Building the Perfect Drive

With the distance between a drive platter and drive head measured in tens of nanometers, dust specks inside a drive are fatal flaws, which is why drives are assembled in clean rooms. Shown here is a view of a Seagate clean room from the outside, with technicians inspecting actuators.

The view from inside the clean room, showing most of a drive assembly line.

This drive-base is near the beginning of the assembly line, before anything has been added to the base.

In this partly assembled drive, you can see the voice-coil magnet (the L-shaped piece near the upper left corner of the drive base), the Fluid Dynamic Bearing (FDB) motor (the round piece showing just right of center of the drive base), and the breather-filter (the rectangular piece just above the motor). The breather filter filters the air that's needed to equalize the air pressure inside the drive with the air pressure outside the drive.

The disc-caddy, which holds 25 platters (discs), stands in position, ready for the platters to be taken and moved to the drive.

Here, two platters (discs) have been picked-up from the disc-caddy by the disc robot in preparation for installation in the drive.

The disk robot positions the platters on the FDB motor, as shown here. The platters are then installed and balanced.

Next, the actuator (which is already attached in this picture) is added, followed by the upper voice-coil magnet (not shown above).

Once all the internal components are assembled, the cover is attached before using the servowriter to write the servo-pattern and then sealing the drive. (The drive electronics use the servo-pattern to control the drive head positioning so it stays precisely on the right track when reading from or writing to the disk.) Once the drive is sealed, it can leave the clean room for final steps of assembly.

No longer in the clean room, a technician uses an acrylic template as an aid to attaching the circuit-board.

Next comes a special foam insulation, which is shown here being positioned. (Seagate says it is the only manufacturer who does this.) The foam serves primarily for sound deadening.

In the final step, a technician attaches the outer "cover" (for lack of a better term). This cover (which Seagate calls a SeaShield) protects the circuit board, helps reduce noise, and serves as a place to mount instructions for jumpers and other drive features.

Copyright © 2004 Ziff Davis Media Inc. All Rights Reserved. Originally appearing in ExtremeTech.