Method for securing core to tool during machining
A method for preparing a part using a rigid tool surface having a shape. The method includes applying a breather sheet comprising gas-permeable material over the rigid tool surface. A vacuum bag is applied over the breather sheet, and a vacuum pressure is applied underneath the vacuum bag to conform the breather sheet and the vacuum bag to the shape of the rigid tool surface. A resin pre-impregnated ply is applied over the vacuum bag, and the part is positioned over the ply.
1. A method of preparing a part using a rigid tool presenting a rigid tool surface having a shape, the method comprising:
applying a vacuum bag over the rigid tool surface;
applying vacuum pressure to the vacuum bag to conform the vacuum bag to the shape of the rigid tool surface;
applying a resin pre-impregnated ply over the vacuum bag;
applying the part over the ply;
curing the resin pre-impregnated ply, the part comprising a honeycomb core having a portion with a thickness during the curing;
applying a machine tool to the portion of the part after the curing of the resin pre-impregnated ply to reduce the thickness;
removing the vacuum pressure from the vacuum bag to at least partly release the part from the rigid tool surface; and
peeling the ply from the part.
2. The method of claim 1 , further comprising applying a breather sheet over the rigid tool surface before applying the vacuum bag.
3. The method of claim 1 , wherein the honeycomb core comprises one or both of fiberglass and aluminum.
4. The method of claim 3 , wherein the rigid tool comprises one or more of aluminum, steel and fiberglass.
5. The method of claim 1 , wherein the part comprises two pieces each comprising an interface surface, further comprising —
applying an adhesive to at least one of the interface surfaces,
positioning the interface surfaces against each other.
6. The method of claim 1 , wherein the vacuum bag comprises a first perimeter portion and a substantially opposite second perimeter portion, and the rigid tool comprises a first perimeter portion and a substantially opposite second perimeter portion, further comprising performing the following before applying the vacuum pressure to the vacuum bag —
sealing the first perimeter portion of the vacuum bag against the first perimeter portion of the rigid tool,
sealing the second perimeter portion of the vacuum bag against the second perimeter portion of the rigid tool.
7. The method of claim 6 , wherein releasing the part from the rigid tool further comprises releasing the first perimeter portion of the vacuum bag from the first perimeter portion of the rigid tool and releasing the second perimeter portion of the vacuum bag from the second perimeter portion of the rigid tool.
8. The method of claim 1 , wherein the vacuum pressure is supplied by a first vacuum source, further comprising —
applying a second vacuum bag over the part,
applying a second vacuum pressure to the second vacuum bag using a second vacuum source to press the part against the ply.
9. The method of claim 8 , further comprising —
applying a breather sheet over the part before placing the second vacuum bag over the part, the breather sheet comprising gas-permeable material and being positioned between the second vacuum bag and the part.
10. The method of claim 9 , wherein the part comprises two pieces each comprising an interface surface, further comprising —
applying an adhesive to at least one of the interface surfaces,
positioning the interface surfaces against each other,
the curing including heating the part on the rigid tool to cure the adhesive and the resin pre-impregnated ply after applying the second vacuum pressure.
11. The method of claim 10 , further comprising —
removing the second vacuum pressure from the second vacuum bag after the heating of the adhesive and the resin pre-impregnated ply;
removing the second vacuum bag and the breather sheet from the part, the application of the machine tool occurring after the removal of the second vacuum bag and the breather sheet;
removing the vacuum pressure from the first vacuum bag after the application of the machine tool to the part to at least partly release the part from the rigid tool.
12. The method of claim 11 , further comprising the peeling of the ply from the part after release of the part from the rigid tool.
13. The method of claim 12 , wherein each of the first and second vacuum bags comprises a perimeter portion, and the rigid tool comprises a perimeter portion, further comprising performing the following before the curing of the resin pre-impregnated ply —
sealing the perimeter portion of the first vacuum bag and the perimeter portion of the second vacuum bag against the perimeter portion of the rigid tool.
14. The method of claim 13 , wherein —
the perimeter portion of the rigid tool comprises an edge flange having an inner portion nearer the part and an outer portion further from the part,
the perimeter portion of the first vacuum bag is sealed against the inner portion of the edge flange,
the perimeter portion of the second vacuum bag is sealed against the outer portion of the edge flange,
the vacuum pressure is supplied by the first vacuum source along the inner portion of the edge flange,
the second vacuum pressure is supplied by the second vacuum source along the outer portion of the edge flange.
15. The method of claim 1 , wherein the curing includes heating the part on the rigid tool surface.
16. The method of claim 12 , wherein the first vacuum bag is attached to and peeled away with the ply.
17. The method of claim 16 , wherein the ply is a wet peel ply.