Disk drives have been around since the 1950's. Since their inception, disk drives have undergone significant improvements and considerable downsizing. Personal computers and lap top versions have fueled increased demand for smaller, more powerful disk drives. To keep up with this demand and the need for greater disk drive performance, many electronic firms are sourcing OEM drives for their product lines. Although the basic disk drive components are similar, one should not assume that all drives are created or evaluated equally. Beyond the obvious mechanical design differences, supplier fragility specifications seem to be creating a form of "specmanship". This term is intended to denote or suggest that some of the shock data appear to give one OEM design a more robust or rugged character than that of a competitor. With the help of GHI's Shock Response Spectrum software, several shock signals were created and evaluated against each other in the frequency domain. Various shock signal parameters including pulse width, wave shape, peak or faired acceleration and filtering were compared against each other for effects on input energy. Beyond this initial comparison, the IBM Model 0663 3.5" fixed disk drive was instrumented for shock response to these various inputs in an effort to improve package design evaluation efficiency. A major finding of this study is that by altering the method of acceleration measurement (peak g, vs. "faired" g), the length of the shock pulse (11, 20 ms), the application of signal filters and the type of waveform shape, dramatically different shock results can be created. These findings lead one to ask, "just what is a 50g product?" Without specifically stating each of these parameters in a "50g"shock specification, the users of OEM disk drives really don't know what shock fragility conclusions to draw. These omissions will lead to unequal conclusions.
Library of Congress Subject Headings
Data disk drives--Packing; Packing for shipment; Packaging
Department, Program, or Center
Manufacturing and Mechanical Engineering Technology (CAST)
Neuburg, Kenneth, "A Study in the application of shock response, spectrum analysis to disk drive shipping and handling shock tests" (1995). Thesis. Rochester Institute of Technology. Accessed from
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