Spring Push or Pneumatic Push Digital Probes

In a conventional ‘pencil’ probe the tip pushes outwards under the influence of an internal spring. When installed in a fixture a mechanism is frequently required to bring the probe into contact with the piece part being gauged.

In contrast, pneumatic operation allows the number of moving parts in a fixture to be reduced, resulting in improved reliability and reduced fixture costs. It also enables fast and safe automatic loading of components into a gauge when required.

Feather Touch Digital Probes

Feather Touch probes have been designed especially to gauge delicate surfaces such as car windscreens, TV tubes, pharmaceutical bottles, electrical components and plastic parts. Whereas a normal probe exerts a tip force of approx. 70 grams, the Feather Touch is a mere 18 grams when used in the horizontal position. This is achieved by replacing the naturally elastic traditional gaiter with a close tolerance gland. On pneumatic versions the air leakage through the gland is restricted to less than 6.0 millilitres per second at 1 bar to minimise the possibility of contamination to the surface being gauged.

Replaceable nylon tips guard against surface damage although for measuring hot glass, tungsten carbide tips can be fitted. Optional woven steel braid covering on the cable provides additional protection for applications where down time is critical.

For the ultimate low force, Feather Touch probes can be supplied with no spring at all (Suffix---/F). Forward and return strokes are activated by pneumatic push/vacuum retract, but adjustment of air pressure allows all probes to have identical tip force, constant over the entire stroke. If the probe is mounted vertically (tip at the top), retraction is by the dead weight of the moving parts, eliminating the need for vacuum.

Gauging with the Digital Probe

While the Digital Probe is superior to the LVDT / Half Bridge probe, standardisation against a setting master in the traditional way is recommended. This provides security against any long term drift or error caused by expansion/contraction of the supporting fixture or machine.

The performance figures quoted include all mechanical errors within the probe head together with any errors in the electronics interface modules.

Absolute measurement

The Solartron Digital Probe is an absolute measurement device: when switched on, it returns to the correct output regardless of movements during the off period.

Multi-application fixtures

An LVDT gauging probe provides its best performance close to its null point, requiring dedicated fixtures for each size of component being gauged. In contrast, the Digital Probe can be used at any point over its entire stroke. This permits different sizes of component to be gauged in one fixture.