Improvement Of SMT Process In OUYI Electronices Production Line

In recent decades,with the booming development of electronic industry in China,great progress has been made in terms of the size,type and structure of the electronic devices,as a consequence,general THD was gradually replaced by SMD.The application of SMD makes the production of smaller and lighter electronic devices possible with improved reliability.furthermore,it improve the automation manufacturing process with enhanced productivity and lower cost.At the same time,the quality of SMT products required by the market are also increasing,SMT product quality control has become a hot topic of concern and research gradually.This paper analyzed 3 product quality problems of EUROITALIA SRL SMT manufacturing line:Parameter setting of solder paste printer,reflow oven temperature control,screen printing process.the paper put forward the improvement approach respectively.The inputs of printing parameter settings is one of the key factors in the printing process,determining the quality of jet printing.EUROITAILIA SRL applies the inputs by the comparison of the product quality with different settings.However,this method simply relies on human experience which lacks efficiency and precision.In this paper,gaussian process regression model is applied to the parameter Settings,extracted the characteristics of surface mount devices to establish the sample library.The setting of the parameters of solder paste can be completed accurately by the established model.The core of SMT reflcw soldering is the control of temperdture curve,which is the setting of temperature parameters of reflow furnace.In the actual production of EUROITALIA SRL,SMT reflow furnace temperature curve is set by the experimental methods which constantly tried and used furnace temperature measuring instrument to measure the temperature curve until a reasonable temperature curve is determined.the high cost and low efficiency of the method is an urgent problem to be solved.This paper introduced the method which is based on Principal component analysis(PCA)and Improved BP neural network to predict the temperature profile.PCA was used to find the main element in the input characteristic parameters,then the main element was used as the input characteristic parameter of BP neural network,so that the training of BP neural network is completed.The BP neural network model predicts the temperature curve of reflow oven,which can effectively solve the problem of setting the temperature parameters of reflow oven so that it can have improved efficiency and saved production cost.Solder paste screen printing is of great importance in SMT manufacturing process since it determines the assembling quality of SMD.This paper analyzes the defects of the solder paste screen printing process and the improvement of defect problem was completed by the contrast experiment.Finally the design specification of steel net opening was formed,This specification can greatly reduce the product quality defects caused by poor solder paste printing and effectively improve the welding quality of products.