Effect of Substrate Contact Angle on Ink Transfer in Flexographic Prin=ng. F. E. HIZIR and D. E. HARDT MassachuseEs Ins=tute of Technology

Transcription

1 Effect of Substrate Contact Angle on Ink Transfer in Flexographic Prin=ng F. E. HIZIR and D. E. HARDT MassachuseEs Ins=tute of Technology

2 Outline - Introduc=on - Mo=va=on and Objec=ves - Simula=ons. Methodology. Results - Conclusions and Future Work

3 Flexography Flexographic Prin;ng Prin9ng$plate$ Prin9ng$substrate$ thin film transistor [1] OLED [2] Plate$ Impression$ RFID blade! Anilox$ roller$ photovoltaic cell [3] Ink$supply$ (Chambered$doctor$ blade$system)$ [4] [1] H. Kang et. al., Advanced Materials, 2012 [2] Wikimedia/meharris [3] Gyou- Jin Cho/Sunchon Na=onal University [4] A. Hubler et. al., Advanced Energy Materials, 2011

4 Ink Transfer in Flexography Flexographic Prin;ng INK TRANSFER TO THE ANILOX ROLLER Prin9ng$plate$ Plate$ Impression$ Prin9ng$substrate$ BLADING OF THE ANILOX ROLLER (fill the cells + remove excess ink layer) INKING OF THE STAMP (par=al cell evacua=on by ink spli_ng) blade! Anilox$ roller$ INK TRANSFER TO THE SUBSTRATE (ink spli_ng) stamp AIR substrate Ink$supply$ (Chambered$doctor$ blade$system)$ INK anilox cell stamp

5 Ink Transfer in Flexography Flexographic Prin;ng INK TRANSFER TO THE ANILOX ROLLER Prin9ng$plate$ Plate$ Impression$ Prin9ng$substrate$ BLADING OF THE ANILOX ROLLER (fill the cells + remove excess ink layer) INKING OF THE STAMP (par=al cell evacua=on by ink spli_ng) blade! Anilox$ roller$ INK TRANSFER TO THE SUBSTRATE (ink spli_ng) stamp substrate Ink$supply$ (Chambered$doctor$ blade$system)$ AIR INK anilox cell stamp

6 Mo=va=on and Objec=ves blade! Prin9ng$plate$ Plate$ Anilox$ roller$ Flexographic Prin;ng Impression$ Prin9ng$substrate$ Ink Transfer from Stamp to Substrate - Thickness of printed product - Device performance Objec5ves - Guidelines for substrate and stamp design - Control printed layer thickness - Inves=gate contact angle effects substrate Ink$supply$ (Chambered$doctor$ blade$system)$ stamp

7 Simula=on Domain Simula5on domain and its dimensions y" x" direc0on&of&mo0on&& symmetry' LIQUID& 2µm' SUBSTRATE& STAMP& AIR& 8µm' 8µm' Parameters used in the simula5on Ink$dynamic$viscosity$ 0.1$N.s/m 2$ Ink$density$ 1000$kg/m 3$ Air$dynamic$viscosity$ 1.81e;5$N.s/m 2 $ Air$density$ 1.16$kg/m 3$ Gravity$accelera@on$ 0$ Separa@on$speed$ 0.1$m/s$ Volume$of$liquid$ 32µm2$ Surface$tension$coefficient$ 1$N/m$

8 Simula=on Setup Interface Reaches Equilibrium Shape t=0$sec$ t=2.5$µsec$ t=7.5$µsec$ t=50$µsec$ Ink splits into Two t=810%µsec% t=872%µsec% t=925%µsec% t=990%µsec% - - Moving mesh interface is coupled with laminar two- phase flow, phase field interface. Ini=al velocity and pressure values are set to zero for the two fluids. - Ini=al mesh displacement is set to zero. - Pressure is set to zero at right boundary which is defined as inlet. - Sta=onary boeom surface is defined as weeed wall with 60 o ink contact angle. - Upper surface is defined as moving weeed wall with 60 o contact angle.

9 Mesh Refinement (θ top = θ boeom = 60 o ) Pressure&(Pa)& Pressure%(Pa)%at%(1µm,%2µm)%!10000$!20000$!30000$!40000$!50000$!60000$!70000$ Index& 0$ 0.09" 0$ 2$ 4$ 6$ 8$ $ $ $ $!100000$!200000$!300000$ 1""2""3"""4""""5"""6"""7" Velocity)magnitude)(m/s)) Simula'on*domain* at*t=0*s* A" Test_1b( B" Test_1d( C" Test_1e( 0.08" 0.07" 0.06" 0.05" 0.04" 0.03" 0.02" 0.01" A& B& C& Test_1b Index) Test_1d Test_1e Velocity)magnitude)(m/s)) 0" 0" 1" 2" 3" 4" 5" 6" 7" 8" 0.09" 0.08" 0.07" 1b" A* 0.06" 1d" B* 1e" C* 0.05" 0.04" 0.03" 0.02" 0.01" " 7" 6" 5" 4" 3" 2" 1" Simula'on*domain* at*t=0*sec* 0" 0" 1" 2" 3" 4" 5" 6" 7" 8" Index) 0$ 0$ $ $ $ $ 0.001$ Time%(s)% Maximum mesh element size for lef of domain: Aà 0.25 µm, Bà 0.08 µm, Cà 0.06 µm Change in total mass < 2% 1b" A* 1d" B* 1e" C*

10 Effect of Contact Angle a)# Upper plate contact angle=60 o Lower plate contact angle=60 o Transfer ra;o=0.5 Young- Dupre Equa;on W adhesion = γ. [1+cos(θ)] à θ W adhesion t=0$ t=810$µsec$ t=922.5$µsec$ t=1015$µsec$ b)# Upper plate contact angle=30 o Lower plate contact angle=60 o Transfer ra;o=0.65 Results - Expected trend is observed - Results do not exactly match with literature - High computa=on =mes t=0$ t=810$µsec$ t=892.5$µsec$ t=1015$µsec$

11 Conclusions and Future Work - Spli_ng of ink between two parallel plates is simulated - Ink transfer ra=o to the upper plate is found to increase with decreasing ink contact angle on its surface - High computa=on =mes due to fine mesh requirements is the main difficulty - Future work is to cover a larger range of contact angles in the simula=ons

12 Thank you Q&A