The use of jigs and fixtures within manufacturing is widely employed. Their design and the parameters to be taken in to account are discussed with the aid of a case study.

1. Design for Manufacturing:
Jigs & Fixtures
HNC Year 1
in Aircraft Industries Boeing 767-400 Case Study
Author: Leicester College
Date created:
Date revised: 2009
Abstract;
The use of jigs and fixtures plays a major role in modern production engineering. The basic methods for
determining the requirements and configuration of these devices is described . Examples of common practice are
also given.
© Leicester College 2009. This work is licensed under
a Creative Commons Attribution 2.0 License.

2.  Design for Manufacturing
Contents
 Principles of Producibility Design
 Tools and Manufacturing
 What is a Fixture?
 What is a Jig?
 Jigs & Fixtures’ Advantages
 Jig & Fixture: Construction methods and materials
 Jig & Fixture: different types
 Jigs & Fixtures: Step by Step
 Using jigs to build the Boeing 767-400
 Credits
These files support the Edexcel HN unit – Design for Manufacture (NQF L4)
File Name Unit Outcome Key Words
FMS 2.2 Models, work cycles, volume, machine utilisation,
automation, flexible, systems
Industrial Robots 2.2,2.3 Robot, industrial, robot arm, Cartesian, polar, cylindrical,
jointed arm
Jigs and Fixtures 2.1,2.3 Efficiency, production, jigs, fixtures, tooling, production,
Kinematics 2.1,2.3 Machines, kinematics, Degrees of freedom, configuration,
space, work space, robot, joints, forward, inverse
For further information regarding unit outcomes go to Edexcel.org.uk/ HN/ Engineering / Specifications
Jigs & Fixtures in Aircraft Industries

3. Design for Manufacturing
 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.
Jigs & Fixtures in Aircraft Industries

4. Design for Manufacturing (Cont.)
Other
 Maintainability: Civil airliner, Military aircraft
 Producibility: A structure must not be so complex
or difficult in concept that its realisation will
– Create great difficulties or
– Increase the cost of the manufacturing process;
 Tooling: Low cost production is possible only
by accounting for every possible manufacturing
advantage.
Jigs & Fixtures in Aircraft Industries

5. Principles of Producibility Design
(1) General Configuration
(2) Major breakdowns
(3) Structure and Equipment
Jigs & Fixtures in Aircraft Industries

6. Principles of Producibility Design
 General Configuration:
– Rectangular vs. tapered wing sections, flaps and
control surfaces,
– Minimum number of major structures,
– Cylindrical, straight, or conical surfaces vs.
compound curvature,
– Extend of fairing and filleting required;
 Interchangeability is difficult because of tolerance
accumulation, should be used only when essential!
Jigs & Fixtures in Aircraft Industries

7. Principles of Producibility Design
(Cont.)
 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.; Centre wing-box assembled as a single part rather
Jigs & Fixtures in Aircraft Industries
than more subsections

8. Principles of Producibility Design
(Cont.)
 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 Aircraft Industries
Jigs & Fixtures in edge distances, Machining
economy, etc. ...

9. 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! Jigs & Fixtures in Aircraft Industries

10. What is a Fixture?
 A Fixture is a special tool used for
– Locating the work,
– Clamping the work,
– Supporting the work,
– Holding all the 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.
Jigs & Fixtures in Aircraft Industries

11. What is a Jig?
 A Jig is a type of Fixture with means for positively
guiding and supporting tools.
 For both Jigs & 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.
Jigs & Fixtures in Aircraft Industries

12. Jigs & Fixtures’ Advantages
 Ensure the interchangeability and accuracy of
parts manufactured,
 Minimize the possibility of human error,
 Permit the use of medium-skilled labour,
 Reduce the manufacturing time,
 Allow the production of repeat orders
without retooling.
Jigs & Fixtures in Aircraft Industries

13. Jig & Fixture: Construction
methods and materials
 Cast in iron,
 Fabricated from steel plates, sections and
machined parts by
– welding,
– Built-up by bolting etc.
 Materials such as
– Magnesium,
– Resin, Wood,
– Plastics and Composite materials, are also used.
Jigs & Fixtures in Aircraft Industries

14. 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. ...
Jigs & Fixtures in Aircraft Industries

15. 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 structure,
 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!
Jigs & Fixtures in Aircraft Industries

16. Design for Manufacturing:
Jigs & Fixtures
in Aircraft Industries
HNC Year 1
Boeing 767-400 Case Study
Shane Payne
Jigs & Fixtures in Aircraft Industries

17. This resource was created Leicester College and released as an open educational resource through the Open
Engineering Resources project of the Higher Education Academy Engineering Subject Centre. The Open
Engineering Resources project was funded by HEFCE and part of the JISC/HE Academy UKOER programme.
© 2009 Leicester College
This work is licensed under a Creative Commons Attribution 2.0 License.
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England & Wales Licence. All reproductions must comply with the terms of that licence.
The HEA logo is owned by the Higher Education Academy Limited may be freely distributed and copied for educational purposes
only, provided that appropriate acknowledgement is given to the Higher Education Academy as the copyright holder and original
publisher.
The Leicester College name and logo is owned by the College and should not be produced without the express permission of the
College.
Jigs & Fixtures in Aircraft Industries