we use Vitronics Delta 6622 solder wave.I try to adjust high of backplate, but I don't know whether the adjustment is correctly.Now, when the frame enter in the main wave, solder flow in the same direction as PCB.But when the frame go above main wave the solder stop to flow.Is that correctly? I looked in the mashine documentation but I can't find nothing about adjustment of this backplate.
You want the backplate set up so that when there's no PCB the wave stands still or moves towards the PCB. When the PCB moves over the wave, it should just pull the wave towards the back (in the same direction as the PCB). This will help reduce bridging. Best to use the glass plate to set this up.