BioHorizons Fatigue Test System

1
BioHorizons Fatigue Test System

• Corp 3
• Midterm Concepts Presentation

2
Team Members

• Jonathan Hill
• John Maddox
• Allen Lindsay
• Crichton Neal
• Chris Howell
• Felicia Craig
• Bradley Johnson

3
Project Overview

• General Specification
• ISO Standards
• Primary Concept
• Solid Edge
• Advantages/Disadvantages
• Water Bath
• Economic Analysis
• Secondary Concept
• Phase II

4
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

5
ISO Standards

• ISO provides more specific specifications and
  constraints in ISO 14801DentistryFatigue 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 manufacturers
  instruction for use.

6
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 occurtesting 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 37C 2C 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
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Other Applicable ISO Standards

• ISO 1099 Metallic materialsFatigue
  testingAxial force controlled method
• ISO 1942-1 Dental vocabularyPart 1 General and
  clinical terms
• ISO 3696 Water for analytical laboratory
  useSpecification and test methods
• ISO 4965 Axial load fatigue testing
  machinesDynamic force calibrationStrain gauge
  technique
• ISO 7500-1 Metallic materialsVerification of
  static uniaxial testing machinesPart 1
  Tension/compression testing machinesVerificati
  on and calibration of the force- measuring system

8
Concept Overview
9
Different Views
10
Exploded View
Exploded View
Temperature Sensor
Liquid Bath Container (Pyrex)
Frame (steel)
Washer (Rubber)
Thumb Screw
Insert (will be tapped to hold test piece)
Container Base
Linear Motor/Load Cell
Base (steel)
Mounting Screws
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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

12
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

13
Water Bath
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Major Components

• Heating element
• Small and compact
• Low fluid volume rated
• Temperature switch
• Small and compact
• -2C tolerance
• Dish
• Metal bottom
• Glass sides
• Water tight
• Water level switch
• Small and compact
• Safely maintain water level

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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

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Standards

• ISO 148012003
• 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
  C2C or -2 C

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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

18
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

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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 105C
• 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

20
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

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Load Cell

• Piezoelectric sensing cell
• Highly repeatable
• Fatigue Rated load cell
• Low profile to fit easily within machine

22
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

23
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

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Alternative Design
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Advantages

• Cheap saline bath container
• Rotary motor is cheaper than linear motor

26
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

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Phase II-Completed by Dec.

• Obtain more quotes on linear motors
• Dimension Concept
• Stress Analysis
• Finalize Concept