At the end of the line is the reflow oven itself, through which the boards pass on a belt through carefully graded hot air zones. Certainly a step up from a toaster oven with an Arduino controller!

V-grooves that go most of the way through a PCB are one way to go about this, but a line of perforations along ... Too weak, and the board may break or twist before its time.

Implementing flash memory on a PCB. Implementing, in this case, refers to bringing the circuit onto the motherboard, also ...