Design Of A Microfabrication Module Based On The PMAC System

With the rapid development of technology,the use of high-precision small parts is becoming more and more widespread,both in the daily civilian aspects and in the military,are an integral part.Small machine tools are therefore beginning to attract more and more attention.Small machine tools have significant advantages such as low cost,low energy consumption and space saving,but the machining method and accuracy of small machines has been a major challenge.This topic is based on the design and research of micro milling machine processing module under PMAC open CNC system.The aim is to design a micro-milling module with high accuracy,high robustness,good stability and able to meet the test requirements.The main elements of this research are as follows.1.This paper analyses the current development status and trends of small machine tools,and in-depth study of the "PC + NC" type CNC system,using the PMAC motion controller as the core control element for the control of micro-fine milling machine,and IPC to form the upper and lower dual CPU system structure,designed a PMAC system based on the micro-fine The hardware architecture of the milling machine is designed.The performance of the Power PMAC motion controller CK3 M has been studied in depth and is used in conjunction with the servo system,high precision feed axes and electric spindle system to form the hardware system of the micro milling machine.The feedback elements for position and speed are the scales and servo motor encoders mounted on each feed axis respectively,forming a fully closed-loop servo control system as a whole.2.The choice of communication method and the design of the control structure of the micro milling machine system are carried out.Comparing the two communication methods "axis module + communication cable" and "Ethernet-based communication protocol + network cable",the Ether CAT protocol was chosen because of its interference-free digital signal,the general speed of analogue signal transmission and the high synchronisation accuracy.The Ethernet-based Ether CAT protocol is used for communication between the PMAC and the servo drive.Among the three control system structures designed,the PMAC motion controller is selected for real-time control and the servo drive position control mode for three-servo-loop control of the position,speed and current loops.The Power PMAC IDE software is then used to configure Ether CAT and to introduce the various functions.3.Design and commissioning of the micro milling machine module.The design of the CNC software for the micro milling machine is described and the design of the machining module is elaborated.The global variable file,the configuration file,the PLC program module and the motion program module are described and the servo control system is tuned using a composite control algorithm of PID + velocity/acceleration/friction feedforward + feedforward filtering to obtain the gain parameters.4.The Servo Studio software was used to configure the Takatron servo drive.Three BSample tests,PVT mode tests and L-block machining tests were then carried out.Real-time data acquisition of the motion axes of the micro milling machine was carried out using the plotting function in the IDE,and the test results showed that the data obtained using the machining module met the machining requirements of the micro milling machine.