Larry E. Wittig
Digital Equipment Corp., 146 Main St., Maynard, MA 01754
Hard disk drives used in computer equipment make noise while at idle and while seeking because the outer shell vibrates. A number of treatments thought to be useful to reduce this vibration were identified, and the most effective ones were determined by conducting one-at-a-time screening tests. Since no single treatment provided sufficient noise reduction, a fractional fractorial experiment was conducted using a Taguchi L[sub 16](2[sup 15]) array to determine the best combination of seven different treatments. This approach reduced the total number of combinations for the experiment from 128 to 16. The experimental results showed that a combination of just two or three of the seven treatments gave the most noise reduction.