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DISK DRIVE OPERATION
SpinPoint V40 Product Manual
25
5.1.3 Disk Stack Assembly
The disk stack assembly in the SpinPoint V40 hard disk drive consists of 1 or 2 disks and disk spacers
secured on the hub of the spindle motor assembly by a disk clamp. The aluminum-alloy disks have a
sputtered thin-film magnetic coating.
A carbon overcoat lubricates the disk surfaces to prevent heads and media wear due to the repeated head
contacts with disk surfaces during head take-offs and landings. Contact between heads and disk surfaces
occurs only in the landing zone outside of the data area, when the disks are rotating at slower than normal
speed during spin up or down. The landing zone is located at the inner diameter of the disk, far beyond the
last cylinder of the data area.
5.1.4 Head Stack Assembly
The head stack assembly consists of an E-block/coil sub-assembly, read/write heads, a flexible circuit, and
bearings. The E-block/coil sub-assembly is assembled with an E-block and over-molded coil. Read/write
heads are mounted to spring-stainless steel flexures that are then swage mounted onto the E-block arms.
The flexible circuit connects the read/write heads with the PCBA via a connector through the base casting.
The flexible circuit contains a read/write Preamplifier IC.
5.1.5 Voice Coil Motor and Actuator Latch Assemblies
The rotary voice coil motor consists of upper and lower permanent magnets and magnetic yokes fixed to the
base casting and a rotary over-molded coil on the head stack assembly. Each magnet consists of two
alternating poles and is attached to the magnet yoke. Rubber crash stops mounted on the over-molded coil
and a magnetic yoke physically prevent the head(s) from moving beyond the designed inner boundary into
the spindle or off the disk surface.
Current from the power amplifier induces a magnetic field in the voice coil. Fluctuations in the field around
the permanent magnets move the voice coil so that heads can be positioned in the requested cylinder.
5.1.6 Air Filtration System
Heads fly very close to the disk surfaces. Therefore, it is very important that air circulating within the drive
be maintained free of particles. Samsung HDAs are assembled in a purified air environment to ensure
cleanliness and then sealed with a gasket. To retain this clean air environment, the SpinPoint V40 is
equipped with a re-circulating filter, which is located in the path of the airflow close to the rotating disk and
is designed to trap any particles that may develop inside HDA.