Software developer ANSYS recently helped Hutchinson Technology, Inc. cut about 20 percent from the time it was taking to solve various engineering-analysis problems in the design of its computer-disk-drive suspension assemblies. The assemblies, barely an inch long, consist of an arm that holds a read/write head and flies over the disk, much the same as the spindle on a record player.
Critical to the design is the control and damping of the assembly as it stops to read a track. "These devices can't vibrate," says Ray Wolter, HTI development engineering supervisor. "We have to make sure that the suspensions' natural frequencies are sufficiently far away from those of the full disk drive assembly that they won't resonate with and amplify each other."
Wolter and his engineering staff use ANSYS to calculate the frequencies. The result: "We've cut the number of prototypes we have to do," Wolter says. Plus, he adds, they can do some analyses—such as non-linear, transient dynamic modeling, and studies of the interaction of multiple components—that they wouldn't be able to do quickly if at all by hand.
ANSYS also helped Wolter and his team one other way: The company showed them how to get the computers to run faster. ANSYS engineer Gene Poole developed a procedure to increase the amount of memory on their Dell PCs available to the ANSYS solvers. "He manipulated controller mechanisms and limit switches to almost double the memory so we can run bigger models faster," Wolter says. "That helped us run 20% faster.
Among the tasks the engineers now do with the software: structural static analysis to characterize key suspension performance factors under steady loading conditions; steady-state analysis to characterize inertial forces stemming from lift-off and static shock; and thermal analysis to find stresses that will create hot spots and material failures.