机械英语文章

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 high 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 process 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 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-point 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 grinding 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 airflow 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 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 parameters 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 can 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 designed 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 grinding process, it is the point contact between wheel and workpiece due to the point grinding angles and the thin 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.