Fluid Dynamics & Acoustics

How inkjet printing really works

Monday 10 - Tuesday 11 June, 2019

Møller Centre, Cambridge, UK

COURSE FOCUS

Inkjet printing is a process of depositing on demand small droplets with a specified volume onto a precise location on a substrate. This definition covers a wide variety of applications like document printing, label printing, 3D printing, and functional applications like patterning of displays and biosensors. During the course we follow the ink all the way through the printhead, through droplet formation and on to landing on the substrate.

The course is mainly restricted to 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 on 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 10 June 2019

12:30 - 13:30 Registration

13:30 Course begins

  • General introduction

  • Introduction on physics & mathematics

  • Basic concepts (single degree of freedom system)

    • Waveforms

    • Fluid dynamics

    • Mathematics

  • Different piezo designs

  • Helmholtz theory and waveforms (two and five degree of freedom systems)

    • Single nozzle printheads

    • Multi-nozzle devices

17.00 Session ends

18.00 – 19.00 Reception

Join us for beers, wines and good company!

Tuesday 11 June 2019

9:00 Course begins

  • Long duct theory

  • Droplet formation

  • Speed of sound

  • Damping

  • Refilling

12:30 - 13:30 Lunch

13:30 Session begins

  • Maximum jetting frequency

  • Drag on droplets

  • Droplet impact and spreading

  • Jetting of viscoelastic inks

  • Examples: polyLED display printing, printing of biomolecules (co-authored by Dr Anke Pierik, Philips Research)

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.

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