Vacuum bagging apparatus and method including a thermoplastic elastomer film vacuum bag
OwnerPatricia Evans, David Evansinventors
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Abstract
Thermoplastic elastomer film vacuum bags are provided which readily conform to the surface contour of the workpiece at low pressures without failure. The thermoplastic elastomer film can be made into thin films which are able to withstand higher pressures and temperatures than the prior art nylon films. The films can also withstand the presence of epoxide and phenolic resins during pressure and cure without degradation. Preferred thermoplastic elastomers are block copolymers such as Hytrel. The films are pliable and can be used with minimal or no pleating.
Claims26
A method for forming a workpiece comprising the steps of:
- placing the workpiece on an air-tight base;
- applying an impervious bag of a thermoplastic elastomer film over the workpiece and base, the film having a thickness of no greater than about 10 thousandths of an inch and a secant modulus of elasticity at 100% elongation of no greater than about 2500 psi at room temperatures;
- and
- applying a pressure differential across the film to cause the film to stretch and yield to conform to the workpiece.
A method for forming a workpiece comprising the steps of:
- placing the workpiece on an air-tight base;
- applying an impervious bag of a thermoplastic elastomer film over the workpiece and base;
- forming an air-tight seal around the workpiece between the film and base;
- and
- applying a pressure differential across the film to cause the film to stretch in a substantially elastic manner up to a yield stress and thereafter yield at substantially the yield stress up to at least about 400% elongation to conform to the workpiece.
An improved vacuum bagging apparatus comprising:
- a base for supporting a workpiece;
- an impervious bag positionable over the workpiece and attachable to the base;
- and
- means for applying a pressure differential across the bag causing the bag to exert substantially uniform pressure on the workpiece;
- wherein the bag comprises a thermoplastic elastomer film having a thickness of no greater than about 10 thousandths of an inch and a secant modulus of elasticity at 100% elongation of no greater than about 2500 psi at room temperature, wherein the film stretches and yields to conform to a workpiece when a pressure differential is applied.
An improved vacuum bagging apparatus comprising:
- a base for supporting a workpiece;
- an impervious bag positionable over the workpiece and attachable to the base;
- and
- means for applying a pressure differential across the bag causing the bag to exert substantially uniform pressure on the workpiece;
- wherein the bag comprises a thermoplastic elastomer film which upon application of a pressure differential exhibits a substantially elastic stretch up to a yield stress and thereafter yields at substantially the yield stress up to at least about 400% elongation to conform to the workpiece.
A vacuum bagging assembly for forming a workpiece comprising:
- an air-tight base on which a workpiece is placed;
- a stretchable thermoplastic elastomer film as an impervious bag to be laid across the workpiece and held securely to the base, the film having a thickness of no greater than about 10 thousandths of an inch and a secant modulus of elasticity at 100% elongation of no greater than about 2500 psi at room temperature;
- a fastening means to secure and form a continuous air tight seal between the film and the base;
- and
- a means for applying a pressure differential across the film, wherein the film stretches and yields to conform to the workpiece when a pressure differential is applied.
Dependencies are inferred from the claim text.