The Role of Wave Solder Machines Preheating System

 

Automatic DIP/ THT line machine wave soldering machine, DIP selective soldering machine, with a maximum working width of 400x300mm, to meet the soldering of automotive electronics, communications, electronics, computers and mobile phones, and other consumer electronics.

Each wave solder machine must be preheated before the wave soldering of the circuit board, and the preheated circuit board will not have the problem of batch wave soldering during the wave soldering. The preheating temperature and time of the printed board should be determined according to the size and thickness of the printed board, the size and number of components, and the number of mounted components. ETA will share a detailed explanation of the function and function of wave soldering preheating.

 

The preheating temperature is 90-130℃ (PCB surface temperature), and the upper limit of the preheating temperature is used for multilayer boards and more mounted components. For the preheating temperature of different PCB types and assembly forms, refer to the table below. For reference, the specific conditions of the assembled board must be combined, and the settings must be performed after process test or trial welding. The preheating time is controlled by the conveyor speed.

1. Before wave soldering, the circuit board must be sprayed with flux to help wave soldering. The solvent component in the flux will be heated and volatilized when passing through the preheater. In this way, it can avoid the phenomenon of explosion caused by high-temperature vaporization of the solvent component when passing through the liquid surface, and ultimately prevent the quality of tin particles.

 

2. The parts of the products to be immersed in tin are slowly heated up when they pass through the wave soldering preheater, which can avoid damage to the parts due to the physical effects of sudden heat during wave passing.

 

3. The parts or terminals that have been preheated by wave soldering will not significantly reduce the soldering temperature of the solder joints due to their own low temperature during the wave, so as to ensure that the soldering meets the temperature requirements within the specified time.

 

The wave soldering preheating temperature is well controlled to prevent false soldering, pulling and bridging, reduce the thermal impact of the solder wave on the substrate, and effectively solve the problem of PCB board warpage, delamination and deformation during the soldering process. If the preheating temperature is too low or the preheating time is too short, the solvent in the flux will not evaporate sufficiently, and the gas generated during soldering will cause soldering defects such as pores and solder balls; if the preheating temperature is too high or the preheating time is too long, the flux will be Decomposition in advance will deactivate the flux, which will also cause welding defects such as burrs and bridges.

 

Therefore, it is necessary to properly control the preheating temperature and time. The best preheating temperature is that the flux applied on the bottom surface of the PCB is viscous before wave soldering. There are three common preheating methods in wave soldering machines: ①air convection heating; ②infrared heater heating; ③heating by a combination of hot air and radiation.

❙ Wave Solder Machine Video