The guide rail is the most important support component in the machine. Its processing accuracy directly affects the working accuracy of the machine. However, the guide rails are mostly hollow thin-walled parts that are cast and have a complicated structure. It is easy to produce warpage, bending or distortion under the action of grinding force during processing. If the workpiece is improperly clamped or under the influence of its own weight, it will also produce large deformation. In addition, under the influence of grinding heat, temperature difference and internal stress of casting, large deformation will also occur, which are unfavorable factors affecting the machining accuracy of the guide rail, and effective control and prevention measures must be taken. The machining quality of the guide rail surface is required to be high. For example, a bed rail, flat rail and straightness tolerance are 0.008 mm/1000 mm in the horizontal plane; 0.009 mm/1000 mm in the vertical plane; and the straightness tolerance of the V-shaped rail is 0.01 mm/ 750 mm; the surface roughness Ra of the surface of the rail is 0.4 μm or the like. Therefore, it is very important to correctly select the grinding method and process parameters of the guide surface.
Most of the rail faces are made up of a combination of flat and beveled surfaces, so circumferential grinding or end grinding is used for grinding. In order to improve the grinding efficiency, it is also possible to use a plurality of forming grinding wheels and an auxiliary grinding head (grinding side plane) to achieve forming grinding and to use a combined forming grinding wheel to grind the rail surface at a time. Obviously, multi-grinding wheel grinding and combined forming wheel grinding have high grinding efficiency, but the structure of the grinding head is complex and suitable for mass production. It must be pointed out that when the plane of the guide rail is coarsely ground by the end grinding method, the axis of the grinding wheel can be inclined by 3° to 5° to reduce the contact area between the grinding wheel and the workpiece, and to improve the heat dissipation condition. In order to ensure the customized metal cutting disc, the diameter of the grinding wheel should not be too small, generally 1.3-1.5 times the width of the guide surface.