Aluminum / Silicon Carbide Matrix Material Machining for Targeting Systems NCDMM Project No. 06-0081-02

PROBLEM / OBJECTIVE
Lockheed Martin Missiles and Fire Control (LMMFC) of Orlando, FL, are currently in the process of producing components using Metal Matrix Composite (MMC) materials. This material is most desirable in high performance applications due to the improved material properties over monolithic metals. The most common MMC is cast aluminum reinforced with various amounts of silicon carbide. LMMFC is currently machining very high precision components for targeting systems made from cast aluminum/silicon carbide (AISiC) matrix material (with a very high SiC content) and is experiencing difficulty achieving the accuracy required due to excessive tool wear and failure from the properties of this material.

Due to the increased demand for the manufacturing of targeting system components made from AISiC matrix material, LMMFC called upon the National Center for Defense Manufacturing and Machining (NCDMM) to research and provide a more efficient solution to produce these components to specifications required by LMMFC.

ACCOMPLISHMENTS / PAYOFF

Tests were conducted by thread milling #6-32 & #8-32 in the AISiC material.

Process Improvement
The NCDMM initiated the development of a solution by having test material, supplied by LMMFC sent to the NCDMM testing and development lab. The first phase of testing began by researching various tool geometries and the coatings that are associated with them. Once the cutting tool geometries were selected, they were tested and evaluated. Photos of the tools were taken, tool wear was measured and all the data was recorded.

Test data results showed excessive tool wear, along with flaking of the tool's coating. In order to enhance the quality of the coating, the NCDMM investigated the use of a more advanced tool coating along with implementation of new machining methodologies.

Follow-up test results showed a significant improvement to the tool wear issue. The NCDMM, with the assistance of its Alliance Partners, was able to combine key technologies and develop an advanced cutting tool that would efficiently produce these components to specifications required at the LMMFC facility.

Implementation and Technology Transfer
The following process and tool recommendations were made to LMMFC:
- Verification of the process to be implemented at LMMFC
- New advanced cutting tool technology tailored for machining very high precision components

Expected Benefits from the new Tool Geometry
- Increased productivity
- Thread milling instead of hand tapping
- Better part quality
- Greater use of AISiC material components is now possible

TIME LINE / MILESTONE
Start Date: February 06
Recommendations Made: July 06

PROJECT FUNDING
NCDMM Effort: $70K

PARTICIPANTS
Diamond Tool Coating
Lockheed Martin Missiles & Fire Control, Orlando, FL Precorp
Threadmills USA

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