Issue link: https://iconnect007.uberflip.com/i/1466505
MAY 2022 I SMT007 MAGAZINE 61 Sue was excited as she explained her answer. "e challenge is to know how many compo- nents to move from the chip shooter to the flexible placer. at requires using algebra. I actually think I know how to do that." Andy's heart sank. He wanted to impress Sue but didn't even know where to begin to solve this problem. Sensing his apprehension, Sue suggested they had mastered the third question and it was time to move on to the next one. 4. What is a fiducial on a printed wiring board (PWB)? a. It shows the PWB manufacturer that the etching process is within specification. b. It is used to align the PWB to the assembly equipment. c. It is needed as a reference for solder mask. d. It is the most cost-effective way to minimize PWB warpage. "I've got this one," Andy said. "e answer is B. I work on the stencil printer most of the time and we need to align the PWB to the printer. When Sam Reynolds was teaching me to do this, he said, 'Andy, this step is called aligning the PWB fiducials to the printer.'" "Well, I work mostly on the reflow oven and setting the kits up for the next jobs, so that is a new one to me," Sue responded as they moved on to the final question. 5. What is closest to SAC305's melting point? a. 230°C b. 210°C c. 183°C d. 220°C e. 200°C "Since you are the reflow, hotshot, you should know this one," Andy teased. "e peak temperature of our reflow ovens is between 240°C and 245°C," Sue mused. Figure 1: Sue March works on a reflow oven like this one.