Sensor Selection Guide for "No-Label-Look" Clear Packaging
"No-label-look" ultra-clear BOPP and PET film labels on premium cosmetics and craft spirits require dedicated sensor hardware:
- Standard Optical Label Sensor (Infrared / Red LED):
- Works ONLY when label material has >20% optical contrast difference relative to the release liner.
- Fails completely on transparent film on clear PET liners.
- Ultrasonic Gap Sensor (Recommended: Leuze GSU 76 / SICK UF):
- Physics: Emits high-frequency ultrasonic acoustic pulses (300kHz–1MHz). When the acoustic wave passes through the single layer of backing liner, amplitude is higher; when it hits the dual layer (label + liner), acoustic attenuation increases.
- Benefit: 100% material independent. Detects transparent film on transparent liner, metallic foil, holographic film, and paper labels with equal ease.
- Capacitive High-Speed Label Sensor (Recommended: Lion Precision LRD):
- Physics: Measures micro-capacitance changes in the dielectric field as labels pass through the slot plate.
- Benefit: Extremely high frequency response (up to 400 m/min conveyor speed) with zero acoustic noise sensitivity.
