Different machining methods have different machining errors caused by spindle rotation errors. When machining the outer circle and inner hole on the lathe, the radial rotation error of the spindle can cause the roundness and cylindricity errors of the workpiece, but it has no direct effect on the end face of the workpiece. The axial rotation error of the spindle has little influence on the machining of the outer circle and inner hole, but has a greater influence on the verticality and flatness of the end face to be machined. When threading, the spindle rotation error can cause periodic errors in the lead of the machined thread.
Properly improving the manufacturing accuracy of the spindle and the box, selecting high-precision bearings, improving the assembly accuracy of the spindle components, balancing the high-speed spindle components, and preloading the rolling bearings can improve the rotation accuracy of the machine tool spindle.
The guide rail is the benchmark for determining the relative positional relationship of each machine tool component on the machine tool, and it is also the benchmark for the machine tool movement. The accuracy requirements of the lathe guide rail mainly include the following three aspects: straightness in the horizontal plane; straightness in the vertical plane; parallelism (twist) of the front and rear guide rails
In addition to the manufacturing error of the guide rail itself, the uneven wear and installation quality of the guide rail are also important factors that cause the guide rail error. Guideway wear is one of the main reasons for the decline of machine tool accuracy.
Transmission chain error refers to the relative motion error between the transmission elements at the beginning and end of the transmission chain. It is generally measured by the angle error of the end element of the transmission chain.
The influence of tool error on machining accuracy varies with the type of tool. When a fixed-size tool is used to form a tool, the manufacturing error of the tool will directly affect the machining accuracy of the workpiece; while for general tools (such as turning tools, etc.), the manufacturing error has no direct impact on the machining accuracy of the workpiece.
Any tool will inevitably wear during the cutting process, which will cause the size and shape of the workpiece to change. Correct selection of tool materials and new wear-resistant tool materials, reasonable selection of tool geometric parameters and cutting amount, correct sharpening of tools, correct use of coolant, etc., can effectively reduce the dimensional wear of the tool. If necessary, a compensation device can also be used to automatically compensate for tool size wear.