Extrusion Head Research Articles

Layer path updating algorithm based on Voronoi diagrams for material extrusion additive manufacturing

ABSTRACT In Material Extrusion (MEX) types of Additive Manufacturing (AM) technologies, the continuity of the trajectories affects the surface quality of the artifacts manufactured and the time of fabrication. Continuous paths result in lower surface roughness values and lower fabrication times. AM machines employing MEX technologies have the flexibility to fill the interior of objects with regular or irregular patterns to serve various applications. Any of these infill patterns can be modelled with 3D Voronoi diagrams. Therefore, developing a continuous path planning algorithm based on Voronoi diagrams would increase the flexibility of the approach. Accompanied with an encryption method, the proposed approach can represent the motion trajectories of the extruder head in a compact manner, decreasing file sizes representing them. Based on the results of various test cases, the proposed approach improves surface quality, decreases fabrication time and the size of the manufacturing files.

Pellet-Based Extrusion Additive Manufacturing of Lightweight Parts Using Inflatable Hollow Extrudates

Additive manufacturing (AM) has become a key element of Industry 4.0, particularly the extrusion AM (EAM) of thermoplastic materials, which is recognized as the most widely used technology. Fused Filament Fabrication (FFF), however, depends on expensive commercially available filaments, making pellet extruder-based EAM techniques more desirable. Large-format EAM systems could benefit from printing lightweight objects with reduced material use and lower power consumption by utilizing hollow rather than solid extrudates. In this study, a custom extruder head was designed and an EAM system capable of extruding inflatable hollow extrudates from a variety of materials was developed. By integrating a co-axial nozzle-needle system, a thermoplastic shell was extruded while creating a hollow core using pressurized nitrogen gas. This method allows for the production of objects with gradient part density and varied mechanical properties by controlling the inflation of the hollow extrudates. The effects of process parameters— such as extrusion temperature, extrusion speed, and gas pressure were investigated—using poly-lactic acid (PLA) and styrene-ethylene-butylene-styrene (SEBS) pellets. The preliminary tests identified the optimal range of these parameters for consistent hollow extrudates. We then varied the parameters to determine their impact on the dimensions of the extrudates, supported by analyses of microscopic images taken with an optical microscope. Our findings reveal that pressure is the most influential factor affecting extrudate dimensions. In contrast, variations in temperature and extrusion speed had a relatively minor impact, whereas changes in pressure led to significant alterations in the extrudate’s size and shape.

Advancements in Artificial Intelligence-mediated Fabrication of 3D, 4D, and 5D Printed for Fabrication of Drug Delivery Formulations

: One of the most powerful and inventive fabrication techniques used to create novel structures and solid materials using precise additive manufacturing technology is 5D and 4D printing, which is an improved version of 3D printing. It catches people's attention because of its capacity to generate fast, highly complex, adaptable product design and fabrication. Real-time sensing, change adaptation, and printing state prediction are made possible by this technology with the use of artificial intelligence (AI). The process of 3D printing involves the use of sophisticated materials and computer-aided design (CAD) with tomography scanning controlled by artificial intelligence (AI). The printing material is deposited according to the specifications of the file, typically in STL format; however, the printing process takes time.4D printing, which incorporates intelligent materials with time as a fourth dimension, can solve this drawback. About 80% of the time will be saved by this technique's self-repair and self-assembly qualities. One limitation of 3D printing is that it cannot print complex shapes with curved surfaces. However, this limitation can be solved by using 5D printing, which uses rotation of the print bed and extruder head to achieve additive manufacturing in five different axes. Some printed materials are made sensitive to temperature, humidity, light, and other parameters so they can respond to stimuli. With its effective and efficient manufacturing for the necessary design precision, this review assesses the potential of these procedures with AI intervention in medicine and pharmacy.

Mechanical characterization of new bi-material generated by additive manufacturing: IZOD test–puncture impact behaviour

PurposeThe purpose of this paper is to characterize a new structural bi-material (scaffold and filler).Design/methodology/approachThe bi-material has been obtained by means of an additive manufacturing system consisting of a fused filament fabrication extruder head and an epoxy resin depositor head. The new bi-material will consist of a thermoplastic material that will serve as the main structure and an epoxy resin that will serve as a filler and adhesion between layers. The creation of this new bi-material will improve the physical–chemical and mechanical properties with respect to the thermoplastic material. This paper will focus on the impact behavior of IZOD and the impact behavior of punctures.FindingsThe new polylactic acid (PLA) and epoxy bi-material allow improvements in toughness and puncture impact resistance compared to the PLA thermoplastic. This increase in toughness is between 20% and 30% depending on the orientation of the print. In the same way, the energy absorbed in the puncture impact test has been increased by 42%–48%.Practical implicationsThe improvement in the impact absorption capacity of this new bi-material makes it ideal for the manufacture of medical parts in which customization, lightness and impact resistance are their main characteristics such as sports protection systems.Originality/valueThe originality of creating parts through additive manufacturing that combines a material generated with cold extrusion, such as epoxy resin and a material generated with hot extrusion, such as thermoplastics, lies in the unique synergy that this mixed and simultaneous technique offers. By uniting these two manufacturing methods, it allows the exploration of new physical and chemical properties in the resulting parts, taking advantage of the individual advantages of each material. This combination opens the door to the creation of components with a wider range of characteristics, from strength and durability to flexibility and temperature resistance, thus offering innovative and versatile solutions for various applications in fields such as engineering, medicine and design.

Effect of Rheological on the Physical and Electrical Properties of Extruded Micro Carbon -LLDPE Composites

This study focuses on formulating and optimizing a conductive polymer composite (CPC) material tailored for electromechanical applications. Linear Low-Density Polyethylene (LLDPE) polymer and micro carbon particles derived from rice husk were compounded using a hot compaction process and melt blended through a single-screw extrusion machine. A mix of 50% loading of microcarbon particles was used in this research. It was determined that the experiment was successfully conducted, resulting in a stabilized density of approximately 1 g/cm³. The research demonstrates how the prototype Extruder Head effectively stabilizes the density of composites. Electrical conductivity demonstrated a notable increase in conductivity toward higher density. These findings underscore the successful development of a CPC material with improved electrical conductivity, making it a highly suitable tool for high carbon-loading composite material.

From multilayer LDPE/EVOH flexible film scraps to new multilayer films

This study explores the mechanical and optical properties of multilayer films incorporating recycled materials, mimicking the structure of industrial films. Using a coextrusion blown film line with a three-layer ABC configuration extrusion head, films were produced using two different recycled multilayer films, from post-industrial scraps, in layers A and B and virgin low-density polyethylene (LDPE) in one of the external layers (C). These recycles result from multilayer films mainly constituted of LDPE; one has also linear-LDPE (LLDPE) Metallocene, and the other has Ethylene Vinyl Alcohol (EVOH). Both recycled materials enabled to maintain blown film extrusion process stability during film production. The multilayer films produced with the incorporation of recycles were characterized using scanning electron microscopy (SEM), haze and gloss measurements, and tensile tests. Films with Recycled EVOH presented haze values much higher than those obtained for the Recycled Metallocene. However, all films presented good mechanical properties when compared to single layer virgin LDPE film. Anisotropic behaviour was observed, emphasizing the directional dependence of mechanical properties. The findings provide insights into the behaviour of multilayer films with recycled content, offering valuable information for the development of sustainable packaging solutions.

State of art on evaluation of three- to six-dimensional novel additive manufacturing technology for biomedical applications

Additive manufacturing has evolved over the last few decades. Three-dimensional printing is a digital manufacturing technology that provides nearly endless options for the creation of an accessible instrument for all parts of various medical practices, including tissue engineering, through meticulous optimization of material, processing, and geometry for every point in an object. Three-dimensional printing has opened up a new, faster, and safer manufacturing process, despite its incapability to fabricate complex structures and objects. Recently, novel four-dimensional printing techniques have been developed for the transformation of typical stable three-dimensional printed parts into smart objects. The limitations of three-dimensional printing could be remedied with four-dimensional printing, by applying time as the fourth dimension. Self-repairing and speedy printing are two additional benefits of this technology's by using smart materials. By adapting this technology, numerous medical domains could be profited. Four-dimensional printing does not have the ability to produce curved complicated forms. However, five-dimensional printing overcomes the flaws seems in four-dimensional printing. Five-dimensional additive manufacturing relies on the rotation of both the print bed and the extruder head. Five-dimensional printing outlasts in terms of durability than three- and four-dimensional printing. Currently, a combination of the principles of four- and five-dimensional printing into a single process is called six-dimensional printing. In six-dimensional printing, the form changes over time due to the reaction of environmental factors, which is primarily used in biomedical applications. This paper summarizes extensive research on biomaterials in the field of biomedical science and discusses the present implications of three-, four-, five-, and six-dimensional printing techniques.

Sawtooth scanning strategy for additive manufacturing

PurposeThis study aims to improve the acceleration in the additive manufacturing (AM) process. AM tools, such as extrusion heads, jets, electric arcs, lasers and electron beams (EB), experience negligible forces. However, their speeds are limited by the positioning systems. In addition, a thin tool must travel several kilometers in tiny motions with several turns while realizing the AM part. Hence, acceleration is a more significant limiting factor than the velocity or precision for all except EB.Design/methodology/approachThe sawtooth (ST) scanning strategy presented in this paper minimizes the time by combining three motion features: zigzag scan, 45º or 135º rotation for successive layers in G00 to avoid the CNC interpolation, and modifying these movements along 45º or 135º into sawtooth to halve the turns.FindingsSawtooth effectiveness is tested using an in-house developed Sand AM (SaAM) apparatus based on the laser–powder bed fusion AM technique. For a simple rectangle layer, the sawtooth achieved a path length reduction of 0.19%–1.49% and reduced the overall time by 3.508–4.889 times, proving that sawtooth uses increased acceleration more effectively than the other three scans. The complex layer study reduced calculated time by 69.80%–139.96% and manufacturing time by 47.35%–86.85%. Sawtooth samples also exhibited less dimensional variation (0.88%) than zigzag 45° (12.94%) along the build direction.Research limitations/implicationsSawtooth is limited to flying optics AM process.Originality/valueDevelopment of scanning strategy for flying optics AM process to reduce the warpage by improving the acceleration.

Evaluating the performance of Bi58Sn42 mold produced by material extrusion additive manufacturing system for agile manufacturing

PurposeThe purpose of this study is to produce a low-cost sheet metal forming mold made from the low melting point Bi58Sn42 (bismuth) alloy by using an open-source desktop-type material extrusion additive manufacturing system and to evaluate the performance of the additively manufactured mold for low volume sheet metal forming. Thus, it was aimed to develop a fast and inexpensive die tooling methodology for low-volume batch production.Design/methodology/approachInitially, the three-dimensional printing experiments were performed to produce the sheet metal forming mold. The encountered problems during the performed three-dimensional printing experiments were analyzed. Accordingly, both tunings in process parameters (extrusion temperature, extrusion multiplier, printing speed, infill percentage, etc.) and customizations on the extruder head of the available material extrusion additive manufacturing system were made to print the Bi58Sn42 alloy properly. Subsequently, the performance of the additively manufactured mold was evaluated according to the dimensional change that occurred on it during the performed pressing operations.FindingsResults showed that the additively manufactured mold was rigid enough and proved to have sufficient strength in sheet metal forming operations for low-volume production.Originality/valueAlternative mold production was carried out using open-source material extrusion system for low volume sheet metal part production. Thus, cost effective solution was presented for agile manufacturing.

An enhanced spatial extrusion method to manufacture large-scale thermoplastic lattice structures

Recent advances in additive manufacturing have enabled a rapid and cost-effective fabrication of complex geometries such as lattices. At the architectural scale, the emerging robotic arm spatial material extrusion method with a customized extrusion head has been used to build free-form lattice structures, but most existing studies primarily focused on the realization of geometric forms other than their mechanical properties. This work developed an enhanced extrusion-based robotic free-hanging printing method with a well-planned printing path, proper process parameters, and a specific robotic control strategy to manufacture thermoplastic lattice cubes and beams. The proposed method improved the lattice quality in terms of better strut alignment and stronger bonding on the joints, leading to increased compressive and flexural strengths by 230 % and 685 % compared to the existing method. We envision that the proposed method can be applied to build more large-scale lattice structures with diverse and tailorable geometries from art installations to structural skeletons.

On-Machine LTS Integration for Layer-Wise Surface Quality Characterization in MEX/P.

Material Extrusion (MEX) currently stands as the most widespread Additive Manufacturing (AM) process, but part quality deficiencies remain a barrier to its generalized industrial adoption. Quality control in MEX is a complex task as extrusion performance impacts the consistency of mechanical properties and the surface finish, dimensional accuracy, and geometric precision of manufactured parts. Recognizing the need for early-stage process monitoring, this study explores the potential of integrating Laser Triangulation Sensors (LTS) into MEX/P manufacturing equipment for layer-wise 3D inspections. Using a double-bridge architecture, an LTS-based sub-micrometric inspection system operates independently from the manufacturing process, enabling comprehensive digitization and autonomous reconstruction of the target layer's topography. Surface texture is then computed using standardized indicators and a new approach that provides insight into layer quality uniformity. A case study evaluating two alternative extruder head designs demonstrates the efficacy of this integrated approach for layer quality characterization. Implementing a generalized layer-wise procedure based on this integration can significantly mitigate quality issues in MEX manufacturing and optimize process parameter configurations for enhanced performance.

Multimaterial extrusion of programmable periodic filament structures via modularly designed extruder heads

There is a growing interest in patterning multimaterial structures into one-dimensional, two-dimensional, and three-dimensional motifs with spatially programmable inner structures. Harnessing material extrusion technology with customizable extruder heads greatly expands the possibilities of 3D printing to generate diverse multimaterial structures. However, the current choices of extruder heads are still limited largely due to the complexity in the design and fabrication of high-resolution microfluidic channels for multimaterial ink extrusion. Here, we report a modular strategy in multimaterial extrusion to program periodic structures and material compositions in printed objects. Our modular design greatly simplifies the design and manufacturing of multimaterial extruder heads to rapidly print complex multilayered architectures. Moreover, different extruder head modules can be combined in series or in parallel and different filament morphologies can be controlled by adjusting printing parameters such as flow rate and pressure. As exemplars, two immiscible materials with similar rheological properties but different mechanical properties are used for co-extrusion. The lamellar composite filaments and printed woodpile structures exhibit high toughness and superior energy-absorption capability, respectively. Our strategy provides new insights for the design of innovative filament structures for 3D printing and shows broad application prospects in tissue engineering, structural systems, optoelectronics, and beyond.

Direct ink writing of viscous inks in variable gravity regimes using parabolic flights

Additive manufacturing (AM) has significant utility for off-planet fabrication where dedicated infrastructure is severely limited, weight reduction and in situ resource utilization is desirable, and demands for complex systems are high. Direct ink writing (DIW) is a useful AM technique since it enables the deposition of a broad set of materials and the co-printing of multiple materials simultaneously. This allows for the fabrication of complex functional devices and systems in addition to structural objects. To evaluate this technique for space applications, this study characterized DIW in low gravity environments. Parabolic flights were used to simulate Martian, Lunar, and Micro gravity, and the effects that these 3 gravity regimes have on two critical print performance parameters, drooping and slumping, was evaluated using viscous paste inks deposited with an auger-driven extrusion head. In the drooping case, bridging structures were printed across gaps without support material, and the deformation was monitored. In the slumping case, a wall was printed through sequential layer deposition, and the vertical displacement of each layer under reduced gravity was explored. As expected, we found that a reduction in apparent gravity led to a decrease in the droop of a printed line, and as apparent gravitational acceleration is decreased its impact on the magnitude of drooping becomes less significant. For wall structures printed in simulated Lunar or Martian gravity regimes, the total structure height was found to be similar to that of a structure printed under Earth's gravitational conditions. In contrast, for prints performed in microgravity, it was found that slumping was significantly reduced and structure height was larger. These results provide experimental data to enable the design and optimization of appropriate structures and tool paths for printing objects using DIW for off-planet manufacturing.

Machine Vision-Based Surface Defect Detection Study for Ceramic 3D Printing

A set of online inspection systems for surface defects based on machine vision was designed in response to the issue that extrusion molding ceramic 3D printing is prone to pits, bubbles, bulges, and other defects during the printing process that affect the mechanical properties of the printed products. The inspection system automatically identifies and locates defects in the printing process by inspecting the upper surface of the printing blank, and then feeds back to the control system to produce a layer of adjustment or stop the printing. Due to the conflict between the position of the camera and the extrusion head of the printer, the camera is placed at an angle, and the method of identifying the points and fitting the function to the data was used to correct the camera for aberrations. The region to be detected is extracted using the Otsu method (OSTU) on the acquired image, and the defects are detected using methods such as the Canny algorithm and Fast Fourier Transform, and the three defects are distinguished using the double threshold method. The experimental results show that the new aberration correction method can effectively minimize the effect of near-large selection caused by the tilted placement of the camera, and the accuracy of this system in detecting surface defects reached more than 97.2%, with a detection accuracy of 0.051 mm, which can meet the detection requirements. Using the weighting function to distinguish between its features and defects, and using the confusion matrix with the recall rate and precision as the evaluation indexes of this system, the results show that the detection system has accurate detection capability for the defects that occur during the printing process.

Annular expansion for enhanced orientation and mechanical properties of extruded amorphous PPESK/PES pipes

AbstractWith the discovery of deeper oil fields, conventional metal pumping pipes have been proven to be ineffective in meeting the requirements for deep well oil production due to their high weights and limited corrosion resistance. Therefore, in this study, a composite of Poly(phthalazinone ether sulfone ketone) (PPESK) and polyethersulfone (PES) was used to fabricate nonmetal pipes. To enhance the mechanical properties of the PPESK/PES pipes, a self‐designed annular expansion pipe extruder head was used. The circumferential burst stress and axial tensile strength of the PPESK/PES pipes subjected to 30° expansion were 73.0% and 48.9% higher than those of the unexpanded sample, respectively. When annular expansion was integrated into the extrusion of PPESK/PES/carbon fiber pipes, the axial tensile strength and circumferential burst stress were 45.9% and 88.8% higher than those of the unexpanded sample, respectively. Results of polarized infrared testing and metallographic microscopic examinations demonstrated that molecular chains present a regular orientation at a certain angle to the extrusion direction, under the effect of annular expansion extrusion. These findings highlight the efficiency of annular expansion in promoting the large‐scale production of pipes.

Parameter optimization of 3D printing process for ceramic sculptures

Abstract In this paper, for the problems of ceramic sculpture 3D printing process, such as the accuracy is difficult to predict and the process control parameters are difficult to choose, we propose to establish an accuracy prediction model using BP neural network optimized by particle swarm algorithm, and put forward the optimization algorithm of the printing process parameters based on genetic algorithm, and construct the fitness function by using the method of the weight coefficients, to achieve the search for the molding angle under the optimal surface quality and to improve the printing efficiency. In the simulation experiments of printing accuracy prediction, the average errors of dimensional error and surface roughness prediction of the PSO-BP network model proposed in this paper are 5.59% and 5.02%, respectively, and the prediction is accurate and reliable. In the 3D printing parameter optimization experiments, the average deviation of the Y and Z dimensions of the physical size printed with the optimized parameters is 0.0496mm and 0.058mm, respectively, which is smaller than the deviation before optimization. Parameter optimization has also reduced surface roughness in the molded parts of the porcelain sculpture. The extrusion head and hot bed temperature were adjusted to reach the temperature target after maintaining hollow finger precision within 3 degrees.

A thermo-chemo-mechanical model for material extrusion of frontally polymerizing thermoset polymers

The material extrusion of thermoset polymers that undergo frontal polymerization produces three-dimensional structures with complex freestanding shapes without the use of sacrificial support material. In this technique, a gelled monomeric ink is extruded from a nozzle and undergoes rapid curing by a self-energized reaction front. Between extrusion and complete curing, the material experiences large deformations, viscous dissipation, rapid heating, and solidification. A mathematical model for these processes is developed in the current study to guide the selection of process parameters for achieving defect-free prints and high dimensional stability. A thermo-chemo-mechanical theory is presented to model the extruded viscoelastic filament and its transition to a fully cured thermoset polymer. Additionally, a computational model is developed to simulate the 3D printing of common structures. Numerical examples are included for linear and curvilinear extrusions to illustrate the role of printing parameters like the extrusion, front, and printer head velocities. Comparisons with experiments, including some new experiments, for archetypal geometries demonstrate the utility of the model in the identification of process parameters for defect-free prints.

Using the Single Minute Exchange of Die (SMED) Method to Minimize Machine Setup Time: A Case Study

PT. GTC is a company that produces automobile tubes facing problems with an increase in demand of up to 20% from the previous year. From 4 existing divisions named mixing, extruding, splicing, and curing, it was found that the extruding division was unable to meet the production targets set by the company. There are several causes, including high setup time. This research aims to reduce setup time by applying the Single Minute Exchange of Die (SMED) method to the production process in the extruding machine-1 that produces automobile tube sizes 5.50-13 and 7.00-14. Converting activities no. 2, 3, and 14 from internal activities to external activities, changing the layout of the die, core, and adjuster key storage table, dies unification, and installing a Temperature Control Unit to control steam to the extruder head can reduce setup time from 45 minutes to 22 minutes or 51% from the initial setup time. These improvements succeeded in increasing the productivity of the extruding division up to 93.9% in January 2023. Keywords: single-minute exchange of die, SMED, setup time, production achievement, unification

Straightforward Design Strategy toward 3D Near-Net-Shape Stoichiometric SiC Parts.

Fused deposition modeling (FDM), traditionally reserved for thermoplastics, is modified here with a granule-based extrusion head to be extended to advanced nonoxide ceramics via a straightforward design strategy that considers the shaping opportunities and the chemical richness offered by preceramic polymers. Specifically, 3D near-net-shape stoichiometric silicon carbide (SiC) objects are designed by manipulating the key features of a commercially available polycarbosilane (fusibility, high carbon content, relatively high SiC yield). In the early stage of the process, the carbon-rich polycarbosilane is first mixed with Si and SiC fillers and then thermolyzed at 120 °C to increase polymer branching while offering tailored rheological properties during the subsequent extrusion process at 90 °C and adequate shape retention once extruded. This allows for the design of tailored and complex 3D complex polycarbosilane-based architectures with features down to 400µm. Polymer-based parts are further converted into 3D stoichiometric SiC objects with quasi-near-net-shape-a volume shrinkage reduced to 9.1% is measured-by heat treatment at a temperature as low as 1400 °C (argon flow). Given the flexibility to tune the preceramic polymer chemical and rheological properties, a new combined design approach is leveraged to generate bespoke advanced ceramics with a high freedom in geometry complexity.

Design of a large format printing platform that allows the extrusion of composite materials based on pellets and continuous fibers.

Commonly additive manufacturing (AM) through the technique of extrusion of molten material is used to manufacture prototypes. This is mainly because the materials commonly used in these technologies are thermoplastics of low mechanical performance. That is why this project seeks the development of an extrusion head that uses polymeric matrix composite materials in the form of pellets and reinforcements of natural or synthetic continuous fibers in order to be used in a large format MA system, which allows the manufacture of objects with better functional and mechanical performance than those found conventionally. For this purpose, different stages were carried out for the development of the project, starting with the design and construction of the printing platform; followed by the design of an extrusion head that allows the integration of a polymeric matrix and continuous fibers. As a result, printed traces were obtained using PLA pellets and glass fiber, resulting in a total coating of the fiber on the printed material.