| 摘要 |
In the prior art, vacuum skin packaging processes are performed by placing the product to be packaged on an impervious backing board; placing the product and board in a vacuum chamber; positioning a sheet of thermoplastic film above the product and backing board in the chamber; evacuating the chamber; then, either pulling the film down over the product or pushing the product up into the film; and, thereafter sealing the film to the board. In the present invention, a portion of the film is drawn by differential air pressure against the concave interior surface of the upper portion of a vacuum chamber; the film is then heated by surface contact; and then, after evacuation of the chamber, air pressure is used to blow the film down over the product and against the backing board. Thus, in the present invention, the film is shaped in a concave fashion surrounding the upper portion of the product and it is not necessary for the product to move. The height of the chamber may be adjusted for different products so that excess film is not used and wrinkling is prevented.
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