Applied Inkjet Printing – composites, rockets and electronics


Applied Inkjet Printing – composites, rockets and electronics

Wed, 28/03/2018 - 14:30 to 15:30


Dr Patrick Smith
University of Sheffield

Applied Inkjet Printing – composites, rockets and electronics
Dr. Patrick J. Smith, University of Sheffield, UK

Inkjet Printing is an additive manufacturing technique that builds features droplet by droplet on account of the high level of reproducibility in producing each droplet. As a printing technique it is employed in millions of printers.
In this talk, I will discuss the research we undertake in Sheffield University’s Applied Inkjet Printing lab’. I will show how inkjet has been used to manufacture tougher carbon fibre composites and in producing micro-rockets made from silk. I will also high-light recent work involving the production of metal tracks.
Carbon fibre composites are being increasingly used in structural applications, such as Boeing’s 787. In my research, we have exploited inkjet’s ability to form uniform droplets to create arrays of discrete droplets that increase the interlaminar fracture toughness of composites by 40% for an overall weight gain of less than 0.5wt%. Higher values are possible and improvements to other properties such as apparent interlaminar shear strength are also within reach.
Reactive inkjet printing (RIJ) is a central theme of my research. At Sheffield, we have employed RIJ to precipitate silk, which we build up into columns resembling rockets. The top of the rocket can contain a payload, whereas the base, where we have focussed most of our research to date, contains the means of propulsion.
In terms of printed electronics, much of my research has focussed on printed silver carboxylate solutions. These inks can be quickly sintered (less than five minutes) at low temperature (150 °C) to produce highly conductive tracks (>50% bulk silver). They can also be chemically reduced at room temperature (10% bulk silver conductivity). I’ll conclude my talk by discussing recent work we have begun in my lab investigating a combined laser/inkjet system that we are currently using to produce conductive copper features. Early results show that we can obtain acceptable conductivities (5% bulk copper) in ambient atmosphere.