Canning and Fish Packaging Technology

Unit 14 - Glass containers and Closures

14.1.13.2.Roll-on closures
This is a variation of screw cap, aluminium blank shall is supplied complete with the liner to the processor/packer. Sealing pressures is applied by special equipment called gaping machine when the thread is formed in situ using bottle thread as the former. A recent development in closure for external screw finish of the bottle incorporates an internal sealing surface by crimping or by making small indentation at the top edge of the cap which is sufficient to prevent leakage. These caps can be made tamper evident by making perforations on the cap just above the bead of collar of the bottle.