Cast baseplate for a disk drive having an arcuate shroud wall and adjacent arcuate groove
View Patent ↗A disk drive includes a cast baseplate, and a disk having a major surface and an outer circumference. The cast baseplate includes a casting inlet gate region, a planar area underlying the disk, an arcuate shroud wall that is substantially orthogonal to the planar area, and an arcuate groove immediately adjacent the planar area. The planar area is separated from the disk major surface by less than 0.8 mm. The arcuate shroud wall is disposed less than 0.8 mm from the disk outer circumference, and includes a first shroud wall portion and a second shroud wall portion. The first shroud wall portion is more proximate to the casting inlet gate region than is the second shroud wall portion. The arcuate groove is immediately adjacent the first shroud wall portion, and defines a groove depth in the range 0.2 mm to 2 mm relative to the planar area.
1. A disk drive comprising:
a disk having a disk major surface and a disk outer circumference;
a cast baseplate including
a casting inlet gate region;
a planar area underlying the disk and separated from the disk major surface by less than 0.8 mm;
an arcuate shroud wall that is substantially orthogonal to the planar area and disposed less than 0.8 mm from the disk outer circumference, the arcuate shroud wall including a first shroud wall portion and a second shroud wall portion, the first shroud wall portion being more proximate to the casting inlet gate region than is the second shroud wall portion;
an arcuate groove immediately adjacent the planar area and immediately adjacent the first shroud wall portion, the arcuate groove defining a groove depth in the range 0.2 mm to 2 mm relative to the planar area.
2. The disk drive of claim 1 wherein the arcuate groove is disposed between the planar area and the first shroud wall portion.
3. The disk drive of claim 1 wherein the arcuate groove defines a groove width in the range 0.8 mm to 3 mm, measured parallel to the planar area.
4. The disk drive of claim 3 wherein the first shroud wall portion is separated from the disk outer circumference by a radial clearance less than 0.8 mm, wherein the disk major surface includes an annular written region that contains data, wherein the disk major surface includes an annular unwritten region adjacent the disk outer circumference that does not contain data.
5. The disk drive of claim 4 wherein the annular unwritten region defines an unwritten region radial extent, and wherein the radial clearance plus the annular unwritten region radial extent is greater than the groove width.
6. The disk drive of claim 1 wherein the cast baseplate comprises aluminum.
7. The disk drive of claim 1 wherein a surface finish of the casting inlet gate region is substantially different from a surface finish of the planar area.
8. The disk drive of claim 1 wherein the arcuate shroud wall is disposed at an angle relative to the planar area that is different from 90° by a draft angle in the range 1 to 3 degrees.
9. The disk drive of claim 1 further comprising a parting line region, and wherein a surface finish of the parting line region is substantially different from a surface finish of the planar area.