Past projects at the Centre for Additive Manufacturing

We are carrying out further development and optimization work on a new powder bed based reactive inkjet printing technique, which has been patented by CfAM, to generate chemically ‘sintered’ structureswith more homogeneous spatial properties and better inter-particle binding than traditional laser or IR sintering processes.

Electromagnetic energy in the microwave and/or radio frequency (RF) spectrum is used to volumetrically solidify selective regions of a polymer powder bed. This volumetric sintering approach has the potential to produce parts with better mechanical properties, along with a reduction in product development cycle time relative to commercial Laser Sintering.

The 3D printed formulation project is sponsored by GlaxoSmithKline. The aim of the project is to study the feasibility of manufacturing drug releasing solid dosage forms (tablets) using inkjet, SLA, and extrusion printing. These additive manufacturing platforms offer geometric flexibility and additional control over dosage design, which may allow for the production of personalized medicine.

Our research has focused on UV curable and solvent evaporation type inkjet formulations for highly water soluble Active Pharmaceutical Ingredients (APIs). We have also investigated the drug release behaviour from extrusion printed paste formulations. Future work will involve the formulation of poorly water soluble APIs inks for inkjet and SLA printing processes, as well as on implantable drug delivery devices.

In this figure we demonstrate the drug release behaviour of Ropinirole HCl, a low dose, highly water soluble API from a UV cured tablet matrix. The inkjet printed tablets contain a commercially relevant dose (0.41 mg) of Ropinirole HCl.  Release (89%) of the API is observed over four hours.

Industrial partners: Martin M. Wallace (GSK), Sonja Sharpe(GSK), Jae Yoo(GSK).

This project looks at the feasibilityof manufacturing drug release solid dosage forms (tablets) using inkjet, SLA and extrusion printing. These AM platforms offer geometric flexibility and additional control over dosage design, which may allow for the production of personalised medicines.

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.

The requirements for future Additive Manufacturing systems to produce complex multi-material and multifunctional components are reliant on two aspects: increased material capability and increased resolution. NANOS specifically targets these aspects through the research and development of nano-resolution manufacturing systems, principally multi-photon lithography, that are capable of producing 3D structures of the order of 100 nm in materials that have relevance to sensing applications and beyond. In addition, NANOS utilises developments in optical tweezer technology to functionalise the structures made using multi-photon lithography. NANOS is enabling the deposition of nanoscale structures in new materials that promote the development of novel sensory systems.

Highlights

• A multi-photon lithography system has been developed with extended capabilities – to process composites, including polymers and metals, in a controllable way; and to combine with optical tweezer technology to functionalize the structure made by multi-photon lithography.
• Since the project’s inception, additional funding has been awarded from EPSRC and the United States Air Force’s European Office of Aerospace Research & Development to extend the system’s capabilities.
• Nine PhD students are working on spin-off projects that involve collaborations with Nottingham’s Electrical Engineering, Biomedical Sciences and Physics Department, demonstrating the wide relevance of the technology across the engineering and science fields.
• A technique to fabricate complex 3D Au-containing nano-composites by simultaneous two-photon polymerisation and photoreduction in a single step has been developed. Feature size as small as 78 nm has been demonstrated. The in-situ generated Au nanoparticles have surface plasmonic effect. This technique opens a door for various application studies, such as plasmonics, metamaterials, flexible electronics and biosensors.
• Suitable photoinitiators suitable for two-photon lithography have been identified and synthesized in lab.

Tissue engineering and regenerative medicine are key healthcare challenges for manufacturing. The CfAM involvement in this field has been to examine the feasibility of 3D printing complex tissue structures. Potential applications for this research include the manufacture of cell based biosensors, in-vitro models of complex organs, implanted cell-factory devices, or external assist devices for organs.

In collaboration with the Centre of Biomolecular Sciences (CBS) and the School of Pharmacy research areas ranging from bioprinting to pharmaprinting were explored, taking basic science to application.

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.

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.

The combination of additive manufacturing technologies with data science and human-centred design methods can have a transformative effect on the functionality, cost and personalisation of prosthetic limbs, but that an integrated design environment that is open to all stakeholders is needed to realise this. Additive manufacturing brings the potential to automatically ‘print’ prosthetics, and potentially orthotics too, that are personalised to their owners in terms of their size, shape, fit to the human body, aesthetic and functionality, including how they are controlled using physiological signals and the specific ways in which they respond to these such as performing particular combinations of grips. Achieving this level of personalisation however requires the analysis of a diverse collection of data including bodily measurements, the results of clinical tests, statements of user preferences and even knowledge about operating context, all of which need to be quantified in order to drive manufacturing equipment. In turn, the capture and analysis of this data requires input and validation from a variety of human stakeholders including various kinds of clinician, patients and their carers.

The manufacturing engineering research challenge in this project is to be able to intelligently design, automatedly evaluate and efficiently manufacture innovative prosthetic solutions. Numerical tools such as MSC ADAMS software used in conjunction with MATLAB Simulink allow for the identification of performance index (for instance grip and dexterity) for a wide range of prosthesis in an automated fashion. This virtual evaluation makes the investigation into the variety of prosthetic options possible. Advanced prosthetic designs benefit from the multi-functional optimisation tools developed as part of the CfAM to allow for electrical/electronic componentry to be embedded within structurally optimised housing.

The aim of ALMER was to develop the UK Additive Manufacturing capability through a consortium of both large and small companies, research organisations and academic institutions. ALMER was specifically designed to tackle the manufacturing challenges that must be overcome so that the potential design opportunities afforded by Additive Manufacturing can be exploited fully. The primary objectives of the ALMER project included the generation of production standard data for a nimonic alloy (C263), optimisation of post processing techniques, development of inspection methods, process development of a high temperature alloy (CM247LC) and the generation of a design and optimisation tool that would seek to exploit the weight reduction opportunities in component design. The combination of these developments will enable the advancement towards productionisation of Additive Manufacturing components.

The focus of the ongoing work at The University of Nottingham was to build upon research that had been conducted in the fields of topological optimisation methods and design and optimisation of lattice structures for Additive Manufacture.  The work sought to advance these methods closer to commercial realisation by exploring existing and new methods to fully exploit the design freedoms offered by Additive Manufacturing, whilst incorporating the nuances and performance limitations of this modern manufacturing method. In doing so, ALMER investigated design optimization and experimental validation of titanium samples manufactured using Selective Laser Melting.

The highly collaborative ASID project was aimed at demonstrating the potential of a number of manufacturing technologies for the aerospace sector. This included the realization of various components of a door assembly via these technologies. Topology optimized hinges, components that attach the door to an air vehicle were realized via selective laser melting, an additive manufacturing technique that allowed the consolidation of layers of molten powder. Novel thermoplastic materials, manufacturing and joining technologies were used to derive the other components of the assembly.

Additively manufacturing the hinges allowed the production of an optimal design with little need for feature penalization. The hinges were simultaneously optimized while experiencing multiple load cases to simulate loads experienced by the door during service in an open and close position. The dimensions of the hinge were constrained to the build envelop of the machine while various topology optimization strategies for fatigue was investigated.  This work showed that complex hinge designs realised via additive manufacturing could be incorporated in an aerospace assembly. However, complications arising from building large parts necessitate the use of unconventional supports to avoid build failures.

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.

The key to unlocking the benefits of multifunctional Additive Manufacturing lies in the design freedoms that the additive approach engenders. A major challenge is to produce a methodology that enables the design of multifunctional Additive Manufacturing parts that are optimised. This optimisation problem must consider: efficient topology generation with integrated lattices and opto-electrical pathways (for embedded functionality). The multifunctional Additive Manufacturing design paradigm presents a radical advance in product design where weight, performance, functionality and aesthetics are combined in one part and manufactured as a single item.

In order to exploit the potential benefits of this emergent technology, new design, analysis and optimization methods are needed. This project, currently running in its fourth year, progress the planned work on several fronts, particularly contributing towards the development of a coupling method to allow for optimisation of the structure comprised of a number of connected functional components. This is achieved by incorporating the effects of a system on the structural response of a part within a structural topology optimization procedure. The potential of the proposed method is demonstrated by performing a coupled optimization on a cantilever plate with integrated components and circuitry.

Such a coupled optimization formulation allows for the optimal material and system lay-out to be identified as it tackles a system design problem overlaid on a structural design problem. Although, the immediate application for this development is enabling the design of additively manufactured multi-material parts with embedded functional systems, for example a structural part with electronic/electrical components and associated conductive paths, nevertheless, the developed method should be considered for tackling a more general class of engineering problems. For instance, civil engineering structures (buildings/bridges) that incorporate systems (pipes/cables). This coupled optimization development marks a significant step towards being able to exploit the design freedom offered by multi-material AM processes.

Regarding lattice structure design, an emphasis has been placed on expanding the functional grading capability to include both cell size and material variation which will provide greater scope for optimisation. In addition, efficient hierarchal finite element analysis based topology optimisation protocols have been developed to advance the field of topology optimisation for real-life AM structures.

 

Jetting is one of the integral AM techniques for the manufacture of the multifunctional devices that are the core deliverable of the EPSRC Centre. In order to understand, develop and optimise the jetting process it is essential to develop models of the process that can accurately simulate the delivery, deposition and post-deposition behaviour of materials. This requires the development of a suite of multiphysics modelling tools.

The modelling techniques required can be divided into two parts. Firstly, those required to model the material deposition process itself, which involve computational fluid dynamics and fluid-solid interactions. Secondly, those required to model the post deposition behaviour of the manufactured devices, which involve Multiphysics finite element analysis and multi-scale mechanical modelling.

The project was divided into two stages. The first stage involved state of the art reviews and pilot studies to identify future research directions. This led to combined modelling-experimental investigations into nano-fluid drop formation and the accurate finite element representation of jet printed dielectric and bio-degradable polymers, which are on-going. In the second stage, PhD projects in the two parts introduced above will be used to further develop the models and techniques required to model the deposition of materials via the jetting process and the post deposition behaviour of the manufactured parts. This work underpins and informs work carried out at the EPSRC Centre in the areas of jetting of conductive and dielectric elements and the jetting of biodegradable materials.

3D Printing (3DP) technology promises supply chain innovation by enabling manufacturing configurations yielding value through product differentiation, including spatial location. Pursuing distributed 3DP supply chains may be the result of strategic deliberation, yet it is also frequently noted that 3DP is prone to higher unit costs than conventional manufacturing where quantities become large. Additionally, 3DP faces the challenge of being integrated into existing manufacturing and information systems, which may be operated in a centralised location. The implementation of appropriate supply chains is now seen as a core capability for manufacturing businesses.

Building on previous work on computational build volume packing for 3DP this project has implemented a feasibility demonstrator for an integrated build volume packing and scheduling approach. Labelled the “3D Packing Research Application Tool” (3DPackRAT), the resulting operational software tool enables a flexible and reactive manufacturing execution methodology that is designed to complement the strengths of 3DP.

To achieve the project goals, the integrated computational framework enables the inclusion of a wide range of general and location related aspects in a single optimisation-based production planning procedure. Being fed an order stream, the demonstrator thus aims to determine the best 3DP system for each build request. Crucially, this approach is also capable of considering the benefits resulting from re-distributed 3DP, driving supply chain structures towards such configurations where beneficial. The flow chart shown in Figure 1 illustrates the general working principle and informational inputs and outputs of the developed demonstrator system.

The overarching aim of the project was to address the existing lack of a fundamental understanding of the process economics that underpin the commercial application of 3D Printing. Forming a main element in the identification of the business case for the adoption of 3D Printing technology, existing costing approaches have concentrated on capital investments, i.e. the 3D Printing systems and ancillary equipment, and consumables, most importantly the build material. The focus on such “well-structured” costs has shown that utilising the available machine capacity constitutes a pre-requisite for the efficient operation of 3D Printing. However, existing investigations of the cost of 3D Printing have mostly ignored other costs resulting from, for example, build failure, and the rejection of parts. The consequence of the omission of such “ill-structured” costs is that existing cost models for 3D Printing lack realism.

The undertaken work developed new methodologies and executed a campaign of build experiments to collect a body of data allowing the formulation of a novel, more comprehensive, costing. The model resulting from this research provides a basis for further investigations into the processes economics of 3D Printing and the development of more robust process selection tools.

To create dataset required to achieve the project’s objectives, a series of build experiments was performed on a polymeric EOSINT P100 Laser Sintering (LS) system, with additional builds on the metallic Renishaw SLM 250 Selective Laser Melting System. The main series of experiments on the LS system consisted of ten identical builds which reflected machine operation at full capacity and four builds at sub-maximal levels of capacity utilisation. A sufficient number of repetitions of the build experiments was obtained by artificially limiting machine capacity to a 30 mm thick horizontal band of build space and extrapolating the obtained results to the full height of the available build cuboid (330 mm). The used build space was populated with test geometries and tensile specimens using a computational build volume packing tool.

Key publications:

• Baumers, M. and Holweg, M., 2016. The Cost Impact Of the Risk of Build Failure in Laser Sintering. Solid Freeform Fabrication Symposium, 2016, University of Texas at Austin.

 

• Baumers, M., Tuck, C. and Hague, R., 2015. Selective Heat Sintering versus Laser Sintering: Comparison of Deposition Rate, Process energy Consumption and Cost Performance. Solid Freeform Fabrication Symposium, 2015, University of Texas at Austin.

• Despeisse, M., Baumers, M., Brown, P., Charnley, F., Ford, S.J., Garmulewicz, A., Knowles, S., Minshall, T.H.W., Mortara, L., Reed-Tsochas, F.P. and Rowley, J., 2016. Unlocking value for a circular economy through 3D printing: A research agenda. Technological Forecasting and Social Change.

 

• Baumers, M., Holweg, M., and Rowley, J., 2015. The economics of 3D Printing: A total cost perspective. Project Report. 3DP-RDM project.

• Baumers, M., 2017, “Digitalisation of manufacturing and restructuring of value chains”, Presentation held on 23 February 2017 by ETUI in Naples/Italy.