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Final Midterm Presentation Fall 06

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Final Midterm Presentation Fall 06 Powered By Docstoc
					BioHorizons Fatigue Test System


                Corp 3
     Midterm Concepts Presentation
Team Members
           Jonathan Hill
          John Maddox
          Allen Lindsay
          Crichton Neal
           Chris Howell
           Felicia Craig
         Bradley Johnson
Project Overview
 General Specification
 ISO Standards
 Primary Concept
  •   Solid Edge
  •   Advantages/Disadvantages
  •   Water Bath
  •   Economic Analysis
 Secondary Concept
 Phase II
Specifications and Constraints
 General Constraints
      small and light enough to operate on a tabletop
      clean and quiet enough to operate indoors at the
       BioHorizons offices
      Able to perform fatigue tests as well as static load tests
      Control system and sensors must measure failure load and
       cycles to failure and discontinue operation at this point
      Entire system must be able to be calibrated accurately
       enough for continuous operation within ISO 14801
       specifications and constraints

 Economic Constraints
      to produce a fatigue testing machine that can be reproduced
       and used for less than it currently costs to have the dental
       implants tested from an outside company
ISO Standards
 ISO provides more specific specifications and constraints in ISO
  14801—Dentistry—Fatigue test for endosseous dental implants
 Several of the more pertinent specifiations are covered below,
  obtained from the ISO document:
    The testing machine should be capable of applying the
     specified load with an error not exceeding ± 5% at maximum
     load.
    The endosseous dental implant shall be clamped such that it
     makes a 30° ± 1° angle with the loading direction of the
     testing machine.
    The device shall clamp the specimen at a distance 3.0 mm ±
     0.1 mm apically from the nominal bone level as specified in
     the manufacturer’s instruction for use.
 ISO Standards (continued)
  More constraints and specifications:
        The dimensions of the loading member shall be chosen to
         define a distance l = 11.0 mm ± 0.1 mm from the centre of
         the hemisphere to the clamping plane.
        For endosseous dental implants that include materials in
         which corrosion fatigue has been reported or is expected to
         occur…testing shall be carried out in water of Grade 2
         according to ISO 3696, in normal saline [.09%]* or in
         physiologic medium. The fluid and the test specimen shall
         be kept at 37°C ± 2°C during the testing.
        Fatigue testing shall be carried out with a unidirectional load.
         The load shall vary sinusoidally between a nominal peak
         value and 10 % of this value. The loading frequency shall
         be ≤ 15 Hz. Testing in liquid media shall be conducted at
         frequencies ≤ 2 Hz.

*As specified by BioHorizons
Other Applicable ISO Standards
 ISO 1099:     Metallic materials—Fatigue testing—Axial force
                controlled method

 ISO 1942-1:   Dental vocabulary—Part 1: General and clinical terms

 ISO 3696:     Water for analytical laboratory use—Specification and
                test methods

 ISO 4965:      Axial load fatigue testing machines—Dynamic force
       calibration—Strain gauge technique

 ISO 7500-1:  Metallic materials—Verification of static uniaxial testing
               machines—Part 1: Tension/compression testing
               machines—Verification and calibration of the force-
       measuring system
Concept Overview
Different Views
    Temperature         Exploded View
    Sensor
             Exploded View
 Liquid Bath
 Container                                  Frame (steel)
 (Pyrex)


      Washer                                   Thumb Screw
      (Rubber)
                                    Insert (will be
Container Base                      tapped to hold
                                    test piece)




Linear
Motor/Load
Cell


                                                      Base (steel)




                                        Mounting Screws
    Advantages
 Long life
 Excellent precision and
    reliability
   Ease in varying load and
    frequency
   Low maintenance
   Easy setup
   Small number of parts
   Conduct static and
    fatigue tests without
    changing setup
Disadvantages
                 Initial costs are high
                 Replacement parts would
                  be high
                 Possible motor cooling
                  may need to be
                  addressed
                 Different inserts need to
                  be tapped for each
                  implant tested
Water Bath
Major Components
 Heating element
    Small and compact
    Low fluid volume rated
 Temperature switch
    Small and compact
    +-2°C tolerance
 Dish
    Metal bottom
    Glass sides
    Water tight
 Water level switch
    Small and compact
    Safely maintain water
     level
Dish
 Metal base
    Base for mounting heating
     components
    Able to drain the dish
     through a ball valve
 Glass tube
    Forms sides
    Able to withstand high
     temps incase of heating
     problems
    Able to see the test
     specimen during testing
 Washer
    Or sealant as of yet to be
     determined
    Seals the base to the glass
Standards
 ISO 14801:2003
     5.4 Testing Environment
         testing shall be carried out in water of Grade 2
          according to ISO 3696
         fluid and the test specimen shall be kept at 37
          °C+2°C or -2 °C
Heating Element
 Compact Cartridge-Style Immersion Heater
      1 5/8" long type 316 stainless steel element
      Maximum temperature of 100° C
      CSA Certified and UL-Registered
      Can be fully immerged in saline solution
Temperature switch
 Submersible Cartridge Temperature Switch
    Operates as a thermostat
    300 series stainless steel outer shell
    adjusted between -73° and +315° C
    2” long element
    UL-Registered
 Search continues to refine this component
Water Level Switch
         Vertical-Mount Liquid-Level Switch
            Maintain a safe water level for the
             Immersion heating element
            Over all length of 1 7/8“
            Max temperature rating of 105°C
            When the fluid level drops too low
               cut power to the heating element

               turn on a warning light or trigger a

                system warning in the testing
                program letting the tester know to
                add more fluid
Linear Servo Motor

 Handles static loading up to 500 lbf.
 Handles a cycling load from 0 to 150 lbf. at a
  rate up to 15 Hz
Load Cell
             Piezoelectric sensing
              cell
             Highly repeatable
             Fatigue Rated load cell
             Low profile to fit easily
              within machine
Controls
 Load cell sends a signal through a DAQ card to
  LabView
 LabView takes the data and depending on the load it
  will send a signal to the Driver which will in turn
  increase or decrease the current
Economic Analysis
Linear Motor, Cooling Jacket, Controller, and Driver: $19600
Load Cell: $1000
Lab View: $1200 per year
Jig Frame and Base: $2000
Computer: $600
Heating Accessories: $300
Cables and Connectors: $200

Total Costs: $25000
Alternative Design
Advantages
              Cheap saline bath
               container
              Rotary motor is cheaper
               than linear motor
Disadvantages
                 Bearings
                    (maintenance)
                    Expensive to machine
                   Small error in load cell
                    reading due to the
                    bearing friction
                   Angle of applied force
                    will be less reliable
                    Complicated – many
                    possible places for
                    failure
Phase II-Completed by Dec.
 Obtain more quotes on linear motors
 Dimension Concept
 Stress Analysis
 Finalize Concept

				
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