Nozzle Clogging Research Articles

Parameter Tuning for Sustainable 3D Printing (3DP) of Clay Structures

Due to high carbon emissions, traditional construction methods are often costly, resource-intensive, and environmentally harmful. This study investigates the potential of additive manufacturing (AM) or 3D printing (3DP) using earthen clay as a sustainable alternative for building structures. Despite its promising benefits, challenges such as water/clay ratio, nozzle clogging, and temperature variations hinder widespread adoption. Employing the design of experiment (DOE) approach, this research systematically optimizes 3DP parameters, including nozzle diameter, layer height, infill percentage, and printing speed, using commercial earthen clay. Chemical compositions are analyzed using X-ray photoelectron spectroscopy (XPS) and energy-dispersive spectroscopy (EDS). Quantitative analysis compares measured dimensions of 3DP structures to assess dimensional accuracy, while buildability assessments explore structural integrity. Results indicate that lower layer heights generally enhance dimensional accuracy, with larger nozzle diameters enabling faster printing speeds. ANOVA analysis reveals significant relationships between printing parameters and dimensional outcomes, emphasizing the importance of 3DP process parameters selection. Optimal printing parameters lead to high-quality prints, although with limitations in scalability. This research contributes valuable insights for stakeholders seeking sustainable 3DP practices in construction, paving the way for more environmentally friendly and cost-effective building solutions.

CFD Investigation of a Co-Flow Nozzle for Cold Spray Additive Manufacturing Applications

This current work evaluates the efficacy of a co-flow nozzle for cold spray applications with the aim of mitigating nozzle clogging issues, which can occur during long-duration operations, by replacing the solid wall of a divergent nozzle section with an annular co-flow fluid boundary. Simulations were conducted on high-pressure nitrogen flowing through convergent–divergent (C–D) axisymmetric nozzles, with a stagnation pressure of 6 MPa and a stagnation temperature of 1273 K. In these simulations, Inconel 718 particles of varying sizes (15 µm to 35 µm) were modeled using a 2-way Lagrangian technique, and the model’s accuracy was confirmed through validation against experimental results. An annular co-flow nozzle with a circular cross section and straight passage covering the primary C–D nozzle has been designed and modeled for cold spray application. Co-flow was introduced to the reduced nozzle length to compensate for particle velocity loss at higher operating conditions. It was found that co-flow facilitates momentum preservation for primary flow by providing an annular gas boundary, resulting in increased particle speed for a longer axial distance beyond the nozzle exit of the reduced divergent length nozzle. The particle acceleration performance of the reduced divergent section nozzle, when combined with co-flow, is comparable to the original length nozzle.

Fabrication of PVDF/TiO2@CQDs photocatalytic films by ink-jet printing for dye degradation under visible light

PVDF/TiO2@CQDs hybrid photocatalytic thin films were prepared by ink-jet printing. The printing ink was prepared with the TiO2, TiO2(s)@CQDs (surface composite), and TiO2(i)@CQDs (situ doping) nanoparticles as precursors, respectively. Compared to TiO2(s)@CQDs, TiO2(i)@CQDs has a smaller particle size (about 10.01 nm) and a narrower particle size distribution (6∼14 nm), which can improve the photocatalytic effect while avoiding nozzle clogging. The PVDF/TiO2(i)@CQDs hybrid film exhibited a high degradation efficiency (η) of 93.71 % for Rhodamine B (RhB) within 150 min under visible light with a catalyst load of only 0.49 wt%. The reaction rate constant (ks) of the PVDF/TiO2(i)@CQDs film was about 4.3 times higher than that of the PVDF/TiO2(s)@CQDs film. The small particle size of this S-scheme TiO2(i)@CQDs heterostructure nanoparticle and the more effective contact interface formed between TiO2 and carbon quantum dots (CQDs) further facilitated electron transfer and enhanced photoactivity. The firmly immobilized catalysts on the Polyvinylidene fluoride (PVDF) film substrate through Ti-F coordination bonds ensured the reusability and stability of the photocatalytic film (the η of RhB still reached 88.05 % after 10 consecutive cycles). This work provides a new strategy for the application of ink-jet printing technology in photocatalysis.

Development and Outlook for the FDM Printed Nozzle Structure

Abstract:: The nozzle is one of the parts of a 3D printer that cannot be missed because of its widespread popularity in recent years. The nozzle's structure determines the quality of the printed product; therefore, selecting a suitable nozzle structure is crucial. With the advancement of 3D printing technology in recent years, 3D printers have progressively come under investigation. Examining the design of the nozzle, feeding mechanism, and printing platform can help to increase the quality of the prints. The design and enhancement of the nozzle structure are beneficial to the advancement of 3D printing technology since it is one of the key elements influencing print quality. Using the research methods, research content, and invention structure of the most recent representative patents on this nozzle structure, the features and operating principle of the 3D printed nozzle structure are illustrated. To classify and examine the nozzle temperature and nozzle clogging that impact the nozzles, a patent analysis of various types of 3D printing nozzle structures is carried out. Future trends in 3D printing nozzle structures are also covered. The issues caused by nozzle work can be resolved to increase product quality and precision by comparing various 3D printing nozzle structures. This will also lead to the invention of more relevant patents in the future, including those about printing numerous nozzles and high-strength metals.

Adhesive and alloying properties of dual purpose polyfurfuryl alcohol binder for binder jet additive manufacturing of steel

In-situ alloying in steel can be achieved in the binder jet additive manufacturing process by incorporating alloying elements into the binder. However, using binders with nanoparticle suspensions often leads to challenges with particle dispersion uniformity and nozzle clogging. To circumvent these limitations, we investigated the feasibility of using a particle-free binder based on poly(furfuryl alcohol) (PFA) for binder jet 3D printing of steel. The PFA binder serves dual purposes – (i) imparting structural integrity to the as-printed green part and (ii) providing carbon upon pyrolysis to alloy the printed iron parts into steel. The PFA binder was first dispensed layer-by-layer into a low alloy steel powder bed to produce green parts with a storage modulus of 3360 MPa and a compressive strength of up to 9 MPa. Compared to the control, a commercial carbon binder ink, the present particle-free PFA formulation offered better green part rigidity (+18%) and strength (+18.5%) for the same amount of carbon alloying. The green parts were then subjected to debinding and sintering to consolidate the steel powder particles. During vacuum sintering, the PFA was pyrolyzed and left behind a carbon residue which diffused into the steel part to form a hard and strong ferrite-carbide aggregate phase that significantly enhanced the hardness, yield strength and ultimate tensile strength of the sintered steel parts. Furthermore, by varying the amount of this particle-free binder formulation at different locations, components with site-specific microstructures and mechanical responses, confirmed through hardness tests and digital image correlation, were also demonstrated.

Precise control of atomization initial stage to address nozzle clogging issue in the vacuum induction-melting gas atomization process

Vacuum induction-melting gas atomization (VIGA) is considered a widely applied method to prepare metal powders. However, the nozzle clogging problem in the VIGA process seriously affects the continuity of production and greatly increases the economic and time costs. In the atomization initial stage, the existence of unsteady state atomization mainly results in the nozzle clogging challenge. To understand the formation mechanism of nozzle clogging, a computational fluid dynamics (CFD) model was established to simulate the influence of unsteady state atomization sequence on the primary atomization of alloy melt. Typically, there are two kinds of sequence including starting the gas before pooling the alloy (namely, GA) and pouring the alloy before opening the gas (AG). The movement trajectory of the alloy melt droplet at the end of the delivery-tube was clarified. Based on CFD simulation, the atomization sequence of AG and GA was precisely controlled in the atomization pressure range of 2.5 MPa, 3.5 MPa, and 4.5 MPa to address the nozzle clogging issue. In the GA process, relatively finer powder was obtained at 3.5 MPa without nozzle clogging occurring. In contrast, the AG process greatly reduces the probability of nozzle clogging at 2.5–4.5 MPa, the final prepared powder is coarser. The predicted results of industrial experiments and numerical simulations are consistent. This study provides theoretical support for understanding the formation mechanism of nozzle clogging during the VIGA process.

A Review of Print Heads for Fused Filament Fabrication of Continuous Carbon Fiber-Reinforced Composites.

The print head is one of the most critical components in an additive manufacturing (AM) system. It can significantly affect the quality of printed parts. Recently, because continuous carbon fiber-reinforced composites can have excellent mechanical properties, a relevant AM technique, fused filament fabrication (FFF), has been attracting increasing attention. This has extended the requirements demanded of print heads. To this end, different FFF extrusion methods have been rapidly developed based on various methods of impregnating fibers into the matrix for the corresponding print heads. Generally, these extrusion methods are of three types: single extrusion, in situ extrusion, and dual extrusion. All these methods face substantial challenges, such as the nozzle clogging and damage to the continuous carbon fibers during extrusion. These common issues still need to be fully addressed. This study's aim is to summarize and discuss the different extrusion methods and their FFF specific components in terms of their advantages and disadvantages for continuous carbon fiber-reinforced composites.

In situ Synthesis of Single Layered Metal-Organic Frameworks via Inkjet Printing on a Cellulose Nanofiber Film.

The inkjet printing is a simple method to develop pattern-controlled 2D metal-organic frameworks (MOFs) due to its cost-effectiveness and ease of operation. Despite the sophisticated structures of MOF crystals, the MOF surfaces are easily contaminated by the adsorption of an ink solution, and the printing nozzle can be clogged by the aggregates of MOFs during printing. Unlike the mixture inks of MOFs and a carrier medium, the surface-specific patterning by in situ synthesis provides the film surface with the controlled patterns of an MOF single layer having different morphologies of MOFs without changing the ink cartridges. It enables facile printing due to the low viscosity of inks and escapes the risk of nozzle clogging because MOFs are synthesized at the printed patterns on the substrates. The ion-exchanged cellulose nanofiber (CNF) films form strong coordination with metal ions enhancing the stability of the MOFs on the film surface. It also demonstrates the controlled coverage of the MOFs by the printing pass number and the carboxylate content of CNF and the tunable adsorption of the guest molecules for different loading capacities of the printed patterns.

Primary and secondary breakup of molten Ti64 in an EIGA atomizer for metal powder production

Electrode Induction melting Gas Atomization (EIGA) is a free-fall gas atomization process used to produce metal powders, where a swirling supersonic gas jet hits a molten metal stream atomizing it into droplets through various fragmentation mechanisms. Fragmentation mechanisms of molten Ti64 are investigated by high-speed video visualization. The role of gas pressure and melting chamber overpressure on the fragmentation mechanisms and on the particle size distribution is determined. The mechanisms observed are fiber breakup, bag breakup and Rayleigh breakup for primary fragmentation and bag breakup and shear breakup for secondary fragmentation. Increasing the gas pressure promotes shear breakup and creates finer droplets. A model based on log-stable law is proposed to fit the mass distribution according to the dominant fragmentation regime. A good agreement is observed between the different analysis (dominant atomization regime, mass cumulative distribution evolution, parameters of log-stable law). A criterion for prediction of nozzle clogging is devised.

Nozzle-Free Printing of CNT Electronics Using Laser-Generated Focused Ultrasound.

Printed electronics have made remarkable progress in recent years and inkjet printing (IJP) has emerged as one of the leading methods for fabricating printed electronic devices. However, challenges such as nozzle clogging, and strict ink formulation constraints have limited their widespread use. To address this issue, a novel nozzle-free printing technology is explored, which is enabled by laser-generated focused ultrasound, as a potential alternative printing modality called Shock-wave Jet Printing (SJP). Specifically, the performance of SJP-printed and IJP-printed bottom-gated carbon nanotube (CNT) thin film transistors (TFTs) is compared. While IJP required ten print passes to achieve fully functional devices with channel dimensions ranging from tens to hundreds of micrometers, SJP achieved comparable performance with just a single pass. For optimized devices, SJP demonstrated six times higher maximum mobility than IJP-printed devices. Furthermore, the advantages of nozzle-free printing are evident, as SJP successfully printed stored and unsonicated inks, delivering moderate electrical performance, whereas IJP suffered from nozzle clogging due to CNT agglomeration. Moreover, SJP can print significantly longer CNTs, spanning the entire range of tube lengths of commercially available CNT ink. The findings from this study contribute to the advancement of nanomaterial printing, ink formulation, and the development of cost-effective printable electronics.

A Novel Powder Addition Method for Improving Tensile Strength of Polylactic-Acid Prepared by Using Fused Filament Fabrication (FFF)

Although Fused Filament Fabrication (FFF) technology has gained popularity and is used extensively since the last decade, the low mechanical properties of the resulting product have been recognized as the major limitation of this technique. The anisotropic nature of the printed products due to the layered structure and many cavities that are present inside the printed parts are among the main causes of this problem. In this study, the powder addition reinforcement (PAR) method had been developed by introducing reinforcing powder into the polylactic acid (PLA) as the base material during the printing process so that nozzle clogging can be avoided and powders can be placed between the layers. In this work, iron oxide nanoparticles (Fe2O3) were used as a reinforcing powder. The addition of this powder was carried out by using two methods, namely brushing and compressed air-assisted techniques. The results showed that the compressed-air assisted technique demonstrated better results in terms of mechanical properties. In this case, the tensile strength of the composite with the compressed-air assisted technique was higher by 28.95% than that of the PLA and by 5.53% - 25.2% than that of the brushing method. Finally, this study showed that the compressed air-assisted method is the potential to be developed in the future as a powder addition reinforcement technique in the FFF process.

Determination of fan height based on FDM nozzle temperature field analysis—an example of babbitt alloys

In this paper, the phenomenon of nozzle clogging or drooling droplets in the process of FDM metal 3D printing of tin-based Babbitt alloys was evaluated by simulation to assess the effects of different heights of cooling fans on the printer’s nozzle cooling module, and the optimal height of the fans was determined. Based on the thermal analysis results, a thermodynamic coupling analysis was carried out to analyze the thermodynamic changes of the nozzle at a given temperature. Finally, the printing trials of tin-based Babbitt alloy were carried out using self-developed forming equipment to verify the accuracy of the theory. The results show that the print quality can be effectively improved by controlling the heat dissipation module of the printer nozzle. The printed material exhibited a uniform and fine microstructure in the 3D printing trials of tin-based Babbitt alloy.

Study on the Causes and Control Measures of Mg–Al Spinel Inclusions in U75V Heavy Rail Steel

U75V heavy rail steel production uses an aluminum-free deoxidation process; however, large particles of MgO–Al2O3 inclusions form in the steel, which has a great impact on product quality. In this paper, we try to explain how spinel inclusions, which affect the metallurgical quality of heavy rail steel, are produced by thermodynamic and experimental methods, and then determined measures for avoiding such inclusions. The formation mechanism of spinel inclusions in U75V heavy rail steel was determined through the analysis of nozzle clogging in the pouring process and typical inclusions in steel. The results show that there are two types of spinel inclusions in heavy rail steel: one is pure Mg–Al spinel inclusions and the other is Mg–Al spinel inclusions coated with calcium aluminate. The small, pure Mg–Al spinel inclusions were precipitated during the solidification of the molten steel, and the precipitation temperature was related to the composition of the molten steel. The large spinel inclusions were derived from clogging of the submersed nozzle. Mg–Al spinel inclusions coated with calcium aluminate were transformed from CaO–SiO2–Al2O3–MgO complex inclusions in the steel during cooling, and the formation temperature was related to the content of Al2O3 and MgO in the inclusions. The content of Al2O3 and MgO in the inclusions was the key to the formation of the Mg–Al spinel inclusions. Therefore, in order to control the production of spinel inclusions in steel, it is necessary to strictly control the content of impurity elements such as magnesium and aluminum in the alloy auxiliary materials, to reduce the secondary oxidation of liquid steel and to reduce the erosion of refractory materials.

Effect of Nozzle Clogging on Bubble Movements and Slag Behaviors in a Slab Mold

Effect of Nozzle Clogging on Bubble Movements and Slag Behaviors in a Slab Mold

The Influence of Spraying Parameters and Powder Sizes on the Microstructure and Mechanical Behavior of Cold-Sprayed Inconel®625 Deposits

Cold spraying (CS) of high-strength materials, e.g., Inconel®625 is still challenging due to the limited material deformability and thus high critical velocities for achieving bonding. Further fine-tuning and optimization of cold spray process parameters are required, to reach higher particle impact velocities and temperatures, while avoiding nozzle clogging. Only then, sufficiently high amounts of well-bonded particle–substrate and particle–particle interfaces can be achieved, assuring high cohesive strength and minimum amounts of porosities. In this study, Inconel®625 powder was cold sprayed on carbon steel substrates, using N2 as propellant gas under different spray parameter sets and different powder sizes for a systematic evaluation. Coating microstructure, porosity, electrical conductivity, hardness, cohesive strength, and residual stress were characterized in as-sprayed condition. Increasing the process gas temperature or pressure leads to low coating porosity of less than 1% and higher electrical conductivity. The as-sprayed coatings show microstructures with highly deformed particles. X-ray diffraction reveals that powder and deposits are present as γ-solid-solution phase without any precipitations. The deposits show high microhardness and compressive residual stresses, which is attributed to work hardening and peening effects. The optimized deposits reach almost bulk material properties and are thus well suited for industrial applications.

Boron‐polymer composites engineered for compression molding, foaming, and additive manufacturing

AbstractBoron (specifically 10B) is the element of choice to shield thermal neutrons due to its large (n, α) cross‐section; however, very few polymer composites containing high boron concentrations are available. This study aimed to determine the maximum possible amount of boron that could be introduced into a polymer matrix. Diverse manufacturing techniques, ranging from additive manufacturing to compression molding, were employed to fabricate inks and filaments for 3D printing, foams, and flexible pads. Composites using siloxanes, poly(lactic acid), and acrylonitrile butadiene styrene containing up to 80 wt% boron were sucessufully fabricated. The addition of known plasticizers (polyethylene glycol) and reinforcing agents (carbon nanofibers and fumed silica) helped to overcome fabrication problems such as clogging of the printing nozzle or crumbling of compression molded parts. In addition, the thermal‐mechanical properties of these novel boron composites were determined and shown to vary according to boron concentration, presence of additives, and fabrication techniques utilized.

Formation and Prevention of Nozzle Clogging during the Continuous Casting of Steels: A Review

Formation and Prevention of Nozzle Clogging during the Continuous Casting of Steels: A Review

Synthesis and Characterization of Ti3C2Tx Mxene for Flexible Current Collectors Fabricated through Inkjet Printing

Two-dimensional (2D) materials, as transition-metal carbides and/or nitrides (MXenes), have recently gained great attention due to their combination of electrochemical, electrical and mechanical properties, which can be tailored for the specific application by controlling the chemical composition. As a consequence, MXenes find applications in many fields as energy storage, sensing, photocatalysis and many more [1].MXenes are obtained by selective etching of a precursor layered material, known as MAX phase, and characterized by the general formula Mn+1XnTx, where M is a transition metal with n =1-4, X represents carbon and/or nitrogen atoms and Tx represents surface terminations of different nature (-O, -OH, -F and -Cl). The latter aspect is the one responsible for one important property related to the hydrophilicity of MXenes, which allows easy processing in water and/or solutions [2]. This aspect is particularly attractive for inkjet processing, as an easy water-based ink can be formulated. In addition, in aqueous solutions Ti3C2X flakes are negatively charged allowing the development of additive-free conductive inks.Ultimately, the MXenes extremely high conductivity is particularly attractive for final application as flexible current collector for lithium-ion batteries. The current collector can be considered as a bottleneck, especially when considering substrates selection, i.e. flexible/wearable substrates. Different silver or copper nanoparticles inks are commercially available, but they do require high curing temperatures, which are incompatible with plastic-based substrates, in order to reach the desired electrical conductivity. Another option is carbon-based inks, which despite being more cost-effective, they have limitations in terms of moderate electrical conductivity, which affects the Ohmic losses, and so the overall performance, of the battery device [3].Inkjet printing fabrication requires specific ink properties, in order to ensure a clogging-free condition, in terms of viscosity and surface tension of the ink. Generally, a clogging-free jetting is also forecast when particle size dimension is between 1/100 < d < 1/50 of the nozzle diameter [4]. This is a particularly meaningful aspect when considering MXene-based inks, as flake size should be finely controlled in order to avoid large or multilayered flakes, which can favor nozzle clogging. However, too small flakes can compromise the final electric conductivity.In this study, we provide an in-depth characterization of Ti3C2X MXene synthesis. The as-produced material will be characterized in terms of flake dimensions and electrical conductivity. IJP ink compatibility generally requires adjustments in terms of rheological and physical properties. Once chosen the optimal method, the Ti3C2X aqueous-based ink will be printed to obtain current collectors for lithium-ion batteries, which will be characterized from a morphological, electrical and electrochemical point of view. Preliminary study studies on inkjet printed full cell LTO/LFP were already obtained at the coin level. Flexible LTO/LFP full cell exploiting innovative Ti3C2X MXene current collector will be printed. Morphological and electrical analysis combined with an in-depth electrochemical characterization will be performed to demonstrate the battery device performances retention under different degrees of bending of the device.[1] M. Shekhirev, C. E. Shuck, A. Sarycheva, Y. Gogotsi, Progress in Materials Science 2021, 120, 100757.[2] K. Maleski, C. E. Ren, M.-Q. Zhao, B. Anasori, Y. Gogotsi, ACS Appl. Mater. Interfaces 2018, 10, 24491.[3] S. Uzun, M. Schelling, K. Hantanasirisakul, T. S. Mathis, R. Askeland, G. Dion, Y. Gogotsi, Small 2021, 17, 2006376.[4] Z. Tang, K. Fang, M. N. Bukhari, Y. Song, K. Zhang, Langmuir 2020, 36, 9481.

Advanced Additive Manufacturing of Structurally-Colored Architectures.

Direct ink writing (DIW) stands out as a facile additive manufacturing method, minimizing material waste. Nonetheless, developing homogeneous Bingham inks with high yield stress and swift liquid-to-solid transitions for versatile 3D printing remains a challenge. In this study, high-performance Bingham inks are formulated by destabilizing silica particle suspensions in acrylate-based resin. A colloidal network forms in the shear-free state through interparticle attraction, achieved by disrupting the solvation layer of large resin molecules using polar molecules. The network is highly dense, with evenly distributed linkage strength as monodisperse particles undergo gelation at an ultra-high fraction. Crucially, the strength is calibrated to ensure a sufficiently large yield stress, while still allowing the network to reversibly melt under shear flow. The inks immediately undergo a liquid-to-solid transition upon discharge, while maintaining fluidity without nozzle clogging. The dense colloidal networks develop structural colors due to the short-range order. This enables the rapid and sophisticated drawing of structurally-colored 3D structures, relying solely on rheological properties. Moreover, the printed composite structures exhibit high mechanical stability due to the presence of the colloidal network, which expands the range of potential applications.

Towards a predictive understanding of direct ink writing of graphene-based inks

Direct ink writing (DIW) presents a flexible and resource-efficient approach towards the prototyping of functional materials and devices with complex shapes. Printed functional materials for electronic devices depend on conductive fillers such as graphene nanoplatelets (GNPs), which are increasingly popular in printed electronics and energy materials thanks to their low cost, non-toxicity and high specific surface area. However, non-spherical colloids with large filler-to-nozzle size ratios like GNPs present a challenge for high-resolution DIW due to risk of nozzle clogging. As DIW of platelet-based inks is gaining traction in several fields, the feasibility of high-resolution DIW of platelet-based inks is demonstrated here on the example of GNPs (< 50 μm). A workflow for the combined optimization of ink rheology and printing process parameters was developed to gain a predictive understanding of filament quality and morphology. Using two inks and two nozzle diameters per ink, filaments ranging from <100 – 1200 μm in width and 30 – 300 μm in height were produced, with conductivities suitable for application in sensors or electrodes. The derived predictive models were successfully deployed to predict filament dimensions and to achieve excellent print quality even for fine sub-nozzle size structures with very high filler-to-nozzle size ratios within only one iteration of the workflow. With this study, we advocate for the integrated development of materials for processes and processes for materials. This study will benefit high-resolution rapid prototyping of a large class of functional materials for wearable electronics, sensors, RF passives, energy materials and tissue engineering.