【正文】 C1 外文翻譯：英文 +中文 16 頁(yè) 5909 字?jǐn)?shù) Highspeed grinding with CBN grinding wheels applications and future technology . Jackson,*, . Davis, . Hitchhiker, B. Mills Abstract The basic mechanisms and the applications for the technology of highspeed grinding with CBN grinding wheels are presented. In addition to developments in process technology associated with highspeed machining, the grinding machine, coolant system, and the grinding tool also need to adapt to highspeed machining. Work piecerelated factors inurning the results of machining are also discussed. The paper concludes with a presentation of current research and future developments in the area of highspeed grinding, and the development of highspeed CBN camshaft grinding. All rights reserved. 1. Introduction More than 25 years of highspeed grinding have expanded the field of application for grinding from classical finish machining to highperformance machining. Highspeed grinding offers excellent potential for good ponent quality bined with high productivity. One factor behind the innovative process has been the need to increase productivity for conventional finishing processes. In the course of process development it has bee evident that highspeed grinding in bination with preliminary machining processes close to the finished contour enables the configuration of new process sequences with highperformance capabilities. Using the appropriate grinding machines and grinding tools, it is possible to expand the scope of grinding to highperformance machining of soft materials. Initially, a basic examination of process mechanisms is discussed that relates the configuration of grinding tools and the requirements of grinding soft materials. The effect of an effective and environmentally friendly coolant system is also investigated in addition to the effect of work piecerelated variables on the suitability of using highspeed grinding techniques. 2. Theoretical basis of highspeed grinding In view of the random distribution of cutting edges and cuttingedge shapes, statistical methods are applied to analyses the cutting mechanism in grinding. The mean unreformed chip thickness, hcu, and the mean chip length, lcu, are employed as variables to describe the shape of the chip. The unreformed chip thickness is dependent on the static density of cutting edges, Cstat, and on the geometric and kinematics variables [1,2]: C2 (1) where Vw is the work piece speed, VS the grinding wheel speed, ae the depth of cut, deq the equivalent grinding wheel diameter, and α，β，γ are greater than zero. On the basis of this relationship, it can be established that an increase in the cutting speed, assuming all other conditions are constant, will result in a reduction in the unreformed chip thickness. The work piece material is machined with a larger number of abrasive grain contacts. At the same time, the number of cutting edges involved in the process decreases. This leads to the advantages promised by highspeed grinding which is characterized by a reduction in grinding forces, grinding wheel wear, and in work piece surface roughness. Consequently, increasing the speed of the grinding wheel can lead to an increase in the quality of the work piece material, or alternatively, an increase in productivity. The process technology depends on the characteristics and quality requirements of the work piece to be machined. As the cutting speed increases, the quantity of thermal energy that is introduced into the work piece also increases. An increase in cutting speed is not normally acpanied by a proportional reduction in the tangential grinding force, and thus results in an increase in process power. Reducing the length of time the abrasive grain is in contact with the work piece can reduce the quantity of heat into the work piece. An increase in the machining rate of the process is necessary for this to happen, where the chip thickness is increased to the level that applies to lower cutting speeds without C3 overloading the grinding wheel. Experimental results [3] illustrate that increasing the cutting speed by a factor of two while maintaining the same metal removal rate leads to a reduction in the tangential force but, unfortunately, leads to an increase in the amount of work done. Owing to constant grinding time, there is an increase in the process energy per work piece and, subsequently, in the total thermal energy generated. When the material removal rate is also increased the rising tangential force results in a further incre