The device on the left is an example of a simple bell crank, along with the illustration on the right to describe how a bell crank transmits force or displacement in one direction into another.
This project seeks to demonstrate advanced manufacturing technologies to the Air Force for developing sustainment solutions for legacy aircraft, by doing a deep dive into using advanced manufacturing technology to learn how to qualify these Bell Crank parts for flight, transitioning this to AFLCMC for implementation.
The AF faces significant challenges to replace out of production spares, replace low-volume parts, and repair legacy tooling to support aging aircraft. The bell crank family of parts was identified by the AF as a challenging part to develop direct part fabrication capability to include initial process and part qualification strategies.
The bell crank was chosen because:
- Difficult to fabricate using convention technologies such as casting or machining,
- Opportunity to develop the powder bed fusion process structure for future sustainment implementation,
- Very complex component with several thick to thin transitions,
- It has fracture critical requirements and requires air worthiness certification,
- Challenging part to inspect.
Phase 2 manufacturing demonstrations target direct part production of components and develop the necessary technology, data, and repeatable processes needed for future implementation of additive manufacturing for a series of part families.
The objectives for this program are:
- Identify barriers to powder bed aluminum AM fabrication of bell cranks to include technical barriers, workforce development barriers, flight worthiness barriers, and any others.
- Determine the design and manufacturing information necessary to fabricate and certify the part to include best practices for obtaining that information.
- Create an end-to-end AM Process Specification (AMPS) for the bell crank and similar parts within the bell crank family. Identify means to mitigate barriers through end-to-end process optimization and provide recommendations for next steps towards implementation.
- Accomplish limited serial production on multiple machines and types of machines using the AMPS in order to establish initial repeatability data for part fabrication.
- Assess the benefits and drawbacks of using an additive manufacturing approach versus other traditional methods.
- Creation of DRAFT implementation plans for future insertion into AF sustainment operations.
With a comprehensive methodology, this project will systematically fabricate a significant number of bell cranks and coupons on two metal laser powder bed fusion system types (EOS and 3D Systems). During the build, each layer of each structure will be meticulously measured and recorded to provide improved confidence in the final article and populate the digital thread not previously recorded. During each post-processing step after fabrication (e.g. stress relief, build plate removal, anneal, hot isostatic pressing (HIP), heat treatment, machining), thorough metrology will be executed and recorded further realizing the digital thread. The outcome of the project will be improved confidence in one specific fabricated part, but much more importantly, the learning of the project will provide a baseline for AM execution in a tooling-based sustainment community. Barriers to qualification and certification will be identified and solutions explored. This project will prove out that the material and process has the nominal structural properties such as strength, stress cycle capability, and other requirements for the bell crank and similar parts, shown to be repeatable and transferrable to various build platforms, leading to a path for qualification by AFLCMC.
Other Project Participants
- Penn State University ARL
- Lockheed Martin
- M-7 Technologies
- Youngstown Business Incubator
- U.S. Department of Defense
- Air Force Research Laboratory (AFRL)
- Air Force Life Cycle Management Center (AFLCMC)