Patent ID: 9469065
Filing Date: 2016-10-18
CPC Classification: B29C,B29K,B29L

Claim Text:
1. A process for forming a sheet of thermoplastic material into a three-dimensional shape, the process comprising the steps of: (i) starting with a thermoplastic material having an average thickness of less than about 1.0 mm; (ii) forming the sheet at a temperature below its glass transition temperature to produce a first formed shape in the sheet, followed by (iii) raising the temperature of the first formed shape to above its glass transition temperature, to over 100° C.; while a male former, having at least a portion of its profile being substantially the same as that of the first formed shape, is positioned to substantially align at least a portion of its profile with that of the first formed shape, thereby restricting the first formed shape from shrinking back towards its original sheet form, followed by (iv) further forming the first formed shape at a temperature below that of the glass transition temperature, to form a second formed shape, followed by (v) raising the temperature of the second formed shape to above its glass transition temperature, to over 100° C.; while a male former, at least a portion of its profile being substantially the same as that of the second formed shape, is positioned to substantially align at least a portion of its profile with that of the second formed shape, thereby restricting the second formed shape from shrinking back towards its original sheet form; wherein the male former employed in step (v) is the same male former as employed in step (iii); and wherein the thermoplastic material is heated to above its glass transition temperature by directing a heated as stream onto said thermoplastic material.