"Go-Gauge" Tactile Inspection Technique
Use a normal nylon rod with a smoothly polished leading tip that is 0.1 mm smaller in diameter than the hole's nominal inner diameter. Push it coaxially to the hole's bottom slowly. The hole's coaxiality and inner wall smoothness are verified as satisfactory if the rod travels smoothly without snagging, abrupt resistance, or sticking-all without the requirement for specialised measurement tools.
Sheath Insertion/Extraction Inspection Method Fill the hole with a brand-new, appropriately specified armoured sheath. The hole is verified to be free of residual burrs or deformations, guaranteeing correct installation fit, if insertion occurs without hard blockage or binding and subsequent extraction shows no noticeable irregular scratches on the sheath's exterior.
Method of Comparing Ambient Temperature Resistance
Once the sheath has been inserted, measure the thermocouple's cold-state resistance with a multimeter. Potential insulation problems caused by residual metal debris inside the hole may be promptly ruled out if the insulation resistance between the sheath poles and the housing is ≥100 MΩ and the divergence from the typical room-temperature resistance for that kind of thermocouple is ≤5 Ω.
Rapid Temperature Change Verification Technique
Heat the hot runner system quickly to 200°C, keep it there for ten minutes, and then let it naturally drop to room temperature. The hole's thermal conductivity is verified as adequate with no localised heat transfer abnormalities if the temperature signal stays constant throughout, exhibiting no irregular jumps or anomalous drift.
This thorough inspection procedure achieves an accuracy rate of more than 95%, needs no disassembly of the hot runner system, has no additional procurement expenses, and is ideal for quick on-site verification.
