To insure that components of the device met the customer
expectation a number of test were performed on these
components. In validating and verifing these components
the results from these tests were compared to the
customer needs and a pass/fail criteria for each
individual component was noted.
To insure that tolerance did not affect the centering
process, each component of the assembled test rig was
leveled off using the Coordinate Measuring Machine (CMM)
The wobble of the rotary stage used in the mapping of
magnetic fields and measuring of the bushings center was
tested. The wobble would affect the results of the readings
therefore producing false results corrupting the centering
This test was performed on the load cell from
Transducer Technique, model DSM 50. The test was to verify
and calibrate the load cell for device. However, when
weight was applied to the load cell, the change in voltage
was low, too low for the data acquistion card to pick up.
Therefore an operation ampliflier was added to increase the
voltage output and then the test was performed.
The test for the lower and upper vacuum chucks were
performed to verify that the holding force of the
components is acceptable to hold the magnet and bushing.
Weight was added to each component, at different psi, and
when the vacuum failed to hold the weight that value was
For the test involved in measuring the accuracy and
repeatability of the Thorlabs linear stage, the laser
sensor from Acuity was used. Because the of precision in
the measuring ability of the laser was small, the factory
calibrations were used as verification for the laser.
Therefore the linear stages were moved in one micron steps
and the numbers from the linear stages and laser were
The upper vacuum chuck was tested to center it to the
axis of rotation of the rotary stage. The precision of the
centering the upper vacuum chuck is not crucial, however
having the upper vacuum chuck near the axis of rotation
will decrease the time to center the magnetic field. There
is no pass/fail criteria for this test, the test was done
to insure that the upper vacuum chuck is near the axis of
Once the bushing and magnetic field have been
centered, the bushing and magnet need to be attached to one
another. To accomplish this a number of adhesives were test
and compared to identify the best adhesive.
Analysis of Shear Force required to move bushing or
Test were performed using the Acuity laser, XY linear
stages and the lower vacuum chuck. The bushing was placed
on the lower vacuum chuck and the peak values were
determined and the difference between them were taken. This
was done until the bushings center was less than a micron.
Test were performed using the each component of the
assembly. The bushing was placed on the lower vacuum chuck
and the magnet was placed on the upper vacuum chuck. The
magnetic field and bushings centers were determined. Once
the centers were found the bushing and magnet were attached
to one another. The results of this test need to be within
25 microns per customer needs.
Complete Tabulation of Test Results
Chart illustrates the engineering spec. to the tested