With the continuous miniaturization of SMT electronic components and increasing chip integration, array-packaged devices such as BGA and CSP are being increasingly used in products ranging from laptops and smartphones to medical equipment, automotive electronics, military, and aerospace products, leading to higher quality requirements. 5G was a buzzword in 2019, and now the 5G era has begun. From the perspective of internal PCBA circuit boards in mobile phones, compared to 4G phones, the design challenges of 5G phones, besides baseband chips, mainly focus on RF and antennas. This is because 5G operates at frequencies at least twice as high as 4G, with five times the bandwidth, up to 29 frequency bands, five times the power, ten times the speed, and dozens of times more antennas.

This requires us to continuously improve process capabilities, increase equipment, and ensure high-reliability products through high-quality soldering. In high-precision electronic manufacturing processes, there are various SMT production equipment. Key automated devices include SMT automatic X-RAY component counters, SMT first-article inspection systems, fully automatic solder paste printers, online 3D-SPI solder paste inspection systems, pick-and-place machines, reflow ovens, online AOI optical inspection systems, and online PCBA fully automatic milling cutters for board separation. Each device has specific functions and purposes. The reflow oven is the final process in the SMT production line, responsible for melting the solder of assembled PCB circuits and components to bond them to the mainboard.

Reflow soldering has become the mainstream process in SMT. Most components on commonly used smartphone boards are soldered to the circuit board through this process, which relies on the effect of hot air flow on solder joints. The paste-like solder undergoes physical reactions under specific high-temperature airflow to achieve SMD soldering. It is called "reflow soldering" because gas circulates within the machine to generate high temperatures for soldering purposes. There are also many types of reflow ovens, such as hot air reflow ovens, nitrogen reflow ovens, vapor phase reflow ovens, and vacuum reflow ovens.