| 摘要 |
Tools for moulding pre-expanded thermoplastic beads are provided with internal heat exchange fluid passages shaped so that the wall thickness between the passages and the cavity surface is constant. Ancillary passages are connected directly to the cavity so that the cavity may be linked in turn (a) to a vacuum, to assist cavity filling, (b) to the heat exchange fluid supply, for some direct heating/chilling, and (c) to a compressed air supply for pneumatically assisted ejection. Used esp. for moulding thin walled forms, e.g. multi pocket egg packs. The mould design provides uniform and rapid heating for materials having a relatively small interval between their surface adhesion and bulk fusion temps. |
