design for assembly
DESCRIPTION
A major cost factor in the production of and component or assembly is its assembly. This section looks at some commonly used techniques which a designer can employ to ensure that assembly is cost effective and efficient. This is then linked to the use of jigs and fixtures for this purpose.TRANSCRIPT
Design for Assembly
© Leicester College 2009. This work is licensed under a Creative Commons Attribution 2.0 License.
Author: Leicester CollegeDate created:Date revised: 2009
Abstract: A major cost factor in the production of and component or assembly is its assembly. This section looks at some commonly used techniques which a designer can employ to ensure that assembly is cost effective and efficient. This is then linked to the use of jigs and fixtures for this purpose.
HNC year 1Design for Manufacture
Design for Assembly
Contents Introduction Assembly Methods Design Guidelines for Manual Assembly Using Jigs & Fixtures Design Guidelines for Automated Assembly Basic DFA Guidelines Credits
These files support the Edexcel HN unit – Design for Manufacture (NQF L4)
For further information regarding unit outcomes go to Edexcel.org.uk/ HN/ Engineering / Specifications
File name Unit outcome Key words
Design for assembly 1.1, 1.2,1.4 Overview, Cost, quality, reliability, assembly, guidelines
FMS 2.2 Models, work cycles, volume, machine utilisation, automation, flexible, systems
Geometric Tolerancing 3.1,3.2 Geometric, tolerance, system, symbols, orientation, BS, ISO, location, runout, datum
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
DFM introduction 1.1, 1.2, 1.4 design
Design for Assembly
Design for Assembly
"a process for improving product design for easy and low-cost assembly, focusing on functionality and on assemblability concurrently."
--Vincent Chan & Filippo A. Salustri
Design for Assembly
Design for Assembly
Reduce cost of assembly Improve quality and reliability Reduce part inventory Reduce production equipment
Design for Assembly
Assembly Methods
Manual assembly Fixed automatic assembly Flexible automatic assembly
Design for Assembly
Design Guidelines for Manual Assembly
eliminate the need for workers to make decisions or adjustments.
ensure accessibility and visibility. eliminate the need for assembly tools
and gauges (i.e. prefer self-locating parts).
Using Jigs & Fixtures
Hull Forming Jigs at Offshore Steel Boats Ltd.Image source: www.geograph.org.uk/photo/1230702 © Copyright David Wright and licensed for reuse under this Creative Commons Licence.
Design for Assembly
Design Guidelines for Manual Assembly
Minimise the number of standard different parts – use ‘standard parts.’
minimise the number of parts. avoid or minimise part orientation during
assembly (i.e. prefer symmetrical parts). prefer easily handled parts that do not
tangle or nest within one another.
Design for Assembly
Design Guidelines for Automated Assembly
reduce the number of different components by considering does the part move relative to other parts? must the part be isolated from other parts
(electrical, vibration, etc.)? must the part be separate to allow assembly
(cover plates, etc.)? use self-aligning and self-locating
features avoid screws/bolts
Design for Assembly
Design Guidelines for Automated Assembly
use the largest and most rigid part as the assembly base and fixture.
Assembly should be performed in a layered, bottom-up manner.
use standard components and materials.
Design for Assembly
Design Guidelines for Automated Assembly
avoid tangling or nesting parts. avoid flexible and fragile parts. avoid parts that require orientation. use parts that can be fed automatically. design parts with a low centre of gravity.
Design for Assembly
Basic DFA Guidelines
Minimise part count by incorporating multiple functions into single parts
Modularise multiple parts into single sub-assemblies
Assemble in open space, not in confined spaces; never bury important components
Make parts such that it is easy to identify how they should be oriented for insertion
Prefer self-locating parts
Design for Assembly
Basic DFA Guidelines
Standardise to reduce part variety Maximise part symmetry Eliminate tangling parts Colour code parts that are different but
shaped similarly Prevent nesting of parts; prefer stacked
assemblies Provide alignment features
Design for Assembly
Basic DFA Guidelines
Design the mating features for easy insertion
Insert new parts into an assembly from above
Eliminate re-orientation of both parts and assemblies
Eliminate fasteners
Design for Assembly
Basic DFA Guidelines
Place fasteners away from obstructions; design in fastener access
Deep channels should be sufficiently wide to provide access to fastening tools; eliminate channels if possible
Provide flats for uniform fastening and fastening ease
Ensure sufficient space between fasteners and other features for a fastening tool
Prefer easily handled parts
DESIGN FOR ASSEMBLYHNC year 1
Design for Assembly
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.