Assessing the Relationships between Interdigital Geometry Quality and Inkjet Printing Parameters

Area of Science:

• Materials Science
• Additive Manufacturing
• Microfabrication

Background:

• Drop on demand (DoD) inkjet printing is a versatile additive manufacturing technique for microscale geometries.
• Existing research often focuses on droplet dynamics, with limited systematic studies on parameter-geometrical outcome relationships.
• Accurate control over process parameters is crucial for reproducible microfabrication in flexible devices and printed electronics.

Purpose of the Study:

• To investigate the influence of key printing parameters on the geometrical accuracy of interdigitated comb-shape electrodes fabricated using DoD inkjet printing.
• To establish a systematic approach for correlating process parameters with the precision of printed micrometer-scaled geometries.
• To identify optimal parameter combinations for achieving high-accuracy electrode patterns.

Main Methods:

• Utilized Design of Experiments (DoE) methodology for a structured experimental campaign.
• Systematically varied drop spacing, printing speed, and nozzle temperature.
• Employed image analysis with a MATLAB algorithm to quantify geometrical accuracy of printed comb-shape electrodes.

Main Results:

• Identified optimal parameter combinations: a drop spacing of 140 µm and 170 µm in the printing plane directions and a nozzle temperature of 35 °C yielded the most accurate target geometry.
• Printing speed showed no significant impact on the geometrical outcomes within the tested range.
• The highest printing speed can be selected to enhance manufacturing throughput without compromising accuracy.

Conclusions:

• Drop spacing and nozzle temperature are critical parameters for controlling geometrical accuracy in DoD inkjet printing of microelectrodes.
• Printing speed can be maximized for increased productivity, as it does not adversely affect the precision of the printed geometry.
• This systematic approach provides valuable insights for optimizing DoD inkjet printing processes for flexible devices and printed electronics.