Issue link: https://iconnect007.uberflip.com/i/1284035
60 SMT007 MAGAZINE I SEPTEMBER 2020 pad. If BOM says 0201, for instance, but they have 0402, that's a design issue. Our engineers could provide a DFM report to the customer to correct that design; most of the time, it's a design issue that causes a problem with the manufacturing process. Johnson: Once those are worked out, the pro- cesses are clear, and you're manufacturing it correctly. After you've shaken out all the BOM and component issues and it's running through manufacturing, most of those config- uration issues for reliability are now removed. At that point, what starts to pop up on the list of failures? Are we talking primarily about sol- dering issues and failure? Castro: Soldering is the most common issue. Sometimes, we have a problem with profiling. The solder has an issue for melting because the profile temperature is not correct. Most defects are soldering issues. Johnson: Do you find that your customers are starting to specify different kinds of solder for different sorts of functions? Castro: We have different kinds of solder that customers request for RoHS lead-free, tin-lead, no-clean, or RoHS wash. We have many differ- ent kinds of solder that customers request. Johnson: Does that put a challenge on you to reconfigure the floor or in any sort of method like that? Is that something that takes extra consideration on the floor for you, or does it just flow through? Castro: We have two general kinds of lead- free and leaded solder. The lines have specific equipment capabilities to run if it's RoHS lead- free or leaded. When the customer requests it, we have to understand which products are RoHS and which ones are leaded. It's been set up already that way with all the tooling because we have to set those aside, like the squeegees in the stencil process. We have to separate it on the manufacturing floor already for us to do it right away, so we don't have any hassle or any issues when you run the product. Johnson: When a customer comes to you, look- ing for a solder that is new to you, do you go through a qualification process with that new solder? Castro: Everything is new, even the products. If they ask us to build a new product, we have to have a qualification process to verify all the materials, the process, the components, etc. We have to make sure that's then indicated on the qualification build, and then we're going to send this qualification build report to the cus- tomer to approve. If they say the design is not good, then we'll change it. The customer will provide us a new design or a new drawing or a new solder paste if there's some issue on the qualification build. It should be approved by the customer before we continue running. Johnson: If they're specifying a new solder paste or a solder mask that's new to you, how much qualification does Green Circuits put onto that component as a part of the process? Castro: We ask the supplier to provide us all documentation I'm doing the supplier qualifi- cation, so I have to check the documentation. For example, for a solder I don't know at all, I request the supplier to provide information for me to accept it and buy this product. I need to require an FAI for this new solder paste, what kind of solder paste, and what kind of chemi- cal they have on this because I need to put this on MSDS if this is a chemical. Johnson: There's much more to it than just making sure that it works just okay to hold the component on the board. You have a whole lot of administrative work to do for safety. Castro: We have to ask them for a sample so we can run it to make sure the customer approves before we order. Johnson: How often are you facing that sort of a process with a new material going on to your manufacturing floor? Is this something