Rewind guiding

Yes. The SCU5 and SCU6x controllers can process two sensors simultaneously with independent enable/disable control. This is ideal for bidirectional coating machines that run forward and backward between passes.

Typical dual-sensor configuration:

• Sensor 1: Mounted on the rewind moving frame—enabled during forward winding
• Sensor 2: Mounted on the fixed machine frame—enabled during reverse (unwind) direction

Instead of repositioning a single sensor when direction changes, operators simply switch which sensor is active via the controller touchscreen or a PLC command over EtherNet/IP, PROFINET, or EtherCAT.

This eliminates sensor repositioning time, enables instant direction changes, and simplifies machine design by removing the need for motorized sensor positioners.

Roll-2-Roll Technologies rewind guides use electromechanical actuators (RLA and BLA series) instead of traditional hydraulic cylinders. This completely eliminates:

• Hydraulic fluid—no oil to leak, change, or dispose of
• Filters and seals—no consumables to replace quarterly
• Valve balancing issues—no unequal extension/retraction speeds
• Contamination risk—critical for food, pharmaceutical, and medical applications
• Hydraulic pumps—quieter operation without pump noise

Typical plants using hydraulic systems report spending 10–20 hours annually on rewind guide maintenance alone. Electromechanical systems reduce this to near-zero, with only periodic inspection required.

The SCU6x controller includes an integrated motor driver, eliminating the need for separate drive cabinets and simplifying installation.

Roll-2-Roll Technologies electromechanical rewind guides can handle loads up to 30,000 lbs (13,600 kg) when paired with low-friction linear rail bearings (coefficient ~0.01).

Key specifications:

• Maximum thrust: 50–1,500 lbf (222–6,670 N)
• Stroke length: 1–12 in (25–300 mm)
• Maximum speed: Up to 2 in/sec (51 mm/sec)

The critical factor for sizing is breakaway force—the static friction the actuator must overcome to start moving the loaded stand. Using low-friction linear rail bearings dramatically reduces the required actuator size compared to sliding shaft designs (coefficient ~0.25).

For extremely heavy loads, the RLA Series ball screw actuators provide thrust up to 1,500 lbf while maintaining precision positioning.

In rewind chasing applications, the sensor must be mechanically attached to the shifting stand because the control system is designed to keep the sensor output at "zero." When the sensor moves with the roll, the system naturally drives the stand until the sensor aligns with the web edge.

If the sensor were fixed to the floor (like in intermediate guiding), the system would lose the relative position between the web and the roll face. The result would be telescoped or uneven rolls because the guide has no reference point for where the roll edge should be.

The sensor should observe the web at a fixed idler immediately upstream of the shifting stand. This provides a stable reference point while the stand—and sensor—move together.