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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 - PowerPoint PPT Presentation
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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.”
Project Background
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
Concept Research
In-house Testing of Units
Teleconferences/On-site Visits
Team Research
Final Decision
Meeting with B&L experts Further Investigation
Feasibility AssessmentEvaluation of Results
Summary of Senior Design I
22 Companies8 Companies
4 Companies2 Companies
6 Technologies
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 studyCost/Benefit analysisEvaluate manufacturing lines to develop an
integration plan
Systems Received for Testing
Micro-Epsilon – Dry, out of the moldFilmetrics – Dry, out of the moldLumetrics – Dry, in the moldPanametrics – 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
Fixturing
Testing Performed
Gage R&R’sMeasurement Verification
- Per lens specification
- Using Rehder GaugeDry/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:
)*,,(& POPORVarianceR
*15.5tionStudyVaria
Tolerance
tionStudyVariaReRPercentGag &
Gage R&R Procedure
10 lenses were measured in a random order by 3 operators.
Each operator measured the 10 lenses 3 timesThe data from the 90 measurements was
entered into the B&L Gage R&R spreadsheetThe R&R percentage was calculatedToric 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.
Correlation ResultsDry - Wet Correlation Data Averages
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250.00
7T 7Z HF HE HD HC HB HA 7A
SKU
Th
ickn
ess
Val
ue
Lumetrics
Wet Rehder
Correlation ResultsDry To Wet Correlation Using Averages (without Lot 7)
R2 = 0.9997
60.00
80.00
100.00
120.00
140.00
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180.00
200.00
60.00 80.00 100.00 120.00 140.00 160.00 180.00
Lumetrics (um)
Reh
der
(u
m)
Recommendations
Lumetrics Parallel path with Micro-Epsilon
Measurement System Summary
SYSTEM R&R (CWB) R&R (CWT) SYSTEM COST PER LINE COST
Lumetrics 8% 6% $60,000 $ 9 - 60 K
Micro-Epsilon 8% 14% $17,000 $17,000
Filmetrics 3% N/A $17,000 $17,000
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 lensLumetrics
– 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 studyCost/Benefit analysisEvaluate manufacturing lines to develop an
integration plan
Project Challenges
Lengthy Research PeriodVendor Lead TimesLens Fixturing TolerancesSetup and OptimizationVendor Support and CapabilityCorrelation Study LogisticsDevice Sensitivity
Project Stewardship
Purchase Lumetrics SystemFabricate Line FixtureInstall System and Collect Preliminary DataExecute Integration PlanValidate on R&D LineTransfer to Manufacturing
Thank You
Bausch & LombBill Appleton – Project CoordinatorRyan Williams – Project SponsorDave Martz – Metrology SupportKevin Beebe – Process SupportJohn Giallombardo – StatisticianProf. Esterman – R.I.T. Mentor Prof. Stiebitz – R.I.T. Coordinator
Questions
Any further questions?
Backup Slides
Process Flow Chart
Casting / Cure
Release
Hydration
Inspection
Packaging
Molding
Key Senior Design I MilestonesTask Finish Date
Needs Assessment Fri 12/17/05
Research Compilation and Review Thu 1/6/05
Vendor CDA Agreements Wed 1/19/05
Peer Presentation Fri 1/28/05
Feasibility Assessment Tue 2/8/05
Vendor Selection Summit Wed 2/9/05
Sample Testing / Capability of Vendors Thu 2/11/05
B&L Presentation Wed 2/16/05
Preliminary Design Packet Thu 2/17/05
Order Demo Systems Fri 2/18/05
PDR Presentation Fri 2/18/05
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
Judging criteriaRequirements Document
Weighting criteria5 = Most Important1 = Least Important
Scoring1 = Not quite able to meet needs3 = Exceeds needs
Feasibility
Feasibility Matrix
Correlation
Dry - Wet Correlation Data
0.00
50.00
100.00
150.00
200.00
250.00
=
Data Points
Th
ickn
ess
Val
ue
Lumetrics Wet Rehder
Example Show ing Process Variability
Example Show ing Difference in Gage R&R
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.
Product Specification Research (Cont.)
Definitions:DF – Degrees of FreedomSS – Sum of SquaresMS – Mean SquareF – F-Valuea – Number of partsb – Number of operatorsn – Number of replicatesx-bar i.. – Mean for each partx-bar… - Grand Meanx-bar .j. – Mean for each operatorxijk – Is each observationxij. – Is mean for each factor level
Source DF SS MS F
Part a-1 b*n* Σ(x-bar i.. - x-bar…)2 SS Part / DF PartMS Part / MS Part*Operator
Operator b-1 a*n* Σ(x-bar .j. - x-bar…)2 SS Operator / DF OperatorMS operator / MS Part*Operator
Part*Operator
(a-1)*(b-1)
SS Total - (SS Part+SS Operator+SS Repeatability)
SS (Part*Operator) / DF (Part*Operator)
MS Operator*Part / MS Repeatability
Repeatability n-(a*b) ΣΣΣ(xijk - x-barij.)
2SS Repeatability / DF Repeatability
Total n-1 ΣΣΣ(xijk - x-bar...)2
Anova Table:
ANOVA Table Equations and Abbreviation Definitions
Variance and Standard Deviation
parts ofNumber * trialsofNumber
Part*Operator MS -Operator MSO
parts ofNumber * trialsofNumber
Part*Operator MS -Part MSP
parts ofNumber * trialsofNumber
ityRepeatabil MSPart *Operator MS* PO
)*,,(& POPORVarianceR
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
*15.5tionStudyVaria
Tolerance
tionStudyVariaReRPercentGag &
Study Variation:
Percent Gage R&R:
(5.15 is a constant that covers 99% of the process.)
Study Variation and Percent Gage R&R Calculations
Experimentation Plan
Small initial trialBased on results, large trial, or halt trialsGauge R&RDOE as necessary
Calibration & Maintenance
Sensor is self calibrating (laser wavelength)Telecommunications grade 15-20 yearsCleaning Lens and Fiber Optic cablesSolid state components
PLC
National Instruments Drivers and SupportContinuous OperationNo Triggering or Nominal Values Fed to
DeviceAll Decisions made by PLCReal Time Control
Importance of Central Thickness
Optical properties
Durability
Comfort
Desired Process
Non-contact methodAutomated and fully integrated into lineNo manual, non-value added laborIncreased sampling rateNo discarding of good lenses after
measurement is performedMeasurement performed at an earlier stage of
production
Requirements of New Process
Non-Contact method of measurement Measure thickness range of 20 – 250 μm Measurement tolerance of ±10 μm Gauge R&R of ≤ 18% User Interface PLC Interface Plan Extensibility to future products
Concepts Researched
MechanicalVision SystemCapacitanceLaser TriangulationLaser AutofocusOpticalUltrasonic
Patent Search
13 related patents foundVisual Inspection SystemsLens ProductionContact Methods
No conflictsKey Words:
Thickness MeasurementThin FilmsContact lenses
Beta Laser Mike: – transmit and receive laser– Focal diameter too large for the application – Only good for flat applications
FRT of America: – They were not confident they could measure a curved surface such as a
contact lens.
MicroPhotonics: – Could only measure up to 50 microns
SolveTech: – Capacitive method – Requires a much larger spot size than required– Develop fixture to position the lens accurately between two plates – Separation distance to small
Eliminated Companies
Lumetrics (Cont.)
Possible install locations: Before mold separation Immediately before/after lens release from mold
Possible install locations: Immediately before/after lens release from mold Before the lenses are placed on the trays
Micro-Epsilon (Cont.)
Company Research
Lumetrics Keyence Elektrophysik FRT of America Mission Peak Optics Micro-Photonics Filmetrics Thermo Electron
Corp. ABB Adetech Onosokki
Lumetrics Mission Peak Optics Filmetrics MTI Instruments LMI Technologies, Inc. Micro-Epsilon ORYX Panametrics
Long List Short List MTI Instruments Inc. LMI Technologies Micro-Epsilon Beta Laser Mike ORYX Panametrics AccuSentry Norman N. Axelrod and Associates Dr. Schenk Inspection Systems Optical Data Associates, LLC. Solve TECH Inc
Keyence: – Device incapable of measuring the size and accuracy required
AccuSentry: – camera or vision system
– Entire concept of a vision system discarded due to the current lack in
adequate technology. Norman N. Axelrod and Associates:
– Do not sell a specific technology
– On-site visit , analyze the problem, and custom develop a solution. Adtech, ABB and Thermoelectron:
– No response when contacted
Eliminated Companies
Contact Lens Quick Reference Guide– Research was completed to create a reference guide for Bausch &
Lomb’s contact lens specifications.
– The specifications include:• Product line
• Lens type
• Monomer used
• Diameter and tolerance of the lenses
• Wet central thickness range and tolerance of the lenses
• Sagittal depth range and tolerance of the lenses
• Power range of each lens
• Refractive index of each lens
• If the lens is tinted
• Finished Product Specification
Product Specification Research
Radius of curvature– During research the radius of curvature (base curve) was questioned by
some of the vendors as this could potentially pose a problem in obtaining the central thickness measurement.
– This is another area where experts at Bausch & Lomb were able to inform the team of the dimension.
– Due to proprietary information this measurement may not be released.
Mold Information
– During the early stages of the project the mold material was introduced as Polypropylene and PVC depending on which contact lens it will contain.
– The refractive index is unknown at this point for any of the molds, but is being investigated in one of Bausch & Lomb’s labs.
Product Specification Research (Cont.)
Dr. Schenk inspection systems:– Sell products to measure thin films
– All products are meant to be installed on a high speed manufacturing line
– Take a measurement based on the profile view of the thin film
Optical Data Associates, LLC:– Specializes in high precision inspection of various components for their
optical properties
– This company is just a testing firm and therefore would not be able to help
or sell any technology that would meet the needs of the application.
Onosokki:
– Contact method systems for measurement
Eliminated Companies
Several patents were found that are within the realm of the given application. The topics varied from a contact probe that measured the actual thickness of a contact lens, other technologies used in taking measurements of a contact lens, to automated visual inspections of a contact lens. Since the application that is being dealt with is more process oriented on the measurement of the central thickness of a contact lens the patents are not being infringed upon by our application.
Patent Search
Patent number 4,665,624 – deals with a soft contact lens analyzing apparatus.
– This apparatus utilizes a fixturing device and several measurement scales to determine the diameter, sagittal depth and central thickness of a contact lens. All of the scales use probes that must come into contact with the actual lens.
– A mechanical, contact system which is not what our application calls for.
Patent number 4,403,420 – Digital gauge for measuring the sagittal depth and thickness of a lens, and the
related systems and methods
– This method involves a fixturing device and several linear encoders to measure the diameter, sagittal depth and central thickness of a lens. Each of the encoders is connected to some type of probe that needs to come into contact with the lens.
– A mechanical contact system in which our application will not infringe on.
Patent Search (Cont.)
Patent number 6,134,342: – Visual inspection method and apparatus for a contact lens.
– The method described is automated. The visual inspection system is looking for defects such as foreign material, scratches, breakage and so forth.
– No quantitative dimensional measurements performed and therefore does not have to do with our application.
Patent number 6,765,661:– A lens (such as contact lens) inspection method.
– This system looks for such flaws as tears or surface defects.
– No quantitative dimensional measurements preformed and therefore our application will not infringe with this patent.
Patent Search (Cont.)
Patent number 6,490,028: – Variable pitch grating for diffraction range finding system
– What is described is a very precise method to determine the range or distance from a reference point to an object. Utilizing a variable pitch grating does this.
– This system uses a completely different methodology than any of the apparatuses
the team has evaluated for the given application.
Patent number 6,815,947: – A method and system for thickness measurements of thin conductive layers
– This system utilizes an electrically conductive method known as eddy current. Extremely thin films that also have conductive properties are the only applicable item that may be measured using this system.
– Due to its limitations, the team ruled out this technology initially. None of the systems being evaluated use this or any related technology.
Patent Search (Cont.)
Patent number 6,847,458: – A method and apparatus for measuring the shape and thickness
variation of polished opaque plates
– In this system dual interferometers are used. One is placed on each side of the plate to perform its surface mapping and other calculations. Since the system is attempting to measure opaque plates two interferometers must be used.
– This system is different from any of the researched systems that have been evaluated because it is a dual interferometer system. All of the systems researched used only one interferometer.
– Also, this is for measuring opaque substances, as our application is to measure optically clear lenses.
Patent Search (Cont.)
Patent number 6,822,745: – Optical systems for measuring form and geometric dimensions of precision
engineered parts
– This patent does describe a similar technology that we will be utilizing. However, it describes the specific equipment and not the overall process of the measurement. Whichever piece of equipment that is decided upon to use in our application, should be protected by that respective companies patents.
– Other than that, no process issues are present that would violate this patent.
Patent number 6,791,691: – A measuring method that uses attuention in total reflection
– This patent describes a similar technology that we will be utilizing. Furthermore, it describes the specific equipment and not the overall process of measuring the object. That respective companies patent should protect whichever piece of equipment the team decides to use in our application.
– No process issues are present.
Patent Search (Cont.)
Patent number 6,301,005: – Inspection system for optical components
– This system contains a device to hold the optical component into place. It has the means to inspect the optical component for any apparent defects.
– No quantitative dimensional measurements are taken into account thus, compared to our
application is not the same and will not infringe.
Patent number 6,791,696: – An automated optical measurement apparatus and method
– This patent describes the method to measure lens properties, such as central thickness, utilizing a wavefront analysis.
– None of the technologies researched involve this type of technology. For this reason, our application will not infringe on this patent
Patent Search (Cont.)
Patent number 5,206,076: – A self aligned manufacturing system and method– This method does not pertain to the metrology of contact lenses. It describes a
method on how to actually produce contact and intra-ocular lenses. – Since this is describing the manufacturing process and not a measurement
process our application does not conflict.
Patent number 6,775,003: – Apparatus and method for total internal reflection spectroscopy– This also describes a similar technology that is being evaluated. Again,
although it has a similar technology it does not describe the process. – Therefore, the researched technologies respective companies patent should
protect the equipment in the end that the team decides to put into use. – No process issues are present.
Patent Search (Cont.)