The PO40 is Chotest's compact infrared touch probe for on-machine workpiece measurement and inspection on 3-axis and 5-axis CNC machining centers and turning-milling composites. The Φ40 mm × 50 mm body weighs just 260 g without holder, making it suitable for standard BT/HSK toolholders and automatic tool-changer magazines. A 360° infrared transmission system with anti-interference modulation links the probe to a dedicated receiver at distances up to 5 m, with Z-axis coverage across ±85°.

How does the PO40 achieve <1 μm repeatability?

The PO40 uses a 3-point kinematic trigger mechanism — the most stable configuration for touch-trigger probes. Three precision-ground contact points form a kinematic seat that constrains the stylus in six degrees of freedom until a triggering event occurs. When the stylus contacts the workpiece surface in any of the five sensing directions (±X, ±Y, +Z), the kinematic circuit opens and a trigger signal is transmitted. This design yields unidirectional repeatability below 1 μm (2δ) when tested with a 50 mm straight stylus at 480 mm/min. Trigger force is 0.5–0.9 N in XY and 5.8 N in Z, with generous overtravel limits of 12.5 mm (XY) and 6 mm (+Z) to protect the mechanism during approach.

What makes infrared transmission suitable for machining center use?

Infrared transmission offers a balance of speed, reliability, and cost that suits the majority of machining center applications. The PO40's 360° IR optical window covers ±85° in Z, ensuring the receiver maintains line-of-sight regardless of spindle orientation. The modulated IR signal resists interference from ambient lighting and coolant mist. Power comes from two 1/2 AA 3.6V lithium cells delivering approximately 150 hours of continuous trigger use — extending to 90 days or more at typical 5% duty cycles. Activation is via standard M-code, and an intelligent LED indicator displays power-on, trigger, and battery status at a glance. The IP68-sealed probe body withstands direct coolant exposure and submersion during machining.

How does the PO40 compare to other Chotest probes?