Reflow Profile Simulation System Development

With the implement of RoHS/WEEE, lead-free solders are used more and more extensively in the field of the electronic packaging, which requires higher welding reliability of the lead-free solder joints. The quality of the solder joints lie on the control of the reflow profile when the solders are reflowed. At present, the control and optimizing of soldering is carried out by analyzing the defects of the solder joints. This instrument is designed to heat one solder joint under different reflow profiles, then analyze defects of the solder, and finally optimize the parameters of the reflow oven through simulating the environment of the reflow oven. At the same time, this instrument can also be used for the thermal cycle testing and the thermal impact testing.In this paper, the principle of Gleeble 1500 thermal mechanical was simulated through comparing the heating modes such as HIF and resistance heating. It turned out that the heating instrument can not only rise temperature quickly, but also cool down rapidly when accompanied with water cooling, when huge current pass the heating instrument with using heat of resistance.The system involves multiple techniques such as electronics, computer, auto-control, MCU etc. Traditional temperature control mostly uses the pure analog circuits to drive the heating circuit apartment. The system not only uses the PID parameter automatic tuning to carry out temperature control, but also introduces offline temperature measuring to improve the precision of the instrument. The system adopts the structure of superior/below position operator. The position operator above employs software programs of VB to achieve simple and friendly controlling interface; the position operator below is built up by date gathering module, output controlling module, and communication module etc.