31 Oct '13, 5am
Another Reflow Soldering Solution
[Don] started by modifying the hotplate by reversing the handle mount — this provides a useful location to mount the IR temperature sensor. The control circuit uses PWM to adjust the temperature of the hot plate using the solid state relay. Because the IR temperature sensor has a cone of visibility it ends up reading an average area temperature as opposed to an individual point — for reflow soldering this is perfect. [Don] notes that some calibration is required, as depending on the emissivity of the object being measured the readout can differ — shiney objects will read a lower temperature than dark objects. He recommends doing the calibration with a scrap PCB and your chosen solder paste to get a general baseline for your project.