Purpose The purpose of this study is to demonstrate and characterise a soft-tooled micro-injection moulding process through in-line measurements and surface metrology using a data-intensive approach. Design/methodology/approach A soft tool for a demonstrator product that mimics the main features of miniature components in medical devices and microsystem components has been designed and fabricated using material jetting technique. The soft tool was then integrated into a mould assembly on the micro-injection moulding machine, and mouldings were made. Sensor and data acquisition devices including thermal imaging and injection pressure sensing have been set up to collect data for each of the prototypes. Off-line dimensional characterisation of the parts and the soft tool have also been carried out to quantify the prototype quality and dimensional changes on the soft tool after the manufacturing cycles. Findings The data collection and analysis methods presented here enable the evaluation of the quality of the moulded parts in real-time from in-line measurements. Importantly, it is demonstrated that soft-tool surface temperature difference values can be used as reliable indicators for moulding quality. Reduction in the total volume of the soft-tool moulding cavity was detected and quantified up to 100 cycles. Data collected from in-line monitoring was also used for filling assessment of the soft-tool moulding cavity, providing about 90% accuracy in filling prediction with relatively modest sensors and monitoring technologies. Originality/value This work presents a data-intensive approach for the characterisation of soft-tooled micro-injection moulding processes for the first time. The overall results of this study show that the product-focussed data-rich approach presented here proved to be an essential and useful way of exploiting additive manufacturing technologies for soft-tooled rapid prototyping and new product introduction.

The effects of mould temperature (cooling temperature) on molten HDPE (Hostalen GC 7260) during manufacture, is evaluated in this paper. HDPE gears were produced at varying mould temperatures using Injection Moulding. Optimised injection values for melt temperature, injection volume, hold pressure, and hold time were obtained, and then held constant while the mould temperature was altered. Analysis on how the mould temperature affected peak melting points and crystallinity were then carried out using differential scanning calorimetry (DSC). These revealed that crystallinity improved as the mould temperature was increased from 22 degrees C to 65 degrees C. Gears produced at similar cooling temperatures were then meshed on a gear test rig and run at 1000 rpm, using different torque loadings. Their wear rates, and modes of failure were then analysed, and comparisons were made to ascertain how the differing mould temperatures employed during the injection moulding manufacturing process affected their wear characteristics. Topographical analysis of worn gear teeth was performed using scanning electron microscopy (SEM). It was noted that gear tooth wear and failure was dependent on the mould temperature employed during the manufacturing process. Gears produced at 65 degrees C showed improved tooth surface wear resistance at lower loads (0.5 Nm and 1 Nm) compared to those produced at 22 degrees C, but were more likely to fail through tooth fracture at the pitch line due to excessive material removal. Gears produced at lower mould temperatures, on the other hand, exhibited better wear resistance for higher loads (3 Nm and 4 Nm), compared to those produced at higher mould temperatures, and were more likely to fail due to material flow. The results show a correlation between mould temperature, crystallinity, and gear performance. Based on wear rate responses of gears produced at differing mould temperatures to the application of varying torque loadings, a Mould Temperature to Torque Reference Chart for HDPE is presented.

The market dynamics, and their impact on a future circular economy for lithium-ion batteries (LIB), are presented in this roadmap, with safety as an integral consideration throughout the life cycle. At the point of end-of-life (EOL), there is a range of potential options—remanufacturing, reuse and recycling. Diagnostics play a significant role in evaluating the state-of-health and condition of batteries, and improvements to diagnostic techniques are evaluated. At present, manual disassembly dominates EOL disposal, however, given the volumes of future batteries that are to be anticipated, automated approaches to the dismantling of EOL battery packs will be key. The first stage in recycling after the removal of the cells is the initial cell-breaking or opening step. Approaches to this are reviewed, contrasting shredding and cell disassembly as two alternative approaches. Design for recycling is one approach that could assist in easier disassembly of cells, and new approaches to cell design that could enable the circular economy of LIBs are reviewed. After disassembly, subsequent separation of the black mass is performed before further concentration of components. There are a plethora of alternative approaches for recovering materials; this roadmap sets out the future directions for a range of approaches including pyrometallurgy, hydrometallurgy, short-loop, direct, and the biological recovery of LIB materials. Furthermore, anode, lithium, electrolyte, binder and plastics recovery are considered in order to maximise the proportion of materials recovered, minimise waste and point the way towards zero-waste recycling. The life-cycle implications of a circular economy are discussed considering the overall system of LIB recycling, and also directly investigating the different recycling methods. The legal and regulatory perspectives are also considered. Finally, with a view to the future, approaches for next-generation battery chemistries and recycling are evaluated, identifying gaps for research. This review takes the form of a series of short reviews, with each section written independently by a diverse international authorship of experts on the topic. Collectively, these reviews form a comprehensive picture of the current state of the art in LIB recycling, and how these technologies are expected to develop in the future.

Increasing plastic recycling rates is key to addressing plastic pollution. New technologies such as chemometric analysis of spectral data have shown great promises in improving the plastic sorting efficiency to boost recycling rates. In this work, a novel deep learning architecture, PolymerSpectraDecisionNet (PSDN) was developed, consisting of convolutional neural networks, residual networks and inception networks in a decision tree structure. To better represent the conditions in the plastic recycling industry, the models were built to identify the most widely recycled polymers – polyethylene, polypropylene and polyethylene terephthalate from open-sourced infrared and Raman spectral dataset containing over 20 different polymers. PSDN performed better than end-to-end neural networks, obtaining an accuracy of 0.949 and 0.967 with the Raman and infrared datasets respectively. The use of deep learning can also distinguish between weathered and unaged polymer samples, with accuracies of 0.954 for high density polyethylene and 0.906 for polyethylene terephthalate.

This work presents X-ray computed tomography (XCT) as a dimensional quality assurance technique for micro-injection moulded polymeric test objects for the establishment of predictive quality models and quantifying soft-tool deformation. The results are compared against an industry standard laser-scanning-confocal microscope (LSCM) for the evaluation of XCT’s capability. The work demonstrates; (i) the exploitation of a XCT equipment for dimensional characterisation of micro-injection moulded products made out of polymers with adequate acquisition times, (ii) that acquired XCT data from the 3D visualisation of the micromouldings perform on par with a laser-scanning-confocal microscope in a quality prediction model, (iii) that the deformation occurring in an additively manufactured soft-tool can be quantified using XCT. The technique was particularly superior in volumetric data acquisition compared to LSCM in the filling prediction of the micromouldings. Better accuracy and repeatability in predicting the quality of the mouldings up to 92% achieved with XCT, in conjunction with an in-line collected soft-tool surface temperature data as an indirect quality assurance method. Given the capability of the XCT for the 3D data acquisition of polymeric miniature components, the approach described here has great potential in high-value micro-manufacturing process quality modelling for in-line quality assessment of miniature and added value products in data-rich contexts.Rendered 3D animation of the X-ray CT data: https://youtu.be/KwZty_yoDfs.

The use of chemometric techniques with spectral data for sorting plastics to improve recycling rates have gained more attention in recent years. However, insufficient representation of polymer spectra in spectral databases has been one of the barriers to the further development of these techniques. This work aims to develop a polymer spectra dataset that builds upon existing spectral databases on two fronts. Firstly, the data collected includes Laser-induced Breakdown Spectroscopy (LIBS) data in addition to more commonly available Infrared (IR) and Raman data. Secondly, the dataset includes unaged and weathered conditions of the same sample. In total, the dataset includes 732 spectra, with the LIBS, IR and Raman spectra of 122 unique samples, both before and after accelerated weathering. The data collected were qualitatively analyzed and visualized. Further work will explore the effect of using hybrid spectroscopic methods on chemometrics analysis results.

Automated sorting through chemometric analysis of plastic spectral data could be a key strategy towards improving plastic waste management. Deep learning is a promising chemometric tool, but further development through multi-modal deep learning has been limited by lack of data availability. A new Multi-modal Plastic Spectral Database (MMPSD) consisting of Fourier Transform Infrared (FTIR), Raman and Laser-induced Breakdown Spectroscopy (LIBS) data for each sample in the database is introduced in this work. MMPSD serves as the basis for novel cross-modality generative model technique termed Spectral Conversion Autoencoders (SCAE), which generates synthetic data from data of another modality. SCAE is advantageous over traditional generative models like Variational Autoencoders (VAE), as it can generate class specific synthetic data without the need to train multiple models for each data class. MMPSD also facilitated the exploration of multi-modal deep learning, which improved the classification accuracy as compared to an uni-modal approach from 0.933 to 0.970. SCAE can further be combined with multi-modal methods to achieve a higher accuracy of 0.963 while still using a single sensor to reduce costs, which can be applied for multi-modal augmentation from FTIR sensors used in industrial sorting.

Replacement of indium tin oxide with the intrinsically conducting polymer poly(3,4–ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been of significant interest in recent years as a result of lower processing and material costs. In addition, the inclusion of additives has been reported to further enhance the conductivity, rheology, and wettability of PEDOT:PSS. In this study, Tween 80 was shown to decrease the sheet resistance of PEDOT:PSS films from approximately 1000 to 76 Ω□−1 at a 2.67 wt% surfactant concentration. Through X-ray diffraction, Raman spectroscopy, and atomic force microscopy, it was shown that the surfactant caused phase separation and structural ordering of the PEDOT and PSS components, leading to this improvement in conductivity. Furthermore, Tween 80 altered the rheological properties and decreased the surface tension of PEDOT:PSS, making coating common commodity polymers, often used as flexible substrates, more viable.

Abstract As electric vehicles become more widely used, there is a higher demand for lithium‐ion batteries (LIBs) and hence a greater incentive to find better ways to recycle these at their end‐of‐life (EOL). This work focuses on the process of reclamation and re‐use of cathode material from LIBs. Black mass containing mixed LiMn2O4 and Ni0.8Co0.15Al0.05O2 from a Nissan Leaf pouch cell are recovered via two different recycling routes, shredding or disassembly. The waste material stream purity is compared for both processes, less aluminium and copper impurities are present in the disassembled waste stream. The reclaimed black mass is further treated to reclaim the transition metals in a salt solution, Ni, Mn, Co ratios are adjusted in order to synthesize an upcycled cathode, LiNi0.6Mn0.2Co0.2O2 via a co‐precipitation method. The two reclamation processes (disassembly and shredding) are evaluated based on the purity of the reclaimed material, the performance of the remanufactured cell, and the energy required for the complete process. The electrochemical performance of recycled material is comparable to that of as‐manufactured cathode material, indicating no detrimental effect of purified recycled transition metal content. This research represents an important step toward scalable approaches to the recycling of EOL cathode material in LIBs.

Mismanagement of plastic waste globally has resulted in a multitude of environmental issues, which could be tackled by boosting plastic recycling rates. Chemometrics has emerged as a useful tool for boosting plastic recycling rates by automating the plastic sorting and recycling process. This paper will comprehensively review the recent works applying chemometric methods to plastic waste sorting. The review begins by introducing spectroscopic methods and chemometric tools that are commonly used in the plastic chemometrics literature. The spectroscopic methods include near-infrared spectroscopy (NIR), mid-infrared spectroscopy (MIR), Raman spectroscopy and laser-induced breakdown spectroscopy (LIBS). The chemometric tools include principal component analysis (PCA), linear discriminant analysis (LDA), partial least square (PLS), k-nearest neighbors (k-NN), support vector machines (SVM), random forests (RF), artificial neural networks (ANNs), convolutional neural networks (CNNs) and K-means clustering. This review revealed four main findings. (1) The scope of plastic waste should be expanded in terms of types, contamination and degradation level to mirror the heterogeneous plastic waste received at recycling plants towards understanding potential application in the recycling industry. (2) The use of hybrid spectroscopic method could potentially overcome the limitations of each spectroscopic methods. (3) Develop an open-sourced standardized database of plastic waste spectra would help to further expand the field. (4) There is limited use of more novel machine learning tools such as deep learning for plastic sorting.

Coatings are widely used in a range of aesthetic, protective and durable applications, often leading to extension of the in-service period of many components. There is sizable demand for coatings in the transport sector across road, rail, marine and air. However, the issue of materials circularity with consideration of their surface treatment is an under researched and often overlooked area. The aim of this paper is to explore challenges and enabling factors that can catalyse industrial growth of a new material, technology, or process by investigating coatings within the transport sector. We do this by studying six new or novel approaches that have garnered significant research interest in the last decade, set against system-level drivers and enablers of circularity. Our findings highlight the complications, assumptions and benefits of a circular transition. We conclude that policy and regulation play a key role in supporting or hindering the transition, and further consideration of material 'lock-in' is required to understand how materials can be phased out from a design standpoint.

This article describes a process for the repair and re-use of an aluminium-containing pouch used as an outer casing for a Lithium-ion battery cell.

Lithium-ion batteries are the state-of-the-art power source for most consumer electronic devices. Current collectors are indispensable components bridging lithium-ion batteries and external circuits, greatly influencing the capacity, rate capability and long-term stability of lithium-ion batteries. Conventional current collectors, Al and Cu foils have been used since the first commercial lithium-ion battery, and over the past two decades, the thickness of these current collectors has decreased in order to increase the energy density. However to improve the performance further, alternative materials and structures, as well as specific treatments such as etching and carbon coating, have also been investigated to enhance the electrochemical stability and electrical conductivity of current collectors, for next-generation lithium-ion batteries with higher capacities and longer service lifetime. This work reviews six types of materials for current collectors, including Al, Cu, Ni, Ti, stainless steel and carbonaceous materials, and compares these materials from five aspects of electrochemical stability, electrical conductivity, mechanical property, density and sustainability. The effects of three different structures of foil, mesh and foam as well as two treatments of chemical etching and coating are also discussed. Future opportunities are highlighted at the end of this review.

Waste disposal strategy for composites is dominated by the so called four "R"s: reduce, reuse, recycle, recover. For polymer and elastomeric matrix composites this process is complicated by the mixed nature of the constituent parts and their subsequent economic viability. Therefore, this article outlines the various process options and major issues in reuse, recycling and recovery of these materials. As composite materials have become increasingly widespread due to their advantages, commercially viable recycling and recovery solutions are yet to be satisfactorily defined for all materials streams. For this reason this article will consider major themes in relation to the reprocessing distinction between thermoset and thermoplastic matrix materials and the impact of various components on the subsequent recovery efforts. It will also cover processes for recycling and recovery. The design concepts of 'reduce' are also covered as part of more holistic design possibilities and future prospects and conclusions are presented in the drive towards the circular economy.

Polymer gears are an effective solution to lightweighting, which are highly demanded in the automotive industry. Acetal is one of the most widely used polymer gear materials. In this study, two commercial grades of acetal, homopolymer (POM-H) based and copolymer (POM-C) based, were injection moulded into gears with their wear performance compared. Noticeable differences were discovered in failure mechanism, and thermal and mechanical characteristics, which led to a difference in performance prediction. The service life of over two million cycles was expected under a torque up to 10 N m, with POM-H gears having 35% better service life than POM-C. The differences in the properties of POM-H and POM-C should be considered in future industrial applications such as the replacement for metal gears.

This literature review covers the solubility and processability of fluoropolymer polyvinylidine fluoride (PVDF). Fluoropolymers consist of a carbon backbone chain with multiple connected C–F bonds; they are typically nonreactive and nontoxic and have good thermal stability. Their processing, recycling and reuse are rapidly becoming more important to the circular economy as fluoropolymers find widespread application in diverse sectors including construction, automotive engineering and electronics. The partially fluorinated polymer PVDF is in strong demand in all of these areas; in addition to its desirable inertness, which is typical of most fluoropolymers, it also has a high dielectric constant and can be ferroelectric in some of its crystal phases. However, processing and reusing PVDF is a challenging task, and this is partly due to its limited solubility. This review begins with a discussion on the useful properties and applications of PVDF, followed by a discussion on the known solvents and diluents of PVDF and how it can be formed into membranes. Finally, we explore the limitations of PVDF’s chemical and thermal stability, with a discussion on conditions under which it can degrade. Our aim is to provide a condensed overview that will be of use to both chemists and engineers who need to work with PVDF.

This revised 3rd edition details the factors involved in the injection moulding process, from material properties and selection to troubleshooting faults, and includes the equipment types currently in use and machine settings for different types of plastics. Since material flow is critical in moulding, the book covers rheology and viscosity. High temperature is also discussed as it can lead to poor quality mouldings due to material degradation.

With the widespread adoption of e-mobility, there are high numbers of lithium Ion batteries (LIB) entering the waste stream. It is imperative that disposal and recycling strategies are developed and implemented. There is an urgent need for safe, environmentally friendly and economically affordable disposal routes for End of Life (EoL) LIBs. This study has looked at 44 commercial recyclers and assessed their recycling and reclamation processes. A novel qualitative assessment matrix termed "Strategic materials Weighting And Value Evaluation" (SWAVE) is proposed and used to compare the strategic importance and value of various materials in EoL LIBs. The sustainability and quality of recycled material are assessed by comparing the final form or composition after the recycling processes, the industrial processes and the industry type (primary sector, manufacturer or recycler). SWAVE is applied to each company, producing a score out of 20, with a higher number indicating that more materials can be recycled. The separation processes and resources from six of the prominent recycling companies are discussed further. The majority of recyclers use one or more of mechanical treatment, pyrometallurgy, or hydrometallurgy, concentrating upon high value metal extraction rather than closed-loop recycling of the metals or component materials, highlighting an environmental and technological gap. To improve the current circular economy of batteries reuse and repurposing of materials (closed-loop recycling), instead of purely recycling or recovery of metals should be considered for further development. Further studies of environmental trade-offs from recycling or recovering one material in preference to another is required.

A review of separating methods used in domestic and electric vehicle lithium ion battery recycling is presented, focusing on physical processes which are commonly utilized prior to further chemical processing and purification steps. The four processes of stabilization, disassembly, separation and binder negation are reviewed and the strengths and weaknesses in current research identified. The main limitation with current recycling methods is the comminution step, which mixes, sometimes intimately, the materials from different cell components. This mixed waste stream requires further physical separation, and produces cross contamination in the different material streams. Effective separation of battery components, which produces enhanced purity of waste streams is essential to providing a cost-effective recycling process for direct or “closed loop” recycling. Improvements in the separation process are possible if the materials are separated prior to comminution, to prevent contamination of the different materials streams. In addition to purity of waste streams, one area mostly neglected in the literature is the health and safety implications and hazards associated with the chemicals contained within the cells. Little information is known about the chemical reactions which may occur during the physical separation processes and this has been identified as an area which needs substantially more investigation.

It is predicted there will be a rapid increase in the number of lithium ion batteries reaching end of life. However, recently only 5% of lithium ion batteries (LIBs) were recycled in the European Union. This paper explores why and how this can be improved by controlled dismantling, characterization and recycling. Currently, the favored disposal route for batteries is shredding of complete systems and then separation of individual fractions. This can be effective for the partial recovery of some materials, producing impure, mixed or contaminated waste streams. For an effective circular economy it would be beneficial to produce greater purity waste streams and be able to re-use (as well as recycle) some components; thus, a dismantling system could have advantages over shredding. This paper presents an alternative complete system disassembly process route for lithium ion batteries and examines the various processes required to enable material or component recovery. A schematic is presented of the entire process for all material components along with a materials recovery assay. Health and safety considerations and options for each stage of the process are also reported. This is with an aim of encouraging future battery dismantling operations.