Abstract: Method and apparatus for determining the rotational direction of a rotatable article, such as a spindle motor used in a data storage device to rotate a data recording disc. The article includes an index mark which is detected by an index sensor to identify an index reference position on the article. The index sensor and index mark are further used to detect the direction of rotation of the article. In some embodiments, a second sensor is provided so that first and second timing pulses are generated from the index mark by the index sensor and the second sensor. In other embodiments, a second (detection) mark is added to the article so that first and second timing pulses are generated by the index sensor. In either case, a rotational direction detection circuit determines the rotational direction of the article in relation to the first and second timing pulses.

Abstract: A method for automatically correcting the dynamic imbalance of a disc pack of a disc drive, the disc pack conveyed to a first selected position in a balance correction assembly station where a rotary positioner lifts and rotates the disc pack to a reference position for the attachment of weighted shims to the disc pack. A shim selector assembly delivers a selected shim, and an end effector transfers the selected shim to a shim attachment assembly. The shim attachment assembly rotates and spreads open the shim so that the disc pack can be receivingly engaged thereby, and the shim attachment assembly releases the selected shim to lockingly engage the disc pack. A flipping assembly reverses the disc pack for placement of another selected shim to the other end of the disc pack, as required.

Abstract: A method of automatically measuring the dynamic imbalance of a disc stack of a disc drive assembly, the disc stack conveyed to a first selected position in a balance measure assembly station where a rotary positioner lifts and rotates the disc stack above a sensor to locate an electrical lead of the disc drive motor. The disc stack is positioned in a reference position to position the electrical leads a for powering the disc drive motor. The disc stack is then conveyed to a second selected position where a motor power assembly clamps and powers the motor and discs. A balance head assembly measures the magnitude and phase angle of the dynamic imbalance of the disc stack and records the measurement to a production control computer.

Abstract: An apparatus of automatically measuring the dynamic imbalance of a disc stack of a disc drive assembly, the disc stack conveyed to a first selected position in a balance measure assembly station where a rotary positioner lifts and rotates the disc stack above a sensor to locate an electrical lead of the disc drive motor. The disc stack is positioned in a reference position to position the electrical leads a for powering the disc drive motor. The disc stack is then conveyed to a second selected position where a motor power assembly clamps and powers the motor and discs. A balance head assembly measures the magnitude and phase angle of the dynamic imbalance of the disc stack and records the measurement to a production control computer.

Abstract: An apparatus and method for automatically correcting the dynamic imbalance of a disc pack of a disc drive, the disc pack conveyed to a first selected position in a balance correction assembly station where a rotary positioner lifts and rotates the disc pack to a reference position for the attachment of weighted shims to the disc pack. A shim selector assembly delivers a selected shim, and an end effector transfers the selected shim to a shim attachment assembly. The shim attachment assembly rotates and spreads open the shim so that the disc pack can be receivingly engaged thereby, and the shim attachment assembly releases the selected shim to lockingly engage the disc pack. A flipping assembly reverses the disc pack for placement of another selected shim to the other end of the disc pack, as required.