Issue link: https://iconnect007.uberflip.com/i/686649
June 2016 • SMT Magazine 9 Stephen Las Marias is managing editor of SMT Magazine. He has been a technology editor for more than 12 years covering electronics, components, and industrial automation systems. At EMSCAI, Knoll Evangelista said that more than 50% of defects in assembly of printed cir- cuit boards are attributed to the solder paste printing process. Given that, he explained why solder joint reliability is the biggest issue when it comes to solder paste printing, and the key factors to consider to ensure the quality of sol- der joints. Given the users' challenges and issues, I in- terviewed the solder paste suppliers to get their insights on such challenges and find out how they are helping their customers address their solder paste printing issues. Mitch Holtzer, global director of customer technical support at Alpha Assembly Solutions and one of our expert columnists here at SMT Magazine, talks about the impact of solder pastes on the printing process and the best practices to consider such as good board support, a reason- ably well-controlled environment, high-quality stencils, and using a wipe frequency suitable for the process set up. Meanwhile, Watson Tseng, general manager of Shenmao America Inc., talks about the vari- ables involved when it comes to selecting the appropriate solder paste for the printing pro- cess. From the equipment side, I interviewed Adam Sim of Speedline ITW EAE at the recent NEPCON China show in Shanghai to discuss is- sues, including the challenges in solder stencil printing, how printing cycle times may be im- proved, and the key factors to consider when selecting a solder paste printing solution. I also sat down with Eric Gu of Nordson Asymtek China to talk about the challenges and innovations in solder paste dispensing, and factors to consider when using solder paste dis- pensers. At NEPCON China, I also spoke with Thom- as Bredin of Mycronic about solder paste print- ing, and innovations being done in jet printers to help them get up to speed with challenges such as tighter tolerances and finer lines and pitches in board assemblies. Finally, to know more about the solder paste inspection (SPI) side, I spoke with Vi Technol- ogy's Jean-Marc Peallat and Chong Choon Hee about the latest innovations happening in the SPI space to help customers address inspection challenges amid tighter tolerances and finer lines and pitches. In their technical article, "3D Solder Joint Reconstruction on SMD based on 2D Images," Pedro M. A. Vitoriano and Tito Amaral of Visteon tackle the issue of solder joint inspec- tion in surface-mount devices and present an algorithm for 3D solder joint reconstruction to help improve the inspection process. Of course, SMT Magazine would not be com- plete without our expert columnists providing their insights on current manufacturing issues and technologies in the SMT industry. For his column this month, Alpha's Mitch Holtzer dis- cusses which method—pad defined or mask defined—is optimal in designing electronic cir- cuits. Tom Borkes, of The Jefferson Project, dis- cusses production engineering students as cus- tomers, and how the education system can re- ally help by providing real-world experience to complement their academic achievement. Bob Wettermann of BEST Inc. addresses the debate around the issue of baking out moisture in a PCB during rework, and the need for the board, as well as neighboring components, to be taken into account in terms of moisture pro- tection during the reflow cycle. And last but not least, Robert Voigt of DDM Novastar continues on his topic of choosing a selective soldering system, covering the com- mon types of soldering technologies available as well as nitrogen inerting systems. I hope you enjoy this month's issue of SMT Magazine. For comments or suggestions, or if you want to become a contributor to our maga- zine, feel free to send me a note. Next month, we'll focus on one of the chal- lenges reflected in our survey above: PCBA test- ing and inspection. Stay tuned! SMT SOLDER PASTE EXPLORATION