Main project: EPSRC Centre for Innovative Manufacturing in Additive Manufacturing
Funder: EPSRC (EP/I033335/2)
Total value: £5,576,219 (main project)
Start date: Oct 2012
End date: March 2017
- Prof Chris Tuck
- Prof Ricky Wildman
- Prof Ian Ashcroft
- Prof Phill Dickens
- Prof Richard Hague
- Dr Ehab Saleh
- Dr Jayasheelan Vaithilingam
Multifunctionality is foreseen as the future of AM, however the move to multifunctionality is littered with technical challenges, from the accurate and reliable deposition of different materials together and their interaction, to the design of these components and how best to integrate different materials for a given function. Current AM technologies such as laser sintering or fused deposition modelling, whilst having some advantages, have some clear drawbacks for the production of multi-material parts. These are namely, in their accuracy, resolution and the processing environment required during manufacture. In the first phase of this project a strategic review of the available manufacturing routes open to multi-functional AM has been carried out, with significant promise being shown by drop-on-demand inkjet techniques for processing conductive, dielectric and other materials.
On this basis, new experimental material deposition test beds have been procured and adapted along with the necessary characterisation equipment to ensure material applicability to the jetting processes. In total, seven jetting systems have been commissioned, three printers based on the FujiFilm Dimatix DMP2831, three based on the PixDro LP50 architecture and a 6-head bespoke jetting system, commercially known as JetX 3D, also based on the PixDro architecture. All these systems are capable of depositing particulate based inks (such as those filled with silver nanoparticles) and a host of other materials with various viscosities and surface tensions. In particular, the PixDro systems have five different configurations to enable contemporaneous multi-material printing, particulate printing and elevated temperature printing of hot melt polymers.
The project is now concentrated on multi-material printing in 3D (especially in vertical direction), as well as the integration of printing onto existing additively manufactured substrates, such as those produced by ultrasonic consolidation, or materials developed in the sister projects, Reactive Jetting of Engineering Materials. Various inks were specially formulated to enable printing conductive routes in the Z direction as well as real-time UV and heat curing sources to establish printing functional multi-material structures in a single process.
The project has achieved a breakthrough in sintering conductive silver nanoparticle based inks where traditionally this process takes many minutes to transform these inks into conductive tracks whereas the sintering time achieved in this project was only few seconds. Other exciting achievements were also made during the past two years, particularly on graphene based applications including all-printed graphene supercapacitors and graphene based transistors, which were fabricated using a novel graphene oxide rapid reduction method that was developed by the project team. Printed meta-materials and flexible sensors were highly successful during the past year. RF metamaterials working in the 10 GHz range were successfully printed using various conductive and non-conductive materials. A wide variety of sensors were demonstrated such strain sensors, temperature sensors, touch sensors and humidity sensors.
A number of collaborations took place as a result of recent findings the project has achieved. An ongoing collaboration with the quantum hub group at Nottingham University is investigating printing conductive tracks to be used under ultra-high vacuum for cold atom trapping applications. Metamaterial devices were produced in collaboration with national physical laboratory (NPL) and further more collaboration with NPL is in progress. Unique design antennas were thought to be largely challenging to fabricate, expect that JET has shown a route to fabricate such complex devices in collaboration with the Terahertz Group at Queen Mary University.
JET has produced a number of high quality journal and conference publications reporting results on the quality of the conductive tracks produced using different sintering methods. Highly thermal resistive polymers were also reported and successfully used as a structural material for 3D electronic circuits. Multi-material devices were also reported particularly on metamaterial structures for RF applications. A full list of publication is available elsewhere in the annual report.