Author: MULAN -Plastic Molding Manufacturer
1. Position accuracy mainly refers to the coaxiality of the matching journal of the assembly transmission part relative to the supporting journal of the assembling bearing, which is usually expressed by the radial circular runout of the matching journal to the supporting journal; according to the injection mold manufacturer The use requirements stipulate that the high-precision axis is 0.0010.005mm, and the general precision axis is 0.010.03mm. In addition, there are requirements for the coaxiality of the inner and outer cylindrical surfaces and the perpendicularity requirements between the axial positioning end face and the axis line. 2. Surface roughness can have different surface roughness values according to the different surface working parts of the parts. For example, the surface roughness of the bearing journal of the main machine tool spindle is Ra0.160.63um, and the surface roughness of the matching journal is Ra0. 632.5um, with the increase of machine speed and precision, the surface roughness of shaft parts will be smaller and smaller.
3. Dimensional accuracy The journal is the main surface of the shaft parts, which affects the rotation accuracy and working state of the shaft. The diameter accuracy of the journal is usually IT69 according to its use requirements, and the precision journal can reach IT5. 4. Geometric shape accuracy The geometric shape accuracy (roundness, cylindricity) of the journal, the mold parts should generally be limited within the range of the diameter tolerance point.
When the geometric shape accuracy is required to be high, the allowable tolerance can be specified separately on the part drawing.