Hardware Development Methods and Tools

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Hardware Development Methods and Tools

• Design Methodologies
• Component Variations
• Misuse
• Extended TRIZ

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Six Sigma

• Six Sigma is a revolutionary business process
  geared toward dramatically reducing
  organizational inefficiencies that translate into
  bottom-line profitably. The steps are
• Define
• Measure
• Analyze
• Improve
• Control.

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The basis of Six Sigma is measuring and improving
processes re defects

• Six Sigma 3.4 defects per million opportunities
• Most current methodologies operate at 3 to 4
  sigma, allowing 25 loss of revenue because of
  failure rates due to defects
• Result unhappy, non-returning customers!

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Design for Six Sigma

• Design for Six Sigma (DFSS) is an approach to
  designing or re-designing product and/or services
  to meet or exceed customer requirements and
  expectations (VOC). It begins by conducting a
  gap analysis of your entire product development
  system. This analysis finds the gaps in your
  processes that are negatively affecting new
  product performance

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Methodology 1 DMADV

• Define determine goals, VOC requirements
• Measure assess customer needs specs.
• Analyze- examine solution options
• Design develop to meet requirements
• Verify verify that you met requirements

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Other Methods

• DMADOV prior Optimize
• IDEAS Identify/Design/Evaluate/Affirm/Scale up
• IDOV Identify/Design/Optimize/Validate
• DMEDI Define/Measure/Explore/Develop/Implement
• DCCDI Define/Customer/Concepts/Design/Implement

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In General, Design for Six Sigma

• Is a structured approach to responding to the
  voice of the customer
• Is augmented by standard tools such as QFD,
  Failure Modes and Effects Analysis, Pareto Charts
  analyses, Feather Diagrams, designsafe
  analyses, input from reliability groups, input
  from QA and customer complaint inputs, possible
  analyses from MAUDE data, etc.

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Some Six Sigma Tools

• Robust design Taguchi Method
• Quality Function Deployment QFD (done)
• Design Failure Modes and Effects Analysis
• Axiomatic Design Nam Suh

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Robust Design

• By considering the noise factors (variation
  component deterioration) and the cost of failure
  this method helps ensure customer satisfaction.
  The focus is on improving the fundamental
  function of the product or process, facilitating
  flexible designs and concurrent engineering. It
  assists in reducing product cost, improving
  quality, while simultaneously reducing
  development interval.

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Your Circuit Choice?

• Compensate the customers for their losses.
• Screen out circuits having large offset voltage
  at the end of the production line (discard).
• Institute tighter tolerances through process
  control on the manufacturing line (inspect).
• Change the nominal values of critical circuit
  parameters such that the circuit's function
  becomes insensitive to the cause, namely,
  manufacturing variation.

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Parameter Diagram, aka P-Diagram
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Robust Design Overview Step 1

• Problem FormulationThis step consists of
  identifying the main function, developing the
  P-diagram, defining the ideal function and S/N
  ratio, and planning the experiments. The
  experiments involve changing the control, noise
  and signal factors systematically using
  orthogonal arrays.

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Robust Design Overview Step 2

• Data Collection/SimulationThe experiments may
  be conducted in hardware or through simulation.
  It is not necessary to have a full-scale model of
  the product for the purpose of experimentation.
  It is sufficient and more desirable to have an
  essential model of the product that adequately
  captures the design concept. Thus, the
  experiments can be done more economically.

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Robust Design Overview Step 3

• Factor Effects AnalysisThe effects of the
  control factors are calculated in this step and
  the results are analyzed to select optimum
  setting of the control factors.

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Robust Design Overview Step 4

• Prediction/ConfirmationIn order to validate
  the optimum conditions we predict the performance
  of the product design under baseline and optimum
  settings of the control factors. Then we perform
  confirmation experiments under these conditions
  and compare the results with the predictions. If
  the results of confirmation experiments agree
  with the predictions, then we implement else
  repeat.

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Design for Failure Modes Effect Analysis Form
Data Process

1. Number (No.)
2. Item/Function
3. Potential Failure Mode
4. Potential Effect(s) of Failure
5. Severity (S)
6. Potential Cause(s)/Mechanism(s) of Failure
7. Occurrence (O)

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Design for Failure Modes Effect Analysis
Continued

1. Classification
2. Current Mitigations
3. Verification
4. Detection (D)
5. Recommended actions
6. Action Results

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Classification Classification Classification
Code To Indicate Criteria
SC A potential Safety Characteristics Severity 5 and Occurrence 2 to 5
KC A potential Key Design Characteristics Severity 4 and Occurrence 3 to 5 Severity 3 and Occurrence 3 to 5 Severity 2 and Occurrence 4 to 5
AO Action Is Optional Not SC nor KC
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Axiomatic Design

• CTS Critical To Satisfaction (or CR, customer
  requirements)
• FR Functional Requirements
• DP Design Parameters
• PV Process Variable
• Matrix based, aim is to develop FR vectors that
  are independent wrt DPs and result in minimal
  complexity.

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Redundancy

• Active redundancy MTBF 1/? gt 3/2?
• Standby redundancy MTBF 1/? gt 2/?
• Active units are in parallel always active
• Standby units swap out when bad

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Component Selection Considerations

• Component reliability
• Vendor assessment (Hx, failure, etc.)
• Vendor audit (check facility)
• Vendor evaluation (inspect incoming)
• Vendor qualification (on-list?)
• Component history
• military reliability groups
• government info bases
• Safety (FMEA, etc.)

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Hardware Software Techniques ctd.

• Component Derating
• Practice of limiting the stresses
• Use 2 watt R in 1 watt situation, decrease
  failure rate gt30 (T, humidity, P, V, I,
  friction, vibration)
• Usage ratio max stress/stress rating (.5-.9)
• Goal is reliability!
• Pacemaker example

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Hardware Software Techniques ctd.

• Safety Margin
• (mean safety factor) - 1
• (mean strength/mean stress) - 1
• Elevator safety margin2
• Medical devices Fries - .5 and up.
• Load Protection
• Environment
• Product misuse
• Design for variation (6 sigma)

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Product misuse Plan for

• excess application of cleaning solutions
• physical abuse
• spills
• excess weight applied to certain parts
• excess torque applied to controls or screws
• improper voltages, frequencies or pressures
• improper or interchangeable electrical or
  pneumatic connections.

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The Clean-Room Approach To Reverse-Engineering

• One person or group takes a device apart and
  describes what it does in as much detail as
  possible at a higher level of abstraction than
  the specific code. That description is then given
  to another group or person who has absolutely no
  knowledge of the specific device in question.
  This second party then builds a new device based
  on the description. The end result is a new
  device that works identically to the original but
  was created without any possibility of
  specifically copying the original.
• -Mathew Schwartz

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Extended TRIZ Design TechniquesExample Effect
of a grounding pad
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Problem Statement

• Grounding pad is needed in order to conduct
  current from scalpel to ground
• Grounding pad must adhere to the body, otherwise
  there might be hot spots or burns
• Removal of the grounding pad causes injury, as
  seen in the photo. Injuries may include tearing
  of the skin, not just what is seen here.

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Concept Map for Skin Problem
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Ideation Process Fill in the blanks -

• Brief description of the problem
• Problem Formulation build the diagram

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Formulate

• 1. Find an alternative way to obtain the
  (conducts electricity well) that does not require
  the (Adheres tightly to skin).
• 2. Consider transitioning to the next
  generation of the system that will provide the
  (conducts electricity well) in a more effective
  way and/or will be free of existing problems.
•  

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Continued

• 3. Find an alternative way to obtain the
  (Adheres tightly to skin) that offers the
  following provides or enhances the (conducts
  electricity well), does not cause the (Tears
  skin).
• 4. Try to resolve the following contradiction
  The useful factor the (Adheres tightly to skin)
  should be in place in order to provide or enhance
  the (conducts electricity well), and should not
  exist in order to avoid the (Tears skin). 
• 5. Find a way to eliminate, reduce, or prevent
  the (Tears skin) under the conditions of the
  (Adheres tightly to skin).

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Continued -

• Select likely suggestions,
• Expand upon
• Select solution

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End of chapter -