Quick Answer:
Equal path lengths ensure the Slave guide corrects for a Master error at the exact moment that error reaches the lamination point.
In Master/Slave guiding, timing is critical. The Slave guide must correct for a Master web movement at the exact moment that movement reaches the lamination nip.
The rule: Web path distance from Master Sensor → Lamination Nip should equal the distance from Slave Sensor → Lamination Nip.
Why it matters: If paths are unequal, the Slave might correct too early or too late (phase mismatch), causing misalignment at the actual lamination point.
The fix: Match the path lengths at installation. Contact Roll-2-Roll if your layout cannot.