Redrill of Plugged Plated Through Holes
Original Publication Date: 1988-Mar-01
Included in the Prior Art Database: 2005-Feb-15
Plated through holes (PTHs) in printed circuit boards (PCBs) which have undersized hole diameters must be redrilled in order to achieve desired hole size. Redrilling a PTH risks damaging the hole rim if the drill enters off center of the existing hole. This risk is addressed in a drilling procedure which redrills the PCB using the same spindle configuration originally used during the initial drill. A calculation is then made to determine where the spindle should be to ensure that the drill is centered over the hole to reduce misalignment. The procedure is as follows.