Hot Nozzle Research Articles

The influence of the raster angle on the dimensional accuracy of FDM-printed PLA, PETG, and ABS tensile specimens

3D printing is a rapidly advancing method in digital manufacturing techniques and produces objects in layers. Fused Deposition Modelling (FDM) is a 3D printing technology where the material is melted in a hot nozzle and then placed on a build platform to create a prototype layer by layer. In this study, the effects of different raster angles (0°, 45°, 90°, 45°/-45°, 0°/90°) on dimensional accuracy for PLA, PETG and ABS materials produced using FDM were investigated. The results show that PETG generally shows higher dimensional deviations compared to PLA and ABS, and samples with a scan angle of 90° generally have lower deviation percentages than other angles. Width deviations (approximately 1.5% on average) were lower than thickness deviations (approximately 9.5% on average). Analysis of the cross-sectional areas shows that all samples are above the theoretical area (41.6 mm2). PETG samples with a scan angle of 45°/-45° exhibit the largest cross-sectional area (46.78 mm2), while ABS samples with a scan angle of 90° exhibit the smallest (45.46 mm2). This study is important to understand the impact of material selection and raster angle on dimensional accuracy, and it is recommended to account for cross-sectional deviations and calculate the stress based on the actual cross-sectional area to achieve more accurate results in applications requiring precise measurements. These data offer valuable information for those interested in 3D printing and its professionals and can lead to further research in this field, so that printing techniques can be further developed and product quality can be improved.

Numerical Simulation of Deformation in Hot Runner Manifold.

This study simulated the deformation of a hot runner manifold and nozzle assembly during operation, aiming to address potential leaks and premature failure. Both thermal and mechanical models were used simultaneously to accurately capture system behavior. A simplified set of boundary conditions was proposed for efficient problem-solving. Analysis of the simulation results revealed that thermal deformation posed a risk of catastrophic failures and leaks. Deformation from melt pressure was relatively small compared to thermal loading, not exceeding 12%. The study provided design recommendations based on the simulation findings, guiding the development of hot runner systems for improved reliability.

Numerical study of post-combustion characteristic in a smelting reduction furnace

Abstract For a smelting reduction furnace, the main role of the post-combustion operation in the upper space is to supply the energy required by the endothermic reduction reaction of iron oxide occurring in the melt bath, and thus the post-combustion behavior is important in the respect of reducing the coal consumption. In this paper, based on a developed 3D model composed of the Realizable k–ε model and DO radiation model, the post-combustion characteristics in a smelting reduction furnace was studied by numerical simulation, and the effects of top lance height, top-blown hot air flowrate and nozzle inclination angle of top lance on the flow and temperature fields, CO content distribution in the upper space were investigated. The results show that with the increase of top lance height, the length and temperature of combustion flame in the upper space increase, which is beneficial to expanding the post-combustion zone and improving the post-combustion of CO gas. And as the top-blown hot air flowrate increases, the position of the maximum temperature in the upper space gradually moves down and the CO content in gas mixtures decreases, which is conducive to the heat transport back to the melt bath. In addition, a proper velocity and temperature distribution in the upper space and distribution of CO content is obtained under the nozzle inclination angle range from 10° to 15°, but a larger nozzle inclination angle reduces the velocity and temperature in the central zone.

Mechanical performance and supermolecular morphology of void free polypropylene manufactured by fused filament fabrication

AbstractIt is known from the literature that freedom from macroscopic defects (voids) is an essential prerequisite for good mechanical properties of 3D‐printed components manufactured using fused filament fabrication. The present study further shows that the morphology and mechanical properties of void free components are significantly influenced by the choice of process parameters. Components that were printed at low temperatures and high speeds show fair and inhomogeneous supermolecular morphology, clearly visible weld seams and a special flow‐induced staggered structure of the individual strands laid‐up. At higher magnification in the optical microscope, transcrystalline structures are visible starting from the contact area between the strands, that is, crystallization has started at the interface between the strands and is moving forward towards the center of the strands. In contrast, the samples printed at high temperatures and low speeds show a homogeneous supermolecular morphology with overall larger spherulites and a higher degree of crystallinity and compared to the specimens printed with the low temperature/high speed‐set much better mechanical properties. A numerical simulation of the temperature at the contact point of the strand emerging from the hot nozzle and the cooled strand neighbor agrees well with the measured behavior. The thermal simulation thus enables the temperature to be calculated at any point in time in the welding contact and thus access to the local thermal conditions during joining, cooling and the formation of the morphology.

ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ РАБОТЫ ГЕНЕРАТОРОВ ГОРЯЧИХ ГАЗОВ ПРИ ОБОГРЕВЕ АГРЕГАТОВ АВТОТРАКТОРНОЙ ТЕХНИКИ

Hot gas generators are used as a source of thermal energy for pre-start preparation of motor vehicles in cold climatic conditions. Their wide application is due to the high thermal power and safety. (Research purpose) The research purpose is in determining the possibilities of using thermoelectric modules to reduce the energy consumption of the battery by hot gas generators. (Materials and methods) Authors used research methods based on the application of standard techniques, while the object of research was the power supply system of a thermal energy source. (Results and discussion) Authors conducted research on ways and methods to reduce the electric consumption of a hot gas generator by recuperating thermal energy into electrical energy using thermoelectric generator modules. The thermoelectric converters installed on the heat pipe of the hot gas generator, due to the high temperature difference, will allow to obtain a high value of the electromotive force. Modeling of the nozzle in the software package of the Ansys three-dimensional modeling system showed that part of the heat energy goes through the surface of the heat pipe. The article proposes the use of a nozzle with a thermoelectric converter installed on the outer surface of the cylinder instead of a heat pipe. The article presents the mathematical model of an improved hot gas generator nozzle. (Conclusions) The use of a thermoelectric converter for the utilization of thermal energy and the replacement of energy losses of the battery, which feeds the hot gas generator, will reduce the internal power losses of the battery and increase the technical readiness of automotive equipment. The introduction of a comprehensive heat treatment system, which is intelligently and functionally linked to a remote monitoring system, will significantly increase the service life of the units most exposed to temperature influences.

Control plastic pellet feeding double extruders for 3D printing symmetric bilateral

Three Dimensional Printing (3DP) is one of the technologies that support industry 4.0. One of the common 3DP technology is FFF (fused filament Fabrication), the technology is also known as Fused Deposition Modelling (FDM). In this case, extrusion thermoplastic through a hot nozzle with certain melting temperature. The extrusion machine (extruder) will melt the plastic pellet and push the pellet through a heating zone that has a different temperature and pushed out by a screw to the nozzle to be printed into objects. This research aims, to make a control innovation for plastic pellet feeding double extruders. Those extruders for a bilateral 3DP symmetrically to print an object with a size of 2000x2000x2000mm using FDM method. The research simulation results showed that the extruder melts the plastic pellets with a temperature of melting is 200°C, temperature controlled by PID. In this research using 4mm plastic pellets diameter polyethylene high density (HDPE). The double extruders is controlled by two stepper motors Y- and Y+ axis with speed 70mm/s, on 2mm nozzle diameter. The extruder can be produce 110mm melted plastic filaments in 250 steps.

Finite element analyses of the effect of weld overlay sizing on residual stresses of the dissimilar metal weld in PWRs

Dissimilar metal welds are commonly used in various types of reactors to connect low alloy steel nozzles and austenitic stainless steel piping systems. To mitigate the degradation of stainless steel pipe welds that are affected by intergranular stress corrosion cracking in BWRs, weld overlays have been implemented to provide the structural reinforcement. They have also been applied to repair dissimilar metal welds at nozzles in BWRs and PWRs. A weld overlay can favorable reverse residual stresses from tensile to compressive around interior of the susceptible materials. The ASME Code Case N-504 series suggest that the evaluation of repaired welds should consider residual stresses that are generated by the weld overlay with other applied loads on the system. This study considers a dissimilar metal weld that joins the low alloy steel nozzle to the stainless steel safe end in a typical PWR, and is to calculate the post-overlay residual stress states using ANSYS finite element analysis software. Based on the stress report and site survey of the hot leg nozzle, models for analyzing residual stresses were developed on various assumptions. Computational results demonstrate that the weld overlay process probably provides compressive distributions of axial and hoop residual stresses at the inside surface of the dissimilar metal weld. The residual stress distributions that are induced by weld overlays of various sizes are compared to determine the effect of weld overlay sizing on the residual stresses in the original weld. The comparison reveals that weld overlay length has a greater effect on residual stresses than weld overlay thickness. As the applied overlay length increases, the compressive residual stresses increase markedly. Each nozzle/safe end design is somewhat unique; using a feasible weld overlay dimension in consideration of technical and economic is necessary. This investigation has provided a reference for optimizing the weld overlay design of dissimilar metal welds in PWRs.

Direct Filament Dryer With Moisture And Dust Absorbent For 3D Printing Plastic Filaments

Industrial Revolution 4.0 requires every line of life to apply technology, especially in the field of prototyping. 3D PrintingFDM (Fused Deposition Modeling) technology is used for the needs of rapid prototyping. The plastic filament material is the main requirement in printing FDM or FFF (Fused Filament Fabrication). However, there are poor print quality problems in this storage process because all types of plastic filaments used in this 3D printing technology are affected by moisture and dust. The moisture of the plastic filament can be seen if there is a hiss in the printing process and the surface of the printing result becomes rough. At the same time, the dust on the filament will clog the hot end nozzle. Current 3D printing technology is used to reduce this problem by storing filaments in the filament box dryer. However, this storage has several drawbacks. It is less efficient and practical because the filament box can only hold one of the plastic filament rolls. From this problem, we tried to create "Direct Filament Dryer with Moisture and Dust Absorbent for 3D Printing Plastic Filaments". The principle of this tool is to put the filament into the heating chamber. This room contains silica gel as a damper for moisture and a sponge to clean the dust on the filament's surface. The heating room temperature is controlled by a thermostat, which will keep the temperature between 40-50 °C. This research uses R&D techniques with the 4D method, namely, Define, Design, Develop, and Disseminate. Meanwhile, to test the results of this research by comparing the printing results between plastic filaments that are allowed to become damp and dusty with technology. Therefore, it was concluded that using made the filament surface smooth without any rough parts.

Design and Fabrication of Less Cost and Efficient Delta 3D Printer Parts

This project is to fabricate the most essential parts of Delta type 3D printer parts so as to make it more efficient in cost and working. This project has 3 vital parts of a 3D printer and they are Effector, Rod end bearings, Connecting rod (Diagonal rod). The Effector is a component that holds the hot end nozzle and other heat dissipating material within it and we in our project made a multi utility Effector so as to hold many hot ends such as Laser cutting, CNC tool, Food extrusion and 3D printing hot end. This Effector is also categorized into two as uphold and bottom hold since uphold and down hold. Rod end bearings are the motion transmission bearings that would transmit motion in a spherical path. We have made a different mechanism to transmit the motion same as to rod end bearing by coupling two universal joints and making some modification in it and made it cheaper in cost and efficient in working process. The connecting rod is the linking rod between the carriage and the effector. This connecting rod is used to transmit the motion from the carriage to the effector and this works in accordance to the design imbedded on the printer. The conventional 3D printer has carbon fibre pipes as their connecting rod and in this project this connecting rod is changed to steel and this one is made so as to withstand the load acting on it and cost efficient. All these parts are connected and made as a single setup and can be used in any delta type 3D printer. The overall cost of this setup is ½ times the cost of the conventional setup.

Design and Simulation of Multi-nozzle FDM 3D printer for fabricated Solar thin-film cells

In order to widely realize the personalized use of solar thin-film cells in every family, save costs and generate clean energy, our team wants to fabricate a 3D printer of solar thin-film cells. The solar film cells were 3D printed fabrication by FDM3D printer would improve their performance as battery. In this paper, for fabricate P nano-diamond/ZnO solar film cells the hot bed and nozzle of 3D printer were designed to achieve 3D printing of solar cells. A printer for fabricated solar thin-film cells was designed. PID was used to set the temperature of printer nozzle, and a refrigeration device was added to the substrate. And then finally, the printing device was simulated by SW.

Single-step, DC thermal plasma-assisted synthesis of Ag-C nanocomposites with less than 10 nm sizes for antibacterial applications

A single-step, thermal plasma-assisted technique is reported for size-controlled synthesis of silver-carbon (Ag-C) nanocomposites, to be used for antibacterial applications. Silver nanoparticles of sizes less than 10 nm can directly penetrate into the core of the bacteria, while stiff, nanocrystalline carbon may rupture the microorganisms with their sharp edges. Experiments demonstrated that silver nanoparticles nucleate anchoring tightly on carbon sheets, which can inhibit their aggregation and growth in size and becomes more effective as crystallinity of the carbon enhances further. Nanocomposite samples were synthesized using a hot graphite nozzle and with variation of ambient pressure in the sample collection chamber. The Ag-C sample synthesized at 190 mbar chamber pressure demonstrated the best antibacterial activities. The zone of inhibition was measured for this sample as 18 mm for the gram-positive E. hirae and 15 mm for the gram-negative E. coli bacteria at their corresponding minimum inhibitory values of 0.54 mg ml−1 and 0.9 mg ml−1 respectively. The crystallinity of the carbon nanosheets was measured to be the best for this particular sample and the average size of the silver nanoparticles remaining entangled on them was measured as 4.6 nm, which to our knowledge is the smallest ever synthesized by a plasma-assisted method. The gas temperature at the injection section was measured using the C2 Swan band system, (0, 0) vibrational transition located at 516.5 nm, which confirms temperature enhanced substantially in presence of the graphite nozzle, which had led to the enhanced material crystallinity and synthesis of particles with the smallest sizes.

Simplified elastic-plastic analysis procedure for strain-based fatigue assessment of nuclear safety class 1 components under severe seismic loads

This paper proposes a simplified elastic-plastic analysis procedure using the penalty factors presented in the Code Case N-779 for strain-based fatigue assessment of nuclear safety class 1 components under severe seismic loads such as safety shutdown earthquake and beyond design-basis earthquake. First, a simplified elastic-plastic analysis procedure for strain-based fatigue assessment of nuclear safety class 1 components under the severe seismic loads was proposed based on the analysis result for the simplified elastic-plastic analysis procedure in the Code Case N-779 and the stress categories corresponding to normal operation and seismic loads. Second, total strain amplitude was calculated directly by performing finite element cyclic elastic-plastic seismic analysis for a hot leg nozzle in pressurizer surge line subject to combined loading including deadweight, pressure, seismic inertia load, and seismic anchor motion, as well as was derived indirectly by applying the proposed analysis procedure to the finite element elastic stress analysis result for each load. Third, strain-based fatigue assessment was implemented by applying the strain-based fatigue acceptance criteria in the ASME B&PV Code, Sec. III, Subsec. NB, Article NB-3200 and by using the total strain amplitude values calculated. Last, the total strain amplitude and the fatigue assessment result corresponding to the simplified elastic-plastic analysis were compared with those using the finite element elastic-plastic seismic analysis results. As a result of the comparison, it was identified that the proposed analysis procedure can derive reasonable and conservative results.

Desain dan Pembuatan Prototype Piston Honda MEGAPRO FI Menggunakan 3D Printing

3D printing technology has great potential in today's manufacturing world, one of its uses is in making miniatures or prototypes of a product such as a piston. One of the most famous and inexpensive 3D printing (additive manufacturing) technologies is Fused Deposition Modeling (FDM), the principle FDM works by thermoplastic extrusion through a hot nozzle at melting temperature then the product is made layer by layer. The two most commonly used materials are ABS and PLA so it is very important to know the accuracy of product dimensions. FDM 3D Printing Technology is able to make duplicate products accurately using PLA material. FDM machines work by printing parts that have been designed by computer-aided design (CAD) and then exported in the form of STL or .stl files and uploaded to the slicer program to govern the printing press according to the design. Using Anet A8 brand 3D printing tools that are available to the public, Slicing of general CAD geometry files such as autocad and solidwork is the basis for making this object. This software is very important to facilitate the design process to be printed. Some examples of software that can be downloaded and used free of charge such as Repetier-Host and Cura. by changing the parameters in the slicer software is very influential in the 3D printing manufacturing process.

Development of a novel TIG hot-wire process for wire and arc additive manufacturing

The presented work deals with the development of a novel TIG hot-wire process for the additive manufacturing of metallic components, which, in contrast to previous arc processes, enables a significant increase in melting performance with simultaneously reduced heat input. This is achieved by means of an upstream resistance heating of the wire between two contact points within the hot wire feeding system. The torch, hot wire feeder and gas nozzle are designed in such a way that a constant bead geometry can be guaranteed regardless of the machining direction. On the one hand, this can improve the dimensional accuracy; on the other hand, an increase in productivity is achieved through a significant reduction of process times. Essential parts of the work include the simulation-supported development of the processing system, the design and implementation of an innovative process control system and the testing of the new technology.

Electrospinning on 3D Printed Polymers for Mechanically Stabilized Filter Composites.

Electrospinning is a frequently used method to prepare air and water filters. Electrospun nanofiber mats can have very small pores, allowing for filtering of even the smallest particles or molecules. In addition, their high surface-to-volume ratio allows for the integration of materials which may additionally treat the filtered material through photo-degradation, possess antimicrobial properties, etc., thus enhancing their applicability. However, the fine nanofiber mats are prone to mechanical damage. Possible solutions include reinforcement by embedding them in composites or gluing them onto layers that are more mechanically stable. In a previous study, we showed that it is generally possible to stabilize electrospun nanofiber mats by 3D printing rigid polymer layers onto them. Since this procedure is not technically easy and needs some experience to avoid delamination as well as damaging the nanofiber mat by the hot nozzle, here we report on the reversed technique (i.e., first 3D printing a rigid scaffold and subsequently electrospinning the nanofiber mat on top of it). We show that, although the adhesion between both materials is insufficient in the case of a common rigid printing polymer, nanofiber mats show strong adhesion to 3D printed scaffolds from thermoplastic polyurethane (TPU). This paves the way to a second approach of combining 3D printing and electrospinning in order to prepare mechanically stable filters with a nanofibrous surface.

Carbonized cellulose nanofibers as dielectric heat sources for microwave annealing 3D printed PLA composite

Filament fused fabrication (FFF) is an extrusion-based 3D printing technology for manufacturing thermoplastic components. One major obstacle facing 3D printed thermoplastic material is the reduced crystallinity resulting from a fast quench when material exiting the 3D printer hot nozzle solidifies quickly at the low-temperature platform, leading to weak mechanical performance. Here, we report an accelerated annealing strategy with the assistance of microwave heating, aiming to enhance crystallinity and mechanical performance of FFF 3D printed polylactic acid (PLA) composite. We selected naturally abundant cellulose fibers as precursors for producing carbonized cellulose nanofibers (CCNFs), and compounded CCNFs with PLA to produce bi-component filament for 3D printing final composite. After being irradiated with microwave, the embedded CCNFs in composite selectively absorbed microwave energy and generated heat. Subsequently, the localized heat transferred to the adjacent PLA regions, triggering amorphous PLA chains to repack and convert to new crystallites. In this work, annealing conditions, including heating method (i.e., oven annealing vs. microwave annealing), time (0–120 min), and temperature (80 vs. 120 °C), were systematically studied to understand the relevant effects on the resulting parameters including composite crystallinity and tensile strength. Microwave annealing method was also compared with conventional oven annealing method and results shows that microwave annealing significantly reduced the required annealing time to reach the maximum crystallinity and tensile strength. Notably, microwave annealing performed below cold crystallization temperature was exceptionally suitable to develop an optimized crystallinity and tensile strength for 3D printed PLA composite.

The effect of technological parameters of PMMA thermoplastic welding in the hot air stream on the quality of joints

The work covers the welding of thermoplastic polymethyl methacrylate (PMMA) and concerns the assessment of the impact of the main welding parameters on joint strength. The strength test of welded joints made of thermoplastic material was carried out. The aim of the study was to determine the influence of the main technological parameters of welding, such as: temperature and welding speed, gas stream output, filler rod pressure, diameter and type of hot air gun nozzle on the strength of the obtained joint. The method of sample preparation and testing was performed in accordance with the guidelines of PN-EN 12814-2: 2002 "Tests of welded joints in semi-finished products made of thermoplastics ‒ Part 2: Tensile test". Visual evaluation of welded samples and analysis of results obtained from the tensile test made it possible to draw conclusions about the influence of selected welding parameters on joint strength. The decisive influence on the strength of joints was caused by welding defects, in the form of lack of side wall fusion and porosity.

Investigation of Hot Section (Nozzle Guiding Vane) Distress due to Interaction of Thermal Barrier Coatings with CMAS

An investigation of distress of hot section nozzle guiding vane (NGV) was carried out. Thermal barrier coatings (TBCs) were applied to the components of gas turbine engines to operate at higher temperatures i.e. up to 1200°C. The cause of failure was hot corrosion of TBCs by chemical entities from atmosphere like oxides of Al, Ca, Si and Mg (CMAS). Source of CMAS was dust, which was ingested to airfoil engine components. Different techniques like scanning electron microscope, boroscopy, optical microscopy, X-ray Diffraction and optical emission spectroscopy were utilized to investigate the failure of nozzle guiding vanes.

Optimization of mold thermal control for minimum energy consumption in injection molding of polypropylene parts

Abstract The environmental impact of the injection molding process is mostly due to electricity consumption. This is particularly significant for packaging products, which are the largest application sector for the plastics industry. In this work, electricity consumption measurements of the process were performed, considering a large production plant processing polypropylene packaging parts. In particular, the electricity consumption of mold thermal control was analyzed and minimized through a representative case study. The effects of alternative configurations of cooling channels and different process parameters were experimentally and numerically investigated, considering both the electricity consumption and the molded parts quality. The results indicated that the industrial common practice of maximizing the water flow rate and connecting the mold cooling circuits in parallel, to minimize the increase of coolant temperature, can be satisfactory in terms of part quality but not optimal when considering the energy consumption related to mold thermal control. By setting the hot runner and nozzle temperatures to the lowest suitable values, the coolant flow rate could be reduced significantly (−66%) without compromising the quality of the molded parts and reaching a minimum value of the energy consumption.

Numerical modelling of the interaction between water sprays and hot air jets - Part I: Gas phase Large Eddy Simulations

The paper reports a comprehensive set of large-eddy simulations (LES) of a turbulent hot air jet impinging onto a ceiling. The hot air source is a 72-mm diameter circular nozzle with an exit temperature maintained at 205 °C. Three exit velocities have been tested: 3.3, 4.2 and 5.3 m/s, corresponding to Reynolds numbers of respectively 6800, 8600 and 10900 and Froude numbers of respectively 3.9, 5.0 and 6.3. The horizontal aluminium ceiling plate of 1.22 m × 1.22 m has been placed at a distance of 590 mm above the hot air nozzle. This configuration has been examined experimentally by Zhou [Proceedings of the Combustion Institute, 2015] to characterize gas phase conditions prior to experiments which aim at studying the interaction between hot air jets and water sprays. This paper constitutes the first part of a numerical study that aims at assessing the current modelling capabilities of the two-phase flow configuration examined by Zhou [Proceedings of the Combustion Institute, 2015]. The results show that the centerline mean vertical velocity profiles of the vertical jet are predicted with maximum deviations of less than 6% from the experimental data at the condition of an appropriate set-up of the inflow conditions (i.e., geometry of the inlet and turbulence inflow boundary conditions). Furthermore, the best results were obtained with the dynamic Smagorinsky model for the turbulent viscosity. The modified Deardorff results are nevertheless very good given the substantial decrease in computational time (in comparison to the dynamic Smagorinsky model). A good prediction of the vertical jet allowed relatively good predictions of the ceiling jet maximum velocity, boundary layer thickness and Gaussian momentum width with maximum deviations of respectively 20%, 1 mm and 18%. The numerical modelling of the gas phase described in this paper can thus be relied upon in the two-phase simulations described in the companion paper [Part II: Two-phase flow simulations].