690 likes | 710 Views
Automated Lens Measurement System Project # 05427. Team Members. Rhiannon Casale John Spalding Melissa Groginski Frank Capristo Paul Thompson Matt Place. Presentation Overview. Introduction/Project Overview Summary of Senior Design I Fixture Development Testing Plan Testing Results
E N D
Automated Lens Measurement System Project # 05427
Team Members Rhiannon Casale John Spalding Melissa Groginski Frank Capristo Paul Thompson Matt Place
Presentation Overview • Introduction/Project Overview • Summary of Senior Design I • Fixture Development • Testing Plan • Testing Results • System Recommendation • Implementation Analysis • Cost/Benefit Analysis • Conclusions
Mission Statement “To provide Bausch & Lomb with the most cost effective, non contact solution for accurately measuring the central thickness of a contact lens.”
Current System – Rehder Gage Mechanical contact – wet state, offline Gage R&R (TORIC) ~ 50% at + 20 microns Accuracy within + 2 microns Desired Measurement Specifications Gage R&R < 18% at + 10 microns Measurement accuracy of + 1 micron Cycle time < 1 second Project Background
Summary of Senior Design I Meeting with B&L experts Further Investigation Concept Research Teleconferences/On-site Visits Team Research 22 Companies 6 Technologies 8 Companies Final Decision In-house Testing of Units 2 Companies 4 Companies Evaluation of Results Feasibility Assessment
Desired Outcomes for Senior Design II • Design and create fixtures for device and lens positioning • Bring in and test demonstration units from top vendors • Wet/Dry correlation study • Cost/Benefit analysis • Evaluate manufacturing lines to develop an integration plan
Systems Received for Testing • Micro-Epsilon – Dry, out of the mold • Filmetrics – Dry, out of the mold • Lumetrics – Dry, in the mold • Panametrics – Wet, in inspection water cell
Fixture Design Challenges • Focal length within 125 microns (0.005 inches) • Centration of lens within 50 microns (0.002 inches)
SolidWorks Models Micro-Epsilon Panametrics Filmetrics
Testing Performed • Gage R&R’s • Measurement Verification - Per lens specification - Using Rehder Gauge • Dry/Wet Correlation
Operator Gage R&R • Why? • Means to compare outcomes to old system • Originally it was going to also be used as an off-line station • When system implemented on-line the Gage R&R percentage will only become better as the operator percentage will not be included anymore
Gage R&R Percentage Definition • Repeatability: Gage Error • Reproducibility: Operators and Operators*Parts • B&L Spreadsheet Verified with Minitab • The results are given as a percentage • R&R Variance: • Study Variation: (5.15 is a constant that estimates the width of the interval to cover 99% of the process.) • Percent Gage R&R:
Gage R&R Procedure • 10 lenses were measured in a random order by 3 operators. • Each operator measured the 10 lenses 3 times • The data from the 90 measurements was entered into the B&L Gage R&R spreadsheet • The R&R percentage was calculated • Toric and Bifocal lenses utilized
Testing Results: Micro-Epsilon • Preliminary Gage R&R Results (@ +/- 10 µm): Trial 1: CWT - 46% Trial 2: CWT - 36% Trial 3: CWT - 34% Trial 4: CWB - 8% • Modified fixture Gage R&R Results (@ +/- 10 µm): Trial 5: CWT - 18% Trial 6: CWT - 14%
Testing Results: Lumetrics • Gage R&R Results (@ +/- 10 µm): Trial 1 : CWT - 11% Trial 2 : CWT - 6% Trial 3 : CWB - 8%
Panametrics/Filmetrics • Panametrics • System failed to meet project requirements • Unable to perform Gage R&R • Filmetrics Gage R&R Results (@ +/- 10 µm): Trial 1 : CWB - 3% Trial 2 : CWT – Incapable
Dry/Wet Correlation Procedure: • Measured in the mold w/Lumetrics • Lenses processed through dry-release • Measured dry lenses with Filmetrics system • Hydrate lenses • Measured on Rehder gage (current system)
Dry/Wet Correlation • Number of Lenses: - 135 lenses across 9 SKUs measured in each state - Lot sizes calculated to obtain a 99% confidence level • Verified dry lens measurement systems’ accuracy
Correlation Results • Correlation provides a viable model • Results calculated with and without lot 7* • R2 value of .9997 obtained not including lot 7** Lot 7 represents the worst case SKU for measuring central thickness. The correlation broke down when including lot 7 due to the extremely high Gage R&R on the current wet system.
Recommendations • Lumetrics • Parallel path with Micro-Epsilon
Implementation • Bench top system • No cost benefit to bench top system
Implementation • Device Placement • Fixture Design
Implementation • Calibration & Maintenance • Self Calibrating • Optical Cleaning when Necessary • Surge Protection • PLC Interface • Continuous Measurement • No Decision Making • Real Time Remote Control and Data
Cost/Benefit Analysis • Potential Cost Reduction ~ 1-2% per lens • Lumetrics • Return on Investment < 12 months • Micro-Epsilon • Return on Investment < 6 months • Increase in process control further reduces ROI time
Actual Outcomes for Senior Design II • Design and create fixtures for device and lens positioning • Bring in and test demonstration units from top vendors • Wet/Dry correlation study • Cost/Benefit analysis • Evaluate manufacturing lines to develop an integration plan
Project Challenges • Lengthy Research Period • Vendor Lead Times • Lens Fixturing Tolerances • Setup and Optimization • Vendor Support and Capability • Correlation Study Logistics • Device Sensitivity
Project Stewardship • Purchase Lumetrics System • Fabricate Line Fixture • Install System and Collect Preliminary Data • Execute Integration Plan • Validate on R&D Line • Transfer to Manufacturing
Thank You • Bausch & Lomb • Bill Appleton – Project Coordinator • Ryan Williams – Project Sponsor • Dave Martz – Metrology Support • Kevin Beebe – Process Support • John Giallombardo – Statistician • Prof. Esterman – R.I.T. Mentor • Prof. Stiebitz – R.I.T. Coordinator
Questions Any further questions?
Process Flow Chart Molding Casting / Cure Release Hydration Inspection Packaging
Possible Points of Integration • Dry State: • In the assembled mold • After mold de-capping • After lens is released from mold • Wet State: • During cosmetic inspection • In blister package
Damage from Lens Handling O-ring Signature Extraction Tray Marks Tweezers Mark
Feasibility Judging criteria Requirements Document Weighting criteria 5 = Most Important 1 = Least Important Scoring 1 = Not quite able to meet needs 3 = Exceeds needs
Product Specification Research (Cont.) • Cost Research • Research was done to identify what the overall cost is to actually make the lens. • Cost was broken down by each stage of the lens making process. • The cost of material and operator were gathered. • If the apparatus was eventually integrated into the line as an automated system, in order to cost justify the equipment such costs would need to be known.
ANOVA Table Equations and Abbreviation Definitions Anova Table: Definitions: DF – Degrees of Freedom SS – Sum of Squares MS – Mean Square F – F-Value a – Number of parts b – Number of operators n – Number of replicates x-bar i.. – Mean for each part x-bar…- Grand Mean x-bar .j. – Mean for each operator xijk – Is each observation xij. – Is mean for each factor level
Variance and Standard Deviation Variance:(MS is the mean square) Standard Deviation (SD): O = √Operator Variance P = √Part Variance O*P = √Operator*Part Variance R&R = √R&R Variance
Study Variation and Percent Gage R&R Calculations Study Variation: (5.15 is a constant that covers 99% of the process.) Percent Gage R&R:
Experimentation Plan • Small initial trial • Based on results, large trial, or halt trials • Gauge R&R • DOE as necessary
Calibration & Maintenance • Sensor is self calibrating (laser wavelength) • Telecommunications grade 15-20 years • Cleaning Lens and Fiber Optic cables • Solid state components
PLC • National Instruments Drivers and Support • Continuous Operation • No Triggering or Nominal Values Fed to Device • All Decisions made by PLC • Real Time Control
Importance of Central Thickness • Optical properties • Durability • Comfort
Desired Process • Non-contact method • Automated and fully integrated into line • No manual, non-value added labor • Increased sampling rate • No discarding of good lenses after measurement is performed • Measurement performed at an earlier stage of production