Papers by Author: Yu Fei Gao

Abstract: Temperature variation of KDP crystal is an important reason for its cracking. A finite element model was constructed to analyze temperature and thermal stress distribution of KDP crystal during wire saw slicing. The results showed that the highest temperature of the crystal which was located on the sawing kerf remained stable during slicing. The temperature inside the crystal rose slowly at the start of the slicing, and then tended steady with the continued increase of sawing depth. Because of the good cooling condition during the sawing process, the overall rise in temperature was small, and the maximum thermal stress on the sawing kerf was less than the tensile strength of KDP crystal, so temperature variation during slicing had little effect on crystal cracking.

Abstract: A wire-saw cut KDP crystal geometrical model was founded and a mathematical model was established to calculate the grit average cut depth, based on indentation fracture mechanics theory(IFMT). The relationship between the grit cut depth and wire saw process parameter was analyzed theoretically. The research results indicate that there exists an approximate monotone increasing non-linear correlation between grit average cut depth and the ratio i value of crystal feed speed and wire speed. By increasing the wire speed and crystal feed speed accordantly, the value of i can be maintained invariable, however, this way can simultaneously bring higher machined surface quality and machining efficiency.

Abstract: A mathematical model to calculate the grit average cut depth in wire sawing single crystal silicon was founded. So the grit average cut depths were calculated theoretically by choosing different process parameters, and influences of process parameters on grit cut depths of slicing silicon crystal were analyzed. Analysis results indicate that the grit average cut depth relates to the silicon mechanical properties, grit shape and size, wire speed and ingot feed speed, etc. And there is a monotone increasing non-linear correlation between grit average cut depth and the ratio i value of ingot feed speed and wire speed, when the i value is lower, the average grit cut depth is lower.