The LVDT stylus
shaft rides on a thin air film at 60 psi. The radial stiffness
of the probe stylus is generally 1 microinch of side deflection
per one gram of side load. At very light stylus forces (1/10
gram), the side loading of the probe is very minimal. Spring
based indicators have little radial stiffness and deflect to
the side when loaded radially. With the Colorado Precision Air
Bearing LVDT, measurements where the part contacts the side of
the probe stylus ball are possible due to controlled radial stiffness.
Constant Stylus Force over the Measurement
Range
The stylus
force on the Colorado Precision Air Bearing LVDT is controlled
by air pressure as opposed to a spring. Consequently, there is
no variation in stylus force over the entire motion range of
the stylus shaft as there is with spring type indicators.
Adjustable stylus force to very light
contact forces (1/10 gram)
On the Colorado
Precision Air Bearing LVDT, the stylus force is adjusted by a
needle valve on the back of the probe body. As the needle valve
is opened, a difference in air pressure between the front of
the stylus and the back of the stylus is obtained. This differential
in air pressure is used to control the forward stylus force to
very light contact forces.
Radial Stiffness
