Understand reflow soldering equipment in SMT processing

Understand reflow soldering equipment in SMT processing
Reflow soldering equipment is SMT production line, also known as reflow soldering Reflow soldering is to re melt the solder pre distributed on the PCB pad to realize the mechanical and electrical connection between the pin or solder end of the wafer assembly and the PCB SMT wafer processing Before reflow soldering, use a screen printer to print an appropriate amount of solder paste on the PCB pad, use a chip mounter to paste SMC/SMD components to the corresponding position, and send the circuit board and components in the reflow soldering equipment together. The solder paste is dry, preheated, melted, wetted, and cooled, and the components are welded to the printed circuit board Reflow soldering equipment has two basic structures, one is single temperature zone reflow soldering, the other is multi temperature zone reflow soldering
Circuit board

Single temperature zone reflow soldering furnace controls the temperature change of temperature zone with time according to reflow temperature curve, and PCB is still in the furnace The advantages of this single temperature zone reflow soldering are small investment and easy to track the temperature of the set curve The disadvantages are that the temperature will change periodically, the production cycle is long, and the energy consumption is high It is generally applicable to single piece or small batch production According to the editor of Zhongyan Electronics, many SMT chip processing manufacturers use this method for small batch SMT chip processing and production
Multi temperature zone reflow soldering is to divide the soldering furnace into several temperature zones with different temperatures according to the reflow temperature curve. PCB boards pass through each temperature zone at a constant speed to realize various processes such as preheating, reflow and cooling.
The characteristic of multi temperature zone reflow soldering is that the constant temperature control of each temperature zone is relatively independent and the control calculation is relatively simple. Its biggest advantage is high recovery efficiency, suitable for continuous industrial batch production. However, the physical spacing of each temperature range of multi temperature reflow soldering makes each temperature range have a certain temperature difference, which will have a certain negative impact on the thermal shock and thermal stress of PCB. In this case, more temperature zones can be used to reduce the temperature difference.
Due to the "reflow" and "self positioning" characteristics of reflow soldering, the requirements for the leading patch process are relaxed; Good reflow soldering quality, saving solder and good product consistency make reflow soldering equipment become mainstream equipment and key technology PCBA process equipment
The above is about reflow soldering equipment in SMT wafer processing.