Plated-through Holes of Printed Circuit Board
Through-hole technology, also known as "thru-hole", refers to the mounting scheme for electronic components, including the use of holes in the insert hole and soldering to the printed circuit board pad on the opposite side of the manual assembly or the use of automatic insertion of the mounting machine. As far as I understand, through holes in PCBs are often plated, hence the term PTH.
Plated-through holes
How to make plated-through holes?
For plated-through holes, electroless plating is followed by an additional step of drilling, and then established the thickness of the copper plating. The plates were screened and metallized. The metal becomes resistant and the bare copper is etched away.
The through-hole becomes a plated-through hole so that the assembly contacts the desired conductive layer. Plated through-hole, no longer need to connect with the SMT board manufacturing components, but still use the role of the level and the relationship usually called via.
