The Research On The Key Technologies Of Unattended Digital Manufacturing In Shaft Sleeve Parts

It has received the international recognition and response to vigorously develop the Advanced Manufacturing Technology(AMT) which is characterized by digital,automation and information. It is also the key way for our country to upgrade from a big manufacturing country to a powerful manufacturing country. Therefore, to achieve the unattended digital manufacturing of shaft sleeve parts, the following researches on the integration of the automatic machining subsystem and automatic material feeding subsystem, the on-line measurement and compensation of machining error, the automatic identification of tool failure and so on, meshed with the research project “Enhancing the service capability and technological sophistication of the digital design and manufacturing platform” supported by Shanghai Science and Technology Committee.(1) As the integral parts of unattended manufacturing cell, the principles and methods for achieving the automatic machining and the automatic material feeding are studies. On the basis of these, an integration solution of the unattended manufacturing cell is designed by which the NC machining center, the transfer robot,the industrial camera, the contact measurement device and the tool wear monitoring system cooperate effectively and reliably.(2) The upper computer software is developed to generate NC macro programs for automatic measurement, evaluate the machining error and calculate the compensation value based on the contact measuring device. Firstly, Workpiece Coordinate System of parts can be set automatically to replace the manual operation by using the on-line contact measurement system. And then the roundness and cylindricity of shaft sleeve parts are evaluated according to the measuring data by the upper computer software. At last the PID algorithm is utilized to calculate the compensation value of size error. For this, referring to the dynamics model ofturning processing, an optimization objective function is established and minimized by using the genetic algorithm to achieve the optimized PID parameters.(3) Based on the analysis of the tool wear process and the tool failure criterion,the mean square value of the cutting vibration signal and the feeding times are used to plan the process and rules for judging the tool failure. Then a cutting vibration signal acquisition system based on NI-c DAQ platform is built and the selections of the sensor location, the characteristic signal and the threshold are discussed. The tool wear monitoring software is developed by using Labview. It is verified by experiment that the proposed tool failure recognition function works well under the fixed processing conditions and cutting parameters.(4) The validity of the proposed system integration solutions, the stability and effectiveness of this unattended machining cell are proved by the unattended machining test of sleeve parts. And also the superiority of the method of calculating the compensation value using PID algorithm is verified by the comparison experiments in the practical machining.