Materials

This project developed a novel Additive Manufacturing (AM) system based on material jetting and the processing parameters for printing highly viscous polysiloxanes that could be processed by both thermal and UV curing techniques.A continuation of this project focuses firstly on developing a library of material formulations for UV curable silicone showing variation in extensibility, compressive properties for ink jet printing and potentialfor conformal printing. Secondly, it looks at printing a representative design to demonstrate the capability of photocurable formulations using Micro Stereolithography.

This multidisciplinary project will develop the additive manufacturing production of squalene analogues using synthesis chemistry / chemical engineering approaches, andprove their efficacy by emulsion formulation development and biological evaluation for adjuvant activity in in vitro human and in vivo mouse and ferret models.

A laser powder bed fusion method has been successfully developed in this project for soda lime silica glass. Glass feedstock, laser powder bed fusion set-up and processing parameters have been optimised enabling the formation of glass structures with micro- / macro- scale resolution and high levels of complexity in design that cannot be achieved with conventional glass-forming methods. These findings provide the stepping stone for the formation of a new generation of glass structures for a wide range of applications from chemistry and bio-medical to decorative glass industries.

Two photon polymerisation capability in CfAM was extended to include multibeam capability through the use of diffractive optics. This work was complemented by studies exploring how photoreduction can be used to understand how metal based nanoparticles can be used to create composites on the nanoscale.

FLAC is an ambitious successor to the Aluminium Lattice Structures via Additive Manufacturing (ALSAM) project which ran from 2013 to 2015.  A three year project with £1.7 million in funding from Innovate UK, FLAC builds on the outcomes of ALSAM to develop advanced componentry for the automotive sector. 

In addition to structural lightweighting, which has the potential to significantly improve the efficiency of road vehicles and reduce CO2 emissions, FLAC’s emphasis lies in thermo-mechanically optimised components.  This new class of components draws on the design freedoms of AM, in particular the ability to construct cellular structures such as periodic lattices, as well as the unique, and often superior, mechanical properties of selectively laser melted metal alloys.  Cellular structures based on minimal surfaces, with their high surface areas and torturous flow paths, are of prime interest in FLAC; one of its objectives is to produce a software tool to incorporate these structures in component designs.

FLAC partners include academic institutions, vehicle and component manufacturers, AM design specialists and AM machine manufacturers.  The consortium will use a combined experimental and theoretical approach to advance metal lattice technology beyond its current scope, whilst monitoring the project’s progress for IP and commercial potential.

Project partners

Hieta Technologies Ltd. (Lead)	Renishaw PLC	Moog Controls Ltd.	Bentley Motors  Ltd.
Alcon Components Ltd.	Added Scientific Ltd.	University of Liverpool	University of Nottingham

A unique droplet-on-demand(DOD) technology ‘MetalJet’,which is equipped with four print- heads capable of ejecting and depositing tens-of-microns-sized droplets of high temperature (upto 2,000°C) conductive metals,is used to fabricate multimaterial three-dimensional structures with unprecedented precision. State-of- the-art characterisation techniques are used to investigate the interfaces of dissimilar materials printed using this bespoke technology.

The overall aim of this project is to develop wearable soft robotic technologies with sophisticated sensing, actuation and control for enabling effective and comfortable rehabilitation, functional restoration and long-term assisted living. The EPSRC funded project is a collaboration between the Universities of Bristol, Nottingham, Strathclyde, UWE, Leeds and Southampton.

At the University of Nottingham, we are undertaking targeted materials development for aerosol and material jetting in order to develop new compliant smart materials and structures for fabrication into soft robotic components. Our current focus is on dielectric electroactive polymers, where we are working to improve the dielectric constant of base elastomers through the incorporation of nano-fillers while maintaining high elasticity, two properties needed for increased actuation. These materials are then combined through jetting with layers of conducting electrode materials to produce stacked soft actuators.

Academic collaborators:

Prof Jonathan Rossiter (University of Bristol)	Prof Russ Harris (University of Leeds)
Prof Abbas Dehghani (University of Leeds)	Prof Rory O’Connor (University of Leeds)
Dr Ailie Turton (UWE)	Dr Christopher Freeman (University of Southampton)
Dr Arjan Buis (University of Strathclyde)

 

As part of the EPSRC-funded £5.4M “Next Generation Biomaterials Discovery” programme grant (EP/N006615/1) led by Prof Morgan Alexander, will see the investigation of three-dimensional polymeric materials for biomedical applications in drug delivery, regenerative medicine and medical devices. Hereby, the difference in material performance during the transition from well-investigated 2D surfaces to 3D is of major interest. This programme includes collaborations from the School of Pharmacy, Engineering, Life Science and Medicine at the University of Nottingham.

Our efforts will focus upon the preparation of novel particle libraries using a microfluidic approach. This methodology gives access to a broad range of particulates with ranging variations in chemistry, size and morphology.

In the past year, our research has focused on the establishment of microfluidic particle production to achieve a first generation microparticle library based on acrylates, methacrylates and methacryl amides, which had been previously investigated in 2D by Prof Alexander's group.             

In the course of the project, approx. 120 particle samples have been prepared, using two channel geometries and more than 20 different materials. The particle diameters achieved range from 60 – 150 m.

To achieve the formation of particulates in the microfluidic chip it was necessary to add a surfactant (PVA) to the system. However, subsequent work demonstrated incorporation of PVA into the particles’ surface during the photo-polymerisation process. To avoid this contamination future work will focus on the substitution of the PVA for polymeric surfactants containing the bulk polymer, yielding particles only containing the desired chemistries.

To increase the diversity of our libraries, additional chip designs will be introduced, giving access to particulates from pre-polymerised materials.

The ALSAM project’s main purpose was to realise lightweight components made from aluminium alloys suitable for the automotive, motorsport and aerospace sectors. This was achieved by embedding lattice structures in components selected by our industrial partners. This significantly reduced their weight and provided the advantage of multifunctional capabilities, such as heat dissipation and enhanced metal-composite bonding.

During the ALSAM project, software tools were developed to make use a broad range of lattices in Selectively Laser Melting (SLM) components. This was incorporated into a software package, which will be released commercially by one of the project partners. Other partners were motivated by component performance improvement, which was generally achieved by reducing unnecessary weight, but also by adding new functionality only possible through the adoption of lattice structures.

Within this project, some of the most pertinent results originated from investigations into self-supporting lattice structures. The lattices were examined theoretically by computational methods and experimentally. The findings were presented at several international conferences and led to a number of journals publications. In addition, the results of the lattice characterisation work fed directly into the design of lightweight components for the project partners.

Widening the applicability of Additive Manufacturing (AM) for end-use product instead of prototypes manufacturing is vital for commercializing this revolutionary manufacturing technique. Expanding the material database for AM allows more advanced materials to be processed with this technology and enable it to be used in manufacturing high-performance end-use products. The aim of the reactive jetting project was to develop new ink formulations which are suitable for inkjet-based AM technique, to produce a product made of high-performance functional polymers. The main work involved developing new monomers, pre-polymers, chemistry reactions and printing strategies, which enable the creation of inkjet printable ink formulations that can be triggered after deposition to polymerize and form functional polymeric parts with desired properties.

Since the start of this project, we have achieved a breakthrough in producing parts from several popular polymers through reactive jetting technique. These include: Polyimide (PI), Polycarbonate, Polyvinylpyrrolidone, Polyurethane, Polyurea and Polysiloxanes most of which had never been processed before using inkjet-based AM techniques. These advances enable the manufacturing of parts with specific functions such as high-temperature resistance, water solubility, high optical clarity, flexibility, biocompatibility and drug delivery. The project has already attracted and established collaborations with companies in the field of pharmaceuticals, agro-chemicals, engineering polymers and healthcare industry.