Measurement Sensors
Sensing elements made of two different metals that generate a voltage proportional to the temperature provide the data needed to set up a reflow oven. Thermal profiling thermocouples are attached to specific points on a test board to record the heat experienced by the components. These sensors allow engineers to ensure that every part of the assembly reaches the correct temperature for the right amount of time.
Attachment Methods
The accuracy of the profile depends on how well the sensor is bonded to the board or the component. High-temperature solder or thermally conductive adhesive is often used to ensure good thermal contact. Tape is generally avoided because it can peel off or create an insulating air gap.
The wires must be routed so they do not interfere with the movement of the board through the oven. Sensors are placed on both large components that heat up slowly and small ones that heat up quickly.
Data Accuracy
Regular calibration of the thermocouples and the data logger ensures that the readings are correct. The gathered data is used to create a graph of temperature over time. This graph verifies that the process meets the requirements of the solder paste manufacturer.
