Design of Automatic Test System for Dynamic Performance of Magnetic Head Based on Machine Vision

The dynamic performance test of a hard disk head is the most effective method of evaluating hard disk performance, but it must be conducted in a dust- and electrostatic discharge (ESD)-free environment. With the rapid development of perpendicular magnetic recording (PMR) technology, the flying height of a magnetic head is reduced from 18 nm to less than 2 nm, which makes the testing conditions increasingly demanding, and the traditional way of manual testing by an operator cannot match the requirement of production testing. To meet the technical requirement of the dynamic performance test of a hard disk head, an automatic test system is developed using a CCD image sensor and an Epson robot. In this system, the vision system of the robot can accomplish, in real time and accurately, the image acquisition and image processing of the object in the magnetic head testing process and calculate the actual position of the object after hand-eye calibration. Visual guidance is provided to the robot to grasp and place the target accurately, and related sensors provide various state data during the system operation. Thus, the difficult problem in the development process from manual operation to robot automation in the dynamic performance test of a magnetic head is successfully solved. The results show that the consumption of test materials is considerably reduced, and the test precision and efficiency are markedly improved.