Last week the Rocky Mountain chapter of the Surface Mount Technology Association (SMTA) held their 2015 expo at the United Club of Mile High Stadium (home of the Denver Broncos). The event, which was free to the public, brought together anyone related to the design, procurement, and manufacture of surface mount boards for technical sessions and sponsor exhibits as well as a stadium tour, lunch and happy hour.
Thanks to organizations that hold events like the SMTA expo, the latest technologies can be discussed and explained so everyone in the design chain can understand the challenges that exist in manufacturing. Circuit designers may still consider the PCBA manufacturing process a commodity, but these events will keep (some) engineers from saying ridiculous things such as, ‘It’s just soldering parts to the board, right?’ or ‘So what if you can’t really see them? Why would they make 03015 SMT packages (0.3 x 0.15mm) if they can’t be placed properly?’
Your element14 correspondent couldn’t resist the draw of the technical sessions.
Phil Zarrow (ITM Consulting) gave a candid talk about the deadly sins of SMT assembly drew on his vast experience on running SMT line audits for clients. The big takeaway for the audience was that it is imperative to actually test if a line is working efficiently and effectively. This may seem trite from someone who makes a living doing audits, but it makes sense that such a significant component of product manufacturing time and cost gets double checked. He outlined some tests that can be done by anyone without hiring a consultant. For instance, the application of solder paste is where many errors come into play so it is wise to dial that process in. And to get the most out of the SMT line, it makes sense to have inspection at multiple stages instead of just at the end to save time and material: after paste application and after component placement to start. Another test that can be run easily is to try several different solder pastes by getting some samples and running a few boards. Apparently there are a lot of bad solder pastes out there which can be easily picked out by simple comparison. In all SMT lines there are many ways to do it, but it is important to be able to intelligently answer the question of, ‘Why do you do it that way?’
The second talk, ‘Cleaning assembled PCBs: A Crucial Way of Enhancing Reliability and Avoiding Field Failures’ by Wilfred Clemens (Kolb Cleaning Technology) was also excellent. He discussed the latest SMT parts and how old cleaning processes like ISP on a rag and toothbrush don’t make sense for boards with small and bottom-leaded components. He even suggested that most SMT lines can be run less expensively on new cleaning chemicals relative to ISP due to the losses seen with alcohol. And finally, did you know that ‘no-clean’ flux isn’t really no-clean? The paste manufacturers even say on their datasheets that an appropriate cleaning process must be considered for their no-clean flux. Damn marketers. Once again there are many ways to get a good solution, but it is imperative to actually decide on an approach based on tests and data like any engineering problem.
There was an expo in between the technical sessions which allowed one-on-one conversations and demos with the people who are building the latest and greatest in SMT equipment and services. Everyone knew their stuff and was able to excitedly explain how they will take the technology to the next level. Your correspondent was happy to connect with the contract manufacturers who build his boards and ask them newly-learned questions from the technical talks about their SMT process.
It wasn’t all paste-bake-clean talk either. The organizers put together a behind the scenes tour of the stadium. Getting to see the inner workings of the stadium was a great opportunity for any Broncos fan, even if they didn’t make it to last Sunday’s game. After the official functions everyone got together to enjoy a happy hour, sharing stories of unexpected build experiences.
One thing is for sure: the assembly of PCBs is a significant engineering challenge, and events like these make it much more surmountable. The Rocky Mountain SMTA group really outdid themselves this year, and here’s hoping for an even better 2016 event!