To improve productivity and reach better quality in assembling, measurements and proper process controlling are a necessary factor. This study aims to focus on the monitoring heat-level-based vapour phase reflow soldering (VPS), where – as it was found – different thermocouple constructions can affect the set parameters of the oven and resulting soldering profiles significantly.,The study experiments showed significant alteration of the heating profiles during the process of the reflowing using different construction of k-type thermocouples. In a heat-level-based VPS oven, polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA) gas and water-resistant, fibreglass, thin PFA and ultrathin PFA-covered thermocouples were tested with ±1 °C precision. The oven parameters were swept according to the heating power; the length of the introduced thermocouple cables was also taken into account. An FR4-based sample PCB was used for monitoring the temperature.,According to the results, due to the mass and volume of the thermocouples’ wires, different transients were observed on the resulting soldering profiles on the same sample PCB. The thermocouples with lower thermal mass result in faster profiles and significantly different heating factor values compared to the thermocouples that have larger thermal mass. Consequently, the length of the thermocouple wires put in the oven has also considerable effect on the heat transfer of the PCB inside the oven as well.,The paper shows that the thermocouple construction must be taken into account when setting up a required soldering profile, while the thermal mass of the wires might cause a significant difference in the prediction of the actual and expected soldering temperatures.

中文翻译：

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不同热电偶结构对热级气相焊接曲线的影响

为了提高生产率并达到更好的装配质量，测量和适当的过程控制是必要的因素。这项研究的重点是监测基于热量水平的气相回流焊接 (VPS)，正如我们发现的那样，不同的热电偶结构会显着影响烤箱的设定参数和产生的焊接曲线。研究实验表明使用不同结构的 k 型热电偶在回流过程中显着改变加热曲线。在基于温度的 VPS 烘箱中，聚四氟乙烯 (PTFE)、全氟烷氧基 (PFA) 气体和防水、玻璃纤维、薄 PFA 和超薄 PFA 覆盖的热电偶以 ±1 °C 的精度进行了测试。根据加热功率扫描烘箱参数；引入的热电偶电缆的长度也被考虑在内。使用基于 FR4 的样品 PCB 来监测温度。根据结果，由于热电偶导线的质量和体积，在同一样品 PCB 上产生的焊接曲线上观察到不同的瞬变。与具有较大热质量的热电偶相比，具有较低热质量的热电偶导致更快的曲线和显着不同的加热系数值。因此，放入烤箱的热电偶线的长度对烤箱内 PCB 的热传递也有相当大的影响。, 该论文表明，在设置所需的焊接配置文件时，必须考虑热电偶结构，