Improvement of the indirect measuring capability of the spinedle test stand

Abstract

In media technology, a Track-Per-Inch (TPI) index is estimated as capabilities of the spindle test
stand to verify such a higher capability of hard disk storage. The test stand in this study is capable of testing
the media with up to approximately 200 kTPI. There are several methods to test TPI capacity of the test stand.
In this research, two methods are studied for their possibilities to implement. The first method, an indirect
method, is developed as a technique for the measurement of radial runout of the spindle using the capacitance
probe that measures the representative of mechanical motion between the head and the media to account for the tolerance of the spindle installation. The second method, a direct method, uses the read/write features between the head and the media to measure and estimate from the accessed data. The data could be calculated back to a position error of the media track as the capability of the spindle test stand. In either method, a statistical approach is utilized to estimate for TPI capability of the steady state track holding for the high TPI media. Nevertheless, the indirect method is the preferred technique for implementation due to time consumption and complexity of measurements. This study is reported the improvement of the indirect method to close as the direct method.