Research On The Decision Method Of Stencil Cleaning In The Process Of Solder Paste Printing

Solder paste printing,which is the first process of SMT(Surface Mount Technology)surface mount production line,has a great influence on the output quality of SMT production line.The performance of the printing system will gradually degrade with the increase in the number of production,so stencil cleaning is a necessary measure to improve the printing performance and ensure the printing quality.However,frequent stencil cleaning will cause a large number of production interruptions,affecting the efficiency of SMT production.Therefore,it is necessary to carry out in-depth research on the decision-making problem of stencil cleaning in the solder paste printing process.Combined with the national smart manufacturing project "New Mode of Intelligent Manufacturing of Mobile Terminal Motherboards ",this paper,taking the solder paste printing process of the SMT production line as the object,systematically studies the problem of performance degradation modeling and stencil cleaning decision-making in the printing process.Firstly,combined with the SMT process flow and the characteristics of solder paste printing production,the impact of printing process performance degradation on printing quality and production process continuity are analyzed.A research ideas for stencil cleaning decision-making problem during solder paste printing is developed.A research framework of stencil cleaning decision problem in solder paste printing process is developed and the research content and method are clarified.Then,on the basis of renewal reward theorem,the decision-making problem of periodical stencil cleaning is studied.A Markov chain model of performance degradation in the printing process is developed and the evaluation method of quality loss in the printing process is also researched.Taking the minimal quality loss and production cost as the decision goal,this paper develops the decision-making model of stencil cleaning cycle.The solution method of decision-making model is studied and the characteristics of the decision-making model are analyzed.Finally,the non-periodic stencil cleaning decision-making based on system reliability is studied.The relationship between automatic cleaning,manual cleaning and the improvement of printing system performance is analyzed and the performance degradation model of printing process is developed.And then,a cleaning policy is designed in conjunction with system reliability analysis.A quality loss evaluation method is studied based on the hybrid hazard rate model.The stencil cleaning decision-making model with quality loss and production cost as the decision goal is developed and the model solution method is studied.The optimal cleaning policy characteristics and the impact of model parameters on the cleaning strategy are analyzed.