Research On Bubble Growth Crystal Growth Equipment Control System

Sapphire crystals are becoming more and more important as the market demands.As an excellent multifunctional material,it has outstanding physical characteristics and has been widely used in military,industrial,agricultural and medical fields.The crystal growth furnace,as a device for the preparation of crystals,plays a key role in the growth of high-quality sapphire crystals with large dimensions and fewer defects.This paper chooses a modified foaming method,starting from equal-diameter control and focusing on improving the automation of the growth equipment.This article compares and selects the most popular modified foaming method.the cold heart-shoulder micro-lifting method,the diameter control as the control point of the whole process of sapphire crystal growth,and the crystal basic theory of energy conservation equations such as growing from sapphire crystals.We set out to find out the key factors affecting equal-diameter control,and initially determined the control strategy.Secondly,from the perspective of control,the equal diameter control is further discussed,the selected temperature is the main controlled object,and the corresponding mathematical model is established.Combined with the principle of control diameter,a cascade control system composed of temperature and weighing is proposed.Analyze and contrast several typical temperature control algorithms.the final choice of temperature control strategy is single neuron PID control.Based on the Siemens S7-1200 series PLC,the control system of the sapphire crystal growth equipment was designed in detail.First of all,from the process requirements of the foaming process,the overall design of the crystal furnace and the design of the motion control subsystem were completed.In order to ensure the crystal furnace's long-term low-speed stability,no creep,no jitter operation,the use of precision ball screw and linear guide drive combination,through the planetary reducer connected to the AC servo motor,to achieve the seed crystal rod lifting motion,and its rotation is Relying on the cooperation of the belt drive and the AC servo motor,the design of the motion control subsystem has been calculated in detail and reasonably.The PLC acts as the brain of the motion control and sends instructions to the servo driver connected to it.According to the above theoretical analysis,using the programming software STEP7 of the PLC,the temperature control program using the single neuron PID algorithm and the weighing program of the weighing subsystem are respectively prepared;and still based on the programmable logic controller as the control core,the temperature control The hardware system of the subsystem and weighing subsystem is set up.Next,the two subsystems are combined according to the control purpose of the cascade system,and finally a smooth and precise control of the growth of the sapphire crystal is achieved.Finally,using the WinCC software in the Siemens TIA portal,a sapphire crystal-grown human-computer interaction subsystem was designed based on the SIMATIC Simplified Series panel,from the interface and communication point of view,to monitor,control,and control the crystal growth process in real time.After completing the formation of the growth system,using the Simulink simulation function of MATLAB software,through the compilation of the mathematical model and the construction of the simulation block diagram,the advantages and disadvantages of the single neuron PID algorithm and the conventional PID algorithm in temperature control were analyzed and compared,and the former was found to be stable.It has obvious advantages in responsiveness and accuracy,so it has a certain value for practical application.