The Research On Equal Thickness Compensation Method For Thin-walled Cylinder Workpiece Machining

With the rapid development of aerospace industry in our country, thin-walled cylinder aluminum alloy part is widely used in aerospace, and people pay much attention to how to improve the machining precision of this kind of part. Because the rigid of thin-walled part is weak, it is easily to be deformation by the reason of cutting force, clamp force and the residual stress in processing. In order to ensure the machining precision, it is necessary to control the deformation or to compensate the value of deformation. In this dissertation, my research mainly involves the thickness measuring technology, thickness compensation technology and improve the precision of thickness compensation. The works mainly include:(1) In order to achieve the target of equal thickness, it is need to have the thickness compensation processing. Before thickness compensation, it first to obtain the actual thickness of workpiece and then have the value of compensation. Now, the actual thickness of workpiece was obtained by manual measurement, but this measurement manner will introduce more artificial error and difficult to measure the machining precision and have a low efficiency. In order to overcome these weaknesses, a in-situ thickness measurement system which controlled by numerical control system was introduced in this article and it can replace the manual measurement and ensure the machining efficiency.(2) According to the in-situ thickness measurement system which introduced by this paper, a more optimization thickness compensation technology was introduced. Firstly, the actual thickness measurement points could be gained by the feature of workpiece, and the actual thickness of these points can achieved by the in-situ thickness measurement system, then the actual thickness of every cutting location point can achieved by interpolation and the value of thickness compensation of every cutting location point can be obtained at the end. Finally, the thickness compensation technology was verified by five-axis machining equipment and the experimental results showed that this thickness compensation technology can guarantee the machining quality effective.(3) In five-axis machining, two types of non-linearity which along the direction of feed and vertical to the direction of feed will appeared in the middle of two cutter locations, and non-linearity will reduce the machining quality. Now, researchers mainly aimed at the first kind of non-linear error but neglect the second. In terms of the non-linearity error in the thickness compensation which vertical to the cutting direction, the article introduced an error control method. First, the kinematic model of rotary axes was established. Secondly, the process of error occurring was analyzed by the model. Then, the error control method was achieved. Finally, the error control method was verified by simulation.