Product Design Specification

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Product Design Specification
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Before we consider exactly what a Product Design
Specification (PDS) is, let's do a short design
project.
DESIGN BRIEF A customer has approached your team
and asked to produce a chair for his son.
Read the design brief above and spend five
minutes producing a design that you feels fulfils
the brief. When you are happy raise your hand.
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Is this your design?
Is this your design?
Is this your design?
Are you sure you understand the question?
Is this your design?
Is this your design?
Is this your design?
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• Easy to misinterpret a design brief and design a
  product the customer doesn't want.
• The aim of the PDS is to help you to gain an
  understanding of the nature of the problem
• The more we know about the problem the easier it
  will be to produce a final design that works
  first time
• The PDS will help you understand the problem
  before you start your design.

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• A Project Design Specification (PDS) is a
  document that will change substantially over the
  duration of your project.
• There are many factors that will cause your PDS
  to change. But the one factor that will have the
  greatest impact is the development of a deeper
  understanding of your project.
• The PDS should reflect the common knowledge of
  the team about the project idea.
• The PDS needs to be regularly refined during the
  proposal phase to reflect a deeper understanding
  of your teams project idea. To develop this
  deeper understanding your team needs to do
  research.

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• RESEARCH
• To develop a deeper understanding your design
  team needs to begin by performing research.
• U.S. Patents
• Market Studies
• Logan Library (Has anyone from your team seen Mr.
  Robson?)
• This research will be the foundation of your PDS.
  From your initial research your team was asked to
  develop a HLDD (high level design document).

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• With the research, performance and environmental
  specifications need to be developed for your
  project.
• These performance and environmental
  specifications need to accurately reflect your
  teams present understanding of the project and
  to be as specific as possible about what the
  project will do.
• Performance specifications address a need. For
  examples, a pipe positioning system must deliver
  accuracies of /- 5 inches for each linear mile
  of pipe placed.
• Environmental specification addresses the
  surroundings and conditions of operation. For
  example, the pipe positioning system will use
  trenchless technology to place pipe underground.

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• INTRODUCTION TO PRODUCT DESIGN SPECIFICATIONS
• What is the function of your project? At this
  point it is best to have a few functions for your
  project. Keeping in mind, each function expands
  the project scope and your team needs to be able
  to complete the project in 25-weeks. Each
  function should have several performance
  specifications to measure the success of the
  function
• Performance specifications address needs. For
  examples, a pipe positioning system will deliver
  accuracies of /- 5 inches for each linear mile
  of pipe placed underground. The performance
  specifications also help define the environment
  your project will operate in. Therefore,
  environmental specifications are needed to define
  the operating environment like, underground.
• Environmental specification addresses the
  surroundings and conditions of operation. For
  example, the pipe positioning system will use
  trenchless technology to place pipe underground.
  The environmental specification finally helps
  define technology specifications like,
  trenchless.
• Technology specification defines the type of
  technologies that are being considered. These
  technologies are defined by the research done.

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• INTRODUCTION TO PRODUCT DESIGN SPECIFICATIONS
• A good PDS has a function list for the project
  with a short description for each
  project-function. Each function has several
  performance specifications (measures of success)
  along with the environment these functions
  operate in. Finally, the PDS should identify what
  technologies will be used to meet the performance
  and environmental specification for each function
  of the project. Therefore, the following
  questions must be answered for each PDS
• Is a function list given with a short description
  for each project-function?
• Are performance specification given for each
  function?
• Is the operating environment for the project
  given?
• Are specifications provided relating to the
  operating environment provided?
• Are target technologies identified to meet all of
  above?
• Example PDS
• http//www.ider.herts.ac.uk/school/courseware/desi
  gn/pds/example.html

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Product Development Process
Stage 1 Needs, IP, Market Analysis, System
Definition, Requirements Specification
Needs, IP and Market Analysis
System Definition
Requirements Specs - PDS
High Level Design
Conceptual Design
Detail Design
Stage 2 Design
Stage 3 Planning, Scheduling, Budget,
Personnel Qualifications
Planning, WBS, Scheduling
Budget Resources
Personnel Qualifications
Stage 4 Project Management, Test Plan,
Performance Verification
Project Management
Performance Verification
Test Plan
Social Impact
Stage 5 Social Impact, Risks
Contingencies, and Quality
Risks and Contingencies
Quality
Stage 6 Success!!!
Development Grant
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Conceptual Design
Generate ideas about HOW to fulfill the PDS. What
materials, technologies and processes will be
used? Will you use a tried and true approach or
will you try a potentially revolutionary, yet
unproven, approach? Evaluate ideas Pugh Matrix
Method or Engineering Tradeoff Matrix
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Generation of Ideas
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Generation of Ideas

• Clarify the Problem Identify the problem
  decompose to simpler problems
• Search Externally Experts, patents, published
  literature, related products MR. ROBSON!!!
• Search Internally Group and individual creative
  exercises
• Explore Systematically Organize thinking and
  synthesize system fragments
• Reflect on Solutions Process Identify areas
  for improvements in later iterations and
  subsequent projects

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Evaluation of Ideas

• Evaluation Criteria are established before any
  evaluations are made.
• Evaluation Criteria come from the PDS.
• Evaluation Criteria are unambiguous.
• Evaluation Criteria are to evaluate, not to
  optimize different approaches.

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Pugh Matrix Technique I

• Set up a matrix (table) with concepts across the
  columns and criteria across the rows.
• Rate each concept against important evaluation
  criteria (generated from PDS).

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Pugh Matrix Technique II

• Choose a reference concept without any prior
  solution, choose the one the group intuitively
  thinks is the best.
• Enter a PLUS () if a concept is better than the
  datum enter a MINUS (-) if a concept is worse
  than the datum enter an S if a concept is the
  same as the datum.
• Total the PLUSes and MINUSes for each concept and
  obtain the algebraic sum for each concept.

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Evaluation of Ideas Pugh Method
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Pugh Matrix Technique III

• Carefully look at the pattern of MINUSes try to
  generate improvements to the concept without
  eroding the PLUSes.
• If a number of strong concepts do not emerge,
  usually the criteria are ambiguous or subject to
  different interpretations or concepts are
  similar.
• When one concept is strongest, re-run the matrix
  using it as the datum to validate it as the
  strongest.

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Pugh Matrix Technique IV

• Greater insight into the requirements of the PDS.
• Greater understanding of the design problems.
• Greater understanding of the potential solutions.
• Understanding of the interaction between the
  solutions.
• Knowledge of why one concept is stronger or
  weaker than another.
• Natural stimulus to generate other concepts.

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Detail Design

• Specific details are determined.
• The sort of design in individual courses, but
  with interactions between subsystems.
• Subsystems and components must be defined in a
  similar manner to the PDS.
• Generate Component Design Specification (CDS)
  with emphasis on local performance, environment,
  and constraints.
• Primary emphasis is upon performance.