Multidisciplinary Engineering Senior Design Project 6218 Miniature Membrane Press Critical Design Review 5/16/2006 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

Agenda Introduction Recap of Project Planning Fabrication and Build LabView™ Development Data Analysis Routine Testing & Results Error Recommendations Demonstration

Introduction Purpose is to gather material properties Employing a nontraditional method of property determination Showing much promise

Design Layout

Design (cont.)

Component Selection Motorized Translating Stage: ±0.1 μm resolution Built in linear encoder LabVIEW compatible CMM Style Probe Tip Tightly toleranced diameter 10 gram Load Cell ±0.03 gram resolution Safety pins help prevent damage LabVIEW compatible

Electrical Components Connect Load Cell to User Interface –Signal Conditioner Accuracy: ±0.05% of FS Noise and Ripple: Less than 5 mV P-P at gain=1000 –Data Acquisition 8 Single-Ended, 12-Bit Analog Inputs LabVIEW Drivers and Examples

Electrical Components Connect Linear Stage to User Interface –Single-Axis Low-Power Motion Controller/Driver Compatible for plug-and-play operation 1000x programmable micro-step resolution for ultra smooth low speed stepper positioning RS232 communications link for easy user interfacing LabVIEW Compatible with Drivers

Control and Display LabVIEW interface USB and Serial port links for data input DLL files LabVIEW drivers Load Cell Signal Conditioner/ Amplifier USB Data Acquisition / A/D Converter Motorized Linear Stage/Encoder Motion Controller/Driver LabVIEW ®

Alignment VI

Test VI

Data Operations Purpose –Necessary to extract material properties –To account for not sensing origin

Representative Data Set Smoothness & Continuity Noise contaminated zero values Characteristic curve Both Small and large deflection data

Replication Replication of area of interest Systematically scatter along x- axis

Replication, Curve Fitting & Placement Theory dictates P  3 Cubic is fit to each curve Best fit means best placement

“Small” Deflections Question: What is “small?” Answer: Data points corresponding to the part of the data curve that have yet to deviate from the small deflection equations’ predictions

Investigation of Plastic Wrap

Investigation of Artificial Rhexis

Implementation Methods Two methods of Data Analysis –MATLAB® More Robust Fast Easily Customizable –Microsoft Excel® Easier to adjust Microsoft Excel® is more readily available

MATLAB® Implementation

Excel® Implementation

Poor Data Obvious anomaly in the data curve Severe impact on modulus readings Suspected to be from wrinkles or poor sample loading

Concentricity Testing (BLP0001) Objective: –To evaluate the membrane press alignment. It is critical that the probe tip and stage be centered. Procedure –Set alignment prior to each test and record position per SOP#: TD-PPD-PRO-001. –Use 10 different samples. Results: –The data provided a range for the center point location. –Favorable data results of Young’s Modulus.

Concentricity Testing Results Radius: Mean= Stdev=0.0024

Concentricity Testing Results

Offset Testing (BLP0002) Objective: –To evaluate the membrane press with an offset alignment. –A worst case scenario. Procedure: Determine the offset value, running 10 tests at the offset position. –Determining the offset value: Used centered data collected from the Concentricity Tests. Found the 95 th and 50 th percentiles of the centered x and y positions.

Offset Testing Results Radius: Mean= Stdev=0.0031

Offset Testing Results Young’s Modulus Values:

Realignment Testing (BLP0003) Objective: –To reduce the number of times the stage must be realigned. Procedure: –Run 10 tests, 5 tests, and 2 tests. Acceptance Criteria: Results: After each test the device must be realigned

Realignment Testing Results

Gage R&R (BLP0004) Objective: Measure the Repeatability and Reproducibility of the device. Procedure: –3 operators –10 different samples a piece Acceptance Criteria: Less than or equal to 25% Results: –Gage R&R= 383%

Testing for Misalignment Induced Error 95 th percentile

Error Analysis

Results PVDC (plastic wrap) –352.7 MPa ±50.2 MPa Artificial Rhexis –MPa ±14.3%

Recommendations Eddy current or capacitance sensors Negative pre-strain testing Saline testing grip redesign Continued silicone testing Fitting non-linear constants Shorter

Questions & Discussion

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.