The injection moulding of metal powder is one of the newest processes for producing titanium components. In this research, challenges of fabrication titanium component by low- pressure powder ...injection moulding (LPIM) were studied. A hydride-dehydride titanium powder was kneaded with paraffin wax based binder system in 53 vol% powder loading. Powder-binder was injection moulded using low pressure injection moulding machine to prepare the green part. This process was followed by debinding and sintering. The injection results showed that feedstock with high powder loading was not appropriate for LPIM. The suitable parameters of solvent debinding were obtained from soaking the samples in n-hexane at 60 °C temperature. The open channels were observed in solvent debound components which can help remove the binder in subsequent stages. The hardness and density of the sintered part were 490 HV and 4.11 g/cm3, respectively. Coarse α plates and α/β colonies were observed in the microstructure.
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•The feedstock temperature considerably affects the injection moulding stage.•The hardness and density of the sintered part obtained 490 HV and 4.11 g/cm3.•Coarse α plates and α/β colonies were observed in the microstructure.•The Ti component was manufactured via low pressure injection moulding successfully.
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.
Fused deposition modelling (FDM) in contrast to injection moulding was studied to investigate the effect of processing technique on the mechanical behaviour of virgin ABS. FDM parameters were further ...altered in terms of varying raster angle and gap to further explore the potential of this technique. Results show that an adequate selection of FDM parameters is able to reach mechanical properties comparable to those of injection moulded parts in both static and dynamic loading modes. Here, a negative raster gap proved to be most significant in enhancing mechanical behaviour. A raster angle layup of −45°/+45° proves to offer maximum tensile and impact strength, whereas highest flexural strength was recorded for a 0/90° scaffolding system. In contrast, a positive gap drastically reduces the performance. Dimensional analysis further show no significant alterations of dimensions are to be expected with varying raster angle and gap.
This work focuses on the effective utilisation of varying data sources in injection moulding for process improvement through a close collaboration with an industrial partner. The aim is to improve ...productivity in an injection moulding process consisting of more than 100 injection moulding machines. It has been identified that predicting quality through Machine Process Data is the key to increase productivity by reducing scrap. The scope of this work is to investigate whether a sufficient prediction accuracy (less than 10% of the specification spread) can be achieved by using readily available Machine Process Data or additional sensor signals obtained at a higher cost are needed. The latter comprises Machine Profile and Cavity Profile Data. One of the conclusions is that the available Machine Process Data does not capture the variation in the raw material that impacts element quality and therefore fails to meet the required prediction accuracy. Utilising Machine Profiles or Cavity Profiles have shown similar results in reducing the prediction error. Since the cost of implementing cavity sensors in the entire production is higher than utilising the Machine Profiles, further exploration around improving the utilisation of Machine Profile Data in a setting where process variation and labelled data are limited is proposed.
Titanium (Ti) and its alloys may be processed via advanced powder manufacturing routes such as additive layer manufacturing (or 3D printing) or metal injection moulding. This field is receiving ...increased attention from various manufacturing sectors including the medical devices sector. It is possible that advanced manufacturing techniques could replace the machining or casting of metal alloys in the manufacture of devices because of associated advantages that include design flexibility, reduced processing costs, reduced waste, and the opportunity to more easily manufacture complex or custom-shaped implants. The emerging advanced manufacturing approaches of metal injection moulding and additive layer manufacturing are receiving particular attention from the implant fabrication industry because they could overcome some of the difficulties associated with traditional implant fabrication techniques such as titanium casting. Using advanced manufacturing, it is also possible to produce more complex porous structures with improved mechanical performance, potentially matching the modulus of elasticity of local bone. While the economic and engineering potential of advanced manufacturing for the manufacture of musculo-skeletal implants is therefore clear, the impact on the biocompatibility of the materials has been less investigated. In this review, the capabilities of advanced powder manufacturing routes in producing components that are suitable for biomedical implant applications are assessed with emphasis placed on surface finishes and porous structures. Given that biocompatibility and host bone response are critical determinants of clinical performance, published studies of
and
research have been considered carefully. The review concludes with a future outlook on advanced Ti production for biomedical implants using powder metallurgy.
This paper discusses micromanufacturing process quality proxies called “process fingerprints” in micro-injection moulding for establishing in-line quality assurance and machine learning models for ...Industry 4.0 applications. Process fingerprints that we present in this study are purely physical proxies of the product quality and need tangible rationale regarding their selection criteria such as sensitivity, cost-effectiveness, and robustness. Proposed methods and selection reasons for process fingerprints are also justified by analysing the temporally collected data with respect to the microreplication efficiency. Extracted process fingerprints were also used in a multiple linear regression scenario where they bring actionable insights for creating traceable and cost-effective supervised machine learning models in challenging micro-injection moulding environments. Multiple linear regression model demonstrated %84 accuracy in predicting the quality of the process, which is significant as far as the extreme process conditions and product features are concerned.
Freeform injection moulding is a novel technology for powder injection moulding where a sacrificial 3D printed mould (i.e., a soft tooling) is used as an insert in the injection process. The use of ...3D printed moulds enable a higher geometrical design flexibility as compared to the conventional injection moulding process. However, there is still very limited knowledge on how the sacrificial soft tooling material and powder suspension handles the increased geometrical complexity during the process. In this study, a stainless steel powder suspension is injected into a geometrically challenging sacrificial mould (viz. a helix structure) that is produced by vat photopolymerization additive manufacturing. Computed tomography is used to quantify the geometrical precision of the mould both before and after injection. In addition, a new numerical model that considers the suspension feedstock is developed to investigate the powder injection moulding process. The numerical results are found to be in qualitative good agreement with the experimental findings in terms of pinpointing critical areas of the structure, thereby highlighting a new pathway for evaluating sacrificial inserts for powder injection moulding with a high geometrical complexity.
•The quick heating rate in thermal debinding resulted in the CuO precipitate.•The CuO precipitation was associated with the small amounts of remaining binders.•The quick heating rate in themal ...debinding resulted in the intergranular fracture.•The slow debinding (0.6 °C/min) improved bending strength and magnetic properties.
NiCuZn ferrite ceramics were prepared by injection molding, debinding and sintering at 1150 °C. The effects of heating rate in thermal debinding on microstructure, bending strength and magnetic properties of sintered samples were investigated by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, the Dual Column Tabletop Testing Machine, RF impedance Analyzer and B-H curve analyzer. The results showed the heating rate in thermal debinding played an important role on the sintered NiCuZn ferrite prepared by injection molding. When the heating rate in thermal debinding was quick above 1.2 °C/min in the lager cuboid samples, CuO precipitate was found at the grain boundary of ferrite and the intergranular fracture occurred, which was different from the normal transgranular fracture under the condition of slow heating rate. Furthermore, the density, bending strength, permeability and core loss of the sintered samples were improved with the decrease of heating rate. The influencing mechanism of thermal debinding on the difference was also discussed.
Metal Injection Moulding (MIM) is a well-developed net or near-net shape manufacturing technique for stainless steel, copper and other metallic materials. This process has also received increasing ...attention over the last decade as a promising technique for the manufacture of small and intricate titanium parts for a range of applications in biomedical, aerospace, automotive and other industries. Historically, the necessity to use expensive fine spherical (<45μm), low-oxygen titanium powder has hindered the industrial application of titanium MIM from an economic perspective. However, recent efforts have shown promise in adapting low-cost non-spherical hydride-dehydride (HDH) titanium powder to the MIM process. HDH powder is considerably less expensive than fine spherical powder and thus there is significant potential in expanding the application of titanium MIM. This paper reviews recent developments in MIM of titanium and its alloys as well as the outstanding challenges with a special focus on MIM of HDH titanium powder.
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•Latest progress in MIM of Ti and its alloys•Fundamental issues for this process•Review on application of MIM of Ti
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