Rotating Centering Method And Tooling for Precision Parts Alignment

Rotating Centering Method And Tooling for Precision Parts Alignment

       Disclosed is a method used to center a machine spindle to
a target.  At present, one has to align glassmasters manually via a
target on a jig boring machine prior to the boring of the tooling
holes.

      The previous method used a spindle-mounted microscope. This
microscope must be accurately positioned to the center line of
rotation (a difficult parameter to verify and maintain).  The method
of adjustment is extremely operator-dependent.  The machine table is
moved x and y until the target is aligned to a circular reticle in
the microscope.  This places the machine spindle and target on the
same center line.  The microscope is now removed and tools to bore
the hole inserted and the hole bored.

      The new method uses an optical system to project a spot smaller
than the target offset from the center of the machine spindle.  The
projected spot extends beyond the edge of the target (approximately
half the diameter of the spot). A large area photo detector is then
placed under the glassmaster so that the area of the spot that is not
covered by the target will fall on the detector.  This is shown in
Fig.  1.  The machine spindle is then rotated and the signal produced
by the spot is observed (Fig. 2).  The table is then moved in the x
direction until a minimum variation on the signal from the photo
detector is obtained.  This operation is then repeated by moving the
table in...