Patent ID: 7196798

Claim:
A method for establishing a reference point for a multi-axis machine tool having an X-stage movable along an X-axis, a Y-stage movable along a Y-axis, and a Z-stage movable along a Z-axis, the method comprising: (a) establishing a YZ-plane for the machine tool by: (1) reflecting a light beam from a laser head off of an X-reflector on the X-stage such that said light beam is sensed by an interference detector; and (2) moving the X-stage and repositioning said laser head and said X-reflector as needed such that said light beam remains sensed by said interference detector, thereby aligning said light beam with the X-axis; (b) placing an optical alignment module (OAM) having a beam bending mirror on the X-stage with said beam bending mirror nominally centered about the Z-axis; (c) aligning said OAM optically perpendicular to said light beam, thereby aligning said OAM relative to said YZ-plane; (d) establishing the Z-axis of the machine tool by: (1) setting said beam bending mirror to deflect said light beam from the X-axis to the Z-axis; (2) reflecting the light beam off of a Z-reflector on the Z-stage such that said light beam is sensed by said interference detector; and (3) moving the Z-stage and repositioning said OAM as needed relative to the X-axis and the Y-axis such that said light beam remains sensed by said interference detector, thereby aligning portions of said light beam parallel to both of the X-axis and the Z-axis; and (e) establishing an XY-plane for the machine tool by: (1) setting said beam bending mirror to deflect said light beam from the X-axis to the Y-axis; (2) reflecting said light beam off of a Y-reflector on the Y-stage such that said light beam is sensed by said interference detector; and (3) moving the Y-stage and repositioning said Y-reflector as needed relative to the X-axis and the Z-axis such that said light beam remains sensed by said interference detector, thereby aligning portions of said light beam parallel to both of the X-axis and the Y-axis.