Analysis of the effect of different coatings on ejection forces in micro injection moulding

The purpose of this study was to investigate the effects of different mould coatings on ejection force in micro injection moulding, for a selection of thermoplastic polymers. Two semi-crystalline and two amorphous polymers were sorted. According to their potential affinity with the selected injected polymers, three different coatings were chosen: two types of DLC and a CrTiNbN coatingope

Special Issue of the Manufacturing Engineering Society (MES)

This book derives from the Special Issue of the Manufacturing Engineering Society (MES) that was launched as a Special Issue of the journal Materials. The 48 contributions, published in this book, explore the evolution of traditional manufacturing models toward the new requirements of the Manufacturing Industry 4.0 and present cutting-edge advances in the field of Manufacturing Engineering focusing on additive manufacturing and 3D printing, advances and innovations in manufacturing processes, sustainable and green manufacturing, manufacturing systems (machines, equipment and tooling), metrology and quality in manufacturing, Industry 4.0, product lifecycle management (PLM) technologies, and production planning and risks

Building Urban Resilience in the MENA Region‘The context of Climate Change, Conflict and Displacement’

It might seem plausible to argue that the national monitoring of disaster data loss can help countries achieve progress in reporting to the 2015-2030 Global Agendas of the Sendai Framework for Disaster Risk Reduction (SFDRR), the Climate Change (CC) Agreement, the Sustainable Development Goals (SDGs) and the Habitat III New Urban Agenda. Nevertheless, with the lack of climate security protracted displacement data monitoring in the MENA Region, Arab states fragile contexts of urban disaster, urban conflict and urban poverty, can exacerbate the exclusion of internally displaced persons (IDPs) and refugees from disaster resilience assessments, which remains an obstacle in achieving the global targets at the local level. With the weakness of Disaster Risk Reduction (DRR) governance at the local level, the urgency of this study comes from the assigned timeframe to achieve the SFDRR Target (E) to ‘substantially increase the number of countries with national and local disaster risk reduction strategies by 2020’. Accordingly, this research aims to develop a policy guidance that supports DRR decision-makers in developing ‘Urban Resilience Action Plans’ (U-RAP) in fragile settings, using the SFDRR Disaster Resilience Scorecard ‘New Ten Essentials’ in the Middle East and North Africa Region (MENA) - Arab States. In addressing this aim, the researcher recognises the need to re-shape a regional understanding of resilience concept, accompanied by embedding sustainability principles and profiling of DRR regional policies beyond the internationally standardised terminologies, U-RAP Policy Guidance will provide effective means of translating resilience assessment indicators into sustainable actions in fragile contexts. As urban resilience action plans are increasingly reliant on the voluntary effort and ownership of DRR states’ official bodies, and affected with their organisational structures, it is important to identify the key parameters for understanding risk and assessing resilience in fragile settings from the perspective of DRR key stakeholders most vulnerable groups. This will help develop inclusive operational programs for their engagement in resilience decision making process, and form legislative policy guidelines beyond the theoretically bounded disaster resilience indicators and numerically generated indexes. In this study, evidence from secondary data (published and unpublished studies collected from the public domain and organisational reports) provided an overview of the scale and scope of humanitarian crisis and vulnerability to disasters risks in the MENA. A mixed methodological approach for primary data collection was adopted to develop original scientific based evidence, collected by the researcher from first-hand sources and helped recognise the significance of monitoring ‘Climate Security Displaced’ (CSD) people protracted displacement. Using qualitative and quantitative research methods, the correlation between the indicators of the SFDRR New Ten Essentials and ‘human security’ components of IDPs and refugees was identified, shedding the light on the challenges and opportunities for building resilience in the Arab States, and framed the structure for the U-RAP Policy Guidance. Qualitative exploratory data collection methods were applied through focus group discussions and 42 Interviews with key informative experts and DRR key stakeholders, supporting evidence on their role and level of engagement in measuring and building urban resilience. This was followed by examining two case studies of Khartoum-Sudan and Tripoli-Lebanon to generalise results for the Arab States regional context. Quantitative data was collected from a total of 120 questionnaire survey respondents, associating interlinkages between the U-RAP components and societal resilience domains for CSD people at the local level, and feeding into disaster data losses at the national level. This study formed a set of recommendations for Open Data utilisation to fill the gaps in existing resilience assessment data resourcing, monitoring disaster and conflict displacement patterns, inform resilience decision making process for displacement ‘durable solutions’ and guide financing priorities for DRR governance at the local level. The study concludes that international frameworks and resilience assessment tools overlook the sub-regional challenges that are historically witnessed in the Arab States and similar fragile settings globally, which requires a bottom-up costum based innovative mechanisms to enhance national governments commitments to the 2015-2030 Global Agendas. Similarly, there is a need to overhaul current resilience assessment tools and global framework reporting mechanisms into Arab cities' local context of fragility, to improve the accuracy, transparency and validity of the data required to structure effective and efficient disaster resilience action plans ‘leaving no one behind’. As a result, the U-RAP policy guidance has been developed as the main contribution of this study, providing a step-to-step pathway to help decision makers enhance societal resilience, while complementing the matrix of disaster data loss with human security and conflict displacement in the MENA region fragile settings, and guiding similar future research development approaches that can be adapted into fragile settings worldwide

Fundamental Understanding of Poly(ether ketone ketone) for High Temperature Laser Sintering

High-Temperature Laser Sintering (HT-LS) is a powder bed fusion technique employed to manufacture polymers with high service temperature, usually above 150 oC. The aerospace, automotive, and medical industries have driven the demand for processing high-performance polymers, as they could offer a lighter and cheaper alternative while maintaining the mechanical and chemical performance required to replace metallic parts in particular environments. Kepstan 6002 poly(ether ketone ketone) (PEKK) belongs to poly(aryl ether ketone)s (PAEKs) family and has a promising application in LS. The lower melting temperature united to the high glass transition temperature of PEKK (similar to PEK HP3, first commercially available HT-LS grade) enabled processing at lower temperatures whilst maintaining the high-temperature resistance of the polymer. Furthermore, the kinetics of crystallisation of Kepstan 6002 PEKK is very slow, which can assist layer adhesion during LS and improve mechanical properties in Z orientation. The present research project was developed in collaboration with Arkema. Three different grades of Kepstan 6002 PEKK were selected for initial analyses – HL1327, HL1320, and P12S959a. The powders were characterised for powder size, distribution, morphology, flow, moisture effect, and coalescence behaviour. This screening enabled the selection of HL1327 grade as the most promising for HT-LS application. The PEKK particle and powder analyses continued with an in-depth study of particle size and shape changes as a function of temperature and coalescence. The study revealed individual particle shrinkage prior to melting, followed by increased growth. The same phenomenon was observed for pairs of particles during coalescence and was attributed to the recovering of elastic deformation of the polymeric chains. The effect of intrinsic PEKK characteristics was successfully evaluated and quantified in the overall shrinkage in LS. The results identified powder properties as the main factor causing shrinkage of PEKK, as opposed to crystallisation. These results are supported by the powder characterisation developed in previous chapters. The interaction between material and process was investigated and optimised by testing different combinations of laser parameters and processing temperatures. The resulting properties were monitored regarding mechanical performance, surface topography, porosity, and crystallisation. The optimised PEKK specimens showed excellent mechanical strength (∼90 MPa) and modulus, but poor elongation, a common drawback from the LS process. The combination of fundamental material properties and process optimisation led to the development of a novel route to improve elongation and control the mechanical performance of LS PEKK. The experimental method successfully related cooling time, mechanical properties, and crystallisation of PEKK, and was able to increase elongation at break by 5.4 times. The improvement of elongation at break was attributed to the largely amorphous phase of PEKK when subjected to short cooling times. Lastly, powder recyclability was investigated from a chemical and physical perspective. PEKK can be reused following additional treatment steps, e.g., sieving. The potential for recyclability is an important remark as the material cost is significantly reduced and therefore preferred over the use of metals for high-performance applications

Nano-structured polymer-glass hybrid coatings

The increased attention received by polymer nanocomposites in recent years, has opened the way to research on nanostructured glass polymer hybrids for coating applications. Using polyamide 11 and adding fillers (in this case glass) at the nanometre length scale can lead to innovative modifications to the polymer matrix, giving rise to new structures and properties. This could develop new materials with enhanced properties and may enlarge the coating market to other application areas. Some of the main obstacles to overcome are the control of glass particle size to obtain suitable dispersions on the nanoscale with interaction between components. Nanoscale structures require the development of optimal hybrid precursors. Finding a way to develop the hybrids using melt compounding methods like extrusion, particle size processes and coating techniques have been investigated in this research. The nanostructured hybrids are made using macroscopic fillers, which avoids problems with current regulations on ultra-fine particles. Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy indicate the glass structure during synthesis of tin fluoride phosphate glass was pyrophosphate, mainly built up from phosphate tetrahedral units with one bridging oxygens present within a particular phosphate tetrahedron Qଵ end groups with a low concentration of phosphate tetrahedral units with two bridging oxygens Qଶ polymeric chains. However, sub-optimal melting produced significantly higher concentrations of phosphate tetrahedral units with no bridging oxygens present within a particular phosphate tetrahedron Q଴ orthophosphate structural units. The variations in NH and P − OH vibrations in the spectra revealed that a critical time and temperature of melting were necessary for the conversion of NHସHଶPOସ to produce sufficient PଶOହ for glass forming. During melting, PଶOହ and SnFଶ formed a low-temperature melt, which facilitated melting of the SnO and promoted the formation of a more stable glass structure. The fluorine breaks the P − O − P bonds and induces depolymerisation. The density of the glass reached a maximum at 450 °C for 25 min driven by the need for conversion of NHସHଶPOସ to PଶOହ and miscibility of SnO in the melt. Inadequate melting times and temperatures gave low glass transition temperature (Tg) values because of weak F − Sn and F − P linkages. Glass stability improved with melting due to increased PଶOହ and SnO miscibility enabling stronger Sn − O − P linkages. The results show that melting conditions during synthesis strongly influence critical glass properties and also provide an understanding of optimum processing necessary for future industrial scale-up. Novel hybrids of tin fluoride phosphate (TFP) glass (composition of 50% SnFଶ + 20% SnO + 30% PଶOହ) were synthesized with polyamide 11 and their morphology and mechanical properties investigated. Hybridization was achieved by melt blending up to 25 vol% of glass using different compounding conditions (temperature, screw speed and residence time). Scanning electron microscopy (SEM) showed that the morphology was greatly influenced by the extrusion processing temperature and the glass content. Transmission electron microscopy (TEM) studies revealed nanoparticles of 40 nm in size and suggested good compatibility. In order to determine the existence of miscibility between hybrid components, measurement of the loss tangent using a Dynamic Mechanical Analysis (DMA), was carried out. The presence of two transition peaks in the hybrid containing 34 vol% tin fluoride phosphate glass implied an immiscible system showing heterogeneously distributed regions of very different molecular mobilities. Contrary to the plasticizer effect reported in the literature for some polyamide 6 - TFP glass hybrids, the measurements of mechanical properties by DMA showed a reinforcement effect of glass in the polymer. This was reflected by the increase of storage modulus (Εᇱ) at low and high temperatures in hybrids containing 13, 18 and 25 vol% tin fluoride phosphate glasses, achieving the highest modulus at 25 vol%. Tensile testing revealed a pronounced reduction in ductility for high glass contents. Finally, the first TFP- PA11 hybrid coating was developed with enhanced fire resistance and adhesion to the metal. Hardness and abrasion tests using different glass Tgs showed an influence of the glass Tg on the final coating application

Towards a Conceptual Design of an Intelligent Material Transport Based on Machine Learning and Axiomatic Design Theory

Reliable and efficient material transport is one of the basic requirements that affect productivity in sheet metal industry. This paper presents a methodology for conceptual design of intelligent material transport using mobile robot, based on axiomatic design theory, graph theory and artificial intelligence. Developed control algorithm was implemented and tested on the mobile robot system Khepera II within the laboratory model of manufacturing environment. Matlab© software package was used for manufacturing process simulation, implementation of search algorithms and neural network training. Experimental results clearly show that intelligent mobile robot can learn and predict optimal material transport flows thanks to the use of artificial neural networks. Achieved positioning error of mobile robot indicates that conceptual design approach can be used for material transport and handling tasks in intelligent manufacturing systems

Friction Force Microscopy of Deep Drawing Made Surfaces

Aim of this paper is to contribute to micro-tribology understanding and friction in micro-scale interpretation in case of metal beverage production, particularly the deep drawing process of cans. In order to bridging the gap between engineering and trial-and-error principles, an experimental AFM-based micro-tribological approach is adopted. For that purpose, the can’s surfaces are imaged with atomic force microscopy (AFM) and the frictional force signal is measured with frictional force microscopy (FFM). In both techniques, the sample surface is scanned with a stylus attached to a cantilever. Vertical motion of the cantilever is recorded in AFM and horizontal motion is recorded in FFM. The presented work evaluates friction over a micro-scale on various samples gathered from cylindrical, bottom and round parts of cans, made of same the material but with different deep drawing process parameters. The main idea is to link the experimental observation with the manufacturing process. Results presented here can advance the knowledge in order to comprehend the tribological phenomena at the contact scales, too small for conventional tribology

Towards a Conceptual Design of an Intelligent Material Transport Based on Machine Learning and Axiomatic Design Theory

Reliable and efficient material transport is one of the basic requirements that affect productivity in sheet metal industry. This paper presents a methodology for conceptual design of intelligent material transport using mobile robot, based on axiomatic design theory, graph theory and artificial intelligence. Developed control algorithm was implemented and tested on the mobile robot system Khepera II within the laboratory model of manufacturing environment. Matlab© software package was used for manufacturing process simulation, implementation of search algorithms and neural network training. Experimental results clearly show that intelligent mobile robot can learn and predict optimal material transport flows thanks to the use of artificial neural networks. Achieved positioning error of mobile robot indicates that conceptual design approach can be used for material transport and handling tasks in intelligent manufacturing systems

Surface properties of electrospun polymer nanofibres

PhDFibrous materials are used in a variety of applications due to their relatively high surface area to volume ratio as well as anisotropic behaviour. Electrospinning is a popular fabrication technique which produces polymer nanofibres with a potentially high molecular orientation. The surface of polymer fibres plays a significant role in many applications thus measurement of their surface properties is essential but challenging due to their relatively small size. In this thesis, ultrafine nanofibres have been produced by electrospinning with their nanofibre morphology controlled by varying different processing parameters. Atomic force microscopy (AFM) adhesion contact mechanics and individual nanofibre wetting measurements have been conducted to explore surface properties of the produced electrospun polymer fibres. Results using traditional Owens-Wendt plots applied to our nanomaterials show electrospun nanofibres have a higher dispersive surface free energy compared to bulk polymer film but a lower polar contribution, giving a total surface free energy in excess of bulk equivalents. A novel proposed model indicates that this nanofibre dispersive surface free energy is intimately linked to density of the polymer and ultimately the molecular spacing or orientation for the polymer chains. Comparisons are made with bulk polymer films to show that a high degree of molecular orientation is present at least at the surface of the polymer nanofibre. Structure investigations on electrospun fibres of polyvinyl alcohol using FTIR and XPS surface techniques explore how an increase in hydrogen bonds formed within nanofibres rather than on the fibre surface enhance this dispersive contribution but lowers the polar contribution. The wetting behaviour of electrospun fibre is extended to assemblies at length scales above individual fibres to highlight how superhydrophobic surfaces can be produced from nanofibre networks with defined spacings and geometries. This superhydrophobicity was adequately described by a Cassie-Baxter model modified to account for the fibrous geometry