The touch-trigger probe is a critical component of precision industrial coordinate measuring machines (CMMs) that serves as the primary contact interface between the measurement system and the workpiece. When the probe stylus makes physical contact with the measured surface, it generates an electrical signal that triggers the CMM to record the current position coordinates, enabling dimensional and geometric measurement with high accuracy. The probe contains a sensitive mechanical mechanism, typically a kinematic seat with spring-loaded contacts, that maintains electrical continuity until contact force exceeds a threshold. When the stylus touches the workpiece, the mechanism deflects, breaking the electrical circuit and generating a trigger signal. This signal is transmitted to the CMM controller, which immediately captures the machine's position coordinates at that instant. The probe is available with various stylus materials such as tungsten carbide, sapphire, stainless steel, and ceramic, allowing adaptation to different workpiece materials and measurement tasks. Key parameters include a measuring range that depends on configuration, repeatability of ±0.5 μm (2σ at 50 mm/s probing speed) per ISO 10360-2, adjustable probing force from 0.1 to 0.5 N, overtravel protection of ±12 mm in X, Y, Z directions, protection ratings from IP54 to IP65 per IEC 60529, operating temperature range of 5–50 °C (storage -20–70 °C), supply voltage of 5–24 V DC (reverse polarity protected), current consumption of 20–50 mA at 24 V DC, TTL output signal (open collector, active low), cable lengths from 3 to 15 m (custom lengths available), weight of 50–200 g without cable, and body and stylus holder made of stainless steel per ASTM A276. These specifications are typical reference ranges; actual values must be confirmed with the manufacturer for the specific model and application. The probe is designed for use in CMMs and should be selected based on the measurement task, workpiece characteristics, and environmental conditions. Regular maintenance and verification of probing force and repeatability are recommended to ensure consistent performance.
The probe contains a sensitive mechanical mechanism, typically a kinematic seat with spring-loaded contacts, that maintains electrical continuity until contact force exceeds a threshold. When the stylus touches the workpiece, the mechanism deflects, breaking the electrical circuit and generating a trigger signal. This signal is transmitted to the CMM controller, which immediately captures the machine's position coordinates at that instant.
