Inkjet applications of the Future

Frazer Chesterman interviews  Dr. Patrick J. Smith PhD (Cantab),  BSc,  Head of Inkjet research at University of Sheffield – Applied Inkjet Lab

Could you tell us about the department at the University of Sheffield – the Applied Inkjet Printing Lab . How many people, what technology are you using to research inkjet? What is the aim of the department?

My research group's main aim is to investigate the range of application for which inkjet printing gives us an advantage. Inkjet's advantage is that it gives us reproducibly sized droplets that we can position anywhere on a substrate. Inkjet also gives us the ability to print more than one colour/ink.

There are eight members of the group, myself, three post-docs and four PhD students.

Currently, we have two jetting systems, one is a very simple jetting station, but the other is a JetLab system from MicroFab. We expect to receive a Dimatix Materials printer after Easter.

 Credit: Leon Edney

 Credit: Leon Edney

 Please can you tell us a little about your composites research? How is inkjet used to develop these new composites?

By using inkjet, we position discrete uniformly sized droplets of polymer onto a composite precursor (pre-preg). The polymer 'beads up' during the processing of the final composite. We have seen improvements in interlaminar fracture toughness of 40%. Higher values are possible but we want to get the same quality of standard deviation that we see for the 40% system. The big appeal is that we don't significantly affect the final weight of the composite.

What are the possible Industrial applications, how could this be used on a commercial basis?

Does it have potential in areas such as aeronautical or high performance automotive applications? What are the benefits?

Composites are being increasingly used in aviation, they are strong but light. However, tougher materials are desired. My group's research is showing that we can get tougher composites whilst keeping the weight-saving advantage.

 Credit: Leon Edney

 Credit: Leon Edney

I understand you have done some amazing things with Inkjet and ‘sacrificial structures’. What does this mean? How does it work?

What are the potential applications for this in a commercial environment?

Phase change printing is where we print a liquid droplet and it solidifies on the substrate -3D printing is exploiting this effect. In my lab' we are printing low molecular waxes (Leon Edney's PhD). These are molten when in the printhead but 'freeze' on the substrate. We cast a bulk material around the frozen prints. We then either melt the frozen structures or dissolve them. This leaves us with a bulk material that contains an internal pipework structure. The application is tissue engineering.

Dr. Patrick J. Smith PhD (Cantab). BSc

Laboratory of Applied Inkjet Printing,
D 03, Royal Exchange Manufacturing Building,
64 Garden Street, Sheffield,
S1 4BJ

Telephone: +44 (0)114 222 7738