Ink jetting

Drop-on-demand ink jet

Ink jet firing sequence

Continuos ink jet (CIJ) Derby: Annu Rev. Mater.Res 2010

Numbers nozzles µm in diameter droplet volumes pl pixel size on paper 50 µm shooting frequency up to 10 kHz

Ink jet imaged P.Koltay (IMTEK, Freiburg) in Oosterbroek: Lab-on-a-Chip

Reynolds number (Re) ratio of inertial to viscous forces Re = ρνD/η ρ = density of fluid (kg/m3) ν = linear velocity (m/s) D = dimension of the system, diameter (m) η = viscosity of the fluid (Pa*s = kg/m*s) viscosity is the quantity that describes a fluid's resistance to flow small Re means large viscous forces

Weber number Transducers 2007 p.165

Ohnesorge number Transducers 2007 p.165

Ink jet regimes

Fluidics (3) Transducers 2007 p.165

Ink properties (1) ink viscosity: 8-15 mPa*s, 20 mPa*s limit (water 1 mPa*s) surface tension: mN/m, even 350 (water 72 mN/m) higher temperature, viscosity down (  able to print high M w polymers) particles difficult: clogging

Ink properties (2) Water-Based Ink Jet Ink Ingredients AmountFunction Water50%-90%Ink Solvent Colourant1%-15%Colour Source Co-Solvent/Humectant2%-20%Ink vehicle, prevents evaporation Fixative/Penetrant0%-10%Assist fixing the ink to substrate Surfactant0.1%-6%Surface tension and wetting Resin0.2%-10%Durability and adhesion Biocide0.02%-0.4%Prevents bacterial growth Fungicide0.01%-0.4%Prevents fungal growth Buffering Agent0.05%-1%Control ink pH level Other0.01%-1%Controls specific characteristics

Thermal ink jet in silicon

Thermal ink jet MEMS Handbook

Top shooters

Sideshooter

Arrays of nozzles Gad-el-Hak: MEMS Handbook

Graphic printing vs. Functional materials printing Functional materials perform something, Conduct electricity Respond to enzymes Show iridicence Bend mechanically Host cells

Line definition: droplet spacing & overlap Silver nanoparticle printing of conductor lines. a)Droplets too sparsely b)Wavyness still seen c)Optimal d)Too much liquid leads to bulging

Drop spreading & temperature Substrate temperature is a standard variable in ink jetting experiments. It directly affects surface tension and viscosity and therefore spreading on substrate.

Film formation

Surface coverage

Nanoparticle inks Murata

Metal salt inks

Ink jet etching I.M. Hutchings: Ink-jet printing in micro- mabufacturing, 4M/ICOMM 2009

3D ink jetting I.M. Hutchings: Ink-jet printing in micro- mabufacturing, 4M/ICOMM 2009

Competition: Laser-assisted maskless microdeposition Alemohammad: J. Micromech. Microeng. 18 (2008) (12pp)

Laser-assisted maskless microdeposition (2) Alemohammad: J. Micromech. Microeng. 18 (2008) (12pp)

The MDDW method makes patterns on the substrate by pumping the slurry of suspended nanometal powders. Since it does not rely on the spray mechanism but direct contacting mechanism, it allows to avoid or minimize the ink from oxidation or reduction during the printing process. MDDW: microdispensing deposition write

M3D: maskless mesoscale materials deposition M3D method uses a mechanically or ultrasonically driven device to stir and mix the suspended nanometal powders injecting the slurry through an orifice as a mist with the help of an air injection mechanism. M3D and MDDW devices have been developed beyond the capability that the ink-jet method can perform in handling high viscous materials and they can even handle three-dimensional patterns.

Ink jet dichotomies thermal vs. piezo continuous vs. drop-on-demand (DoD) free pressure vs. free flow boundary conditions printing on porous vs. hard surfaces (paper vs. overhead transparency) printing vs. film formation 2D patterns vs. 3D structures solutions vs. particle-containing inks

Ultimate resolution ?

Creating cell patterns Ink jet printing of PLGA polymer on PS substrate. Cells attach to PLGA but not on PS.

Ink jetting bacteria

Printing DNA arrays

Promise: fewer process steps  faster, cheaper electronics Murata et al: Microsyst Technol (2005) 12: 2–7

Applications: antennas (c) Inductive coil printed on fabric. (d) RFID antenna with metallic joints printed on paper. J. Micromech. Microeng. 17 (2007) 967–974 S M Bidoki, D M Lewis, M Clark, A Vakorov, P A Millner and D McGorman:

Applications: 3D N. S. Kim, A. K. Amert, S. M. Woessner, S. Decker, S. M. Kang, and K. N. Han International Conference on Nano Science and Nano Technology, GJ-NST 2006, Korea Institute Industrial Technology,Gwangju, South Korea, 7–8 December Antenna print on a combat helmet surface by the MDDW technique. Ko & Grigoropoulos: JMM

Printing metallization I.M. Hutchings: Ink-jet printing in micro- mabufacturing, 4M/ICOMM 2009

Printing insulators I.M. Hutchings: Ink-jet printing in micro- mabufacturing, 4M/ICOMM 2009

Printing polymers I.M. Hutchings: Ink-jet printing in micro- mabufacturing, 4M/ICOMM 2009

Printing further I.M. Hutchings: Ink-jet printing in micro-mabufacturing, 4M/ICOMM 2009