Determining the conductivity of a hot runner connector requires a comprehensive evaluation combining contact resistance measurement, dynamic power-on testing, and visual inspection to ensure stable power and signal transmission under high temperature, vibration, and humidity conditions.
1. Contact Resistance Test (Core Indicator)
Use a four-wire Kelvin microohmmeter (e.g., Fluke 1587, Keysight 34420A) to measure the contact resistance of each channel:
Acceptance Standard: Contact resistance < 10mΩ;
Test Points:
Ensure male and female connectors are properly aligned and locked;
Use Kelvin clips to firmly clamp the pins to avoid introducing errors from the test leads;
Test the heating circuit (high current) and thermocouple circuit (low voltage) channels separately.
If the resistance value is high or fluctuates significantly, it indicates contact oxidation, poor crimping, or loss of elasticity.
2. Dynamic Power-On and Temperature Rise Test (Simulated Operating Conditions)
To verify stability during actual operation, a load test is required:
Power-On Aging: Apply rated current (e.g., 10A) for 1 hour and monitor the connector temperature rise;
Judgment Criteria: Temperature rise ≤ 30K (i.e., not exceeding ambient temperature 30℃), no localized hot spots;
Optional Vibration Test: Run at a frequency of 10–55Hz for 2 hours and check for intermittent open circuits.
3. Appearance and Mechanical Condition Inspection
Visual Inspection: Check for burns, discoloration, oxidation, or deformation of the contacts;
Mating and Removal Feel: Smooth insertion and reliable locking, no looseness or jamming;
Sealing Check: Metal housing connectors should be equipped with O-rings to prevent moisture intrusion.
4. Insulation Performance Assessment (Especially for thermocouple signal lines):
Apply 500VDC voltage using an insulation resistance tester;
Insulation resistance should be > 100MΩ to prevent leakage current from interfering with temperature control accuracy.
