process fragility in the manufacture of kevlar wing root panels location of wing root panel 2m james...

Process Fragility in the Manufacture of Kevlar Wing Root Panels

Location of wing root panel

2m

James Curran

• Complex curvature• Kevlar• Sandwich panel• Geometrical tolerances• Foiling cure• Increased production rate

• RED panels further down production line• Unconventional• No destructive analysis• Production item (no interference, limited changes)

Increasing scrap rate NDT (ultrasonic, X-ray, geometry)

Plan to double production rate

Roll-out in Toulouse

1

2

3

4

1*

1*

NDT Failures

Simplified cross-section

14 plies

Steel ToolPlies 1-7

Honeycomb

AdhesivePly 8

Vac bag

Key operations half-way through build

Problems:• Bridging• Core (positioning & moisture content)• Volatiles• Filler material• Poor consolidation

Areas signalled for more intensive working

Steel ToolPlies 1-7

Honeycomb

Adhesive

Vac bag

Bleed pack

Bleed pack introduced for improved consolidation

12 3 (4)

Adhesive lay-up modified

1

2

3

4

1*

1*

Steel ToolPlies 1-7

Honeycomb

Vac bag

Plies 8-14Intensifier

Inadequate moisture management

1

2

3

4

1*

1*

Problems with honeycomb trim under floating intensifier:

2: Resin bleed 3: Poor consolidation

Core filler

Kevlar prepreg volatile content

19.4

19.6

19.8

20.0

20.2

15:00 15:30 16:00 16:30 17:00 17:30 18:00

Time

Mas

s (g

)

1

2

3

4

1*

1*

• New adhesive lay-up• Use of a bleed pack for all consolidation operations• Core moisture control• Core trimming• Core filler control• Kevlar moisture management

• Perforated adhesive• Self-adhesive foil / elimination of separate foiling cure• New tooling

Solutions: