Research On Brazing Process Optimization For The Housing Component Of Electromagnetic Relay

Electromagnetic relay is one of the most basic electronic components.It is the key electronic component in the field of aerospace and national defense.It is the important cornerstone of weapon equipment "high quality,long life,good in peacetime and effective in wartime",and plays an important role in the whole system.The main function of the housing component is to seal electromagnetic relay and provide installation function for users.Therefore,the housing component is one of the most important components,which has an important influence on stability and reliability of electromagnetic relay.The welding quality of the housing component is directly related to whether electromagnetic relay can meet the rigorous requirements of long life and high reliability of the whole system.According to the statistics of the failure phenomena of electromagnetic relay in the test and in the use,there have been many problems such as contact shaking and installation cracking caused by the bad welding quality of the housing component,which have a great impact on reliability of the whole system.In order to solve the problems of unstable brazed joint strength,excessive brazing deformation,welding corrosion,low pass rate of resistance brazing of the housing component,and ensure that electromagnetic relay can meet the rigorous requirements of the whole system,this paper starts with qualitative analysis of factors affecting brazing quality of the housing component,carries out optimization research of resistance brazing through theoretical analysis,orthogonal experimental design,finite element simulation analysis and processing experiment,and the optimal brazing process variables of the housing component are obtained.The main work of this paper is as follows:Firstly,the influence factors of resistance brazing quality of the housing component are qualitatively analyzed.The results show that brazing current,brazing time and brazing pressure are the key variables affecting the quality of the housing component,such as brazed joint strength and deformation,among which brazing current is the most important one.On the basis of the above,using orthogonal experimental design method,the effects of brazing current,brazing time and brazing pressure on brazing quality of the housing component are studied.The optimal combination of single-pulse process variables of the typical housing component is obtained by range analysis,which constitutes a solid basis for subsequent finite element simulation analysis.Secondly,the finite element modeling and simulation analysis of brazing process of the typical housing component are carried out.Firstly,the changment laws of transient temperature field,stress field and deformation of the model are obtained.The main reason for excessive brazing deformation is that the peak temperature exceeds the appropriate temperature range.After that,by reasonably matching the variables of first-pulse and second-pulse in dual-pulse brazing process,the rate of temperature rise in late brazing period is reduced,the peak temperature is in the appropriate temperature range,and brazing deformation is reduced.Finally,by comparing and analyzing the finite element simulation results of peak temperature and brazing deformation,the optimized ranges of brazing process variables for the typical housing component are obtained,which provide a theoretical basis for subsequent determination of optimal brazing process variables.Then,by building a new platform for the housing component,the performance of the equipment is improved,which can meet the requirements of resistance brazing.On the new platform,the results of simulation analysis are validated by process experiment.According to the validation results of the two key indicators of brazed joint strength and deformation of the housing component,optimal process variables of resistance brazing are obtained as follows: brazing press 250N?current and time of first-pulse 15000A/8s?current and time of second-pulse 13000A/2s.After the optimization,brazing quality meets the requirements of technical documents,uniformity of joint strength is better,deformation is reduced from 0.114 mm to 0.091 mm,and pass rate is increased from 83% to 100%.The experiment results of deformation agree well with the simulation analysis,so the validity of the simulation is proved.Finally,the product-level verification of the typical electromagnetic relay is carried out.The results show that brazing quality and pass rate of the housing component have been significantly improved,and there is no adverse effect on relay assembly.The product performance index fully meets the technical specifications.At present,the housing components of many electromagnetic relays have been applied resistance brazing process,which solves the problems of unstable quality and low pass rate,and the purpose of the research has been achieved.The conclusions obtained in this paper can be used for reference for similar products such as low-voltage electrical appliances.