| 摘要 |
Hollow containers made by wrapping sheet blanks on to a rotary mandrel, bonding the edges in a lap joint and heat shrinking the resulting tube to follow the mandrel profile and form a base of smaller dia. than the container mouth. The base may be shaped on to a prefabricated disc located against the end of the mandrel, or simply by contracting and pressing an excess portion of the tube length. Pref. said mandrel has a profile of 5-7 degrees conicity for the upper zones of the beaker, >=15 degrees conicity near the base, leading to a stepped wall above the base. The beaker lip may be mechanically rolled (turned over). The lap joint may be welded by a heating tool with a coating of 'Teflon' (RTM) or by a strip of compatible hot melt adhesive. Esp. suitable for mfr. of stackable vending cups of expanded polystyrene, PVC or polyolefin sheet for automatic vending sales. Equipment described fabricates beakers from flat sheet blanks amenable to prior printing, embossing or other decorative treatments and more cheaply than post-forming decoration of injection-moulded, fused bead or deep drawn mouldings. Produces beakers with enhanced wall thickness near the base for strength and insulation purposes, minimum thickness for the upper walls. |
