Cores, injection molds collapsing

Blow molding cannot be used to produce hollow rubber parts from conventional thermoset rubbers. These must be injection molded over a manually removable collapsible core to form thin-walled rubber shapes such as boots, bellows, and covers. Blow molding is uniquely suited to TPEs as a material for hollow, thin-waUed rubber articles. 

Injection molding is capable of accommodating the broadest range of materials. Nearly all the thermoplastics can be injection molded and, with special equipment, even many thermoset materials can be used. The mold capabilities of the process are also a major asset. Moldmakers have succeeded in constructing incredibly complex molds using side actions to create holes perpendicular to the parting line, split cavities for imusual shapes, and cores which collapse to permit withdrawal from undercuts. 

USM Full shot of foamable plastic is injected into a reduced-size mold cavity. Collapsible core or movable walls then expand the cavity to permit foam to expand. 

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