How should car camshafts be machined with a surface grinder?

The geometric accuracy of a surface grinder refers to the motion accuracy and mutual position accuracy of each part under no-load conditions. It is impossible to achieve absolute precision in machine tools, and there will always be more or less inevitable errors. This type of error will be reflected to varying degrees on the workpiece during machining and will affect the machining accuracy of the workpiece. Generally, there are radial and axial runout of the spindle, straightness of moving parts such as the worktable, mutual position error and transmission error of working parts, etc.

The difference between automotive camshafts and ordinary cylindrical grinding operations lies only in the shape of the grinding cam. The camshaft of a six cylinder engine has 13 camshafts and 3 or 4 bearing diameters. It includes six intake cams, six exhaust cams, and one pump cam along the same center. The shapes of the intake and exhaust camshafts are sometimes different, but in other engines involved, their contours are slightly different.

The camshaft is made of special alloy cast iron, which currently has a wider range of applications. After casting, the cam should be quenched, but the hardness of the bearing surface and gear should not be too high for easy turning.

Use a good ejector pin to support the camshaft. The first operation is to rotate the diameter of the circular bearing, leaving it about 0.040 larger than the specified coarse and fine grinding dimensions. After pouring the cam profile, grind it directly. Assuming that the casting is 0.070~0.080 larger than the specified size camshaft. But in operation, the grinding ability of non-circular and irregularly shaped castings can be increased to 1/8 of the cam profile.

After rotation, the bearings are made in a unified, semi-automatic, or specialized surface grinder. The operation of a grinder is similar to that of a regular cylindrical grinder. When using a grinder, install an independent grinding wheel and grind four bearings to size in one operation. This method can produce about 20 camshafts per hour. Therefore, the diameters of the four bearings are not equal, and their dimensions are specified using multiple gears or micrometers.