Method for manufacturing ring-shaped glass spacer

Patent metadata

Field	Value
Publication number	US-11705158-B2
Application number	US-202217589824-A
Country	US
Kind code	B2
Filing date	Jan 31, 2022
Priority date	Sep 29, 2017
Publication date	Jul 18, 2023
Grant date	Jul 18, 2023

Abstract

A method for manufacturing the ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus, including: preparing a ring-shaped glass blank; and grinding main surfaces of the ring-shaped glass blank by using grinding pads that include diamond particles as fixed abrasive particles.

First claim

What is claimed is:

1. A method for manufacturing a ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus, the method comprising:
preparing a ring-shaped glass blank; and
grinding main surfaces of the ring-shaped glass blank by using grinding pads that include diamond particles as fixed abrasive particles,
wherein the grinding is performed such that a surface roughness Ra of the main surfaces of the ring-shaped glass blank is not larger than 1.0 μm, and an average inclination RΔa of the main surfaces that is obtained using the following Equation (1) is at least 0.02,

R
⁢
Δ
⁢
a

=

1
n

⁢

∑

i
=
1

n

⁢



d
⁢

z
i

d
⁢
X



(
1
)

here, dz i /dX is expressed by the following Equation (2), ΔX represents a data interval (μm) between measurement data pieces of surface roughness, z i (i is a natural number) represents the i-th measurement data piece, and n represents a total number (n>6) of measurement data pieces

d
⁢

z
i

d
⁢
X

=

1

60
·
Δ

⁢

⁢
X

⁢

(

z

i
+
3

-

9
⁢

z

i
+
2

+

4
⁢
5
⁢

z

i
+
1

-

4
⁢
5
⁢

z

i
-
1

+

9
⁢

z

i
-
2

-

z

i
-
3

)

.

(
2
)

2. The method according to claim 1 , wherein
the grinding of the main surfaces of the ring-shaped glass blank is performed by using the grinding pads each including, as each of the fixed abrasive particles, an aggregate formed by bonding the diamond particles through vitrification.

3. The method according to claim 2 , further comprising
forming a conductive film on at least one of the main surfaces of the glass spacer.

4. The method according to claim 2 , further comprising
performing shape processing on the ring-shaped glass blank to provide a transitional surface between at least one of main surfaces of the ring-shaped glass blank and one of an outer circumferential edge surface and an inner circumferential edge surface of the ring-shaped glass blank, wherein
the grinding of the main surfaces of the ring-shaped glass blank is performed after the performing of the shape processing.

5. The method according to claim 4 , wherein
the transitional surface is a chamfered surface.

6. The method according to claim 5 , further comprising
forming a conductive film on at least one of the main surfaces of the glass spacer.

7. The method according to claim 4 , further compri

Assignees

• Hoya Corp

Inventors

• Takano Masao
• Eda Shinji

Classifications

• G11B17/021 Primary

  Selecting or spacing of record carriers for introducing the heads · CPC title

• G11B17/038

  Centering or locking of a plurality of discs in a single cartridge · CPC title

• G11B23/0301 Primary

  Details · CPC title

• G11B25/04

  using flat record carriers, e.g. disc, card · CPC title

• G11B25/043

  using rotating discs · CPC title