Issue link: https://iconnect007.uberflip.com/i/1433652
102 SMT007 MAGAZINE I DECEMBER 2021 "We also found the solder defects book's advice on reducing "insufficients" to be helpful," Maggie said. "I'm a little embarrassed to say that many of our stencils had BGA area ratios 4 of less than 0.66. Apparently, in the past, BE used stencils that were quite thick, and didn't decrease the thickness on some as lead spacings became closer," Maggie said. ere was a lull and it appeared as though discussions were wrapping up, until Frank chuckled. "As an MBA candidate, I was embarrassed to find out that I was the only one of us that didn't know that the 80/20 rule came from Pa- reto and his charts," he said, jokingly. "As soon as I understood "the rule," I ran to the sales department and asked Charlie Beck- er (head of sales, the editor) if it applied to BE sales," Frank said. "Charlie said that almost ex- actly 80% of BE's cash sales come from 20% of BE's customers. A perfect example." Chuck was feeling more comfortable with the executive team of BE. So, out of character, he said, "You know, Frank, I just have a two- year tech degree, you are almost an MBA, and even I knew the 80/20 rule." Everyone burst into laughter. John even tapped Chuck's shoulder as a sign of acceptance. With this moment of levity, it appeared the meeting was over. But then Maggie added, "One more thing. We are planning on buying a competitor, and we would like any suggestions you might offer, Patty." Maggie was feeling felt quite proud that she had finally remembered to call her former professor by her first name. "As long as it is not Ivy Electronics, you should be OK," Patty replied. "But it is Ivy Electronics," John said deject- edly. Why is Patty down on Ivy Electronics? Should Maggie and John not buy it? And what does a Pareto Chart of your first pass yields show? What is your resulting continu- ous improvement action plan? SMT007 References 1. "It's Wrong to Average or Add Cp and Cpk," by Ronald C. Lasky, Dec. 10, 2010. 2. "Continual improvement process," Wikipedia. com. 3. The Printed Circuit Assembler's Guide to… Sol- der Defects, by Christopher Nash and Ronald C. Lasky. 4. "Process Guidelines to Ensure Optimal SMT Electronics Assembly," by Ed Briggs and Ronald C. Lasky, Indium Corporation. Ronald C. Lasky is an instructional professor of engineering for the Thayer School of Engineering at Dartmouth College, and senior technologist at Indium Corporation. To read past columns, or contact Lasky, click here. Learn How to Avoid Solder Defects With New Book by Indium Corporation The Printed Circuit Assembler's Guide to… Solder Defects—the latest title in the I-007eBook library—is specifically dedicated to educating the printed circuit board assembly sector and serves as a valuable resource for people seeking the most relevant information available. This book will be especially beneficial to PCB assemblers in improving their assembly processes and the reliability of the end-product, eliminating field failures, and reducing costs. Download your free copy today!