Even thickness of PVB is very important to the success of lamination. Failure in thickness control will lead to bubbling between glasses during pressurization. In order to ensure the PVB quality, we have a completed on-line thickness control system to monitor the thickness and evenness of every rolls of PVB. Every production line is equipped with one automatic thickness control machine to fulfill 24 hours duty of monitoring. Together with precise calculation from off-line control, the specification of PVB is secured before delivery.