Week 3 – MSE508/L – Spring 2008Design Process and the Role of CAD – Types of Design ModelsAnd Concurrent Engineering

1. Design Process and the Role of CAD Design Process Types of Design Models Concurrent Engineering Modeling using CAD Virtual Collaboration handout (if time permits)

2. Design Process Time to market pressure Design Brief – Overview of the current need for a product. Product Designers:

Explore ways to fill the current need Develop the product for manufacture

Design Analysts – Use analysis and simulation techniques to test design against its intended use

3. Design Process Development Engineers – Experiment on prototypes to improve and refine the

product Research Engineers – Support Development by finding best materials,

processes, or techniques to use for the product Process Planner – Identifies the process and/or operation needed to

manufacture part Production Planner and Controller – Manage production and schedule parts

procurement

4. Design Process Models of the Design Process:

Pahl and Beitz – Four phases of the design process: Clarification of the Task – Collecting information about the design requirement and the constraints on the design Conceptual Design – Establishment of the functions to be included in the design, and identification and development of suitable solutions Embodiment Design – A conceptual solution is developed in more details, problems are resolved and weak aspects eliminated Detail Design – Dimensions, tolerances, materials, and form of individual components of the design are specified in detail for subsequent manufacture.

5. Design Process Models of the Design Process:

Ohsuga – Series of stages in the design process:

Solution proposed Solution evaluated against given standards

If unsuitable … start over and modify Begin Preliminary Design Preliminary design evaluated

Refined until ready to move on Detailed design stage

Complete definition for manufacturing

6. Design Process Summary of Process Design Models:

Both use a series of stages to develop Both follow a traditional view Ohsuga puts the process into a common form while Pahl and Beitz tent to be more general

7. Types of Design Models First distinguish between

Models of the design process – Describe the pattern that designers follow in the design of products Models of designs themselves – Physical or virtual models that represent the product to develop

8. Types of Design Models Choice of model depends on:

What property to model within the part? Who is the receiver of the data after modeling? What function needs to be modeled? Does the structure or assembly need attention? Is the form or shape a concern? Materials? Surface condition? Dimensions?

9. Concurrent Engineering Traditional engineering approach:

‘Over the wall’ – pass documents to the next department after completion Does not take into account all aspects of design phases

Concurrent engineering aims to: Bring together a design team early in the design process Consider all elements of the product life cycle from:

Conception Manufacture Service Maintenance

10. Concurrent Engineering Concurrent Engineering is not always the best approach such as in:

High uncertainty in the development New design varies greatly from former comparable items

Source:CAD/AM Principles, Practice, and Manufacturing, 2ndEdition, Chris McMahon, and Jimmie Browne, Addison Wesley Longman Limited, 1998, pp. 174-181.