The Lead Free Technology Research And Inspection For Electronical Product Base On Surface Mount Technology

IT is the sunrise industry, the electronic manufacturing industry isthe core of human pursuit of the miniaturization of electronic products,multi-function of the growing emphasis on environmental protection atthe same time. In this paper, electronic products SMT productionprocess and Detection Lead technology was studied.With surface mount technology and the rapid development of SMThas become the most common, the most widely used electronicsassembly technology. With the miniaturization of electronic products,light and high-reliability requirements, making short thin componentscontinuously, and in the 0.3 mm spacing small development. On theother hand the environmental requirements also make unleaded brazingtechnology rapidly replace traditional brazing process, the resultingseries of brazing quality issues. The components of the multi-pin andhigh-performance, in particular BGA / CSP / FC promotion, theapplication of lead-free solder materials makes brazing defects areincreased, more and more invisible SMT solder joint defects on thequality of products Detection Technology propose a higher demand.It is precisely because of lead-free electronic products in the future,the reliability and enterprises greater impact on the production process,the paper focused on electronic products unleaded technology wasstudied. To do not change the characteristics of electronic productsunder the premise of the production process accordingly and improvethe program. Lead is the main problem of tin whisker inhibition andassociated with the solder process re-optimization. In addition, onseveral major SMT testing technology, explore its unleaded, the use ofmicro technology and the corresponding enhancement. In this paper, the main research work done:This paper studies the tin whisker produce, the growth mechanismof choice in the two groups were different crystal conditions of theinitial test, submersion hydrotherapy structure test, heating cycle test.Through experiments prove tin whisker can be controlled, developed atin whisker growth assessment method and gives specific formula usedto help assess the risk of tin whisker growth, pointing out that theinhibition of tin whisker growth, thereby reducing electronic productsunleaded production costs.SMT electronic products Lead production requirements mainlyaffect the process involves Lead Solder, screen printing, reflowsoldering, as well as product testing and reliability. In this paper, thecompany chose forward leaded Solder paste FWD - 8038K andunleaded Solder paste FWD - 8038A in the template placed on the timeof 0 and 1 hour after printing. Through " Solder pastecan be printedcomparison experiment" analyzing and comparing the leaded / unleadedSolder paste components, characteristics and performance of theproducts and production process of different influences. Design of the"digital printing results of experimental observation" method, the datawill be measured separately by JMP statistical software mathematicalhypothesis testing (t-Test) for analysis and found a screen / templatePrinting Technology Lead production optimization work parameters.Lead process development in the whole process of returning thedevelopment curve is the most important. This paper is designed "ninecurve experimental design" methodology for determining reflow processLead production parameters and, through the work of the experimentalresults recommended FWD - 8038A temperature curve. This paper also explored electronic products unleaded, after the tiny SMT detectiontechnology and the corresponding enhancement.This paper made by major findings:Simply avoiding the use of pure tin can not completely inhibit thegrowth of tin whisker, the dip can be used tin, plastic packages,appropriate device increases the geometric distance approach to theinhibition of tin whisker growth, in order to reduce the threat ofelectronic device failure.To help assess the risk of tin whisker growth formula:r (growth)＝SUM[r (i)+r (d)+r (cte)+r (ex)]*r8。On Solder paste applications can be 95.5 Sn / 4. 0Ag / 0. 5Cu or96.5 Sn/3.5Ag alloy and flux used in conjunction with. The wavesoldering applications, the solder may be used 99.3 Sn/0.7Cu alloy. Themanual / welding machine, solder line can be used 99.3 Sn/0.7Cu alloy.The return process, the solder may be used Sn / Ag / Cu alloy(Sn/Ag3.0/Cu0.5)." Solder paste can be printed comparison experiment" show, inaccordance with the current production parameters, Solder paste intemplates were placed on the time of 0 and 1 hour printing after Solderpaste thickness detection, the use of unleaded Solder paste and there isthe use of Pb-Sn Paste printing results similarity.From "Digital printing results of experimental observation" to thedeficiencies in the collection and Solder paste height measurementsummary results may be obtained MPM UP2000 Screen Printer, 5 milthick stainless steel template, in the use of FWD - 8038A Lead Solderpaste, consider the entire SMT the rate of the manufacturing processes,optimization of process parameters for screen printing 1. Set up pressure 6~8Kg2. Printing speed 70 seconds + / -10 secondsEach detection technology have their own testing domain, butdomain of a certain intersection and does not have a means of detectionis omnipotent. Product quality assurance in the process of detectiontechnology and the best strategy for the combination of analysis andmodeling tools FMEA (Failure Analysis Model), the yield forecastmodeling tools used together in order to improve the detectionefficiency.This paper points innovation:Design of the "digital printing results of experimental observation,""9 curve experimental design" method, and data were measured by JMPstatistical software mathematical hypothesis testing (t-Test) for analysis,and to find the screen printing process Lead production Optimizationoperating parameters.This paper used in the experimental method, but also to othercompanies for different brands of unleaded Solder paste choiceevaluation process parameters and the corresponding adjustment,optimization. In this paper, research results for unleaded Solder pastechoice, evaluation and the application of the Surface Mount TechnologyLead production and testing have broad guidance significance to theproduction of lead-free electronic products have important practicalengineering value.