Research On Control Technology Of Key Parameters In Vacuum Coating Equipment

The vacuum ion coating equipment is a fully automatic equipment that can coat thin films on glass and other materials.The production process of its coating is complex,and multiple industrial parameters need to be controlled.It is a complex device that integrates knowledge in multiple disciplines.In addition,the controlled object has characteristics such as nonlinearity and large time delay,and it is impossible to establish an accurate mathematical model.It is difficult to achieve system stability using conventional control methods.The use of advanced control theory and computer network control technology can make the entire control system stable and accurate,in line with international coating specifications and requirements.Based on the vacuum coating process and the theory of film formation,this article mainly analyzes and studies three typical industrial parameters that have a greater impact in the film formation process,and achieves precise control of these three key parameters.Based on the film formation mechanism,the influence of temperature,vacuum degree and gas flow rate on the film formation effect is analyzed,and the main factors affecting temperature,vacuum degree and gas flow rate changes in vacuum coating equipment are deeply studied.Design temperature control system.Taking the temperature in the vacuum chamber as the controlled parameter,the working principle of the temperature control system is analyzed,and the design of the temperature control system of the vacuum coating equipment is completed.Two free PID control algorithms and fuzzy PID control algorithms are used respectively to realize temperature control.And use Matlab to carry out simulation comparison,and optimize the control method.Design the vacuum degree control system.Take the vacuum degree of the cavity as the controlled parameter,and use the digital PID control algorithm to switch and control the rotational speed of the turbomolecular pump: The foreline pump set is started when it is turned on.When the vacuum degree reaches a certain value,switch to start the secondary pump group pump to make the cavity reach a higher vacuum.Make the vacuum environment meet the start-up requirements of the coating equipment.When coating the film,the cavity needs to be filled with working gas and reaction gas.The PID control algorithm is introduced to stabilize the vacuum of the cavity within the allowable value range of the film forming process,reducing energy consumption and noise.Design gas flow(working gas and reaction gas)control system.The flow rate of the gas(Ar,H2,etc.)charged into the cavity is the controlled parameter.The PID controller is used to control the gas flow of the gas mass flow meter.Set the flow values of different types of gases according to process requirements.The gas flow rate is controlled at the set value,so that the working gas concentration of the cavity meets the requirements of the coating process.After production practice tests,the system is currently running stable,reliable,accurate and meets the design index requirements.