摘要 |
A method for forming thinned areas in a thin sheet material. The method includes the steps of (1) placing the thin sheet material on a pattern anvil having a pattern of raised areas wherein the height of the raised areas is generally less than the thickness of the sheet material; (2) conveying the sheet material, while placed on the pattern anvil, through an area where a fluid is applied to the sheet material; and (3) subjecting the sheet material to a sufficient amount of ultrasonic vibrations in the area where the fluid is applied to the sheet material to area thin the sheet material in a pattern generally the same as the pattern of raised areas on the pattern anvil. In some embodiments, the thinned areas may be micro areas. |