When unwind splicing or doing winder transfers of thin films at high speeds, strong emphasis must be placed on the engineering, design and manufacture of the bump roll, cut-off knife assembly and their control systems. Failure to minimize the inertia of the bump roll, while maintaining sufficient stiffness and a resilient elastomer covering, is the major cause of missed splices or transfers. Similarly, the critical speed of the roll is a more important factor when operating at higher line speeds. The cut-off assembly must be designed to withstand the greater impact forces encountered when processing at higher speeds. The design must satisfy the requirements of lightweight construction, stiffness and low inertia, to allow repeatability during splice or transfer processes. Finally, the pneumatic and electrical controls selected must be consistent in their high-speed response, thereby optimizing repeatability that ensures proper control of the process.
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