Browse Prior Art Database

Brazed Ceramic Comb for a High Modulus Actuator

IP.com Disclosure Number: IPCOM000123663D
Original Publication Date: 1999-Mar-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 2 page(s) / 113K

Publishing Venue

IBM

Related People

Prater, W: AUTHOR [+2]

Abstract

This disclosure describes a method to manufacture a high modulus actuator comb (or E-block) for a magnetic disk drive. On one end of the comb are the arms with holes used to locate the suspensions to which sliders are attached, in the middle is a bore to accept a pivot bearing that permits nearly frictionless rotation, while at the other end is a yoke holding the voice coil. With each generation of disk drives track densities increase and seeks times decrease which require actuator design improvements. Two ways to make these improvements are to increase bandwidth of the servo control system by increasing the structural resonance frequencies and to reduce the access time of disk drives by reducing the rotational moment of inertia of the actuator comb.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Brazed Ceramic Comb for a High Modulus Actuator

   This disclosure describes a method to manufacture a
high modulus actuator comb (or E-block) for a magnetic disk drive.
On one end  of the comb are the arms with holes used to locate the
suspensions to which  sliders are attached, in the middle is a bore
to accept a pivot bearing that permits nearly frictionless rotation,
while at the other end is a yoke holding the voice coil.  With each
generation of disk drives track densities increase and seeks times
decrease which require actuator design improvements.  Two ways to
make these improvements are to increase bandwidth of the servo
control system by increasing the structural resonance frequencies and
to reduce the access time of disk drives by reducing the rotational
moment of inertia of the actuator comb.  These can be accomplished by
using materials with a higher Young s modulus, higher strength and a
density similar to or less than that of 6061 aluminum, the alloy
currently favored by the industry.

   Ceramic actuator combs can be manufactured of stiff,
strong, low density materials to accomplish these design objectives.
Ceramics of interest are: silicon carbide, silicon nitride, alumina,
boron carbide, titanium carbide, titanium boride, aluminum nitride,
beryllia and magnesia.  These low density ceramics have the desired
material properties of specific stiffness and specific strength
several times that of 6061 aluminum.

   Unfortunately, ceramics are difficult and expensive to
accurately manufacture into precise three-dimensional shapes because
of the processing problems of shrinkage, warpage and cracking.  This
invention works around these problems by brazing together a plurality
of flat arms, spacer rings and a coil yoke to create a single piece
comb of complex geometry, see figure 1.  First, flat components are
economically made by laser scribing of sintered ceramic sheets.
Then, the critical dimensions, such as arm tips and crash stop
locations are ground.  Next, the components are metallized at the
areas that will later form joints.  Then, the parts are secured into
a fixture with...