Study On CAD/CAM System For NC Belt-grinding Of Blade Surface

Blade is key part in the dynamo equipment such as steam turbine, gas turbine, aviation motor and shipping propeller. As typical freeform surface, blade surface has complex geometry feature, which make it difficult to design and manufacture. Focus on polishing of blade surface, there is no reliable and economical NC devices in our country, so every manufacturer has to import multi-axis polishing machine tools and industrial polishing robot with high price. Refer to the practice of our country, base on the reseach of its related technology, to develop an economical and efficient NC polishing device for blade surface will make a great sense.Of couse, this device must satisfy the machining precision, can solve the difficulty existing in the manufacturing.A full NC device includes: its CAD/CAM sub system, CNC sub system and the mechanical machine tool itself, and to develop it we also need to do research on those three parts. In this paper, the effection of blade's geometry to the control of position and orientation for tools is first analised. Proper theoritical explanation is made for the needed numbers of axes to do the blade polishing job. The structure of machine tools is simply made and the scenario which called"Three NC + Two Manual"five-axis coordinated is presented.Base on it, following the NC route, with the blade model as input, NC tool paths are created, thus pre-processing is finished. The typical D-H method in the robotics is adopted to solve kinematics problem for five-axis machine tools successfully.By inverse kinematics, post-processing is skipped, tool paths are translated to motion parameters of every axis of machine tools. These parameters are output to the simulation environment, machining process simulation is created to substitute the toolpaths verification simulation and the NC code verification simulation; output to open architecture NC system, to drive machine tools, so the total integration of CAD/CAM/CNC for polishing of blade surface is realised.For CAD/CAM systems, common commercial 3D software such as UG and Pro/E cannot do simulation and CAM functions for blade surface belt-grinding. So under UG environment, its model module, assemble module, secondary development module and motion module are integrated to do kinematics simulation for three kinds of five-axis machine tools. On the frame of one CAD system based on OpenGL, freeform curve and freeform surface modeling functions are added in, blade surface modeling is realized, and the simulation is also done in this platform.For NC system, GE-400-SV motion controller based on PC bus produced by Googol Technology is adopted, to build a three-axis CNC system called"opensoftCNC"。...