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5.3
CNC and Manual Control Modes
CNC programmable settings
include X-Y stage position, Z-height (for focus adjustment), zoom,
and lighting. M3 CNC metrology software is factory configured for AV300 and AV350 systems.
Please refer to the separate M3 CNC Software manual.
Stage
position can be set manually using the system’s joystick and trackball pendant. Please see
page 12 of this manual.
Focus
can be set manually by rotating the center knob of the joystick.
Zoom and Illumination
can be set manually be via the system’s touch-screen. Note that image
brightness can also be adjusted using the display controls of the all-in-one PC or touch-screen
monitor. Not that changing display settings does not affect edge detection (but changing lighting
does).
5.4 Operating
Considerations
5.4.1 Lighting
Considerations
Once the image has been properly focused and magnification has been set, adjust light levels
as necessary.
Correct lighting is paramount to accurate measurement with any video-based measurement
system. A clear image with lighting toward the low side is recommended. Lighting that is too
low will result in a dark, low-contrast image with indiscernible features. Lighting that is too bright
will result in a washed-out image that distorts features.
When adjusting lighting, start with light that is lower than desired, and then increase lighting while
viewing the image on the monitor. Maintain constant lighting for consistent results. Use the
same light level while sampling points for a single feature. Do not to change the light level between
points used to measure a circle.
Depending on the part characteristics and the feature being measured, the right combination
of lighting from the available sources may aid in bringing out a particular feature. Take time to
experiment by balancing these light sources.
NOTE:
In order to preserve lamp life and to reduce unnecessary heat in the
system, keep the lights turned down when the system is not in use.
5.4.2 Magnification
Considerations
Magnification (or zoom) is also important for proper measurements. In general, higher magnifi-
cation provides greater resolution and accuracy; however, not all features should be inspected
at the highest available magnification. Too high a magnification may make it difficult to discern
the edge of a feature by exaggerating edge defects such as burrs or chips. Try decreasing the
magnification until the edge is more clearly identifiable.
Consider factors such as tolerance requirements, manufacturing processes, functional require-
ments and optical characteristics of the part. Features with loose tolerances may not need to be
inspected at high magnification. Select the highest magnification that is suitable for the feature
being inspected.
NOTE:
Factory certification can only be provided upon satisfactory of the calibration
verification procedures by an authorized representative of the L.S. Starrett Co. Use
of your system without proper verification and certification is not recommended.
