Machining deep hole circular spline groove with digitally controlled milling machine

The company needs to process a batch of workpieces with a length of 1000mm and at a distance of 200mm from the end surface. Four spline grooves of 45 ° are distributed uniformly, the groove depth is 5mm, the groove length is 120mm, and the nominal roughness value of the groove is Ra = 6.3 μm. Material It is 35CrMo, and the angle after tempering is 290 ~ 320HBW.

After comprehensive analysis of the characteristics of the work, we can see that: ① The length of the job is longer, and the rarely used slotting machine and broaching machine have not reached the request. ② The inner hole groove is a circular arc, which eliminates the use of processing forms such as a rotary bed. To complete the arc at the bottom of the groove, a CNC tool must be used. ③ The inner hole is deep. The length of the conventional tool bar on the market is unfortunately satisfied with the needs, and the demand is customized and trial-produced to increase the tool bar. Non-metal processing WeChat, the form is not wrong, it is not worth caring. Analyze the above situation, in order to increase profits, extend the processing cycle, and improve the frequency, it is decided to fully apply the current part of Qiaoyou FD18-22 CNC gantry milling machine to stop processing. The facility can stop both end milling and side milling (the facility's spare parts are equipped with milling heads without corner breaks). In the machining of the internal spline groove, side milling is adopted.

Determination and implementation of processing plan: (1) Design of processing technology. Through the analysis of the parts, the milling process can be divided into four steps: rough milling, semi-fine milling, fine milling, and clearing. (2) Design of fixture. The outer diameter of the workpiece is 150mm and the length is 1000mm. For the clamping of the workpiece, not only the stability and reliability of the workpiece needs to be ensured, but also the axis position of the workpiece must remain unchanged to ensure that the center plane of the shaft groove passes the axis. The overall requirement for tooling is not only to meet the requirements that limit the degree of freedom of the workpiece, but also to have good rigidity, stability and accuracy. The main principle is that the workpiece is fixed on the worktable by a V-shaped iron and a pressure plate, with a guide rod and a nut. (3) Selection of processing tools. Because the hole diameter of the workpiece is smaller than the size of the right-angle milling head, the milling head cannot be processed in the hole after being inserted into the conventional tool. Therefore, during the milling process, a special thickened and extended tool bar is required for processing.

Practice has proved that the above methods are used to meet the processing requirements of the product. The existing CNC milling machine is used to process the deep hole circular spline groove, and its practicality and economy have been strongly proved through actual production. Provided a new solution for the processing of deep-hole circular spline grooves when the methods such as drawing, inserting, and wire cutting cannot be solved.