In Fig. 5D denotes the diameter of the PCB disc; H denotes the thickness of the PCB. Only the edge and centre positions are differentiated due to the disc symmetry. Measurement on rectangular plates was done according to  and .
Temperature data from the different thermocouple positions (shown in Fig. 5) were averaged to get an arithmetic mean temperature of the whole PCB body. This approach BIMU 8 relevant from the aspect of filmwise condensation, and even structure of the PCB substrate.
5.1. Comparison of different models
Fig. 6 shows a measurement run on Plate III where the centre point shows a bit slower heating, than the edge temperatures, which is consequential from the direction of flow and the central thickness of the film layer. However the low deviation between the plots and the fixed maximum already shows the advantage of the VPS method compared to other reflow heat transfer types (such as radiation or convection). A final step of the calculation summarizes the averages of five measurement runs to get a final measurement plot for the verification.