Fluid Dynamics & Acoustics

How inkjet printing really works

Monday 4 - Tuesday 5 July, 2022

Novotel Gent Centrum Hotel, Ghent, Belgium

COURSE FOCUS

Inkjet printing is a process of depositing small droplets with a specified volume onto a precise location on a substrate. During the course we follow the ink through the printhead, into droplet formation and onto landing on the substrate.

The course mainly covers piezo-driven printheads jetting Newtonian inks, although the issue of viscoelastic inks will be discussed. A piezo-driven printhead is modelled as a set of acoustic cavities, the characteristics of which will be presented in the time (response to waveforms) and frequency domain.

The course is based on precise descriptions of the physical phenomena involved and the derivation of the mathematical framework needed to solve the governing equations. Where possible the outcomes will be compared with experimental findings. Different mathematical methods will be presented to calculate the responses of different systems in the frequency and time domain. To describe correctly the behaviour of a printhead with a large number of narrow pitched nozzles, the long duct theory will be presented.

The aim of this course is to couple the characteristics of droplet formation and landing, spreading and permeation to the acoustics and microfluidics of the printhead. The knowledge conveyed during the course will enable the participants to analyse the behaviour of a wide variety of existing printheads and to support the development of new printheads and inks from a physics point of view.


COURSE OUTLINE

monday 4 July 2022

12:30 - 13:30 Registration

13:30 Course begins

General introduction

  • Overview of course

  • Different piezo printhead designs

  • Experimental methods and droplet formation movies

  • Waveforms

  • Fluid dynamics concepts and some mathematics

Single degree of freedom modelling of a single nozzle printhead (or one nozzle out of a multi-nozzle printhead)

Helmholtz theory of a single nozzle printhead (or one nozzle out of a multi-nozzle printhead)

17:00 Session ends

17:30 - 18:30 Reception

Join us for beers, wines, and good company!

Tuesday 5 July 2022

09:00 Session begins

Long duct analysis of a single nozzle printhead (or one nozzle of a multi-nozzle printhead)

Multi-nozzle printhead modelling

Droplet formation

12:30 - 13:30 Lunch

13:30 Session begins

Droplet impact

Electrostatic droplet generation

17:00 Course ends 


Course Leader

Prof Dr J. Frits Dijksman
University of Twente, Faculty of Science and Technology, Netherlands

Prof Frits Dijksman is professor of biomedical applications of inkjet technology at the University of Twente, Netherlands. He has worked with Philips Research for more than 30 years and his main area of interest has been inkjet technology for consumer and non-consumer applications, such as PolyLED display manufacturing and the printing of biomolecules.