The technical requirements for machining of precision metal parts and shaft parts are very importa...
First: Dimensional accuracy. The journal is the main surface of shaft parts, which affects the rotation accuracy and working state of the shaft. The diameter accuracy of the journal is usually IT6-9 according to its use requirements, and the precision journal can reach IT5.
Second: the geometric shape accuracy, the geometric shape accuracy of the journal (roundness, cylindricity), generally should be limited to the range of the diameter tolerance point. When the geometric shape accuracy is high, the allowable tolerance can be specified on the part drawing.
Third: the processing position, the accuracy mainly refers to the coaxiality of the matching journal of the assembly transmission part relative to the supporting journal of the assembly bearing, which is expressed by the radial circular runout of the supporting journal to the supporting journal; according to The use requirements stipulate that the high precision axis is 0.001～0.005mm, and the general precision axis is 0.01～0.03mm. In addition, there are requirements for the coaxiality of the inner cylindrical surface and the perpendicularity between the axial positioning end surface and the axis line.
Fourth: Surface roughness. According to the different surface working parts of the parts, there can be different surface roughness values. For example, the surface roughness of the spindle journal of ordinary machine tools is Ra0.16～0.63um, which matches the surface roughness of the journal. The degree is Ra0.632.5um. With the increase in machine speed and precision, the surface roughness requirements of shaft parts will become smaller and smaller.