Reflow oven is one of the three main processes in SMT mounting process. It is mainly used to solder the circuit board of the components that have been mounted. The solder paste is melted by heating so that the patch element and the circuit board solder pad are fused together. To understand reflow soldering machine, you must understand the SMT process first.
NeoDen reflow oven IN12
The solder paste is a mixture of metal tin powder, flux and other chemicals, but the tin in it exists independently as small beads. When the PCB board through several temperature zones in the reflow furnace, above 217 degrees Celsius, the small tin beads melt. After the flux and other things catalyzed, so that countless small particles melt together, that is to say, make those small particles back to the liquid state of the flow, this process is often said to be reflux. Reflux means that tin powder from the former solid back to the liquid state, and then from the cooling zone back to the solid state again.
Introduction to reflow soldering method
Different reflow soldering machine has different advantages, and the process is also different.
Infrared reflow soldering: high radiation conduction heat efficiency, high temperature steepness, easy to control the temperature curve, PCB upper and lower temperature is easy to control when double-sided welding. Have shadow effect, temperature is not uniform, easy to cause components or PCB local burn out.
Hot air reflow soldering: uniform convection conduction temperature, good welding quality. The temperature gradient is difficult to control.
Forced hot air reflow welding is divided into two types according to its production capacity:
Temperature zone equipment: mass production is suitable for mass production of PCB board placed on the walking belt, to go through a number of fixed temperature zone in order, too little temperature zone will exist temperature jump phenomenon, is not suitable for high-density assembly plate welding. It is also bulky and consumes a lot of electricity.
Temperature zone small desktop equipment: small and medium-sized batch production rapid research and development in a fixed space, the temperature according to the set conditions change with time, easy to operate. Repair of defective surface components (especially large components) is not suitable for mass production.
Post time: Apr-28-2021