Design Of Indexable Formed Disk-type Milling Cutter Of Screw

The key part of the screw refrigerating compressor is a pair of male and female rotors which mesh mutually. At present, the screw compressor trade widely uses finger milling cutter to process the rotor spiral groove roughly which results in low efficiency and high wastage. Whereas, using the indexable formed disk-type milling cutter as the special tool to process screw tooth roughly can improve the efficiency of screw processing greatly, and that is an evolution trend of screw tool. This paper considers the LG16 rotors in the screw processing plant of Dalian Refrigeration Co., Ltd, and preliminary researches on design method of the special indexable formed disk-type milling cutter based on the section shape.Firstly, the structural characteristics and processing economic benefits of the indexable tool are analyzed. Then, after studying the generation of the cylindrical spiral surface and the theory of the spiral groove formed tool, the mathematical model which calculates the axial profile of the tool according to the section profile of the workpiece is established. Thus, based on the section profile data of the LG16 screw, the program is compiled using MATLAB software. The axial profile data of the formed tool is calculated, and the profile curve is drawn. Secondly, according to characteristics of the type of indexable inserts, with the axial profile of the cutter, the standard indexable inserts are selected and purchased from SANDVIK Corporation. Further, a subsection-based parameter-controlled fitting algorithm is proposed. The program is compiled to fit the theoretical profile of the cutter with standard inserts. Meanwhile, the fitting error is controlled and the accuracy of the profile is guaranteed. Thirdly, based on the profile fitting, the geometric model of the milling cutter is established, and the spatial positions of insert seats are calculated using the method of coordinate transformation. With the structural characters of the chip-hold groove and the screw hole, the design of the indexable formed milling cutter is finished.Lastly, the 3D modeling of the cutter is set up with UG software. Through the assembly model of all parts, the design rationality and the condition of interference are tested. The FEM analyses to the indexable insert and cutter body are done respectively in virtue of ANSYS software. The loads on the insert and cutter body are simulated, and the material strength is checked.