Triad factories use a soldering iron tip temperature of 600°F and a touch time of 3 to 4 seconds, touching both the pad and the pin. We have found this to be an optimum point for most applications where we are soldering thru-hole transformers to boards. Your factory floor conditions may vary in terms of equipment used, environment, and type of Lead-free solder used. Your process may need to be adjusted in terms of touch time and temperature in order for you to achieve the desired results for your solder joints.