Intro.
To Aerospace
Eng. Design
• Design for manufacturing in aircraft industry
outline
• Introduction: Airplane design, development, certification, and
production
• Design for manufacturing
• Principles of producibility design
• Tools and manufacturing: jigs & fixtures
• Advantages in manufacturing
• Construction methods and materials
• Types
• Example of assembly fixtures
• Generative design
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Airplane design, development, certification, and
production
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Basic loads
• Basic loads can be obtained using V-n diagrams
• Load factor (n) defines a load in term of weight: L=nW
• Three types of V-n diagrams: Maneuvering, gust, and
combined.
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Basic loads
• Inputs to obtain the diagrams
• Aircraft weight WTakeOff orWZero Fuel
• Wing area (S) and wing span (b).
• Cruise altitude.
• Stall, cruise, and dive speeds (Vstall, VC, VD).
• Output is the load factor for each speed
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Example of a V-n diagram
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Airplane design, development, certification, and
production
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Certification test program
• Bombardier C series water ingestion test
• Determine spray characteristics of the aircraft and whether it
poses a hazard to the general operation (Engine, EPU)
https://youtu.be/VhtUqsDojRM?t=100
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Design for manufacturing
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Design for manufacturing (Cont.)
• Design and manufacturing are successive phases of a single
operation, the ultimate objective: an acceptable final product.
• In aerospace context, such acceptability has several
components:
• Market viability
• Operational efficiency
• Capability for further development
• Structural integrity
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C series aircraft
• Models: CS100 and CS300
• Market segment: 100- to 149-seat commercial jets
• Competitive advantages:
• Designed for growing 100- to 149-seat market
• 15% operation cost advantage
• Reduced noise and emissions
• Operational flexibility (a range of 5,463 km).
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Design for manufacturing (Cont.)
Other important factors are:
• Maintainability: civil airliner, military aircraft
• Producibility: a structure must not be so complex or difficult
in concept that its realization will
• Create great difficulties or
• Increase the cost of the manufacturing process
• Tooling: low cost production is possibly only by accounting
for every possible manufacturing advantages.
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Principles of producibility design
1. General configuration
2. Major breakdowns
3. Structure and equipment
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Principles of producibility design (Cont.)
1. General configuration
• Rectangular vs. tapered wing sections, flaps and control surfaces
• Minimum number of major structures
• Cylindrical, straight, or conical surfaces vs. compound curvatures
• Extend of fairing and filleting required
interchangeability is difficult because of tolerance accumulation
should be used only when essential!
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Principles of producibility design (Cont.)
2. Major breakdowns
• Adequate access for assembly
• Ease of handling and transportation
• Completeness of master breakdown units
• Assembly joints
• Effectiveness
improved producibility does not necessarily follow an increase
in degree of breakdown!
e.g. center wing-box assembled as a single part rather than more
subsections.
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Principles of producibility design (Cont.)
3. Structure and equipment
• Simplicity: adequate access for fabrication and subassembly, etc.
• Parts
• Multiple use and Min. number of different parts.
• Min. total number of parts
• Min. amount and types of attachments
• Effective use of standard parts, material shape and sizes
• Detail design
• Interchangeability, adjustment, tolerances, adequate clearances and
fastener edge distances, machining economy, etc.
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Tools and manufacturing
An aircraft is conceived as a complete structure, but for
manufacturing purposes must be divided into:
• Sections, or main components split into
• Sub-assemblies of decreasing size, resolved into individual detail parts
• To build every single part, special tools are required.
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Boeing 787 sections
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What is a fixture?
• A fixture is a special tool used for
• Locating the work
• Clamping the work
• Supporting the work
• Holding al elements together in a rigid unit during a manufacturing
operation
• The most important considerations are:
• Accuracy and rigidity, followed by ease of use, and economy in
construction.
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Fanuc robot end of arm tooling
• A quick change jaw for a robotic cell.
• The metal plates remain fixed, and operators can rapidly change out
custom jaws.
Markforged 3D printed part
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What is a jig?
• A jig is a type of fixture with means for positively guiding and
supporting tools.
• For both jigs and fixtures
• Origin: traced back to Swiss watch and clock industry!
• Objective: to provide interchangeability, reduction of cost, and accuracy
of the manufactured individual detail parts, sub-assemblies, sections, or
main components, and finally the complete structure.
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Jigs & fixtures’ advantages
• Ensure the interchangeability and accuracy of parts
manufactured
• Minimize the possibility of human error
• Permit the use of medium-skilled labor
• Reduce the manufacturing time
• Allow the production of repeat orders without retooling
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Jig & fixture: construction methods and
materials
• Cast in iron
• Fabricated from steel plates, sections and machined parts by
• Welding
• Build-up by bolting etc.
• Materials such as
• Magnesium
• Resin
• Wood
• Plastic and composite materials can also be used.
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Jig & fixture: different types
• Assembly fixtures
• Machining jigs &fixtures
• Drilling jigs, boring jigs, etc.
• Welding fixtures
• Trim jigs
• Control or master jig
• Apply jig, attaching to a larger jig or an assembly of parts, etc.
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Jigs & fixtures: step by step
For every part of structure
• A mockup is first designed and is made from material such as
wood, plaster, etc.
• The mockup is used to design and to build the fixtures
ensuring the contours and the external form of the structures.
• The master jig is then designed in order to complete the fixture
providing the important reference points, jig and pin points,
and to provide a reference for the regular checks of the fixture
Thermal expansion of fixtures is important.
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Boeing 767-400 assembly line
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Boeing 767-400 assembly line (Cont.)
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Boeing 767-400 assembly line (Cont.)
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