Kneading Block Cnc Grinding Machine

Kneading blocks are a kind of screw elements wildly used in co-rotating twin screw extruders, with complicated shape and high precision. At present, it's lag in technology for kneading block manufacturing, or say, the outline precision of kneading block can not be ensured, which influences the whole property of extruders greatly. Therefore, studying the mechanism of grinding process, resolving the key problems of developing NC grinding machine and developing advanced and effective machine will improve our country manufacture technology level of twin screw extruder undoubtedly.If part rotates at a constant angular velocity during grinding process for its special shape, the linear velocity and grinding force of each grinding point on kneading block profile is different, which influences the grinding quality terribly, resulting in wave, burn and shape errors occurrence. In order to make up the defect of present manufacturing technology, we bought forward the new technology of equal linear velocity grinding. Based on kneading blocks' structure analysis, making the machine grind with equal arc length per unit time, we built up the mathematical model of the equal linear velocity grinding. During the manufacturing process, numerical control instruction can be produced and the trajectory of wheel center can be calculated automatically. Modified by real grinding experiments, the grinding effective is very good.Kneading block NC grinding machines have already been succeeded developing by the mechano-electronic study center in Yangzhou University. According to the movement of kneading block, the bed body, the grind head, the head frame and wheel dressing mechanical structure of kneading block grinding machine can be designed to meet the requirements of precision, stiff and structure rationalization.The control system of kneading block NC grinding machine based on PMAC motion controller uses the"PMAC+PC"structure to study and develop special purpose grinding machine system, building system development platform on PC directly, realizing blocking division of the function of software and hardware, organizing function block coordination work by standard interface and realizing the NC function together. The system that we studied is a control system, which can make the program decade explain, the interpolation algorithm, the servo control and the system administration work at a time. It has not only a common commercial NC system's general function, but also does the specific function for kneading block grinder, such as parameter input, calculation of wheel dressing trajectory, kneading block grinding and the wheel dressing program performing automatically. Meanwhile the system developers and the lathe users can add or delete function block according to real time requirement.The available and practical parameter of grinding kneading block can be obtained by grinding experiments. So does the optimum ones, which makes a contribution to gain the high grinding efficiency and quality.