Function Development
What are functions?
Functions defines “what” a product must do.
Form defines “how” that is accomplished.
Form follows Function!
Functions can be derived from requirements…
What behavior is necessary to accomplish
the requirement(s)?
What are functions?
Functions represent a flow of:
Material, Energy, Information
Functions are hierarchical.
A successful functional analysis will decompose functions to lowest possible level
Why use function analysis?
• Function controls the design process… we won’t waste time generating products which solve the wrong problem.
• Functions are used to facilitate the move from needs/requirements to solutions. Encourages “form independent” solutions.
• Want the customer needs and requirements to drive our concepts for solutions as well as serve as methodology for evaluation.
Why use?
• Finer decomposition of function leads to a greater understanding of the problem.
• May lead to the realization and identification of existing components that can provide the functionality.
How to use?
• Attempt to develop a list of all functions the design must fulfill
• Examine the defined needs/requirements for design,
Ask: “What behavior is necessary to accomplish these requirements?”
• Try to “de-compose” functions to lowest possible/practical level
How to use?
• For each need/requirement…
• Consider :
energy flow
material flow
information flow
• Write in verb/noun format, e.g. move mass, provide information, control energy
• Use list of verbs (on handout) to help you generate list
Examples of Function “verbs”
absorb collect fasten locate rotate transfom
accept conduct grasp move secure translate
actuate control guide orient separate verify
amplify convert hold position shield
apply couple increase produce start
assemble decrease interpret protect steer
avoid direct interrupt provide stop
change dis-assemble
join rectify store
channel dissipate lift release supply
clear drive limit remove support
How to use?
• Example :
For bicycle helmet requirement “safety”,
Consider “What behavior is necessary to provide safety?”
Absorb energy Decelerate mass
Dissipate energy Maintain attachment
• Revise any functions if needed.
• Try to identify and eliminate un-necessary functions.
• Use a tool (such as post-it notes) to organize functions by type and level of hierarchy (decomposition).
How to use?
Revision / Decomposition
Revising and decomposing functions.
From helmet example…
Maintain attachment could become maintain contact
Maintain contact could decompose to…
Provide attachment
Ensure attachment
Provide adjustment
Functions Example (Drill)
Consider a Drill Overall Function is to “Create Hole”
Supply Power > Store Power > Control Power
Create Rotary Motion > Control Rotary Motion
Create Linear Motion > Control Linear Motion
Provide Enclosure
Accommodate Grip > Accommodate Controls
Next Steps
• Examine functions at lowest level of decomposition.
• Use various concept generation techniques
brainstorming,
6-3-5 (a brainstorming alternative),
research (patents, other devices),
TRIZ
to develop a list of potential solutions (“how” for the “what”)
Next Steps
From helmet example:
Function – “provide attachment” (the “what”)
Possible concepts – the “how”
Velcro, snap(s), bayonet style clasp…
Function – “provide adjustment” (the “what”)
Possible concepts – the “how”
Moving panels, insertable pieces, air bladder…
Identify as many potential concepts as possible…
DON’T WORRY ABOUT EVALUATING IDEAS YET!