The repair and adjustment can be performed according to the magnitude of the deviation and the scenario, from easiest to most difficult. In most cases, direct sensor replacement is not necessary:
1. Small Deviations (Temperature Deviation ≤ 3℃, Pressure Deviation ≤ 3%FS): System Compensation Calibration
This is the most common and quick solution, without disassembling the machine:
Temperature Sensor: Locate the temperature compensation parameter for the corresponding channel in the injection molding machine's temperature control system and adjust it according to the direction of the deviation. For example, if the sensor reading is 2℃ higher than the actual temperature, set the compensation value to -2℃, allowing the system to automatically correct the displayed value. After calibration, the deviation can be reduced to within ±1℃.
Pressure Sensor: In the no-load standby zero-pressure state, locate the system's zero-point calibration function and recalibrate the zero point to eliminate most zero-point interchangeability deviations.
2. Deviations caused by dimensional tolerances: Adjust the mounting structure to correct.
If the thermal conduction deviation is caused by probe length/installation gap:
Probe too long: Use a lathe to micro-machine the probe end face to ensure a tight fit between the probe and the bottom surface of the hot runner hole after installation, eliminating temperature detection deviations caused by gaps;
Probe too short: Place a piece of thermally conductive copper foil of matching thickness at the probe tail to fill the tail gap, ensuring the probe tip is close to the detection surface, reducing thermal conduction errors.
3. Output protocol mismatch: Replace the adapter board/conversion module. Deviations caused by incompatibility between the output protocol of small-brand sensors and the original system:
If the output signal range is inconsistent, a signal conversion module can be added to adjust the output to the 0-10V/4-20mA standard signal compatible with the original system, correcting the error without replacing the sensor.
4. Large deviations (temperature deviation > 3℃, pressure deviation > 3%FS): Replace with qualified components. If the above adjustments cannot correct the deviation, it indicates that the sensor itself is not manufactured to the required precision. Replace it directly with a sensor of the same specifications that meets the accuracy requirements. Prioritize mainstream brands that follow industry-standard dimensions and output standards to solve the interchangeability problem at its root.
