What is the Stäubli CGD?
CGD is Stäubli's established metal coupling family for electronic thermal management, with nominal diameters of 3, 5, 8 and 12 mm. The socket closes the circuit automatically on disconnection, while the flush face is intended to limit fluid loss and contamination. Fujitsu selected CGD for blade connections in Fugaku, providing a named operating reference, but that does not make every CGD size suitable for a new rack. Selection should cover seal code, coolant, pressure and temperature, connection force, allowable offset, service access and pressure loss across both mating halves. Stäubli's brochure lists multiple constructions and seal choices, so the project specification must not treat CGD as one uniform material set. The Fugaku source omits its exact part number, coolant, duty point, observed spill and field-replacement history. Request model-specific curves and test evidence for pressure cycling, vibration, contaminated faces and repeated hot-swap operations. The mechanical mock-up should verify guide tolerances and connector support so rack or blade weight does not load the coupling. Procedures should define cleaning, cap use, visual rejection criteria and whether neighboring equipment can remain operating during service.