Reflow soldering is adjusted according to the temperature curve change of reflow soldering to achieve the best reflow soldering effect, and the reflow soldering temperature curve intuitively reflects the soldering temperature change process of the circuit board in the reflow soldering furnace, and it is easy to cause a large number of reflow soldering defective products if not soldering according to the reflow soldering temperature curve.
The temperature curve of the reflow oven is generally set according to the solder paste you use and the device on the PCB and the material it uses, and the temperature curve generated is different in different PCB environments! The temperature profile that we are testing is actually testing the temperature on the PCB board, not the temperature on the furnace that you see. If the reflow temperature profile is not set properly, all quality control in the front end is meaningless. What is the temperature profile of reflow soldering? The process is more complex and can be divided into two types: single-sided placement and double-sided placement
From the analysis of the temperature curve, when the PCB enters the heating zone (dry zone), the solvent and gas in the solder paste evaporate, and at the same time, the flux in the solder paste wets the pad, component ends and pins, and the solder paste softens, collapses, and covers the pad, isolating the pad and component pins from oxygen; When the PCB enters the insulation zone, the PCB and components are fully preheated to prevent the PCB from suddenly entering the soldering area and heating up too quickly and damaging the PCB and components; When the PCB enters the soldering area, the temperature rises rapidly to make the solder paste reach a melting state, and the liquid solder wets, diffuses, diffuses, or reflows the pads, component ends, and pins of the PCB to form solder contacts. The PCB enters the cooling zone to solidify the solder joints and complete the entire reflow soldering.
A reflow temperature profile is a graph that records the temperature changes of a PCB printed wiring board during the reflow soldering process. It provides useful information to help engineers and technicians optimize the PCB reflow process to ensure quality and performance.