The detection stability of a needle detector is closely related to routine cleaning and upkeep. Before each shift, clean the conveyor surface and the probe channel to remove loose threads, dust and metal chips, so that accumulated debris does not cause false alarms or missed detection. Periodically check belt tension and tracking, and confirm that the motor, photoelectric sensors and alarm devices work properly. Place the unit away from strong interference sources such as large motors and inverters, and keep the environment dry to reduce the effect of temperature and humidity changes on the detection circuit.
Sensitivity calibration should use standard test pieces close in size to the contaminants that may realistically appear in the product, testing point by point at the positions specified in the manual to confirm that every channel alarms reliably. Before calibration, complete a no-load run and a product pass test to rule out interference from product effect. After changing product specifications, adjusting detection parameters or relocating the equipment, recalibrate and record the date, test piece size and results in a log for traceability.
Higher sensitivity is not always better; it should be set according to product characteristics and customer acceptance requirements. Excessive sensitivity causes frequent false alarms and reduces line efficiency. A tiered system of pre-shift checks, weekly maintenance and periodic calibration is recommended, with trained operators on duty and prompt shutdown and investigation when abnormalities appear. For older equipment, assess probe and circuit condition based on operating history and contact the manufacturer for service when necessary to keep detection capability reliable.