Method for making a base plate for suspension assembly in hard disk drive
A swage mount that includes a flange, having a first side and a second side, and a cylindrically shaped hub. The hub is primarily comprised of a metal (such as stainless steel), and extends from the second side of the flange, and has an inner surface and an outer surface. The surface of the swage mount is plated with one or more layers of metal, or a combination of metals, which provide a) increased retention torque, and b) increased part cleanliness. This invention may be used in conjunction with surface hardened swage mounts that contain surface protrusions. In this case the metal plating prevents separation of the protrusions from the swage mount, thereby preventing contamination.
1 . A method of providing a metal layer on the boss of a swage mount comprising the steps of:
cleaning the boss;
activating the boss metal; and
subjecting the boss to a first metal plating bath through which an electrical current is passed.
2 . The method of claim 31 wherein the step of subjecting is terminated before the metal layer achieves a thickness of 50 microns.
3 . The method of claim 31 wherein the step of subjecting is terminated after the metal layer achieves a thickness of 0.5 microns but before the metal layer achieves a thickness of 50 microns.
4 . The method of claim 31 wherein the step of activating includes placing the boss into a sulfuric acid bath on which there is applied an electrical potential.
5 . The method of claim 31 including the step of applying a strike plate to the boss.
6 . The method of claim 31 wherein the first metal plating bath is a Wafts Nickel bath.
7 . The method of claim 31 including the step of immersing the boss in a second metal plating bath to deposit a second layer of metal plating.
8 . The method of claim 35 wherein the step of applying includes placing the boss into a Wood's bath having between 10 and 15 oz/gal nickel chloride, and through which an electrical current is passed.
9 . The method of claim 36 wherein the Wafts Nickel bath includes 7 to 10 oz/gal nickel chloride.
10 . The method of claim 36 wherein the Watt's Nickel bath includes 30 to 40 oz/gal nickel sulfate.
11 . The method of claim 36 wherein the Watt's Nickel bath includes 4 to 6 oz/gal boric acid.
12 . The method of claim 36 wherein the boss is exposed to a second Watt's bath containing saccharine.
13 . The method of claim 37 wherein the second metal plating bath is a Rhodium bath.
14 . The method of claim 37 wherein the step of immersing is continued until the second layer of metal plating achieves a thickness of 3 micro inches, but is discontinued before the second layer of metal plating achieves a thickness of 9 micro inches.
15 . The method of claim 38 wherein the Wood's bath includes hydrochloric acid.
16 . The method of claim 43 wherein the Rhodium bath includes 1.3 to 2 g/L rhodium sulfate.
17 . The method of claim 43 wherein the Rhodium bath includes 25 to 80 ml/L sulfuric acid.