| 摘要 |
A method of controlling the stretch of a substrate when forming a contoured article. The method generally includes the steps of: (a) providing a planar thermoformable substrate including a contoured region and a non-contoured region; (b) coating regions of the substrate with a heat-absorption controlling material; (c) heating the substrate; and (d) forming the contoured regions into contours of a contoured article. The non-contoured region (6), typically coated with a the heat-absorptive material, absorbs more heat than the contoured region during the heating step, and stretches to facilitate forming of the contoured regions during the forming step. Consequently in the contoured regions (2), the substrate resists stretching and therefore maintains a consistent, uniform thickness. Specific regions of the contoured and non-contoured regions also may be coated with a heat-reflective material to prevent heat absorption and resist stretching in those regions. Contoured articles formed according to the process of the present invention are of a more uniform thickness and consequently provide consistent and uniform esthetic, structural, magnetic, and electrical properties. |
