solving uv mysteries
play

Solving UV Mysteries Anything that you can measure, you have a - PowerPoint PPT Presentation

Whodat? Whodunit? Solving U V Cu r in g Mysteries with Measurement Jim Raymont Solving UV Mysteries Anything that you can measure, you have a better chance of controlling. Things that you do not measure become the cause of mysterious problems


  1. Whodat? Whodunit? Solving U V Cu r in g Mysteries with Measurement Jim Raymont

  2. Solving UV Mysteries Anything that you can measure, you have a better chance of controlling. Things that you do not measure become the cause of mysterious problems Larry Goldberg-Beta Industries UV Can Be Mysterious Unless You Understand It • Cannot see it with the visible eye • Wavelength is a nanometer (nm)-a billionth of a meter • Reduce UV mysteries and process variables to increase profit • Ask questions as we go • Will share this presentation as PDF • Here to help during the SGIA show (Booth 2800)

  3. UV Curing-Crime Scene Producing a large amount of product before detecting a problem.

  4. Round Up The Usual Suspects Suspect 1A: The Formulator Suspect 1B: The Equipment Supplier

  5. Please Describe the …….. � Abrasion Resistance � Tensile Strength � Scratch Resistance � Gloss � Chemical Resistance � Coating Viscosity � Hardness � Film Thickness � Weatherability � Ability to Over Coat � Non-Yellowing � TBD � Flexibility � TBD What properties are formulation driven? What properties are process/UV source driven?

  6. The UV Process

  7. The UV Process-Analogy Cake: Bake at 350 ° F for 30 minutes Oven Temperature ( ° F) is similar to Irradiance (Watts/cm 2 ) Bake Time (Minutes or seconds) is similar to Energy Density (Joules/cm 2 ) Not Specified: Oven Type Changing the Cake Process Window • 350 ° X 30 = 10,500 Equal Degree Minute Options • 700 ° F for 15 minutes? • 175 ° F for 60 minutes? What if the cake mix only gave you the time?

  8. Speaking the Same Terminology Irradiance (Intensity) • Expressed in watts or milliWatts per square centimeter (W/cm 2 or mW/cm 2 ) • Total radiant power of (all) wavelengths passing from all incident directions onto an infinitesimally small area (cm 2 ) • Depth of cure, penetration through pigments and opaque colors, adhesion to the substrate Energy Density (Dose) • Expressed in Joules (J/cm 2 ) or milliJoules (mJ/cm 2 ) per square centimeter • Incorporates time as part of the measurement • One watt for One second = One Joule • Area under the irradiance curve • Often the only UV exposure guide number supplied

  9. Speaking the Same Terminology Peak Irradiance Time Communication • Process Development • Transition to Production • Production • Within a company • With Supply Chain

  10. Speaking the Same Language Broadband UV Spectrum • UVA: 320-390nm “Black light”, UV Inks, adhesion • UVB : 280-320nm “Toughness” , skin response • UVC : 200-280nm, germicidal (254 nm), surface cure, tack, chemical or scratch resistance • UVV : 395-445nm, opaque/white, thick coats, adhesion, depth of cure Broadband Instrument Responses • Instrument Bandwidths are not defined and vary from manufacturer to manufacturer and how they are specified • EIT UVA 320-390 nm, Full Width Half Max (FWHM), CWL 365 nm • IL UVA 250-415 nm CWL 365 nm IL UVA UV LEDs 250-415 EIT nm Discussed UVA 320- 390 nm Later

  11. Process Window “I am loose and tight in all the wrong places”

  12. Process Window • The range in which a process will work with the desired results – Adhesion, hardness, flexibility, gloss, texture, stain or scratch resistance, chemical rub, cross hatch, abrasion rub, color ID, registration – Often a compromise • Invest before production & confirm when things are working! – Starting guidelines from formulator? – Define your lower limits and document the readings – Increase line speed/decrease applied power until you undercure, note readings and cushion by 20% – Upper limits? • Monitor your readings by job, hour, shift or day as required to maintain quality • Establish your process window during the design/development phase and start monitoring from day one in production

  13. Process Window • Starting Point: Formulator Guidelines • Testing can define a process window Lab testing is less expensive than production testing or • no process window Variables: • Line speed • Lamp distance • Lamp output • Bulb Type • Source Type • Coating

  14. Process Window Normal Operating Window Caution 20% Undercure Buffer Range Stop!Undercure Limit Over cure or over temperature ?

  15. Gathering UV Evidence We can’t ask a UV lamp or a power supply to confess, but we can gather evidence using other means…

  16. Gathering UV Evidence “ Did you perform the maintenance? Did You?”

  17. Gathering Evidence

  18. Gathering UV Evidence Right Tools? • • Right Tests? • Right Expectations? • Documentation?

  19. Gathering UV Evidence = Gather and preserve evidence to use it for when conditions change

  20. Preserving UV Evidence For each UV lamp system • Hour meter • Indicated vs. actual process speed • Power settings (WPI, Amps) Irradiance (W/cm 2 ) • Radiant Energy Density(J/cm 2 ) • • Lamp matched to chemistry • Focus/Reflector condition Poor chain of custody • TBD Line Speed Dwell UV System: North Line Lamp: 2 Time Date FPM/RPM Ind. Actual. Power Hour Irradiance Energy Density (W/cm 2 ) WPI Meter (J/cm 2 ) 10/9 25 22 400 780 0.859 1.45

  21. Gathering UV Evidence Profiling Radiometers Focused lamp • Profile helps determine focus of system and tracks changes UV W/cm 2 • Lamp types • Break down multi-lamp systems Time in seconds Distance Change-Same lamp Non-Focused lamp FOCUSED 858 mW/cm 2 2096 mJ/cm 2 UV W/cm 2 UV W/cm 2 NON-FOCUSED 290 mW/cm 2 1707 mJ/cm 2 Dimensional Curing Gloss Control Time in seconds Time in seconds

  22. Gathering UV Evidence Differences in: • Irradiance values • Lamp Types • Focus of Lamps • Speed collected A typical Irradiance Profile

  23. Gathering UV Evidence In God we trust, all others bring data Dr. W. Edwards Deming

  24. Gathering UV Evidence What Data (Evidence) Is Needed? • Consistent Data Collection Techniques • Fooled by the Equipment? • Do not contaminate the crime scene or • measurement tools

  25. Gathering UV Evidence Unit Ref Readings Readings % Deviation Power Puck Power Puck Unit II II s/n 15678 17654 Speed (f/m) 25 feet/min 25 feet/min UVA mJ/cm2 mW/cm2 mJ/cm2 mW/cm2 mJ/cm2 mW/cm2 1 109.000 450.000 99.000 445.000 -9.17% -1.11% 2 105.000 442.000 103.000 461.000 -1.90% +4.30% 3 104.000 460.000 109.000 439.000 +4.81% -4.57% Average 106.000 450.667 103.667 448.333 -2.09% -0.46% % STEDV 2.496% 2.001% 4.855% 2.537% 7.142% 4.488% Repeat for other UV bands

  26. Analyzing the UV Evidence A Scandal in Bohemia

  27. My Best Cases Inspector Jacques Clouseau : It's amazing how he fell perfectly into the chalk outline on the floor. Ponton : I think they drew the outline after he was shot. Inspector Jacques Clouseau : Ah! We must be working with some kind of mastermind!

  28. Cases of Absent Minded Staff

  29. Human Error … Temperature Reading UV Readings Unit was sent through UV system upside down

  30. Arc lamp performance-Data 55” (140 cm) bulb Irradiance mW/cm 2 Data collected 3/24/16 Band Left Center Right Highest Delta UVA 797 983 635 35.4% UVB 713 888 573 35.5% UVC 200 257 167 35.0% UVV 612 757 492 35.0% Energy Density mJ/cm 2 UVA 243 282 234 17.0% UVB 206 239 195 18.4% UVC 58 68 55 19.1% UVV 231 264 222 15.9% Bulb not installed correctly in UV system

  31. Arc Lamp Performance-Graph Graphically display UV across width of bulb

  32. Instrument Care • Radiometers work better when properly maintained

  33. Optics & Sensor Care • Optics work better when properly maintained

  34. UV Measurement Challenges Irradiance W/cm 2 Data Collected 3/24/16 Before: Data collected Band Before After Difference with contaminated UVA 1223 983 -19.6% optics UVB 1066 888 -16.7% After: Data collected UVC 277 257 -7.2% after cleaning UVV 889 757 -14.9% Energy Density J/cm 2 Band Before After Difference UVA 349 282 -19.2% UVB 284 239 -15.9% UVC 75 68 -9.33% UVV 309 264 -14.6%

  35. UV Measurement Challenges • Two recommended methods: o Lint/Detergent free wipes or IPA with cotton swab • Advantages and disadvantages to each method • First do no harm • Avoid shirt sleeve, shop towel, etc. • Avoid ‘dry’ cleaning instrument

  36. UV Measurement Challenges You Tube Video Link on EIT website

  37. The Case of the Missing ID

  38. How Old Are You? Hour Meter

  39. Lamp Symptoms - Aging Mirroring Devitrification / Clouding Contaminated Airflow Blackening / Erosion

  40. Aged Arc Lamp Middle End 440mW/cm 2 in the middle vs. 317 mW/cm 2 at the end How wide is your line compared to the product?

  41. Variable: UV Energy Wavelength Mercury Gallium Iron Courtesy Heraeus Fusion UV

  42. Variable: UV Energy Wavelength Ratio of different bands to identify bulb type

  43. The Real World: Readings Profiling Radiometers • Trouble shoot two ‘identical’ production lines (Speed, bulb types) Line UVA 1 UVV Blue UVA Red UVV Line Speed Changed Bulb Type Changed UVV Line 2 UVA

  44. UV Sources: Spectral Output With 600 hours of run time would you change this bulb? OLD NEW UVA Energy Density: 537 to 487 mJ/cm 2 UVA Irradiance: 309 to 290 mW/cm 2

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend


More recommend