Etched laminate structures for reducing track mis-registration in a disk drive suspension

• US 7,573,680 B1
• Filed: 02/28/2006
• Issued: 08/11/2009
• Est. Priority Date: 11/01/2005
• Status: Active Grant

• Current Assignee: Magnecomp Corporation (TDK Corporation)
• Original Assignee: Magnecomp Corporation (TDK Corporation)
• Inventors: Kulangara, Sivadasan
• Primary Examiner(s): Cao; Allen T
• Application Number:
  US11/364,127
• Time in Patent Office: 1,260 Days
• Field of Search: 360/244.8, 306/244.8, 306/294.4, 306/244.2, 306/294, 306/245, 306/244.5, 306/244.9, 306/234.6
• US Class Current: 360/244.8
• CPC Class Codes: G11B 5/4833 Structure of the arm assembly, e.g. load beams, flexures, parts of the arm adapted for controlling vertical force on the head G11B5/484 takes precedence

Abstract

Structures and methods for creating a vertical offset between suspension springs or fingers within a suspension head assembly for use in a disk drive are disclosed, the vertical offset helping to reduce track mis-registration errors. The base plate and load beam may be made from three-layer composite materials that have been etched to create either recesses therein into which the suspension springs ends are placed and then welded, or the base plate and load beam may be etched to create mesas on which the ends of one of the suspension springs are welded. The three layers may comprise stainless steel, polyimide, and stainless steel. In another embodiment, one of the suspension springs is a three-layer material that has been etched to create a raised central portion that is vertically offset from the other suspension spring. In another embodiment, spacers are employed as shims underneath one of the suspension springs. Generally, at least one of a spring extension, the load beam and the mount beam comprise a laminate material.

Claims

1. A suspension assembly for a hard disk drive, the suspension assembly comprising:

a load beam;

a mount plate;

first and second spring extensions extending between the load beam and the mount plate;

a vertical offset between the first and second spring extensions; and

at least one etched area on at least one of the load beam and mount plate, the etched area facilitating the vertical offset;

wherein at least one of a spring extension, the load beam and the mount beam comprise a laminate material.

2. A suspension assembly as defined in claim 1, wherein the mount plate and load beam comprise a laminate material.

3. A suspension assembly as defined in claim 2, wherein the laminate material has at least three layers.

4. A suspension assembly as defined in claim 2, wherein the laminate material comprises two layers of stainless steel and a layer of polyimide disposed between the two layers of stainless steel.

5. A suspension assembly as defined in claim 2, wherein a corner of the mount plate and a corresponding corner of the load beam are etched.

6. A suspension assembly as defined in claim 1, wherein the mount plate comprises a laminate material, and wherein on one side of one end of the mount plate, a top portion of the material has been etched off, and wherein a bottom portion of the material on the other side has been etched off, thereby forming two adjacent cantilevers vertically spaced from one another.

7. A suspension assembly as defined in claim 6, wherein the mount plate is pre-split through the layers of the composite prior to being etched.

8. A suspension assembly as defined in claim 1, wherein a spring extension is formed of a laminate material, the spring extension being etched on either end to form a raised center portion.

9. A suspension assembly as defined in claim 8, wherein there is a gap between said load beam and said mount plate, said raised center portion spanning the gap.

10. A suspension assembly as defined in claim 8, wherein the assembly includes two spring extensions, a first spring extension being etched to form a raised center portion and a second spring extension that is relatively flat compared to said first spring extension.

11. A suspension assembly as defined in claim 1, wherein the mount plate has a first mesa and said load beam has a second mesa, said first and second mesas being substantially adjacent one to the other, with a spring extension extending from the first mesa to the second mesa.

12. A suspension assembly as defined in claim 11, wherein a second spring extension extends from a non-mesa portion of the mount plate to a non-mesa portion of the load beam.

13. A suspension assembly as defined in claim 1, wherein the mount plate includes a first recess and the load beam includes a second recess, with a spring arm extending from the first recess to the second recess.

21. A method of achieving a vertical offset between a first and a second spring extension on a suspension assembly for a disk drive as defined in claim 1, the method comprising the steps of:

etching portions of the load beam and mount plates, wherein at least one etched portion is etched from a composite material; and

extending at least one of said first and second spring extensions from an etched portion of said load beam to an etched portion of said mount plate.

22. A method as defined in claim 21, wherein the step of etching portions of the load beam and mount plates comprises etching a mesa on at least one of said load beam and mount plate.

23. A method as defined in claim 21, wherein the etching step comprises etching through at least one layer of a laminate material.

24. A method as defined in claim 21, wherein the method further includes providing means for passive damping.

25. A method as defined in claim 21, wherein a first chemical is used to etch a first layer of at least one of the load beam and the mount plate, and wherein a second chemical is used to etch a second layer of at least one of the load beam and the mount plate.

26. A method as defined in claim 21, wherein said first layer is stainless steel and is etched with ferric chloride, and wherein said second layer is polyimide and is etched with sodium hydroxide.

14. A suspension assembly for a hard disk drive, the suspension assembly comprising:

a load beam;

a mount plate;

first and second spring extensions extending between the load beam and the mount plate;

a vertical offset between the first and second spring extensions; and

means for facilitating the vertical offset;

wherein at least one of a spring extension, the load beam and the mount beam comprise a laminate material.

15. A suspension assembly as defined in claim 14, wherein the means for facilitating the vertical offset comprises at least one etched area on one of the load beam and mount plate.

16. A suspension assembly as defined in claim 14, wherein the means for facilitating the vertical offset comprises an etched corner of the mount plate substantially adjacent to an etched corner of the load beam.

17. A suspension assembly as defined in claim 14, wherein the means for facilitating the vertical offset comprises an etched top portion of the mount plate forming a first cantilever beam, an etched bottom portion of the mount plate forming a second cantilever beam, said etched bottom portion of the mount plate being adjacent to the etched top portion of the mount plate, thereby forming two adjacent cantilevers vertically spaced from one another.

18. A suspension assembly as defined in claim 14, wherein at least one of said mount plate, said load beam, and said spring extension comprises an etched composite material having at least three layers.

19. A suspension assembly as defined in claim 14, wherein the mount plate has a first mesa and said load beam has a second mesa, said first and second mesas being substantially adjacent one to the other, with a spring extension extending from the first mesa to the second mesa.

20. A suspension assembly as defined in claim 14, wherein the means for facilitating the vertical offset comprises the spring extension being formed from a composite material having at least three layers, the spring extension having at least one etched area that facilitates the vertical offset.

27. A suspension assembly for a hard disk drive, the suspension assembly:

a load beam;

a mount plate;

first and second spring extensions extending between the load beam and the mount plate, at least one of the spring extensions comprising a composite material;

a vertical offset between the first and second spring extensions; and

at least one etched area on the spring extension that comprises a composite material, the etched area facilitating the vertical offset.

28. A suspension assembly as defined in claim 27, wherein the first spring extension is etched to form a raised center portion and the second spring extension is relatively flat compared to said first spring extension.

29. A suspension assembly as defined in claim 27, wherein the first spring extension comprises a composite material having at least three layers.

30. A suspension assembly as defined in claim 27, wherein there is a gap between said load beam and said mount plate, said raised center portion extending across the gap.