Diaphragm forming
A method of forming a fibre article, comprising: providing a former having a contoured forming surface; locating a fibre preform between a first diaphragm and a second diaphragm, the second diaphragm being offset from the forming surface; drawing a vacuum between the first and second diaphragms so as to hold the preform captive between the diaphragms; displacing the diaphragms relative to the former so as to bring a part of the second diaphragm adjoining the preform into partial conformity with the former; drawing a vacuum between the second diaphragm and the former so as to increase the conformity between the said part of the second diaphragm and the former; and setting the preform in its configuration.
1. A method of forming a fibre article, comprising:
providing a former having a contoured forming surface;
providing a mechanism for moving a first diaphragm laterally, the mechanism being a laterally moveable support mounted to the first diaphragm;
locating a fibre preform on the first diaphragm at a first station;
laterally moving the first diaphragm carrying the fibre preform to a second station under the former to locate the fibre preform between the first diaphragm and a second diaphragm whilst at the second station, the second diaphragm being offset from the contoured forming surface, the first diaphragm being below the second diaphragm;
bringing the first and second diaphragms together whilst at the second station;
drawing a vacuum between the first and second diaphragms so as to hold the fibre preform captive between the diaphragms;
mechanically displacing the diaphragms relative to the former so as to bring a part of the second diaphragm adjoining the preform into partial conformity with the former, during the said displacing step the former is located above the second diaphragm and the first diaphragm is located at the second station;
drawing a vacuum between the second diaphragm and the former so as to increase the conformity between the said part of the second diaphragm and the former; and
setting the fibre preform.
2. The method as claimed in claim 1 , wherein at the said locating step the first diaphragm is offset from the contoured forming surface.
3. The method as claimed in claim 1 , wherein at least the second diaphragm is supported by a frame and the step of mechanically displacing the diaphragms comprises displacing the frame relative to the former.
4. The method as claimed in claim 1 , comprising storing a plurality of formers in a storage zone located above the second diaphragm and, prior to the step of displacing, automatically moving a predetermined one of the said formers to an operative position over the second diaphragm.
5. The method as claimed in claim 1 , wherein the fibre preform comprises a heat-activatable binder and the method comprises:
when the fibre preform is in contact with at least the first diaphragm applying heat to the fibre preform; and
ceasing to apply heat to the fibre preform prior to the said displacing step.
6. The method as claimed in claim 5 , wherein the step of applying heat to the fibre preform comprises positioning a first heater unit so as to be located between the former and the one of the first and second diaphragms closest to the former, and using the first heater unit to apply heat to the fibre preform; and the step of ceasing to apply heat to the preform comprises removing the first heater unit from between the former and the one of the first and second diaphragm closest to the former.
7. The method as claimed in claim 1 , comprising:
tensioning the first diaphragm; and
locating the fibre preform on the first diaphragm whilst the first diaphragm is under tension.
8. The method as claimed in claim 7 , wherein the first diaphragm is maintained under tension until the vacuum has been drawn between the first and second diaphragms.
9. The method as claimed in claim 7 , wherein the step of tensioning the first diaphragm comprises pressing an object into the first diaphragm.
10. The method as claimed in claim 1 , wherein the fibre preform comprises multiple sheets of fibre material laminated into a stack.
11. The method as claimed in claim 10 , wherein each sheet of fibre material is a sheet of woven fibre material.
12. The method as claimed in claim 1 , wherein the diaphragms are elastic.
13. The method as claimed in claim 1 , wherein the fibre preform is part of a structural part of a vehicle.
14. The method as claimed in claim 13 , wherein the fibre preform is part of a structural part of an automobile and the structural part is an automobile tub.
15. The method as claimed in claim 1 , wherein the laterally moveable support is a wheeled trolley.
16. The method as claimed in claim 1 , wherein the laterally moveable support is a conveyor belt.
17. The method as claimed in claim 1 , wherein the first and second diaphragms are suspended from respective frames and bringing the first and second diaphragms together whilst at the second station comprises moving at least one of the frames so as to bring the frames into sealing engagement at the second station.