Abstract: A gram load measurement assembly is configured to measure the gram load of a head stack assembly (HSA) of a disk drive being manufactured using the HSA's suspension tabs, thereby avoiding contact with the Air Bearing Surface (ABS) of the HSA's sliders when checking the gram load forces after the installation of the Head Gimbal Assembly (HGA) installation on the actuator assembly.

Abstract: A tester including a laser transmitter, a laser receiver, a zero reference plane located between the laser transmitter and the laser receiver, a tower reference plane located between the laser transmitter and the laser receiver, wherein the tower reference plane defines an aperture, and a controller. The controller is configured to measure a pitch static attitude of a head stack assembly by at least determining a zero axis, determining a first horizontal position of the aperture and a second horizontal position of the aperture, determining a mid-point of a first slider of the head stack assembly, determining a first vertical position of the aperture, determining a first horizontal line, and generating a pitch static attitude reference line corresponding to a pitch static attitude of the first slider based on a least squares approximation using the mid-point of the first slider and the first horizontal line.

Abstract: A tester for measuring a pitch static attitude of a head stack assembly including a laser transmitter configured to transmit laser beams, and a laser receiver configured to receive the laser beams from the laser transmitter, wherein the laser transmitter and the laser receiver are configured to receive a head stack assembly between the laser transmitter and the laser receiver. The tester also includes a laser guide located between the laser transmitter and the laser receiver, and configured to block the laser beams from entering a gap in the head stack assembly and reaching the laser receiver.