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

24. Extra Slides - Krissy

25. Base & Load Arm Base Needs –Stable support linear stage –Cone shaped feature for water cell and sample mount.

26. Base & Load Arm Load Arm Needs –Stable to support and align load cell Evaluation –Components will be machined out of stainless steel. –For ease of machining the base and arm will each have two separate pieces

27. Detailed Methods: Load Cell Selection Small Deflection Equation Where a=span radius, R=indenter radius, h=film thickness Noise Range

28. Concept 1- Preliminary B.O.M

29. Concept 2 – Preliminary B.O.M

30. Concept 3 – Preliminary B.O.M.

31. Load Cell Test Follow a “Transducer Checkout Guide” that they provide. Use a set of calibrated weights. See if Bausch & Lomb could have the component calibrated.

32. Probe Tip Test Using a CMM: –Measure spherical diameter –Measure straightness of the stem

33. Base & Load Arm Test Using a CMM verify that the dimensions match original design.

34. Extra Slides - Rob

35. Quality Function Deployment What the customer/sponsor wants –Functional Structure –Feasibility Assessment Ways to satisfy the customer/sponsor –Project Requirements –Needs Statement QFD Chart –Multiple ways to satisfy a need –Important to decision making process

36. Carrying Case Two Cases –Membrane Press –Electrical Components Lightweight Protects Components Transportability

37. Electrical Purchased Part Test Controller –Connect to Motor and Computer Signal Conditioner –Digital Multi-meter or Voltmeter Data Acquisition –Connect to Conditioner and Load Cell –Apply Force

38. QFD Chart

39. Feasibility Assessment Chart

40. Extra Slides - Chris

41. Membrane Slip Calculation R FxFx FyFy θ F Membrane Applied Force O-Ring Assume: μ = 0.3 and θ = 20˚ Area (A) = 3.37mm * π * 0.3mm A = 3.176mm 2 P = Fspring / A = (26.7 N) / (3.176mm 2 * (1e6m 2/ 1mm 2 )) = 8.4x10 6 N/m 2 R = F / cos70 = 0.2868 N F x = R * sin70 = 0.2695 N F actual, x = 0.2695 N F allow = Fspring *.3 = 8.28 N F allow, x = 8.28 N Factual<Fallow,x therefore membrane will not slip

42. Part #10201 – Translating Stage

43. Part #10202 – Load Cell

44. Part #10206 – Spherical Tip Probe

45. Part #11101 – Base Upper Section

46. Part #11102 – Base Lower Section

47. Part #11203 – Load Arm Base

48. Part #11204 – Load Arm Bracket

49. Part #11205 – Probe Adapter

50. Part #11301 – Membrane Clamp Lower

51. Part #11302 – Membrane Clamp Upper

52. Part #11303 – Membrane Clamp Spring End

53. Part #11304 – Saline Bath