Jigs & Fixtures


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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.

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Jigs & Fixtures

  1. 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. 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. 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. 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. 5. Principles of Producibility Design (1) General Configuration (2) Major breakdowns (3) Structure and Equipment Jigs & Fixtures in Aircraft Industries
  6. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. The JISC logo is licensed under the terms of the Creative Commons Attribution-Non-Commercial-No Derivative Works 2.0 UK: 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