Study On The Axial Turn-milling Cutting Tool System For Inner Hole Of Large Caliber Thick Wall Pipe

Large diameter thick wall seamless tube(hereinafter referred to as: large diameter tube) is the Outer diameter larger than 300 mm,and the ratio of Outer diameter to wall thickness is smaller than 20, which is mainly used for manufacturing large Hydraulic Cylinder, Die casting pipe of making Centrifugal cast iron pipe and High pressure boiler tube of the main line of supercritical and ultra supercritical thermal. Large diameter pipe mainly adopt the process of hot rolling, forging or extrusion, the finished product has difference of about 10%, bringing greater difficulties for subsequent processing. At present, the processing of the large diameter pipe adopt the traditional technology of turning circle, and boring hole,which is low machining efficiency and high cost.Turn-milling is a new kind of processing, it uses the rotation of synthetic movement of artifacts and milling cutter to complete cuting processing, divided into axial turn-milling and orthogonal turn-milling. Axial turn-milling is suitable for the processing of inner surface,and the orthogonal turn-milling for the surface, adopting turn-milling technology to process the large diameter thick wall pipe, which can realize one complete inside and outside surface processing, making the precision of the workpiece in shape, position accuracy, surface roughness and residual stress aspects meet the requirements of an advanced processing method.For the present circumstance of most domestic milling cutter are not completely suitable for turn-milling machining requirements, the essay combine with the machining features of the large diameter pipe and the relevant technology of the turn-milling to reserch the special milling cutter of turn-milling, hoping to be able to design a well suitable for the special milling cutters and milling of large diameter internal control. The main research contents as follows: First of all, analyzing the characteristics of the technology of large diameter tube hole and processing characteristics. This topic is about the inner hole diameter of 780 mm before processing, and 800 mm after processing, the length is 8 m large diameter pipe, and calculating the cutting force in the process of milling machining, cutting power, cutting time, etc. Secondly, design the special milling cutter according to the above income condition and the demand for turn-milling cutter, and determine the parameters such as diameter, width and Angle of the milling cutter, and determined the monolithic or set gear milling cutter, determine the fastening form, material selection of the blade, Angle to carry on the design, etc. Based on UG to design the milling cutter, then assembly. In the machining of deep hole in this large component, with the knife rod elongation, the cutting force will make the tool have a large deformation to affect the machining accuracy greatly, and even to produce high frequency vibration. Seriously affect the machining precision and thesurface quality, even have the emergence of hitting knife. In order to eliminate these effects, based on UG 3D modeling, design an auxiliary supporting mechanism to reduce cutting force, eliminate the cutting vibration, promise the tool position, and improve the machining precision.