Cell filling in gravure printing for printed electronics

Area of Science:

• Materials Science
• Mechanical Engineering
• Fluid Dynamics

Background:

• Direct gravure printing offers high throughput and resolution for printed electronics.
• Optimized cell geometry and conditions enable micron-scale features at high speeds.
• Accurate ink cell filling is critical for printed feature size and quality.

Purpose of the Study:

• To investigate the ink cell filling process in direct gravure printing in real-time.
• To understand the factors influencing ink filling and identify failure mechanisms.
• To provide insights for optimizing gravure printing for scaled electronics.

Main Methods:

• Developed a novel experimental setup for real-time observation of the gravure cell filling process.
• Employed numerical simulations to complement and interpret experimental findings.
• Varied ink viscosity and filling speed to study the impact of the capillary number.
• Investigated the effect of gravure cell size on the filling dynamics.

Main Results:

• The capillary number effectively indicates the filling regime in gravure printing.
• Ink viscosity and filling speed significantly influence cell filling efficiency.
• Smaller cell sizes present challenges for complete ink filling.
• Identified air entrapment as the primary failure mode, linked to contact line pinning and interface deformation.

Conclusions:

• Real-time experimental and simulation approaches provide crucial insights into gravure cell filling.
• The capillary number is a reliable parameter for predicting gravure filling behavior.
• Understanding air entrapment mechanisms is essential for improving resolution and quality in gravure-printed electronics.