has uv led technology come of age?
TRANSCRIPT
H A S U V L E D T E C H N O LO G Y C O M E O F A G E ?
S I M O N R O B E R T S – I J C D Ü S S E L D O R F – 2 9 T H O C T O B E R 2 0 1 9
A B O U T I N T E G R AT I O N T E C H N O LO G Y
Founded in 2000 with the focus on UV curing solutions for the Inkjet industry
Based in Oxfordshire, UK
Pioneers of UV LED curing technology in 2002
World‘s largest portfolio of UV-Lamp and UV-LED systems: No bias towards any one UV technology Optimised curing solutions for customer applications
Sales and Service subsidiaries in more than 14 countries across the world
Since 2015 part of the IST METZ Group of companies with over 600 employees
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M E T Z H O L D I N G
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W I D E R A N G E O F U V L A M P & U V L E D T E C H N O LO G Y
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T H E D I G I TA L R E V O LU T I O N
The early 2000’s saw the emergence of new commercial digital graphics platforms initially with wide format platforms - which quickly began adopting UV technology
These machines needed a new form of arc lamp which was compact, light, effective in deep ink film curing and highly robotic with no connected air exhaust system
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T H E D I G I TA L R E V O LU T I O N
This has led to digital technology becoming increasingly adopted in a wide range of industrial applications:
Functional and decorative printingCoatings and adhesives
Due to the nature of many substrates and the requirements for durability the majority of these applications use UV curable materials
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THE EMERGENCE OF UV LED TECHNOLOGY
New advancements in semi-conductor visible lighting and the rapid technology development of digital printing fuelled the advancement of solid state curing solutions – UV LEDs
UV LEDs first appeared in digital platforms from 2010 and today are the standard UV curing technology in this sector
Over the past 4-5 years with the further development of ink chemistry, industrial printing and coating techniques are also increasingly adopting UV LED technology
UV LED is also a technology enabler opening new applications to UV curing which were previously not possible using UV Arc lamps, such as “Pinning” between print heads for higher resolution
UV LED is not necessarily a replacement for UV arc technology, but compliments it. Ongoing chemistry challenges typically surrounding surface hardness, adhesion and durability sometimes call for hybrid LED / Arc solutions
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UV Semiconductor development
Environmental impact
Process advantages
Concerns about a future potential ban on mercury based products
LED disruptive technology synergistic with the Inkjet manufacturers
UV LED MARKET DRIVERS
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U V - S E M I C O N D U C T O R D E V E LO P M E N T
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Very compact
No harmful UVC emmission
No Ozone (O₃)
Cold light source with no IR emmitence
Durable and reliable
Energy efficient: >40% energy conversion
Environmentally friendly – no mercury
Constant UV output with uniform UV disposition
UV LED PROCESS and ENVIRONMENTAL ADVANTAGES
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Over the past 10 years output intensities have grownfrom 8W/cm² to >30W/cm²
While the most powerful systems remain water cooled, advances in packaging and cooling techniques now permit>24W/cm² using air cooled technology
UV LED is now available for wide width processes of >2m
Still commercially restricted to the UVA band the focus today is on delivering high dose rather then higher intensity to yield higher levels of polymerisation
UV LED TECHNOLOGY – THE “STATE OF THE ART”
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C U R R E N T C H A L L E N G E S F O R U V L E D T E C H N O LO G Y
Constantly developing markets and applications
New chemistry - Ink and coating formulations
New substrates
UV LED Measurement – Intensity vs dose
Advancements in UVB and UVC chip technology development
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I N K A N D C O AT I N G F O R M U L AT I O N S
Overcoming oxygen inhibition
Delivering good adhesion in all applications
Generating the required matt and gloss surface finish and special effects
Generating surface hardness and durability for specific industrial inkjet applications
Low migration for food and pharmaceutical applications
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C H A L L E N G E : U V L E D M E A S U R E M E N T
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U V L E D C U R R E N T C H A L L E N G E
Understanding the relationship between intensity and dose
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U V - L E D I N S H O R T E R W AV E L E N G T H S
Available wavelengthUV-A (320nm-420nm)
Common UV-LED wavelength 365, 375, 385, 395 and 405nm (and mixtures of the same) are widely available
UV-B (280-320nm) and UV-C (200-280) limited commercial avialability, expensive and not powerful
Using UV-A chips currently remains the only sensible and commercial UV LED solution
275nm 365nm 395nm
Cost
Performance
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S H O R T W AV E U V L E D – T H E R E A L I T Y
THE REALITY:
Do not offer sufficient power to be effective in curing applications - confirmed by empirical testing
Current costs are c20 x higher than UVA chips and therefore presently not commercially viable
Current useable lifetime is only 2.5% that of UVA chips
The semiconductor manufacturer‘s road maps indicate that this will remain the case for at least the next 5 years with only small incremental improvements
Using UV-A chips currently remains the only sensible and commercial UV LED solution17 of 30
M E E T I N G T H E D E M A N D S - H Y B R I D S O LU T I O N S
Matching of chemistry for all applications remains a challenge for pure LED curingIndustrial application requirements for surface hardness, adhesion and durability more frequently demand HYBRID LED + ARC solutionsThis is particularly prevalent in performance clear coatings which is why tactile / 3D varnishing and digital label production predominantly use a mix of UV LED for pinning and UV Arc for final curing
UV LED Pinning UV Arc final cure
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H Y B R I D S O LU T I O N S
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S U M M A R Y H Y B R I D C U R I N G
Hybrid UV combines the best of both worlds:Compact UV-LED for pinningUV-LED for deepcureArc for final cure and surface hardness
Along with:Wider range of PI availableStronger surface cure, better scratch resistance and durabilityLow migrationAvoidance of expensive additional “work-arounds”
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W H AT N E X T F O R U V L E D T E C H N O LO G Y ?
Market forecasts
Eximer UV Technology
Conclusions
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T H E F U T U R E – W H AT T H E C O N S U LTA N T S S AY
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W H AT T H E C O N S U LTA N T S S AY
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E X C I M E R T E C H N O LO G Y
A N A LT E R N AT I V E M O N O C H R O M AT I C L I G H T S O U R C E
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200n
m
280n
m32
0nm
420n
m
W O R K I N G P R I N C I P L E O F E X C I M E R
UV-C
UV-B
UV-A
100n
m
700n
m
Vacu
umUV Visible Light IRX-Ray
UV-AUV-BUV-C
172nm
Vacuum-UV
UV Spectra
172nm, 222nm or 308
nm (other wavelengths feasible)
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E X C I M E R K E Y FA C T S
Available lengths: 120 mm – 2300 mm
Power Consumption: Approx. 10W/cm, 20-100% power adjustment
Efficiency: approx. 40%
Homogenity over lamp length: >95%
Rapid switch on time and no cool down cycle needed
Alternative wavelengths 222nm or 308 nm
HF filament energising the gas fill as a discharge medium leading to a Dielectric Barrier
Discharge (DBD) reaction with the quarz wall as a dielectric barrier
No use of toxic heavy metals – e.g. Mercury
Similar environmental credentials to UV LED26 of 30
E X C I M E R - C U R R E N T A P P L I C AT I O N S
Delivering Matt coatings:Super matte surfaces can be obtained with conventional UV varnishes without the addition of matting agents by exposure to excimer UV. These can then be final cured using conventional UV technologies. Curing with excimer lamps results in extremely hard, matt surfaces with high resistance to scratches and mechanical abrasion.
Cleaning & modification of surfaces:A decisive factor for the printability and bondability of surfaces, is their surface energy. The high energy 172nm Excimer radiation is able to break bonds in polymers. These then react with ozone and oxygen radicals, which are also formed by the irradiation of atmospheric oxygen. This pre-treatment results in a long lasting increase of the polar surface energy, which is decisive for the wettability and adhesion
Post Cross Linking of High Gloss Coatings:172nm excimer lamps can be used for post cross linking of cured acrylate coatings. Post cross linking can deliver: an increased micro hardness; an improved chemical resistance; and an increased surface energy in the coating.
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I N D U S T R I A L I N K J E T P R I N T I N G W I T H E X C I M E R
Hybrid Curing Example:
UV LED
UV Excimer
UV Arc28 of 30
C O N C LU S I O N S
UV LED has come of age for digital inkjet graphics applicationsUV LED faces ongoing development challenges for new industrial markets and applications:
UV LED is not a commodityUV LED has not taken 100% of the curing market:
Does not meet all the challenges and demands of the market:Surface effects, finish, durability, and hardness
Slow technical advancement of UVB and UVC chips are not a viable commercial replacement solution for UV arc lampsThe market demands require hybrid solutions
An alternative replacement technology is EXCIMERIntegration Technology can supply optimised UV LED + Arc +Excimer solutions
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#WeHaveTheCure