Welcome to Today s Webinar
Best Practices for Creating Strong Bonds using UV LED Curing & Plasma Treatment
Today s Presenters Mike Kay Director of Product Management Excelitas Ryan Schuelke Vice President Sales Enercon Industries
Overview Emerging applications for cured inks, coatings & adhesives. How plasma treatment promotes adhesion Selection criteria and integrating plasma and flame surface treaters Benefits of incorporating a UV LED curing process Determining your Curing Technology New advancements in plasma treaters & curing systems Review Question/Answer Enercon Industries & Excelitas
Enercon Industries Corporation Established in 1974, family owned Global operations include facilities in USA, United Kingdom, and India Manufacturers of equipment for packaging, converting, extrusion, plastics, assembly, printing, coating, bonding & decorating applications Application expertise in improving surface adhesion properties Innovator of Plasma, Flame and Corona Treating Technologies International sales and service network
Excelitas Technologies Lumen Dynamics was acquired by Excelitas Technologies Corporation in November 2013 Excelitas has over 5,000 employees worldwide Global network of design and manufacturing locations in the Americas, Europe and Asia Design and creation of innovative UV curing solutions since 1984 Over 30,000 UV curing systems currently being used in more than 50 countries Lamp and LED UV systems
OmniCure UV Curing Solutions OmniCure offers advanced UV and LED curing solutions that provide global manufacturers with unparalleled, simple to use control and repeatability in light-based curing processes, utilizing significant UV precision assembly expertise and innovative control technology. Control Irradiance adjustment Wavelength selection Radiometry Optical accessories Repeatability Closed-Loop Feedback High quality systems Support Application expertise Special requests Enercon Industries & Excelitas 7
Emerging applications for cured inks, coatings & adhesives
Emerging Applications Spot Curing Applications Area Curing Applications Catheters Endoscopes Camera modules Fiber Connectors Lasers Digital projectors Needle bonding Insulin pens Micro-speakers Lens bonding OLED Display Touch panels Coatings Ink jet Printing 3D Printing Solar Panels Fiber Coating Hydrogels
Emerging Applications Medical Devices Catheters, insulin pens Lower temperatures Difficult plastics such as PE, PP Printing Inkjet, 3D printing, Flexo Sufficient power to meet speed demands Enercon Industries & Excelitas
Surface Preparation & Adhesion Dynamics
Adhesion Dynamics Material type Performance-aiding additive load Surface chemistry Surface roughness Adhesive chemistry Bond stress Enercon Industries & Excelitas
Adhesion Dynamics Surface Wettability is Key When you observe a liquid beading up on a surface you are witnessing the forces of cohesion (the property of the liquid s like molecules to remain attracted) being stronger than the forces of adhesion (the property of unlike molecules to attract.)
Surface Challenges
Surface Preparation Options Liquid Primers Cost, hazardous, clean-up, consumable Mechanical Preparations Cost, time, wear parts, clean-up Vacuum Plasmas Capitol & consumable cost, time, batch process Atmospheric Plasma & Flame In-line, continuous, economic
How plasma treatment promotes adhesion
What is atmospheric plasma? plasma : n ; Fourth state of matter, (Solid, Liquid, Gas, Plasma.) Mixture of charged ions & energetic electrons generally in equilibrium.
How atmospheric plasma improves adhesion Enercon Industries & Excelitas Ionized gas that bombards the surface of a substrate & creates a more hydrophilic, micro etched and functionalized surface. Blown Ion Plasma Blown Arc Plasma Flame
What Plasma Does to the Surface High Energy Surface Contamination Eliminated Increased Bonding Sites Plastic Surface Migrating Additives Removed from Surface Hydrophyllic
Surface Challenges Ink, Adhesive or Coating Before Treatment After Treatment
Bond Strength Enercon Industries & Excelitas Lab Test of Adhesion Strength PE Substrate UV Cured Adhesive Tested After 24 Hours Pretreatment technologies yielded a greater strength by a factor of 3.5 Control Blown-Ion Flame
Selecting & integrating plasma treatment
Selecting treatment technology What material is the part? Conductive or non-conductive? Area to be treated (1 or more sides) How is the part handled? Speed- cycle time- output? Volume? Put it to the test in the lab
Integrating Systems in the field Off-line Over a Conveyor Mounted over existing equipment Configured with an indexing system Integrated with a robot
Benefits of incorporating a UV LED curing process
Benefits of UV Curing Instant Cure: Product immediately ready for next process stage Reduced Cycle Times: Improves production speed & ease of automation Control of Cure: Cure-on-demand, or vary degree-of-cure Energy Savings: 1-4% of energy vs. water-borne/solvent adhesives Derivative Savings: Reduced solvent use, less floor space etc., can save up to 30% vs. traditional assembly Ease of Coating: Single-component systems, lower viscosities, and wide range of cured physical characteristics Environmental/Safety: No VOC emissions, reduced regulatory requirements, and low flammability
Benefits of LED Curing Systems Enercon Industries & Excelitas Lower Temperature Curing Higher yields Lower Running Costs Lower power consumption Long lifetime LED heads Easy Integration PLC control No venting required
Environmental LED Leads the Way UV Curing is considered a green technology Lower solvent, VOC content than other adhesive technologies LEDs are mercury free LEDs do not generate ozone LED systems require up to 80% less input power No consumable items (eg. lamps, light guides) Enercon Industries & Excelitas
Cost Savings Electricity savings alone can pay for LED systems No consumables over lifetime Lamps, reflectors On-line cost savings calculators available Enercon Industries & Excelitas
LED Longer Lifetime = Lower Cost of Operation Enercon Industries & Excelitas LED typical lifetime = 20,000+ hours 10% degradation in first 500 hours
Radiometry LED degradation slower than lamps, but still enough to require a radiometer Requirement for any repeatable assembly process Technology for LED radiometry still being developed; challenges include: Narrowband spectral distribution Narrow beam patterns New systems being released with specific technology to overcome challenges Radiometry designed for lamp-based systems will not be accurate Enercon Industries & Excelitas
Light Cure Factors
Light Cure Factors Light conditions which can affect final cured properties are: Irradiance level Exposure duration Spectral content Heat A light-curing adhesive exposed to different curing conditions will exhibit different physical properties: Flexibility Moisture resistance Bond strength
UV Curing Power Irradiance: Radiant power arriving at a surface, per unit area (W/cm 2 ) Radiant Power: Rate of energy transfer, expressed in Joules/sec Sufficient energy must be received to convert the photoinitiator and begin the curing reaction However, excess irradiance can have a negative effect on the cured properties Microhardness Microhardness vs Irradiance (at constant Dose) 65.0 60.0 55.0 50.0 45.0 40.0 35.0 30.0 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 Irradiance (W/cm^2) YES, it is possible to cure a UV adhesive too quickly LED systems must allow for adjustment of irradiance Enercon Industries & Excelitas
Irradiance vs Working Distance Irradiance levels drop significantly over distance Irradiance measurements at 0mm working distance do not represent energy at cure site Optics can be used to focus the light to specific working distances Need to know the irradiance level at your working distance 365nm 395nm 1mm 4.5W/cm 2 9.0W/cm 2 10mm 3.3W/cm 2 6.5W/cm 2 30mm 1.5W/cm 2 3.0W/cm 2
Optics Allow for Increased Working Distances With lens No lens Irradiance @ 1mm Irradiance @ 20mm LED System with lens 9.0W/cm 2 4.5W/cm 2 LED System no lens 8.0W/cm 2 1.5W/cm 2
Spectral Content UVC UVB UVA UVV Lamp* 3% 12% 45% 40% 365nm LED 0% 0% 99% 1% 400nm LED 0% 0% 3% 97%
Spectral Content: Curing Requirements Effective Irradiance: Radiant power, within a specified wavelength range Sufficient light of the correct wavelength range must be received by the photoinitiator to begin the curing reaction Critical to match the wavelength of LED to the absorption spectra of photoinitiator If they do not match, the material will not cure, regardless of irradiance level 365nm, 385nm, 395nm and 405nm wavelengths available to match the photoinitiator requirements Photoinitiators absorption curves Plots courtesy of CIBA Specialty Chemicals Enercon Industries & Excelitas
Spectral Content: Lower Heat with LED Light is absorbed by the adhesive components and converted into heat Light absorbed by the materials being bonded generates heat Narrow spectrum of LED ensures reduced heat in curing Reduced heating in the curing process can help to increase product yields Sample temperature measurements for lens bonding application
Which LED Wavelength to Choose?
Which LED Wavelength to Choose? Many formulations will specify 365nm Designed to match 365nm peak of Hg lamps Many free radical formulations will cure with wavelengths up to 420nm Many cationic photoinitiators have absorption spectra that cuts off at 380nm Curing with 400nm LED generally provides a better through cure Curing with 365nm LED generally provides a better surface cure 400nm LED systems will generally have significantly higher power than 365nm
Substrate Must be Considered Adhesive specifies 365nm Absorption Curve of Substrate Transmission of light through the substrate: 50% at 365nm 80% at 395nm 60% more 395nm light gets to the adhesive Results 395nm LED cures faster and with less heat than 365nm LED Enercon Industries & Excelitas
Surface Finish Free radical adhesives are susceptible to curing with a tacky surface when exposed to air Oxygen inhibition Formulations available to minimize problem Ways to minimize in your process N 2 purge Exposure to short wavelength UV (UVC: 250-285nm, UVB:285-315nm) High peak irradiance Heat 600 500 400 300 200 100 0 Typical 200W Lamp Output No Filter 250 300 350 400 450 500 550 600 650 Wavelength (nm)
Advancements in LED Curing OmniCure AC2 Series UV LED Systems Compact, lightweight LED array for printing, 3D printing, electronics, medical 10mmx75mm or 114mm Illumination Impressive irradiance Over 4W/cm 2 irradiance Custom optics Reduces output angle for printing Over 20,000 hour typical lifetime 10,000 hour warranty Air-cooled End to end stackable Better than 10% uniformity
Advancements in Plasma Treaters New Technology Intuitive Touch Screen Multiple Head Control Plasma Integrity Monitoring Enercon Industries & Excelitas
Summary Plasma & flame surface treatment is an inline solution that cleans, etches and functionalizes the surface allowing inks, coatings & adhesives to adhere to the substrate Your application & process defines the surface treating technology The best place to integrate plasma or flame treater is directly prior to applying UV curable ink, coating or adhesive. Enercon Industries & Excelitas
Summary New LED products available with higher output, smaller footprint Benefits of LED systems include: Lower cost of operation Lower heat Potential Curing Challenges: Adhesive compatibility Surface cure Testing is the only way to confirm compatibility. Enercon Industries & Excelitas
Questions Mike Kay Excelitas Director of Product Management 905.812.4368 mike.kay@excelitas.com Ryan Schuelke Enercon Industries VP Sales 262.250.3164 rschuelke@enerconmail.com
Thank you