MAE 4292: AEROSPACE ENGINEERING DESIGN II Design Process: Manufacturing February 4, 2009 Mechanical and Aerospace Engineering Department Florida Institute.

MAE 4292: AEROSPACE ENGINEERING DESIGN II

Design Process: Manufacturing

February 4, 2009

Mechanical and Aerospace Engineering Department

Florida Institute of Technology

D. R. Kirk

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PRODUCT DEVELOPMENT PROCESS

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AEROSPACE RELATED MANUFACTURING CHALLENGES• The latest buzz words and philosophies in manufacturing

• Quantity

– Produce 10 million rivets

– Produce 100,000 turbine blades

– Produce 1,000 wide body airplanes

– Produce 100 rockets

– Produce 5 Space Shuttles

– Produce 1 Space Station

• Qualification for unique/harsh/dangerous environments: space, number of cycles, FOS

• Government (Defense, NASA) vs. private consumer drivers

• The global supply chain

• Manufacturing driven by competition?

• Is innovation worth it? Is innovation needed? Where do you focus the innovation? Does aerospace still need the “best and the brightest”?

Lowest cost?Lowest cost/part?Investment into production?Investment into tooling?Insurance?

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LEAN MANUFACTURING

• Production practice that considers expenditure of resources for any goal other than creation of value for end customer to be wasteful, and is thus eliminated

• Pioneered by Toyota, and now applied everywhere

1. over-production 2. motion (of operator or machine) 3. waiting (of operator or machine) 4. conveyance 5. processing itself 6. inventory (raw material) 7. correction (rework and scrap)

• 6 Sigma• Six sigma is a philosophy of doing business with a focus on eliminating defects

through fundamental process knowledge• Six sigma methods integrate principles of business, statistics and engineering to

achieve tangible results

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777 MANUFACTURING/PRODUCTION

• Boeing using a moving assembly line for 777 jetliner• Moves at 1.6 inches per minute during production• "A moving line is the most powerful tool available to identify and eliminate waste

in a production system,“• "A moving line drives efficiency throughout the system because it makes

problems visible and creates a sense of urgency to fix the root causes of those problems.“

• 26 days to assemble the 777’s three million constituent parts• 1/3 time cut over traditional assembly line

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WORLD WIDE SUPPLY CHAIN

• Articles:

– Improving The Management Of Supply Chain Vulnerability In UK Aerospace Manufacturing

– Bridging the Gaps in Defense Manufacturing Supply Chains

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CURRENT CHALLENGE: COMPOSITES

• A recent market study in Aerospace Composites stated that "by any measure, the market for advanced composites in aerospace systems is growing at an unprecedented rate." However, if an aerospace firm doesn't have the engineering tools and manufacturing processes to work effectively with advanced composites, much of that value is lost. Indeed, the advent of innovative new software tools has been critical to encouraging and enabling the increased use of advanced composites.

• adoption of the full carbon fiber fuselage and wings on the Boeing 787

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MICRO-ENERGY AND MICRO-ROCKET DEVICESIn Conjunction with Ventions, LLC and Next Engineering

• Motivation– Centimeter-sized chemical rockets with same features of large-scale systems

(integrated valves, intricate cooling systems, etc.)– Potential for significant performance benefits, such as divert capabilities for

miniature kill vehicles, station keeping, orbital maneuvering, modular propulsion • Objectives and Approach

– Explore silicon vs. metal foil microfabrication techniques– Fabricate prototype engine and verify structural and fluid-dynamic suitability for

eventual hot-fire testing– Leverage existing valve technology for fluidic, biological, thermal applications

• Higher T/W than SSME

910 cm

ROCKETS

• Six Wafers• Eight Masks• Smallest feature ~ 10 m

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DEPARTMENT OF REDUNDANCY DEPARTMENT

Why so many engines?

Why not just use 1 big engine?

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ROCKET SCALING EXAMPLE

• Thrust scales with throat area, A*– Recall Thrust = (mass flow) x (exit velocity)– Mass flow depends on A*– A* scales with L2

• Weight scales with volume, V– V scales with L3

• T/W, therefore scales with 1/L

• So what?– Take ‘baseline’ engine and makes 4, ½-size copies of it

• 1/4th A* of original• 1/8th Volume of original• 4 engines together produce same thrust as baseline, but only weight half as

much!– Do same with half size engine, and make 16 quarter-sized engines

• Together produce same thrust as original, but weigh a quarter of original– In theory, process could be continued indefinitely

• Massively-parallel thrust system with a very high thrust to weight ratio