外文翻译---高速研磨技术的应用与展望(编辑修改稿)

外文翻译---高速研磨技术的应用与展望(编辑修改稿)内容摘要：

ip space after dressing, the sharpening process is simplified, or can be eliminated in numerous applications. Fig. 3 shows a typical microstructure of a vitrified CBN grinding wheel. The selection of the appropriate grade of vitrified CBN grinding wheel for highspeed grinding is more plicated than for aluminium oxide grinding wheels. Here, the CBN abrasive grain size is dependent on specific metal removal rate, surface roughness requirement, and the equivalent grinding wheel diameter. As a starting point when specifying vitrified CBN wheels, Fig. 4 shows the relationship between CBN abrasive grain size, equivalent diameter, and specific metal removal rate for outside diameter grinding operations. However, the choice of abrasive grain is also dependent on the surface roughness requirement and is restricted by the specific metal removal rate. Table 1 shows the relationship between CBN grain size and their maximum surface roughness and specific metal removal rates. The workpiece material has a significant influence on the type and volume of vitrified bond used in the grinding wheel. Table 2 shows the wheel grade required for a variety of workpiece materials that are based on crankshaft and camshaft grinding operations. The stiffness of the ponent being ground has a significant effect on the workpiece/wheel speed ratio. Fig. 5 demonstrates the relationship between this ratio and the stiffness of the ponent. Steels such as AISI 1050 can be ground in the hardened and the soft state. Hardened 1050 steels are in the range 62177。 68 HRc. They are burn sensitive and as such wheels speeds are limited to 60 m s255。 1. The standard structure contains the standard bonding system up to 23 vol.%. Whereas the abrasive grain volume is contained at vol.%. Lower power machine tools usually have grinding wheels where a part of the standard bonding system contains hollow glass spheres (up to 12 vol.%) exhibiting parable grinding ratios to the standard structure system. These specifications also cover most powdered metal ponents based on AISI 1050 and AISI 52100 ball bearing steels. Softer steels are typically not burn sensitive, but do tend to `burr39。 when ground. Maximum wheel and work speeds are required in order to reduce equivalent chip thickness. High pressure wheel scrubbers are required in order to prevent the grinding wheel from loading. Grinding wheel specification is based on an abrasive content in the region of 50 vol.% and a bonding content of 20 vol.% using the standard bonding system operating at 120 m s1. Tool steels are very hard and grinding wheels should contain 23 vol.% standard bonding system and vol.% CBN abrasive working at speeds of 60 m s1. Inconel materials are extremely burn sensitive, and limited to wheel speeds of 50 m s1 and have large surface roughness requirements, typically 1 μ m (Ra). These grinding wheels contain porous glass sphere bonding systems with 29 vol.% bond, or 11 vol.% bond content using the standard bonding system. In addition to the need to select the appropriate bonding system for grinding wheels in accordance with the requirements of the application concerned, the strength of the body of the grinding wheel requires optimization with high cutting speeds. In the case of very high cutting speeds, conventional grinding wheel designs involving a rectangular body and a bore often leads to excessive and irregular extensions of the body and cracking of the abrasive coating. In order to eliminate the possibility of highspeed grinding wheels failing, the material and the geometry of the body must be able to cope with very high cutting speeds. A further aim of the body of the grinding wheel must be to reduce the magnitude of centrifugal forces by optimizing the shape of the body of the grinding wheel without impairing operational safety. Excessive stress in the body of the grinding wheel is to be avoided, and the smallest possible extension of the body is tolerated. A reduction in mass is also necessary to move critical natural frequencies of the system in the direction of higher rotational speeds. Developments in highspeed grinding wheel design have focused on redesigning and optimizing the shape of body for both vitrified CBN [8,9] and electroplated CBN grinding wheels [10]. 4. Highspeed machine tool develop。