Papers by Author: Li Gang Zhao

Abstract: The experimental research on silicon was reported in this paper. The surface roughness under the different workpiece feed speed and linear velocity of the wire saws is studied mainly in this experiment. The effects of the workpiece feed Vs and the linear velocity of the wire saws Vw were analyzed.

Abstract: . In this paper, the model of fixed abrasive diamond wire saw has been set up, and its cutting mechanism has been discussed. Then, the material removal rate model and wire saw cutting efficiency model have been established. the speed of wire saw, the number of the dynamic effective abrasive and the workpiece feed rate have been analyzed to study their impaction on the stability of cutting process. Finally, some rules and suggestions were brought forward.

Abstract: The friction behavior of single silicon wafer sliding against different ice counterparts (α-Al2O3, CeO2 and SiO2) at 10±0.5 °C within a velocity of 60 rpm~300 rpm were studied using a home-made friction and wear testing machine. The morphologies and surfaces roughness of the worn silicon wafers were observed and examined on a non-contact surface topography instrument (ADE). It was found that the friction coefficient of the single silicon wafer decreased with the increase of sliding velocity. Single crystal silicon wafer coupled with α-Al2O3 ice counterpart recorded the highest friction coefficient and the biggest surface roughness, while it had the lowest friction coefficient and the smallest surface roughness as with CeO2 ice counterpart. One reason was that a series of tribochemical reactions occurred at the local contact point between the ice counterpart and the silicon wafer during sliding. Under alkaline condition, there would be a soft corrosion layer formed on the surface of the silicon wafer. Another reason was that the hardness of the abrasive particles was different and this caused different cutting depth of them.

Abstract: This paper introduces and summarizes the slicing technology of large-scare silicon wafers. And the research status of ID slicing, wire saw slicing and WEDM is summed up. Finally, this document indicates the direction of research and the development.

Abstract: High quality diamond film wafers with different thickness are prepared by high power DC arc plasma jet CVD (DCPJ CVD) method using a CH4/Ar/H2 gas mixture. The effects of methane concentration on the growth of carbon balls in anode nozzle and arc stability are studied with theoretical analysis and experimental investigation. The results indicate that different sizes of carbon balls may rapidly grow in the anode nozzle with methane concentration higher than 2 Vol-%, symmetry and uniformity of the rotating arc are strongly affected with the occurrence of carbon balls, which will result in non-uniform deposition of diamond films over a large substrate area. The methane concentration should be controlled at a low level to keep diamond film wafers growth stable. Characterization by X-ray diffraction, Raman spectroscopy and SEM analysis are also carried out.

Abstract: DC-Plasma arc behavior is one of the key factors on growth of diamond film. The results show that keeping steady DC-Plasma arc can grow better quality diamond film. In a long-time growth of diamond film, there is sediment carbon on about 5mm border-entad anode annulus, which was proved to be graphite. It results in fluctuating and instability of DC-Plasma arc and in the DC-Plasma density, which causes graphite generation and much stress in the film. By means of adjusting anode annulus assembly, pausing the supply of carbon source and increasing H2, the problem of sediment carbon cab be effectively resolved. Finally, the mechanism of the effect of arc behavior on growth of diamond film is discussed.

Abstract: This paper brings forward a new type of the tooth profile of noncircular gear—constant pressure angle involute tooth profile, and realizes its wire-electrode cutting. By the design of CAD and CAM, this paper shortens the design time of the noncircular gear and improved the design accuracy of the noncircular gear. By the research of the constant pressure angle involute tooth profile of noncircular gear, this paper has improved the transmission accuracy of the noncircular gear. By the research of the technology of wire-electrode cutting, this paper has improved the manufacturing accuracy of the noncircular gear.