Method for controlling temperature course at soldering points during laser soldering

摘要

For rapid soldering operations at small soldering points, it is necessary to use a fast, contact-free temperature measurement method. In principle, an infrared radiation pyrometer is suitable for this purpose. A disturbing effect in this temperature measurement method is the variation in the emission coefficients from one soldering point to another. According to the invention, this disadvantage is eliminated by calibrating the infrared radiation pyrometer in the course of each soldering operation on reaching a fixed temperature point detected by suitable measurement methods and situated within the temperature range of the method individually for the respective soldering point using previously determined calibration curves. To control the soldering point temperature in accordance with a specified temperature/time cycle, the control circuit is constructed from the infrared radiation pyrometer and the laser, whose power can be controlled. This temperature control method is insensitive to the variations in the volume of solder and the emission factor of the soldering points.