Mechanical and Thermal Design of BEE

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Mechanical and Thermal Designof BEE

• Roderick Lee
• September 13, 2002

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Objectives

• Package and integrate all BEE components
• Proper heat management of electronics

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Material Manufacturing Process Selection
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Material Manufacturing Process Selection

• Sound structural support for the 58 x 53cm PCB
• Integrate additional components including power
  board, power supplies etc
• Convenient access to the SCSI connectors and
  other components that require user interaction
• Economical for small quantity production
• Material Aluminium
• Manufacturing process Shop machining

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Heat Survey Cooling Method Selection
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How hot is BEE?
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Electronics Cooling Methods
Passive Cooling

• Clean, no leak
• Tight space
• Limited to low power application

• Clean (ambient air)
• Thermal interface
• Fan failure
• Occupies space

• Leak, messy
• Complex
• Occupies space
• High power application

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Preliminary Thermal Design
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Concurrent Engineering

• DUCADE, Domain Unified CAD Environment, is a web
  enabled collaborative management system that aids
  the concurrent design process of electronic
  printed circuit boards and mechanical enclosures

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DUCADE

• Tracks couplings between mechanical and
  electrical features over the life cycle of the
  product
• Gives feedback to designers when feature
  properties (size, location, etc.) are altered and
  coupling criteria are violated
• Compiles history of design changes from both
  domains

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BEE Couplings
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Computer Aided Design
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Thermal Analysis

• Historically, experimental methods were the only
  ways to design thermal systems due to lack of
  simulation software and computation capability
• Design of Experiments approach to systematically
  determine the effects of changing variables
  individually on the performance of the system and
  reveal variable interdependencies
• Variables that have strong effect will then
  establish the basis for further simulation and
  analysis

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Design of Experiments Testbed

• DOET is a web based software developed to aid
  designers through the process of design of
  experiments

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Design of Experiments Testbed
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Thermal Simulation

• Build model of mechanical package and electronics
  in FLOTHERM

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Thermal Simulation

• Design of Experiments
• Reveal local hot spots on PCB and blockage of
  airflow

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Rapid Prototyping

• Clearance and fit between electrical components
  and mechanical package can be verifed
• Functionality and structural strength of package
  can also be tested

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Final Design
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Fabrication
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Conclusions

• Importance of effective design cycle and design
  tools to meet aggressive deadline and maintain or
  exceed quality of design
• DUCADE, DOET, SolidWorks, FDM, Flotherm
• Thermal Design Chart

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Qualitative Thermal Design Graph
Chip Size
Method of Cooling
Vapor High speed Coolant Heat pipe Thermocyphon
Heat pipe Heat exchanger Liquid cold plate
Cost Enclosure Volume
Heat sink Forced air convection
Natural convection Conduction
Power Dissipation (W)
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Conclusions

• Importance of effective design cycle and design
  tools to meet aggressive deadline and maintain or
  exceed quality of design
• DUCADE, DOET, SolidWorks, FDM, Flotherm
• Thermal Design Chart

• Other factors that affect success of project

• Early involvement of ME

• Communications between domains DUCADE

• Follow design for manufacturability rules

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Acknowledgements

• BWRC colleagues Prof. Brodersen, Chen Chang,
  Gary Kelson, Kimmo Kuusilinna, Sue Mellers, Elise
  Mills, Brain Richards, and Brenda Vanoni
• Mike Montero
• DUCADE http//spiderman.me.berkeley.edu/ducade/
• DOET http//spiderman.me.berkeley.edu/doet/
• Machine shop at mechanical engineering
• Prof. Wright

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The End