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Flag detection with ODC 384 Sensor

Flag Detection

Flag detection identifies defect flags, markers, and edge protrusions that indicate quality issues in roll-to-roll production. Roll-2-Roll Technologies provides intelligent sensors that detect flags automatically while ignoring normal web movement like flutter or wander—preventing false alarms that plague standard photo-eyes. The system triggers reject mechanisms or marks the location of the defect, ensuring defective material is removed before it reaches the customer.

The Challenge: Missed Flags and False Alarms

Manually flagging defects during production creates downstream problems:

  • Flags Fall Off: Adhesive flags placed by operators often detach during winding, causing the defect to pass unnoticed to the customer.
  • Narrow Sensor Windows: Standard photo-eyes with 10-20mm viewing areas miss flags when the web wanders outside the narrow detection zone.
  • False Alarms from Web Movement: Traditional sensors trigger on normal web flutter or edge wander, creating nuisance alarms that operators learn to ignore.
  • Manual Inspection Failures: Relying on operators to manually inspect and flag every roll is time-consuming and prone to human error.

The Solution: Intelligent Flag Detection with Motion Filtering

Roll-2-Roll flag detection sensors use advanced algorithms to distinguish true flags from normal web movement.

How It Works

  1. Wide Viewing Area: Sensors with viewing areas up to 960mm detect flags even during significant web wander
  2. Flutter Immunity: The system ignores short-duration events caused by web flutter or temporary edge movement
  3. Flag Length Threshold: Operators set minimum flag length (e.g., 10mm) to trigger detection, filtering out noise
  4. Automatic Marking: When a true flag is detected, the system triggers reject mechanisms or logs the defect location

Key Advantage: Intelligent filtering eliminates false alarms while ensuring no actual flags are missed—critical for high-value materials like battery electrodes or medical films.

Key Benefits

  • Eliminate Missed Defects: Automated detection replaces unreliable manual flagging
  • No False Alarms: Intelligent algorithms distinguish flags from web flutter and wander
  • Wide Detection Zone: Captures flags across the full web width, even during movement
  • Automatic Defect Removal: Triggers reject mechanisms to ensure defective material doesn't reach customers
  • Data Logging: Records defect locations and timestamps for quality traceability

Applications by Industry

  • Battery Manufacturing — Detect flagged electrode defects (tears, coating voids) to prevent defective cells from entering assembly.
  • Nonwovens — Identify flagged areas where web breaks or contamination occurred during production.
  • Converting & Packaging — Detect flags marking splice locations, thickness variations, or print defects.
  • Medical Device Manufacturing — Ensure no flagged defects enter sterile packaging lines.
  • Film Extrusion — Monitor rewind stations for flags indicating gels, contamination, or gauge variations.

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