CF34-10A Fan Frame Etching immersion Fixture
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Magellan Aerospace Winnipeg has recently obtained a contract which includes completing an in-house etching immersion process for the CF34-10A jet engine fan frame. A fixture is required to secure, lift and rotate the fan frame to complete this process. The fan frame is the main structural component in the jet engine and provides support to the engine booster assembly through bearings and structurally supports the rotor. The frame also provides ducting for primary and secondary air flows through the engine. The etching immersion process removes an alpha case surface layer that is formed on the titanium from oxidation during the casting process. This layer creates a brittle surface and results in micro-cracks that contribute to a reduction in fatigue properties in the titanium. A nitric-hydrofluoric acid bath is used to remove the alpha case layer. While Magellan Aerospace has the acid bath, they require a fixture that can be used to secure, lift, submerge and rotate the fan frame in the acid. Initially, a set of design criteria and metrics were created by meeting with the client resulting in defining the main functions of the design and its process requirements. Concepts were generated and filtered through a concept screening and weighted decision matrix selection process. The top concept was then analyzed both analytically and numerically to ensure safety standards and criteria were met. Lastly, engineering drawings, a bill of materials, a standard operating procedure, an assembly procedure and a failure modes and effects analysis were completed. A design proposal that meets all functional requirements was achieved during the four-month project. Primary needs met include: • Total cost of $17,913.33 achieving under an allocated budget of $28,000. • Weight of 312 lbs achieving under an 800 lbs weight limit excluding the fan frame. • Minimal maintenance for a 4-year design life while etching one fan frame per week. • Consistent rotation at 1 RPM for 20-minutes using current pneumatic shop resources. • Meets Manitoba Safe Work and ASME safety standards and regulations. • A modular design which can simply attach and detach from the fan frames allowing them to be stored on a future portable stand.