How to Ensure the Accuracy of Hot Runner Sensor Verification

Controlling four crucial elements is the main goal in order to guaranty the accuracy of hot runner sensor verification: "operational procedures, benchmark verification, scenario matching, and result review." The following are specific techniques:

 

1. To prevent basic mistakes, thoroughly prepare before verification.

Clean debris thoroughly: Before verification, remove any oxide residue and debris from the sensor probe and the bottom of the mounting holes using an air pistol and brush. By doing this, debris cannot raise the probe and cause the preload reading to be underestimated.

Push-pull force gages, micrometers, and vernier calipers should all be calibrated beforehand to guaranty measurement accuracy of ≥0.01mm (length) and ≥0.1N (force), preventing intrinsic errors in the instruments.

Preventive troubleshooting: Start by looking for old sensors and loose wiring. Before disassembling the mold for verification, resolve any non-preload/contact force concerns to prevent invalid verification.

 

2. To prevent human mistake, standardize operating procedures.

Establish precise reference points for preload measurement by strictly using the mold mounting surface and the sensor mounting thread end face. The flange end face should not be confused. To minimize the error of a single measurement, take three measurements and average the findings.

Contact Force Testing: When using a push-pull force gage, pull at a steady speed while keeping the pulling direction coaxial with the sensor. When the sensor just moves, note the pulling force. Take the test three times, then average the outcomes. Steer clear of numerical variations brought on either imbalanced pulling or changes in pace.

Verify the uniformity of the lead foil impression by looking at the entire probe end face indentation. To prevent overlooking local off-center load problems, don't just focus on the local area.

 

3. To prevent making poor decisions, match the standard to the relevant situation.

Avoid using universal standards in a one-size-fits-all manner. Choose the appropriate range based on the production scenario and installation structure:

Preload Acceptable Range Contact Force Acceptable Range Installation Structure/Scenario

Conventional Threaded Clamping Type 0.15~0.25mm 8~12N

0.1~0.2mm Set Screw Fixing Type 5~10N

Big High-Pressure Injection Mold 10~15N 0.2~0.3mm

Tolerance Narrowing ±0.03mm Controlled within the middle of the range for High-Temperature Injection Molding (300°C)

 

4. A second verification was carried out to ensure that the results were accurate after adjustment.

The mold cannot be immediately sealed after adjustment; a second check is necessary:

Numerical Verification: Remeasure the preload/contact force to make sure it is within the appropriate range and that the contact force's uniformity satisfies the specifications;

Assembly Verification: Measure the gap around the sensor mounting face again using a feeler gage. The mounting end should be straight and free of skewing if the gap difference around the complete circle is less than 0.02 mm;

Production Verification: After startup, record the temperature rise and temperature control data to ensure that there are no temperature-related product faults, the stable production temperature fluctuation is ≤±3°C, and the temperature rise time difference is less than 30%. Accuracy is confirmed by the final check.