Features of precision parts processing technology for kit parts

In the processing of precision parts, parts such as bushings and sleeves are generally called sleeve parts. Set parts are generally composed of structural elements such as outer circle, inner hole, end face, step, inner groove and so on. Its main feature is that the shape accuracy and position accuracy between the inner and outer cylindrical surfaces and the relative end surfaces are relatively high.

Processing characteristics of sleeve parts

    The sets of parts mainly play a supporting and guiding role in the machine, and generally consist of inner and outer surfaces with higher coaxiality requirements. The main technical requirements of the general set of parts are as follows:

    (1) Dimensional accuracy, surface roughness and roundness requirements of inner hole and outer circle.

    (2) The coaxiality requirement between the inner and outer circles.

    (3) The perpendicularity requirement of the hole axis and the end face.

    Thin-wall sleeve parts have very thin wall thickness and weak radial stiffness. During the machining process, they are easily deformed by factors such as cutting force, cutting heat and clamping force, which makes it difficult to guarantee the above technical requirements. When clamping, corresponding preventive and corrective measures must be taken to avoid deformation of the workpiece during processing; or the deformation of the processed surface due to the deformation of the clamping and the recovery of the deformation after processing, and the processing accuracy cannot meet the technical requirements of the part pattern.

    2. The principle of processing technology for sets of parts

    (1) Rough machining and precision parts machining should be performed separately.

    (2) Use axial compression as much as possible. If radial clamping is used, the radial clamping force should be evenly distributed.

    (3) The heat treatment process should be arranged between roughing and finishing.

    (4) The inner and outer circular surfaces and end surfaces of small and medium-sized sleeve parts should be processed in one installation as much as possible.

    (5) When arranging the machining sequence of the hole and the outer circle, the machining sequence of machining the inner hole first and then positioning the outer circle with the inner hole should be used as much as possible.

    (6) When turning thin-walled sleeve parts, the turning tool should choose a larger main declination angle to reduce the back force and prevent deformation of the processed workpiece.

    3. Blank selection

    The rough parts of the sleeve parts are mainly selected according to the parts materials, shapes, structures, sizes and production batches. When the hole diameter is small, bar stock can be selected, or solid castings can be used; when the hole diameter is large, castings and forgings with prefabricated holes can be used; when the wall thickness is small and uniform, tube material can be used; when the production batch is large, Advanced blank manufacturing techniques such as extrusion and powder metallurgy can also be used, which can improve the production efficiency of precision parts processing and save materials on the basis of the increased precision of the blank.