Original Date: 08/07/1995
Revision Date: 01/18/2007
Best Practice : Design Integration with Computer Mock-up
Lockheed Martin Tactical Aircraft Systems (LMTAS) integrates several design tools to serve company-specific needs. For example, LMTAS selected Computer-Aided Three-Dimensional Interface Applications (CATIA) (a solid modeling package) as the core design software. LMTAS has identified several specific design functions not available with commercial software and has chosen to customize or build software to serve these specific needs. Computer Mock-up (COMOK) provides an example of enhancing commercially-available CATIA software to satisfy LMTAS specific needs.
Although CATIA is a robust design tool, it did not satisfy all LMTAS integrated product development (IPD) needs. Concurrent, IPD is enabled by the dynamic sharing of design iterations. The COMOK database management system is the technology that provides centralized access to multiple configurations defined geometrically by CATIA solid models. As new programs are initiated, COMOK is used in place of metal mock-ups. Since it is available at the start of the design process, it improves design integration and quality.
As COMOK provides a tool for design integration, it also serves to cross organizational boundaries, integrating the conceptual and detail design with the manufacturing and assembly process development. The digital database is populated by engineering and tooling component iterations throughout the development phase of a program, and is used by many functions within the Integrated Product Teams (IPTs). As component parts are integrated, COMOK provides automated utilities checks for interferences and clearance requirements. With this IPD functionality, COMOK is used to communicate design changes to those affected. After the design has been released, the database is used for follow-on design and analysis activities throughout the product's life cycle.
LMTAS realized the implications of limiting access to the conceptual model during the fluid design phase. As a result, it has few restrictions governing the modification of component parts in the fluid design phase. Once the design is finalized, it is released and changes are accomplished within Engineering Change Notice guidelines.
COMOK is currently implemented on the FS-X, F-22 (team-wide), F-16U, and F-16 Singapore programs with over 900 active participants. The F-22 program takes the integrated functionality one step further by allowing the design partners such as Boeing, Lockheed Marietta in Georgia, and LMTAS to share common data during the IPD phase. On this program, there are approximately 1400 megabytes of information shared between the multi-company partnership.
The design integration has had a significant and positive impact on quality, schedule, and cost. Quality improvements are realized through fewer design iterations, a well-integrated product, maximum data reuse, fewer “surprises,” and verification of design and tooling integration. This product performs schedule compression as planning, design, analysis, and manufacturing planning are performed concurrently. On the F-16 program, design change cycle time has been reduced from eight months to three months. Also, the need for metal mock-ups is essentially eliminated.
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