Reflow soldering and hand soldering
At this point, the PCB sits on your assembly workspace, fully populated with SMT components. Now, it is time to turn on your reflow oven or hot plate.
Reflow soldering
Regardless of what type of reflow system you use, exercise extreme care when moving the PCB from your workspace to the oven or hot plate. If you strike the board against an object or, worse, drop it, you are likely to find that all your hard work placing the components was done for naught.
Your level of involvement during reflow soldering depends greatly on the technical capabilities of your reflow system. If you are using a stock hot plate or toaster oven, it is entirely up to you to monitor the state of the PCB as the solder heats and melts. If you remove the board from the heat too soon, you will have areas of unmelted solder, which means electrical contact will be poor to nonexistent, and parts may fall off the board. If you wait too long to remove the board from the heat...