The invention relates to a probe assembly for a wafer probe station having a probe holder and a replaceable probe tip. Therefore, the method is advantageous in that it allows PCB manufacturers to save the efforts for forming and protecting the via holes because the double-sided PCB does not need via holes, and reduces its fabricating cost and time, due to simplicity of this method. The cutting edges are spaced at about 180 degrees apart around a core of the drill and the edge line of a tip section of the cutting edges is depressed toward the core of the drill. The first end is configured to be disposed about a fuel injector. The general idea is to measure the distribution for each individual camera, compress it, and save it in the module.