Edge gripping specimen prealigner

A method for rotating a substantially planar circular specimen having an exclusion zone extending inwardly from a periphery of the specimen, comprising:

• providing a frame;
• movably mounting at least three capstans to the frame;
• positioning the capstans around the periphery of the specimen so as to contact only the exclusion zone of the specimen;
• mounting a rotatable drive hub to the frame;
• coupling the capstans to the rotatable drive hub by continuous belts;
• placing a movable idler pulley in contact with each of the belts;
• and
• moving the idler pulleys to place the belts in alternate tensioned and untensioned states, the tensioned state drawing the capstans inwardly toward the specimen to grip the specimen and the untensioned state releasing the capstans outwardly to release the specimen.

A method for prealigning a substantially planar circular specimen having a periphery, comprising:

• providing a specimen prealigner having at least three movable capstans distributed around a circle sized to surround the specimen;
• coupling with continuous belts the capstans to a rotatable drive hub;
• providing a robot arm for placing the specimen in a position substantially parallel to a plane passing through the capstans;
• tensioning the belts to draw the movable capstans inwardly toward the specimen to grip the specimen by the periphery;
• releasing the robot arm from the specimen;
• rotating the drive hub;
• coupling the drive hub rotation through the continuous belts to the capstans and, thereby, to the specimen;
• prealigning the specimen;
• untensioning the belts to release the movable capstans outwardly away from the specimen;
• grasping the specimen with the robot arm;
• and
• moving the specimen with the robot arm to another position.