Study On Turning Of Monocrystalline Silicon Using Abrasive Water Jet

Monocrystalline silicon, called the cornerstone of microelectronic, is the basic materials in semiconductor devices and solar photovoltaic industry. Therefore, study on cutting of single crystal silicon has not only theory significance, but also application value.Abrasive water jet technology is a special machining technology which is developed in recent years. It is a kind of'cold'cutting processing methods, especially for thermal-sensitive, pressure-sensitive, high hardness, easy break, difficult-to-machine material and composite materials. It has advantages such as no heat affected zone, quality accuarate incision, no spark, environmental friendly etc. Abrasive water jet technology was widely applied in machinery manufacturing, aerospace, military industry, medical, new energy fields.This article conducted a series of abrasive water jet turning (AWJT) experiments on monocrystalline silicon. Furthermore, a train of tests is made to indicate the macro characteristic of surfaces, the processing parameters on cutting capacity and quality in AWJT cutting of monocrystalline silicon. It was found that the geometrical characteristics of abrasive water jet turning have both the common surface features and unique processing characteristics. The formation of convergence, parallel and divergent type in straight-line cutting represented positive cone and backtaper in abrasive waterjet turning. As the straight-line cutting sections, the superficial layer of turning operations also performances wear area, deformation wear area and jet rally area. However, according to the different relative velocity of nozzle speed and workpiece rotational speed, three different areas are circular zones.A number of experiments were made so that the effect of each parameter, such as jet pressure, standoff distance, feed rate and workpiece rotational speed, on performance can be identified. The results show that with the jet pressure increases, cut width and roughness are reduced. There is a better standoff distance of 5mm. It made a minimum cut width. With the increase of standoff distance, roughness reduces at begining then increase. Therefore, there is a best standoff distance. It made the minimum roughness. As the nozzle feed rate increase, the cut width decrease but the roughness has the opposite trend. When the workpiece rotational speed increases, both the width and roughness decrease at first then increase. But the changing trends of roughness are not significant.The experimental research and analysis of abrasive water jet turning silicon were optimized by orthogonal test method. The analysis of range results also show that effect of standoff disitance on the cutting width is the greatest and that of jet pressure is smaller.The optimization results of the best combination is jet pressure 230MPa, standoff distance 5mm, nozzle feed rate 25mm/min, workpiece rotational speed 10r/min. The analysis shows that effect of jet pressure on the surface roughness is the greatest, that of standoff disitance is smaller. Therefore, jet pressure should be cautiously chosen according to the roughness, energy consumption level, and economic cost. Finally, based on the experiment parameters level and the optimization results, the best combination is jet pressure 230MPa, standoff distance 5mm, nozzle feed rate 30mm/min, workpiece rotational speed 10r/min.In this paper, two regression perdiction models of abrasive waterjet turning roughness and cutting width were established using matlab language. The cutting width model is lnW = 703.718P? 0 .8525S 0 .1498V 0.0223 N?0.0239, and the roughness model is ln R = 1.016P -0 .012 S 0.035V 1.171 N-0.037.