The technical requirements for the processing of non-standard parts are generally formulated according to the main functions and working conditions of the shaft, generally including the following:
(a) The surface roughness of precision parts is generally ra2.5 ~ 0.63, and the surface roughness of the shaft diameter matched with the transmission parts μ m. The surface roughness of the bearing shaft diameter matched with the bearing is Ra0.63 ~ 0.16 μ m。
(b) The mutual position accuracy of precision parts and the position accuracy requirements of non-standard parts processing are mainly determined by the position and function of the shaft in the machine. Generally, it is required to ensure the coaxiality requirements of the Journal of the assembled transmission parts to the supporting journal, otherwise the transmission accuracy of the transmission parts (gears, etc.) will be affected and noise will be generated. For common precision shafts, the radial runout of the matched shaft section to the bearing journal is generally 0.01 ~ 0.03mm, and for high-precision shafts (such as main shafts), it is usually 0.001 ~ 0.005mm.
(c) Geometric accuracy of precision parts geometric accuracy of shaft non-standard parts mainly refers to the roundness and cylindricity of journal, external cone, Morse cone hole, etc. generally, its tolerance shall be limited within the range of dimensional tolerance. For inner and outer circular surfaces with high accuracy requirements, the allowable deviation shall be marked on the drawings.
(d) Machining dimensional accuracy of non-standard parts machining the journal with supporting function in order to determine the position of the shaft, it usually requires high dimensional accuracy (it5 ~ it7). The journal dimension accuracy of the assembled transmission parts is generally low (IT6 ~ it9).
The precision parts walking type CNC lathe (walking machine / longitudinal cutting lathe) is a kind of CNC machine tool mainly used for the precision machining of shafts and non-standard shafts. It has a qualitative leap in processing efficiency and processing accuracy compared with the CNC lathe. Because of the dual axis arrangement of tools, the processing cycle time is greatly reduced. By shortening the tool exchange time between the tool arrangement and the opposite tool table, The effective axis movement overlap function of thread chip and the direct spindle indexing function during secondary machining can shorten the idle travel time.
