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Problem Definition Background: Boeing’s Auburn Plant manufactures airplane wing spars which are the primary structural component that runs the length of the wing. The spar mill work holder secures the aluminum work piece while the mill shapes the components, which can be over 150 feet in length. Currently, the work piece is hydraulically clamped down onto the work holder. The current spar mill work-holder in place at the Boeing Company’s Auburn Skin and Spar Division has been causing a maintenance problem for the last 15 plus years due to hydraulic failures. Problem: The product opportunity is to reduce the occurrence of failure in the current work-holder while maintaining clamping specifications. 3

Understanding The Problem Problem tear down- Function chart 4

Requirements and Specifications Specs (a.k.a Functional requirements or Voice of the company) Requirements (a.k.a Voice of the customer or Customer requirements) Clamping force Clamp spacing total downtime Repair time X - Accessability for repair Service life Fits base dimensions Has manual clamps Average clamping time applied force deviation provde linear movement stored force in clamps when not in use Hold work piece in place during cuttingxx x Maintain current clamping positions xx Reduce maintenance effort xx Fit in standard machine base x x Survive hostile environment x Support different work holders (dovetail and flat) with a common actuator base x Allow for the manual clamping x Provide signal that maintenance is needed x Safe operating environment x Units of measurelbinch hr/failur emin/week min/failur eyearsin hourslb in lb Target values to X

Concept designs 6

Final Design Key Features: Common Shaft: Rigidly connects two clamps to reduce the quantity of hydraulic cylinders Spring System: Springs supply 1500 [lb] clamping force rather than the hydraulic cylinders Release Arm: Allows for release of the spar. Prevents side loading of the hydraulic cylinder. 7

Final Design-Exploded View 8

Final Design-Manufactured Prototype 9

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DFMEA- (Design Failure Mode Effects Analysis) ITEM AND FUNCTION POTENTIAL FAILURE MODE(S) POTENTIAL EFFECT(S) OF FAILURE POTENTIAL CAUSE(S) OF FAILURE CURRENT DESIGN CONTROLS RECOMMENDED ACTIONS SpringsIncompressible Spars could not be released/no changeover3 Aluminum chips in spring housings7 Detect failure when clamps do363Change not open Design chip shielding mechanism Quick preventative maintenance techniques Ensure cylinders can't apply more pressure than needed One example with recommended actions 11

Spring Testing Spring rate: 430 [lbf/in] No hysteresis effect 12

Force Testing Hydraulic pressure: 520 [psi] Cylinder Force: 2144 [lbf] Clamping Force: 1244 [lbf] Friction Effects: causing lower clamping force Frictional Torque: 2102 [lbf*in] Clamping Force Torque: 9165 [lbf*in] Spring Torque: [lbf*in] 13

More Force Testing 14

Requirements and Specifications Specs (a.k.a Functional requirements or Voice of the company) Requirements (a.k.a Voice of the customer or Customer requirements) Clamping force Clamp spacing total downtime Repair time X - Accessability for repair Service life Fits base dimensions Has manual clamps Average clamping time applied force deviation provde linear movement stored force in clamps when not in use Hold work piece in place during cuttingxx x Maintain current clamping positions xx Reduce maintenance effort x x Fit in standard machine base x x Survive hostile environment x Support different work holders (dovetail and flat) with a common actuator base x Allow for the manual clamping x Provide signal that maintenance is needed x Safe operating environment x Units of measurelbinch hr/failur e min/wee k min/failur eyearsin hourslb in lb Target values to X4.6y Measured values to x4.6y

Retrofitting Cost Estimate (Per 2 Foot Section) Rocker Arm and Shaft Assembly$ Pushrods$24.00 Springs (2 each)$ Hardware (bolts/pins/chain)$40.00 Spring Housing$80.00 Labor$ Total$ (Costs in bulk would likely be considerably less) 16

Future Work/ Recommendations Shielding of the spring and cylinder. Possible heat treating of common shaft and keyways. Improve ease of cylinder changeout (quick release fittings). Alter design for quick and inexpensive retrofitting of current base. Develop automatic safety lockout system. 17

Appendix of Photos 18

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