Technical

Roll-2-Roll® Sensors provide true spatial awareness—not just binary on/off detection:

This accuracy is maintained across all material types without recalibration—critical for precision applications like battery electrode coating, optical film production, and high-speed converting.

Roll-2-Roll® Sensors are vacuum compatible and can detect clear films in vacuum environments. This is a unique capability that no other edge detection technology can match:

• Ultrasonic sensors cannot function in vacuum—no air means no sound waves for detection
• Many optical sensors struggle with clear films even in normal atmosphere

Roll-2-Roll Technologies fiber-optic technology solves both problems, making it the only solution for applications like:

• Glass manufacturing processes
• Vacuum coating operations
• Semiconductor manufacturing
• Specialty film production

Unlike traditional sensors that require recalibration for each material type, Roll-2-Roll® Sensors use adaptive edge detection algorithms that automatically adjust to different material characteristics.

This eliminates:

• Manual gain adjustments
• Teach mode procedures
• Operator-dependent settings
• Extended changeover times

The impact: Plants using legacy sensors typically lose 2 hours monthly to recalibration—time that Roll-2-Roll Technologies technology completely eliminates.

Roll-2-Roll® Sensors use patented fiber-optic technology based on light scattering rather than light blocking. This means they detect the physical presence of the web edge regardless of optical properties.

Materials that work:

• Clear and transparent films
• Porous nonwovens
• Metallic foils
• Glass
• Mesh and perforated materials
• Rubber and textiles
• Carbon fiber
• Abrasive materials

The only challenging material is matte carbon black that absorbs infrared light without reflection—and even this can be addressed by angling the light source.

Chasing systems move heavy machinery (slitter bases, coating heads) rather than lightweight web rollers. This imposes strict mechanical requirements:

1. Structural rigidity: The carriage must be stiff enough that its natural frequency exceeds the control frequency (typically >25-50Hz). If the sensor bracket wobbles, it creates "false error" and causes oscillation.
2. Breakaway force: The actuator must overcome static friction in the linear bearings. Roll-2-Roll® Actuators provide up to 2,000 lbf (8,900 N) thrust.
3. Acceleration over speed: The actuator must change direction fast enough to match web error rates. Speed alone won't help if the carriage can't accelerate quickly.

Rule of thumb: If the system oscillates or hunts, check carriage rigidity first—it's the most common cause of chasing failures.

In chasing applications, process upsets can cause the web to wander significantly—due to splice passage, tension changes, or roll eccentricity. This exposes a critical weakness in narrow-range sensors:

• Narrow sensor problem: If the target (line, edge, or pattern) moves outside the sensor's field of view, the system loses tracking. With older controllers lacking edge-loss protection, the actuator continues driving in one direction until it reaches its limit—potentially damaging equipment or producing scrap.
• Roll-2-Roll® Sensors + SCU5/SCU6x advantage: Wide-range sensors (up to 960mm) provide a large capture window that maintains lock on the target during extreme wander events. Additionally, the SCU5 and SCU6x controllers include a "Lock on Lost Edge" feature that inhibits actuator movement if the edge is lost—preventing runaway conditions. For line/contrast guiding, loss of contrast also inhibits the actuator.

Example: An ODC 288 sensor provides 288mm of sensing range. If the web edge wanders ±100mm during a splice, the sensor never loses sight of it—and the controller keeps tracking smoothly.

In Li-Ion battery electrode coating, the coating must align precisely with the current collector foil. Steering the foil creates stress and wrinkles that cause defects. Instead, Roll-2-Roll® Sensors enable coating head chasing:

• Sensor placement: ODC 96 or similar mounts directly on the coating carriage
• Edge tracking: The sensor continuously monitors the foil edge position
• Dynamic alignment: If the foil drifts, the coating head moves to follow—maintaining bead position within ±0.1mm

The benefit: No mechanical stress on the foil, no wrinkles, no electrode misalignment. This is critical for preventing lithium plating defects in finished cells.

In slit-to-feature applications, the cut must align with artwork or a printed line on the web—not the web edge. Roll-2-Roll® Sensors enable this through dynamic tool tracking:

1. Sensor mounting: The ODC 96 or ODC 192 sensor attaches directly to the knife holder bracket
2. Target acquisition: The sensor locks onto the printed line, coating edge, or contrast feature
3. Chasing: As the feature wanders, the controller drives the knife carriage laterally until the sensor re-aligns—maintaining ±0.0635mm registration

Why this matters: Print position varies relative to web edges due to registration error at the press. Standard edge guiding cannot solve this—the slitter must chase the print.

Standard web guiding steers the web to a fixed position, but in tool tracking applications like slitting to a printed line, the sensor must see the relative position between the tool and the web.

Here's why fixed sensors fail:

1. Fixed sensor upstream: The sensor sees web wander and commands the slitter to move—but it never sees the slitter move. The error signal remains, and the control loop is open.
2. Fixed sensor downstream: By the time you detect misalignment after the slitter, the cut has already happened. You cannot correct a cut that's already made.

The only solution is to mount the sensor on the moving tool carriage. When the carriage moves, the sensor moves with it, verifying the correction. This closes the feedback loop and enables true chasing.

Roll-2-Roll Technologies electronic Master/Slave guiding eliminates the mechanical components that require constant maintenance in legacy systems:

Eliminated maintenance items:

• Motorized sensor positioner motors and drives
• Lead screws and anti-backlash nuts
• Sliding brackets and linear bearings
• Mechanical linkages between Master and Slave positions

What remains: Standard periodic inspection of sensors and guides—the same maintenance as any web guiding system, without the additional burden of sensor positioning hardware.

Typical customers report saving 10-20 hours annually in maintenance time previously spent on mechanical positioner systems.