1. Multidisciplinary Engineering Senior Design Project 6218 Soft Tissue “Tensile” Tester Preliminary Design Review 2/24/2006 Project Sponsor: Bausch & Lomb Team Members: Ryan Schkoda – Team Lead Christopher Kudla – Lead engineer Kristina Schober – Mechanical Engineer Robert Mc Coy – Electrical Engineer Team Mentor: Dr. Elizabeth DeBartolo Kate Gleason College of Engineering Rochester Institute of Technology

2. Agenda Introduction Theory Overview Objectives and Specifications Concept Development Feasibility Component Selection & Design Component & Assembly Test Plan for Senior Design II

3. Introduction Little is known about material properties of the inner eye. Bausch & Lomb requested tensile testing device. A less traditional method of gathering material property information as been employed.

4. Membrane Theory Small Deflection Equation Where a=span radius, R=indenter radius, h=film thickness Hooke’s Law

5. Objectives & Specifications Compact and easily transportable design. Incorporate ergonomics. Overall weight < 25 lbs. Carrying case. Compliant with FDA, GMP, and OR regulations. Easy to operate user interface. Sterilization using autoclave. Load cell and encoder capable of continuous data acquisition. Repeatable mounting of specimens. Repeatable method of generating a sample out of the original rhexis. Powered by 110V outlet. Ability to test a sample that is submerged in a saline solution. Cost to be on the order of $5,000.

6. Concept 1- Traditional Tensile Tester Baseline Design Advantages: Familiar type of testing Disadvantages: Grips to accommodate sample size

7. Concept 2- Automated Membrane Press Stepper Motor driving a screw. Probe will be forced through material. Uses different method to clamp material.

8. Concept 3- Manual Membrane Press Similar to Concept 2 Less Expensive Manual crank provides more error.

9. Concept 4 – Automated Membrane Press with Servo Motor Servo Motor with linear stage Advantages: Precise operation Disadvantages: Need tight tolerances

10. Feasibility Assessment Introduction –Decision making activity –Attributes Evaluation of Design Concepts Pugh Evaluation –“paired comparison” –Reference concept –Eliminate weak concepts Weighted Concept Evaluation –Modified Version –Group Discussion

11. Load Cell Selection Needs –Load capacity of 10g –Low “repeatability” Evaluation –Used 2 methods: Small deflection equation Test experiment –Noise range Transducer Techniques- GSO Series http://www.transducertechniques.com/GSO-load-cell.cfm

12. Probe Tip Selection Needs –1.5mm spherical tip –Thermal properties strong enough to be autoclaved Evaluation –CMM tips (a.k.a. styli) –Ruby spherical tip Renishaw

13.  0.1 micron resolution  25mm travel  DC servo motor  Linear encoder Motorized Linear Translating Stage

14. Controller Ensures the speed and position of Linear Stage and Servomotor. Single axis Control Plug and Play Compatibility Power Amplifier Compatible with LabView –Drivers –DLL file for Windows

15. Signal Conditioning and Data Acquisition Signal Conditioner –Includes power amplifier for load cell –Increase measurement resolution –Improve signal-to-noise ratios Data Acquisition –Outputs data to user interface –Contains an analog to digital converter –USB capable –LabView® compatible

16. LabView® VI Example

17. Control and Display LabView® interface USB port link for data input End user definable DLL files LabView® drivers

18. Final Design Exploded View Overall Design

19. Membrane Clamp O-Ring Groove Membrane Clamp

20. Estimated B.O.M.

21. Calibrating and Verifying Load Cell Measuring Machined Parts Component Test Analysis

22. Plan for Senior Design II Build Device Develop Strategy For Interpretation Troubleshoot Gage R&R Further Research of Membrane Deflection and Simulation

23. Comments and Questions