| 摘要 |
1298737 Shaping plastics sheet W M SWARTZ 14 Sept 1970 [15 Sept 1969] 43762/70 Heading B5A A method of making an article from a plastics sheet, e.g. polystyrene, having a preprinted surface that is subject to cracking, e.g. aluminium/lacquer, comprises heating the sheet, shaping it in a die 12, e.g. by a plunger 12, or by vacuum forming, and during shaping controlling the amount of elongation over at least a portion of its surface to cause the coating to have a predetermined surface appearance. The elongation can be initially determined by printing a grid on the sheet, which, after shaping, illustrates a variation from a desired pattern, Fig. 4, so that a second gridded sheet can be prepared with a corrected pattern, and shaped with the amount of elongation controlled over the portion where the correction is required. The elongation can be controlled by masking a localized area of the sheet when heating, or by modifying the shaping surface in a localized area by, e.g., placing a block (26), Fig. 6 (not shown), on the surface of the die 12. |
