Simulation of Cone-Jet and Micro-Drip Regimes and Printing of Micro-Scale Patterns on PET Substrate

Area of Science:

• Materials Science
• Microfabrication
• Inkjet Printing

Background:

• Micro-pattern fabrication on polymer substrates is crucial for micro-electromechanical systems (MEMS) and advanced packaging.
• Existing methods face challenges in achieving high resolution and stability on insulating polymer surfaces.

Purpose of the Study:

• To investigate and optimize electrohydrodynamic jet (E-Jet) printing parameters for creating stable micro-patterns on polyethylene terephthalate (PET) substrates.
• To determine the optimal settings for printing distinct functional inks, including micro-drops and linear patterns.

Main Methods:

• Phase field physics simulations were employed to optimize E-Jet printing parameters.
• Experimental validation was conducted using two functional inks (SEMICOSIL988/1 K and Underfill UF 3808) on PET substrates of varying thicknesses.
• Key printing parameters investigated include applied pressure, pulse voltage, DC voltage, duty cycle, pulse frequency, printing height, and printing speed.

Main Results:

• Optimized simulation parameters include 40 kPa pressure, 1.95 kV pulse voltage, 1.60 kV DC voltage, 80% duty cycle, 60 Hz pulse frequency, 0.25 mm height, and 1 mm/s speed.
• SEMICOSIL988/1 K ink produced micro-drops with a minimum size of 200 μm on 1 mm PET, preventing coffee staining.
• Underfill UF 3808 ink achieved linear patterns as small as 105 μm on 0.5 mm PET at 50 kPa pressure.
• Micro-structure consistency and diameter were precisely regulated at 60 Hz pulse frequency and 80% duty cycle.

Conclusions:

• E-Jet printing is a viable technique for fabricating high-resolution micro-patterns on PET substrates.
• Optimized printing parameters ensure stable and consistent micro-structure formation, suitable for MEMS and packaging.
• The study provides a foundation for advanced microfabrication processes using E-Jet technology on polymer materials.