results. This is further illustrated in Fig. 17, where three dimensions are shown:
UV-TiO2 photocatalysis-assisted chemical mechanical polishing 4H-SiC wafer
Published in Materials and Manufacturing Processes, 2018
Zewei Yuan, Yan He, Xingwei Sun, Quan Wen
The surface roughness and flatness of SiC wafer sliced by diamond wire saw are very large. It takes long time for PCMP to remove the original asperities and slicing marks. So five sequential processing steps are arranged to smooth SiC wafer according to experimental results and analysis as seen in Fig. 10. As seen from Fig. 10a, original asperities and slicing marks are first removed in step 1 by lapping with 5 µm diamond powder for 30 min. Then the rough asperities produced in step 1 are removed with gradually smaller diamond grits in the following two steps. But a lot of brittle fractured pits are still remained on surface of SiC wafer as shown in Fig. 10b, c. These brittle fractured pits can be removed by PCMP in steps 4 and 5. Slurry 1# generates the best material removal and surface roughness according to the above analysis. To accelerate the MRR in polishing steps, SiO2 abrasives are replaced with Al2O3 abrasive in step 4 due to the high hardness of Al2O3. As illustrated in Fig. 10d, e, the surface of SiC is very smooth after polished for 2 h.
Final detailed design of an all-in-one attachment-based PHC pile head cutting robot and its structural stability analysis
Published in Journal of Asian Architecture and Building Engineering, 2021
Ji-Young Hwang, Dong-Jun Yeom, Jun-Sang Kim, Young Suk Kim
The PHC pile head cutting robot that is based on a diamond wire saw is designed to use an optical method to perform the PHC pile-cutting position-sensing function, a diamond wire saw to perform the PHC pile-cutting function, and a rotary multigrab to perform the PHC pile-handling function. The clamp of the diamond wire saw-based detailed design was equipped with a number of protruding contacts to increase the frictional force between the PHC pile, and the contact surface, thus maximizing the stable fastening of the PHC pile. In addition, it is designed as an integral frame-cover structure connected to the excavator connecting unit and cutting base frame by a pair of clamp shafts (Figure 5).