MiniFactory Case Study University of Exeter

Challenge

At the time of purchase, the miniFactory Ultra was the only MEX system that was capable of a build environment of 250°C. We have a range of other high temperature MEX systems with lower environment temperatures that we also use for printing high temperature polymers, but this usually limits us to printing semi-crystalline PolyArylEtherKetone polymers in their amorphous state, requiring post treatment to get the maximum material properties. 

The Ultra allows us to explore printing in a semi-crystalline state directly, which adds to our understanding of fundamental polymer characteristics and how they perform in the Additive process. All the work we do on our machines across multiple research projects adds to the understanding of what is happening to the polymer before, during and after the additive process. The miniFactory has a number of material profiles for commercial high performance polymers such as PAEK’s, ULTEM’s, Polyimides which allows us to benchmark our developmental materials.

Introduction and Application

Our main use of the miniFactory Ultra is to print test specimens for materials testing. We are, as a research group mainly focussed on the development of high performance polymers for Additive Manufacturing. We study a range of properties of the polymers or polymer composites, from layer bonding to crystallisation kinetics and shrinkage or deformation. We specialise in understanding the polymer science of why a certain polymer may have poor interlayer adhesion, or why a polymer may be more prone to warping. Once we have that knowledge, we work with material suppliers to help select the right grade of their polymers that are suited for the additive process, rather than using grades which have been optimised for completely different process requirements such as injection moulding grades.

The Ultra allows us to explore printing in a semi-crystalline state directly, which Having an open system like the miniFactory, where we can control any aspect of the MEX process is critical for our research. Whilst end user’s that are closer to the manufacturing process may benefit from the security of fixed material profiles and proprietary materials, for research we need the ability to control MEX process variables to fully understand the effect on the output of the process. We enjoy a good relationship with miniFactory Finland, and they have supported us with specific technical requests relating to hardware and firmware on the Ultra.

We work with a number of material manufacturers, but we are probably known mostly for our research in PAEK polymers for AM. Of the manufacturers in the PAEK sector, we are currently in the sixth year of a technical partnership with Victrex Plc developing new grades of PEEK for both MEX and PBF. Through our use of the miniFactory we help Victrex design the next generation of PAEK which is optimised for the processing conditions of the MEX process. 

Most of our research is funded through industrial collaborations, either directly funded from a partner, or through successful collaborative funding awards such as Innovate UK. We recently completed an Innovate UK funded project focussing on a hybrid manufacturing method, the overprinting of high performance polymers (OverHIPP) on to thermoplastic composite shapes with a consortium of industrial partners. The data gathered from test specimens built on the miniFactory was vital for our partner to create a software tool for the optimisation of MEX geometries. The success of the project will lead to a further collaboration to develop the hybrid process and expand on the range of materials previously tested.

Unfortunately, we don’t use the Aarni as our usage of the machine doesn’t really require it. We have trialled it recently but don’t see much benefit beyond what we are currently testing.

We are always looking at novel material solutions and how to implement them into the additive process, for example our research in high performance nano-composites spans both PBF and MEX. We have created and tested PEEK-GNP composite materials with improved electrical and thermal properties with the goal of directly printing multifunctional components in one process.

Solutions

Having the miniFactory in CALM gives us the ability to print pretty much all of the polymers we specialise in from the high performance range. The machine has an intuitive interface and excellent material storage which means we have the confidence that the materials are in the right condition prior to printing. As an operator there is limited maintenance required, and when we need to swap nozzles for specific polymer composites it’s an easy task supported by firmware wizards for calibration. We’ve taken advantage of the miniFactory annual service option delivered through the UK dealer 3DGBIRE which ensures our machine is up to date with firmware releases and components prone to wear are replaced before any machine failures. Overall, we are very happy with our investment in the miniFactory system and look forward to continuing our research in 3D printing of high performance polymers.