| 摘要 |
A method and apparatus for making an embossed or dimpled combined board is disclosed. The combined board has two outer or facing layers or webs of paperboard which sandwich an embossed or dimpled middle paperboard layer or web. The middle web is embossed by passing it over two apertured vacuum drums. Embossments extending in one direction are vacuum formed on one surface of the middle web by the first vacuum drum, while embossments extending in the opposite direction are formed on the other surface of the middle web by the second vacuum drum. The embossments, i.e., concave and convex impressions, are located in a generally chess board pattern. The vacuum openings or apertures of the second drum are larger (larger average diameter) than those of the first drum, to thereby compensate for diminishing flexibility of the middle web due to drying as it passes sequentially over the first and second vacuum drums. This vacuum opening size difference permits the formation of embossments of equal height on both surfaces of the middle web. Preferably each of the three webs are fed directly from a paperboard making apparatus and the combined board formed prior to final drying of the webs. Alternatively, the middle web may be wetted if already fully or partially dried prior to forming the embossments. While being deformed by the vacuum drums, an external source of heat or radiation, such as steam, hot air, infrared lamps, or the like, may be directed to the web such that the web is concurrently dried as it is being deformed to form the embossments or dimples.
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