Hard disk drive disk media curvature mitigation

A method for assembling a hard disk drive (HDD), the method comprising:

• determining flatness of each disk medium of a plurality of disk media;
• based on the determined flatness, positioning at least some of the plurality of disk media onto a spindle of the HDD such that an outer diameter of each disk medium is offset from an inner diameter of the disk medium in a same direction along an axis of rotation of the spindle;
• and
• positioning a load/unload (LUL) ramp within the HDD, based on the offset, relative to the outer diameters of the at least some disk media;
• wherein:
• the plurality of disk media comprises a first group of disk media;
• the LUL ramp comprises a first ramp portion and a second ramp portion;
• positioning the at least some disk media includes:
• positioning each disk medium of the first group of disk media with its outer diameter offset from its inner diameter in a same first direction along the axis of rotation of the spindle, and
• positioning each disk medium of a second group of disk media with its outer diameter offset from its inner diameter in a same opposing second direction along the axis of rotation of the spindle;
• and
• positioning the LUL ramp includes:
• positioning the first ramp portion, based on the offset in the first direction, to align in correspondence with the outer diameters of the first group of disk media, and
• positioning the second ramp portion, based on the offset in the second direction, to align in correspondence with the outer diameters of the second group of disk media.

A hard disk drive (HDD) comprising:

• a disk stack comprising a plurality of disk media rotatably mounted on a spindle, wherein in an undisturbed state an outer diameter of each disk medium is offset from an inner diameter of the disk medium in a same direction along an axis of rotation of the spindle;
• a plurality of head sliders each housing a read-write transducer configured to read from and to write to a respective disk medium of the disk stack;
• means for moving the plurality of head sliders to access portions of the plurality of disk media;
• and
• means for supporting loading the plurality of head sliders onto the disk stack and for supporting unloading the plurality of head sliders from the disk stack, the means for supporting positioned, based on the offsets of the plurality of disk media, to align in correspondence with the outer diameters of the plurality of disk media;
• wherein:
• the plurality of disk media comprises a first group of disk media;
• the HDD further comprises a second group of disk media;
• the LUL ramp comprises a first ramp portion and a second ramp portion;
• each disk medium of the first group of disk media is rotatably mounted on the spindle with an outer diameter offset from an inner diameter in a same first direction along the axis of rotation of the spindle;
• the first ramp portion is positioned to align, based on the offset in the first direction, in correspondence with the outer diameters of the first group of disk media;
• each disk medium of the second group of disk media is rotatably mounted on the spindle with an outer diameter offset from an inner diameter in a same opposing second direction along the axis of rotation of the spindle;
• and
• the second ramp portion is positioned to align, based on the offset in the second direction, in correspondence with the outer diameters of the second group of disk media.