Issue link: https://iconnect007.uberflip.com/i/1493797
72 SMT007 MAGAZINE I MARCH 2023 are wel l-prepared f or the SMTA Certified Process Engineer's exam 3 . As a matter of fact, I just gave them three practice quiz questions and they teased me that they were too easy." "What were the questions?" Sue asked. He then shared these three questions: 1. What is the area ratio of a 15 mil-round aperture in a 5-mil-thick stencil? 2. A PWB is presented to the reflow oven every 40 seconds. The PWB is 20 cm long and a 5-cm spacing is desired between the PWBs. What must the belt speed on the reflow oven be to support this 40-second cycle time? 3. The PWB in question 2 must be in the heated tunnel of the oven for four minutes. How long must the heated tunnel be? "If they think those questions are easy, that's really promising," Sue said of the staff mem- bers in training. "I think many people would find them challenging." Epilogue Sue and Andy finished all their assignments at Castellanos Electronics. All the workers who took the SMTA Process Engineer Certifi- cation exam passed with flying colors. Defects were reduced by 90% overall. e best news was that the team of workers now had the skills to run the factory when José wasn't there and could also handle new yield, productivity, and quality issues on their own. Since he could now take an occasional vacation, José agreed to stay on as the factory manager, reporting to Maggie and John. Tune in to the next episode to find out the solutions to Andy's three problems. SMT007 References 1. "Pareto chart," Wikipedia.org, Sept. 17, 2022. 2. Handbook of Electronic Assembly and A Guide to SMTA Certification, by Ron Lasky et. al, SMTA Publishing. 3. "SMTA: Certification," SMTA.org. Ronald C. Lasky is an instruc- tional professor of engineering for the Thayer School of Engineering at Dartmouth College, and senior technologist at Indium Corporation. To read past columns, click here. Download The Printed Circuit Assem- bler's Guide to… Solder Defects by Christopher Nash and Dr. Ronald C. Lasky. You can also view other titles in our full I-007eBooks library. Win a Dartmouth Sweatshirt! Can you solve the three questions above? The first person to send me an email with all three answered correctly will win a Dartmouth sweatshirt. Send your answers to Dr. Ron at rlasky@indium.com.