Issue link: https://iconnect007.uberflip.com/i/1137649
JULY 2019 I SMT007 MAGAZINE 91 tip idle temperature, solder joint temperature is more relevant than of the "no-load" tip idle temperature (Figure 5). As noted in Figure 5, the recommended approach to reliable soldering is to focus on joint temperature rather than just tip tempera- ture, since the correct formation of the solder joint is especially reliant on the right amount thermal energy being applied. In these circum- stances, a soldering iron providing better ther- mal transfer is capable of using a lower tip temperature to deliver enough thermal energy to form a reliable solder joint. Soldering irons with less efficient thermal transfer properties generally require higher temperatures to achieve the same result. However, the risk is the formation of a thicker intermetallic layer, which may be stressed and the likelihood of potential damage to compo- nents and the pad. Figure 3: Activation energy increases in relation to the thickness. Figure 5: Tracking solder joint temperature is preferred over soldering tip temperature. Figure 4. Rate of dissolution.