A PZT micro-actuator for a head gimbal assembly includes a pair of separate PZT elements and each PZT element has a body and a plurality of electrical pads. On the supporting disk, in its circumferential area, first grinding tools are arranged concentrically, axially opposite from which second grinding tools are arranged, forming a radial grinding gap. The locations of the functional groups to the backbone of the molecule of the lubricant allows for shorter lengths of free backbone length between functional groups attached to a lubricated surface. The first curing test units are electrically connected with the first group of wires, and the second curing test units are electrically connected with all the wires of the second group of wires.