I. Core Rapid Testing Methods
Insulation Resistance Retest Method
Operation: Use a 500V digital megohmmeter to test the insulation resistance between the heating element, thermocouple core wire, and hot runner housing channel by channel.
Pass/Fail Criterion: Retest twice consecutively at 30-minute intervals. If the insulation resistance remains stable at ≥20MΩ and shows no decline, it indicates that moisture has been completely removed.
Time Required: The entire channel test can be completed in 5-10 minutes, making it the most crucial and rapid testing method.
Heating Curve Verification Method
Operation: Power on the hot runner and heat it from room temperature to 160℃ at a normal rate, recording the temperature changes throughout the process.
Pass/Fail Criterion: There is no prolonged temperature plateau near 100℃ during the heating process, and the heating rate deviates from the standard curve of the same model of dried hot runner by ≤10%.
Time Required: Completed within 30 minutes, allowing for the detection of hidden moisture remaining in deep crevices.
II. Auxiliary Verification Methods
Surface Condition Verification Method
Operation: Open the hot runner junction box and inspect the internal terminals, insulation layer, and exposed metal surface condition.
Pass/Fail Judgment: All parts are completely dry, with no water mist or condensation marks, and the terminals show no oxidation or discoloration.
Time Required: 2-3 minutes to complete the full appearance verification.
High-Temperature Insulation Re-verification Method
Operation: After heating the hot runner to 160℃ and holding for 30 minutes, re-measure the insulation resistance under high-temperature conditions.
Pass/Fail Judgment: High-temperature insulation resistance ≥ 0.5MΩ, with no rapid drop in insulation resistance as the temperature rises.
Time Required: Completed within 40 minutes, avoiding the potential for insulation breakdown due to moisture condensation at high temperatures after passing at room temperature.
III. Rapid Judgment Priority Rules
Prioritize the insulation resistance re-test method for initial judgment, then combine it with the temperature rise curve verification method to complete full-dimensional confirmation within 30 minutes. This ensures complete drying without long waiting times, allowing direct entry into the installation phase.
