Using electronic gauging probes for dimensional gauging of manufactured parts is a common quality assurance technique. Typical gauging probes are cylinders with diameters of about 9mm and length ranging from 65mm to 100mm. The cylinders incorporate a non-contact inductive position sensor, either LVDT or half-bridge, which uses a spring-loaded movable armature coupled to a shaft that is supported in a high-precision linear bearing. These gauging probes generally have a maximum gauging range of .25mm to 2.5mm, with resolutions of fractions of a micron.
In hostile environments, such as the shop floor, gauging probes can encounter serious problems. For example, the zero-clearance linear ball bearing must be protected from the slightest contamination or it jams up and fails. The thinness of the probe body makes it susceptible to accidental damage, which makes it necessary for a replacement.
Many of the problems associated with dimensional gauging in hostile environments can be solved by Macrosensors’ GHS series of rugged and robust LVDT-based gauging probes, which are available from Bestech Australia .
These LVDT-based gauging probes feature a 19mm hermetically sealed stainless steel probe with integral connector, a clearance-fit sleeve bearing, and gauging ranges up to ±25mm. The high accuracy of these GHS series LVDT-based gauging probes mean that they are suitable for any shop floor gauging function.The sleeve bearing offers the repeatability of a zero-clearance linear ball bearing and is less susceptible to jamming. Some versions of the GHS series LVDT-based gauging probes can be connected to a positive-pressure air stream to continuously purge the bearing space and prevent infiltration of contaminants. The probe bodies are large enough to accommodate built-in sensor support electronics. This can reduce the overall system cost by simplifying the gauging apparatus.