1、 毕业设计 论文 外文资料及译文 学 院： 机械工程学院 专 业： 机械设计制造及其自动化 学生姓名 ： 学 号： 指导教师 ： 2011 年 6 月 外文及翻译 - 1 - Study on Effect of Grinding Fluid Supply Parameters on Surface Integrity in Quick-point Grinding for Green Manufacturing Abstract. In high and super-high speed grinding process, there is an airflow layer with hig
2、h speed around the circle edge of the grinding wheel that hinders the grinding fluid into contact layer, namely, the air barrier effect. The speed of airflow layer is directly proportional to the square of the wheel speed. Quick-point grinding is a new type of high and super-high speed grinding proc
3、ess with a point contact zone and less grinding power. The edge effect of the air barrier is weakened because the thin CBN wheel is applied in the process. By the analysis of dynamic pressure and velocity distributions in the airflow layer around the wheel edge, the mathematic models of the flow and
4、 jet pressure of grinding fluid for effective supply in the process were established and the process of optimization calculation of the jet nozzle diameter for green manufacturing was also analyzed based on the thermodynamics and the technical character of quick-point grinding process. The quick-poi
5、nt grinding experiment for surface integrity influenced by grinding fluid supply parameters was performed. Introduction Grinding is the machining process that has heavy effect on both environment and resource. The heavy effect results from the grinding powder and grinding fluid that is used in grind
6、ing process largely for cooling, washing and lubricating functions mainly. Especially for high and super-high grinding speed process, there is the airflow layer with high rotary speed around the circle edge of the grinding wheel that hinders the grinding fluid into the contact layer 1, namely the ai
7、rflow barrier effect. So it has to increase the grinding fluid supply parameters to keep the fluid effect during grinding process. In recent years, it has been the focus of research in engineering to improve the grinding greenness and develop the green grinding process. Quick-point grinding is a new
8、 type of high and super-high speed grinding process with some excellent performances, such as low grinding force and temperature, good cooling conditions, long wheel life and so on. It is possible to achieve the dry grinding by designing the grinding fluid system and the grinding fluid supply parame
9、ters reasonably, and optimizing grinding process parameters for green manufacturing. Analysis of Pressure and Velocity of Airflow Layer around Wheel Grinding heat is generated from the deformation and friction of materials during the grinding process and makes the grinding temperature rise, which ca
10、n result in the thermal surface damage of workpiece. Therefore, a reliable grinding fluid system is necessary for the most grinding process to keep cooling, washing and lubricating functions. For high and super-high speed grinding process, the grinding fluid supply parameters and jet way must be des
11、igned reasonably to overcome the airflow barrier effect on fluid supply, increase the ratio of the effective fluid and reduce the splash and waste of the fluid. In quick-point g外文及翻译 - 2 - rinding process, it is the point contact between wheel and workpiece due to the point grinding angles and the t
12、hin CBN wheel (Fig. 1), so the airflow layer is very narrow and the airflow barrier effect weakens, the fluid effect is improved greatly, as a result, the grinding fluid supply parameters can be lessened. Fig. 1 Principle of quick-point grinding The thickness and pressure of the airflow layer with h
13、igh rotary speed around the circle edge of grinding wheel is the main factors to influence the fluid effect in high speed grinding, the higher the wheel speed, the thicker the airflow layer is and the higher the pressure of the airflow layer is. According to Bernoulli Equation 2, the dynamic pressur
14、e of the airflow layer is given by where va is the airflow speed m/s, a is the air density kg/m3. If the dynamic pressure pa of the airflow layer is measured on the different wheel position, the airflow speed at same position can be calculated. Table1 gives the experiment values of dynamic pressure
15、and speed of air layer. If the diameter of wheel is 600mm and the wheel speed is 30m/s and 60m/s respectively, the measured values of the dynamic pressure and the airflow speed are shown in Table1. It is visible that the dynamic pressure of the airflow layer is increased with increase of the wheel s
16、peed. Table 1 Measured values of dynamic pressure and speed of airflow layer Fig. 2 shows the distribution of the speed of airflow layer with the distance t between the airflow layer and the wheel edge 3. The airflow speed is decreased with the increase of the distance between the airflow layer and
17、the wheel, and increased with the increase of wheel speed. The maximum speed of airflow is generated on the circle of the wheel edge and approaches the maximum peripheral wheel speed. But there are the sharper grads of the airflow speed along the radial direction of the wheel. Therefore, the rotary airflow layer with high pressure keeps the grinding zone off grinding fluid and lowers the
