Convection soldering oven

FIGURE 5.11 Convection soldering oven with view inside the process chamber (graphics courtesy of Rehm Thermal Systems)... 

Just as in the reflow soldering oven, there are multiple solder-wave preheater styles, but only two are in prevalent use radiant preheaters (direct and indirect IR) and forced-air convective preheaters. Both are effective and both have their advantages. In fact, the best configuration is a combination of the two. Some wave-soidering machines can be equipped with both top and bottom preheaters. This can be advantageous for thermally massive boards. 

Reflow solder using a convection reflow oven ... 

FIG. 30 Conceptual drawing of the RSF-4, four-zone convection reflow oven. The nozzle manifold and scirroco fans improve heat transfer efficiency and reduce the temperature gradients across the PCBs during soldering. (Courtesy of Panasonic.)... 

Once SMDs have been placed in solder paste, the assembly will be reflow soldered. Thk can be done in either batch-type ovens, or conveyorized continuous-process ovens. The choice depends primarily on the board throughput/hour required. Whereas many early ovens were of the vapor phase type, most ovens today use IR heating, convection heating, or a combination of the two. The ovens are zoned to provide a thermal profile necessary for successful SMD soldering. An example of an oven thermal profile k shown in Fig. 11.26. 

FIGURE 47.7 Forced-convection oven with 12 top and 12 bottom heating modules (a). Each module is independently heated and controlled. The last two top and bottom modules on the right (b) are for active cooling of the soldered circuit board to ensure that solder has reached solidus before exiting the oven. In this machine, cooling zones are aided by fans blowing over water-cooled radiators. (Courtesy of Heller Industries). 

FIGURE 47.11 Arrows indicate impinging forced-convection flows from oven blowers. The inadvertent thermocouple junction (crossed wires) will record oven local air temperature rather than the intended measurement target the solder-joint area. 

FIG. 28 a) REF-G3 model oven used for FA controller card introduction to lead-free solder, b) This oven concept employed a combination of infrared (IR) and convection heating sources. (From Ref. 20.)... 

---