Design Of Electrical Control System For Medium And Large Selective Laser Melting Equipment

Selective Laser Melting(SLM)is a metal Additive Manufacturing(AM)technology that uses a laser to melt and solidify metal powder on a two-dimensional section of a three-dimensional model,and to form a three-dimensional solid part from bottom-up layer-by-layer printing,which can directly form complex metal parts with high precision,good density and superior performance.It is mainly used in aerospace,automotive,mold and medical fields to manufacture small batches and complex modes.However,the existing SLM equipment is difficult to meet the needs of the industry in terms of forming efficiency,cost and forming size,and has become an important limiting condition for promoting the application of technology in various industries.Therefore,a large-scale SLM equipment with high efficiency and high precision has been developed and it is of great significance.This thesis develops the electrical of the pre-developed selective laser melting equipment with a forming size of 750mm×750mm for the National 863 Program “Efficient and high-precision large-scale laser selection melting forming equipment and its application in aerospace”(Project No.2015AA042501).The control system has been designed and studied in detail.The main design research contents and conclusions are as follows:By analyzing the equipment structure,movement mode,technical index and precision requirements of medium and large selective laser melting equipment,the electrical scheme of machine tool was designed,and the requirements of the control system for medium and large selective laser melting equipment and the design of electrical control system should be considerations and electrical control system design steps for the device.Combining the current main electrical control schemes of machine tool equipment and the control characteristics of medium and large-scale selective laser melting equipment,a set of Siemens CNC system control schemes for SLM equipment is designed,and the electrical hardware is carried out according to the requirements of equipment processing,using and calculation.Using eplan software to complete the electrical schematic and design the electrical cabinet layout to provide guidance for the electrical connection of the equipment manufacturing.This paper analyzes and puts forward the overall overview software structure frame of medium and large scale selective laser melting system,adopts the parallel control scheme of upper computer and lower computer,analyzes the processing flow of equipment and designs the PLC control software for its lower computer.Through the overall planning of the PLC program,including the construction of the hardware platform,the overall layout of the PLC program,functional planning and interface planning,the Step7 programming software is used to complete the Siemens servo control,the servo motor control,the substrate heating program,the pneumatic system control,the preparation of laser galvanometer system control,equipment detection,equipment safety and peripheral auxiliary equipment.The overall debugging of the assembly equipment was carried out.For the machine tool control precision higher machining platform motion axis and the moving axis of the scanner using laser interferometer for precision measurement and error compensation.Under the condition of free load measurement,the one-way positioning accuracy of the forming platform after screw filling is 0.0022 mm,and the one-way repeat positioning accuracy is 0.0020 mm.The one-way positioning accuracy and one-way repeat accuracy of the galvanometer motion shaft after screw compensation should be 0.0052 mm and 0.0029 mm respectively,meeting the design requirements.Therefore,the optimal balance hydraulic parameters of the hydraulic system under different loads of forming were calibrated through experiments.By parameter setting,the positioning accuracy of the platform was realized to be between 0.004 mm and 0.007 mm,and the repeated positioning accuracy was between 0.003 mm and 0.004 mm,which met the design requirements and verified the feasibility of the hydraulic balance system.