On the use of three thermocouples to verify a pcb profile during reflow

An initial study was conducted to determine if just three thermocouples could verify a printed circuit board (PCB) profile during reflow. Three of the 20 channels were used to record the temperatures on the leading edge of the PWB laminate while the other 17 were distributed around the PCB in critical and noncritical locations. Four different Pb-free reflow profiles were planned, a baseline profile and three other profiles that represent changes to the stability of the oven. The data were analyzed by looking at each individual T/C in the group, and second, by looking at the grouped behavior of the three T/Cs. A one-was Analysis of Variance (ANOVA) was conducted. The MCT was used to determine if differences in the performance of the T/Cs between the different profiles are significant. There is evidence to support that the reflow oven used in this experiment may need to be serviced soon.