F-35 Composite Edge of Part Machining NCDMM Project No. 05005602

PROBLEM / OBJECTIVE
Lockheed Martin Aeronautics Company (LMAC), Fort Worth, TX, the world-class manufacturer of components for the F-35 Joint Strike Fighter (JSF), experienced difficulties in machining advanced composite wing skin material for the JSF. With tool life lasting only nine (9) linear feet at one-third the total material thickness and excessive delamination of the composite material, existing tooling and processes were unable to produce quality components efficiently.

Because of the growing demand for F-35 composite components, tight manufacturing schedules and limited machine time to conduct tool testing on new composite materials, LMAC called upon the National Center for Defense Manufacturing and Machining (NCDMM) to provide a more efficient machining solution. The team's goal was to improve tool life and eliminate delamination of the outer edge.

Wing Skin Composite Material

ACCOMPLISHMENTS / PAYOFF

Process Improvement
NCDMM initiated the development of a solution by building a vacuum test fixture (to LMAC's specifications) to hold the composite test panels provided by LMAC. Solution development started with the evaluation of multiple cutting tool geometries at varying application parameters. Once cutter geometries and their associated cutting forces were determined, tool life and delamination were measured and evaluated. These test results lead to the in-depth understanding of the three key elements needed to provide the best solution - tool geometry, tool material and the proper tool coating.

The NCDMM, with the assistance of it's Alliance Partners, was able to combine key technologies and develop a tool that dramatically increased tool life and eliminated costly edge delamination.

Test coupons were ultrasonically inspected by both an external source and LMAC to verify the integrity of the parts - all with successful results.

The tool life increased from nine (9) linear feet at one-third the material thickness to fifty-seven (57) linear feet at full material thickness.

Implementation and Technology Transfer
The following implementation and technology transfer steps have taken place:
- Process verified and implemented at LMAC Ft. Worth
- Three state-of-the-art technologies from three Alliance Partners combined for an ultimate solution
- Proven best practice can now be applied to the JSF (and other aircraft) composite sections

Expected Benefits
LMAC can now machine a complete wing skin using only 2 cutting tools - one to rough and one to finish.
- Increased cutting distance more than 6x (from 9 to 57 linear feet) at full material thickness
- Reduced number of tools per wing skin from 24 to 2
- Reduced programming time and increased productivity while reducing scrap

Cost benefit: $80,000 per aircraft. LMAC is expected to manufacture a total of 2,783 F-35 aircraft, which equates to an estimated savings/cost avoidance of $222.6M over the projected F-35 build.

Note: Cost and timesavings associated with scrap reduction not included in the calculation above.

TIME LINE / MILESTONE
Start Date: February 05
Recommendations Made: November 05

PROJECT FUNDING
NCDMM / LMAC: $105K

PARTICIPANTS
Amamco Tool Company
McCullough Machine
Diamond Tool Coating
RNDT, Inc.
Kennametal lnc
Lockheed Martin Aeronautics Co., Fort Worth, TX

For additional information concerning this project, contact the NCDMM at www.ncdmm.org