3D Printer Head Research Articles

Influence of reinforcement phase content on mechanical properties of hydroxyapatite/carbon fiber/polyether-ether-ketone composites 3D printed by screw extrusion

Hydroxyapatite/polyether-ether-ketone (HA/PEEK) composites are promising prosthesis materials due to their biological activity, but they often have mechanical properties that fall short of clinical requirements, typically with HA content below 40 wt%. This study utilized a customized screw extrusion-based 3D printhead, incorporating carbon fiber (CF) to produce HA/CF/PEEK composites with enhanced mechanical properties and HA content up to 60 wt%. The investigation focused on the effects of HA and CF content on the crystallization process and mechanical properties. Results showed that HA and CF affect crystallization differently due to varying densities; a phase volume ratio above 20 % inhibits crystallization. The elongation at break for composites with 10 wt% HA was 27.9 %, a record for 3D-printed HA/PEEK composites. The tensile strength for composites with 10 wt% HA and 40 wt% CF reached 115.7 MPa, the highest among the tested three-phase composites. Data fitting indicated that the effects of HA and CF on strength are independent. The toughness decreases exponentially with increased reinforcing phase content. This study explored a new method for preparing HA/PEEK and HA/CF/PEEK composites, expanding the performance boundaries of PEEK composites, enhancing their potential applications in bone implants.

Optimal design of an in-situ variable component 3D printhead for SCF/PEEK composite

ABSTRACT Screw-based material extrusion 3D printing technology offers the potential for manufacturing fibre-reinforced composites with component gradients by mixing materials within the printhead. However, mixing composites with high fibre content sufficiently in a limited range for rapid component switching presented a challenge. Herein, an in-situ variable component screw-based printhead was developed. Pins with different geometries were added to 8, 12, and 16 mm diameter extrusion screws, to enhance the mixing efficiency. A particle tracking model based on computational fluid dynamics simulations was used to optimise the geometry and distribution of pins by taking 0-40 wt% short carbon fibre-reinforced polyether-ether-ketone (SCF/PEEK) as an example. The incorporation of pins enhanced the mixing efficiency but aggravated the dead zone, which decreased the variable component response rate. An optimal design of pins that balanced mixing efficiency and response rate was developed, by which the variable component response rate was promoted by 369%, while the degree of mixing was improved by 50%. Benefitting from the enhanced mixing, the tensile strength of in-situ mixed 20 wt% SCF/PEEK composites was increased by 23%. The in-situ variable component screw-based extrusion printhead developed and optimised in this investigation provided a novel approach to fabricating fibre-reinforced composites with variable components.

The magnetic anisotropy of field-assisted 3D printed nylon strontium ferrite composites

Magnetic Field Assisted Additive Manufacturing (MFAAM), 3D printing in a magnetic field, has the potential to fabricate high magnetic strength anisotropic bonded magnets. Here, 10, 35, and 54 wt% strontium ferrite bonded magnets using polyamide 12 binder were developed by twin screw compounding process and then printed via MFAAM samples in zero, and in 0.5 Tesla (H parallel to the print direction and print bed). The hysteresis curves were measured using a MicroSense EZ9 Vibrating Sample Magnetometer (VSM) for 3 different mount orientations of the sample on the sample holder to explore the magnetic anisotropy. The samples printed in zero field exhibited a weak anisotropy with an easy axis perpendicular to the print direction. This anisotropy is caused by the effect of shear flow on the orientation of the magnetic platelets in the 3D printer head. For the MFAAM samples, the S values are largest along the print bed normal. This anisotropy is caused by the field. The alignment of the magnetic particles happens when the molten suspension is in the extruder. When the material is printed, it is folded over on the print bed and its easy axis rotates 90° parallel to the print bed normally. Little realignment of the particles happens after it is printed, suggesting a sharp drop in temperature once the composite touches the print bed, indicating that field-induced effects in the nozzle dominate the anisotropy of MFAAM deposited samples.

Advanced 3D Electrospinning "Xspin" System: Fabrication of Bifiber Floating Oral Pharmaceutical Scaffolds for Controlled Drug Delivery.

Electrospinning has become a widely used and efficient method for manufacturing nanofibers from diverse polymers. This study introduces an advanced electrospinning technique, Xspin - a multi-functional 3D printing platform coupled with electrospinning system, integrating a customised 3D printhead, MaGIC - Multi-channeled and Guided Inner Controlling printheads. The Xspin system represents a cutting-edge fusion of electrospinning and 3D printing technologies within the realm of pharmaceutical sciences and biomaterials. This innovative platform excels in the production of novel fiber with various materials and allows for the creation of highly customized fiber structures, a capability hitherto unattainable through conventional electrospinning methodologies. By integrating the benefits of electrospinning with the precision of 3D printing, the Xspin system offers enhanced control over the scaffold morphology and drug release kinetics. Herein, we fabricated a model floating pharmaceutical dosage for the dual delivery of curcumin and ritonavir and thoroughly characterized the product. Fourier transform infrared (FTIR) spectroscopy demonstrated that curcumin chemically reacted with the polymer during the Xspin process. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed the solid-state properties of the active pharmaceutical ingredient after Xspin processing. Scanning electron microscopy (SEM) revealed the surface morphology of the Xspin-produced fibers, confirming the presence of the bifiber structure. To optimize the quality and diameter control of the electrospun fibers, a design of experiment (DoE) approach based on quality by design (QbD) principles was utilized. The bifibers expanded to approximately 10-11 times their original size after freeze-drying and effectively entrapped 87% curcumin and 84% ritonavir. In vitro release studies demonstrated that the Xspin system released 35% more ritonavir than traditional pharmaceutical pills in 2 h, with curcumin showing complete release in pH 1.2 in 5 min, simulating stomach media. Furthermore, the absorption rate of curcumin was controlled by the characteristics of the linked polymer, which enables both drugs to be absorbed at the desired time. Additionally, multivariate statistical analyses (ANOVA, pareto chart, etc.) were conducted to gain better insights and understanding of the results such as discern statistical differences among the studied groups. Overall, the Xspin system shows significant potential for manufacturing nanofiber pharmaceutical dosages with precise drug release capabilities, offering new opportunities for controlled drug delivery applications.

Effect of fiber content on mechanical properties of carbon fiber-reinforced polyether-ether-ketone composites prepared using screw extrusion-based online mixing 3D printing

The mechanical properties of carbon fiber-reinforced polyether-ether-ketone (CF/PEEK) composites are closely related to the fiber content. However, the low fiber content (typically below 20 wt%) that can be prepared by current material extrusion limits the application of the composites. In this work, CF/PEEK composites with up to 50 wt% carbon fiber content were manufactured using a custom-made screw extrusion-based online mixing 3D printhead. The impact of fiber loading on the rheological and flow characteristics of the composites was thoroughly examined initially. Subsequently, the influence of fiber content on the crystallinity and mechanical behavior of 3D-printed parts before and after annealing was further explored. The results indicated that adding CF and annealing significantly enhanced the strength and modulus of the 3D-printed composites within a fiber content range of 10 wt% to 40 wt%, compared to those of pure PEEK. At 40 wt% CF, the tensile and flexural strengths of the samples reached their maximum values at 135.9 MPa and 251.2 MPa, respectively, which were enhanced by 94% and 111% compared to those of the unannealed pure PEEK specimens. Also, these properties are the highest values achieved in 3D-printed short CF/PEEK composites. The mechanical properties of composites are affected by various factors such as fiber content, crystallinity, and internal pore defects when the fiber content is less than 20 wt%. However, when the fiber content exceeds 20 wt%, the influence of crystallinity on the mechanical properties becomes less significant. This study further explores the potential application of CF/PEEK composites and provides a novel approach for composite preparation.

Optimization of nozzle for pre-impregnated continuous fiber reinforced 3D printing

The combination of 3D printing technology and pre-impregnated continuous fiber reinforced composites (PICRC) has led to the birth of PICRC 3D printing technology. In the actual PICRC 3D printing process, it is found that the existing PICRC 3D printing head is easily blocked during the compensation wire feeding process, which greatly reduces the success rate of printing. In this paper, the mechanism of PICFRCF 3D print head clogging is analyzed, and the method to solve the problem is explored, which is to adopt appropriate transition length [Formula: see text], printing speed [Formula: see text] and high temperature section length [Formula: see text] to optimize the printing head. The final printing experiment shows that the optimized printing head effectively solves the problem of printing head blocking, and greatly improves the success rate of PICRCF printing.

Novel Approach to Pharmaceutical 3D-Printing Omitting the Need for Filament-Investigation of Materials, Process, and Product Characteristics.

The utilized 3D printhead employs an innovative hot-melt extrusion (HME) design approach being fed by drug-loaded polymer granules and making filament strands obsolete. Oscillatory rheology is a key tool for understanding the behavior of a polymer melt in extrusion processes. In this study, small amplitude shear oscillatory (SAOS) rheology was applied to investigate formulations of model antihypertensive drug Metoprolol Succinate (MSN) in two carrier polymers for pharmaceutical three-dimensional printing (3DP). For a standardized printing process, the feeding polymers viscosity results were correlated to their printability and a better understanding of the 3DP extrudability of a pharmaceutical formulation was developed. It was found that the printing temperature is of fundamental importance, although it is limited by process parameters and the decomposition of the active pharmaceutical ingredients (API). Material characterization including differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA) of the formulations were performed to evaluate component miscibility and ensure thermal durability. To assure the development of a printing process eligible for approval, all print runs were investigated for uniformity of mass and uniformity of dosage in accordance with the European Pharmacopoeia (Ph. Eur.).

Recent Patents on Mechanical Structure of 3D Printer

Background: 3D printing technology is widely applied in transportation, industrial equipment, medical, aerospace, and civil industry due to its characteristics of material saving, no model manufacturing, and machinability of complex parts. The mechanical structure of 3D printer mainly includes 3D printer head structure and working platform and plays a major role in the machining efficiency and processing accuracy of the 3D printer. Thus, increasingly attention has been paid to the current trends of the mechanical structure of 3D printers. Objective: To meet the increasing requirements of 3D printing processing efficiency and precision, the mechanical structure of 3D printers, such as 3D print head structure and working platform, needs to be carefully studied, and a feasible mechanical structure of 3D printers should be proposed. Methods: This paper studies various representative patent related to the mechanical structure of 3D printer, analyzes the mechanical structure of 3D printer, and studies the perfect mechanical structure of 3D printer. Results: Through summarizing a lot of patents about the mechanical structure of 3D printers, the main current existing problems such as platform jitter and machining error are summarized and analyzed, a new mechanical structure of 3D printers is proposed. Moreover, the development tendency of the mechanical structure of 3D printers in the future is discussed. Conclusion: The optimization of the mechanical structure of 3D printer is conducive to increasing the machining efficiency and processing accuracy in the 3D printing process. More relevant patents about working platform and 3D printer head will be invented in the future

Investigation on the Temperature Distribution Uniformity of an Extrusion-Based 3D Print Head and Its Temperature Control Strategy

Extrusion-based 3D printing for thermoplastic polymers manifests potential for the fabrication of biocompatible and biodegradable scaffolds. However, the uncontrollable shape of printed filaments usually negatively impacts on the printing processes. Non-uniform temperature in the print head is a primary cause of inaccuracy in the diameter of filaments formed during the process of extruding thermoplastic polymers. Therefore, the temperature distribution inside the print head must be controlled accurately. This study developed a novel print head configuration with two groups of controllable heat sources for extrusion-based printing of thermoplastic polymers. Subsequently, a numerical thermal analysis based on the finite element method (FEM) was conducted to investigate the temperature field in the print head during the heating process. Moreover, a temperature control strategy is proposed under which the temperature distribution of the print head can be regulated. The temperature uniformity can be improved with the proposed temperature control strategy. Lastly, groups of printing trials were implemented, and the printed filaments showed excellent uniformity of diameter when temperature distribution uniformity was controlled in the print head.

Modeling and building a 3D print head

Modeling and building a 3D print head

Modeling and building a 3D print head

The paper presents 3D modeling and the construction of a printing head for plastic, a head that will be used on a CNC milling machine. The component parts were modeled with Solid Edge software, and for manufacturing the parts we use a CNC milling machine and one conventional lathe. Following the manufacture of the parts, they were mounted together. After that, the mechanical parts was connected together with the electrical components and the result is a functional head that uses fused deposition modeling (FDM) technology.

Control system for FDA deposition using a CNC milling machine

This paper presents the command and control part of a 3D printhead, the command and control that is made by combining the PLC of a CNC milling machine with the electrical assembly of an extruded head for FDA(Fusion Deposition Adhesion) processing.The command and control part of an extruder head is presented. On the same, the paper shows how to connect to the PLC of a CNC and presents the use and operation of an extruder block for FDA machining on CNC

Influence of binder content on physical and mechanical properties of composite materials such as metal powder-waxy substance

The scientific basis for the development of working materials from waxy highly filled composites for FDM 3D printing using is not yet sufficiently developed. The need to develop such composites is due to the fact that highly filled waxy composites, on the one hand, have low 3D printing temperatures, and on the other hand, the fact that the waxy substance has a low ash content and is completely removed during annealing and subsequent sintering of the residual framework from the filler. Therefore, in this work, the influence of the binder content on the physical and mechanical properties of composite materials such as metal powder - waxy substance in the ratio of metal to waxy substance, as 50/50, 60/40, 70/30, 80/20 % (by volume), as well as the shape change of composite samples when they are heated at a temperature from 61 to 230 °C. Carbonyl nickel and carbonyl iron were used as metal powder, and beeswax and paraffin were used as a binder. It was found that the developed surface of particles significantly affects the density dependence, the microhardness and compressive strength of composites from the binder content, the actual density of the composite samples after pressing is less than the calculated by the additivity formula with the binder content up to 40 % (by volume) and only with an increase in the binder content to 50 % (by volume) does the actual density approach the calculated additive; the developed surface of nickel particles several times increases the strength of the composite in comparison with iron at the same binder content, at the same time, the dependences of the microhardness differ significantly: on Ni-wax samples, it tends to decrease with an increase in the wax content, and on samples Fe-paraffin - to an increase, which is due to the influence of such phenomena as adhesion and cohesion, mechanical adhesion. The level of strength of composite samples with a binder content of 40-50 % (by volume) is sufficient so that they do not collapse not only in 3D print head The resulting experimental data can be extended to other similar systems when creating working materials for FDM 3D printing based on carbonyl nickel and iron powders.

Using chaotic advection for facile high-throughput fabrication of ordered multilayer micro- and nanostructures: continuous chaotic printing

This paper introduces the concept of continuous chaotic printing, i.e. the use of chaotic flows for deterministic and continuous extrusion of fibers with internal multilayered micro- or nanostructures. Two free-flowing materials are coextruded through a printhead containing a miniaturized Kenics static mixer (KSM) composed of multiple helicoidal elements. This produces a fiber with a well-defined internal multilayer microarchitecture at high-throughput (>1.0 m min−1). The number of mixing elements and the printhead diameter determine the number and thickness of the internal lamellae, which are generated according to successive bifurcations that yield a vast amount of inter-material surface area (∼102 cm2 cm−3) at high resolution (∼10 µm). This creates structures with extremely high surface area to volume ratio (SAV). Comparison of experimental and computational results demonstrates that continuous chaotic 3D printing is a robust process with predictable output. In an exciting new development, we demonstrate a method for scaling down these microstructures by 3 orders of magnitude, to the nanoscale level (∼150 nm), by feeding the output of a continuous chaotic 3D printhead into an electrospinner. The simplicity and high resolution of continuous chaotic printing strongly supports its potential use in novel applications, including—but not limited to—bioprinting of multi-scale layered biological structures such as bacterial communities, living tissues composed of organized multiple mammalian cell types, and fabrication of smart multi-material and multilayered constructs for biomedical applications.

3D printing using powder melt extrusion

Additive manufacturing promises to revolutionize manufacturing industries. However, 3D printing of novel build materials is currently limited by constraints inherent to printer designs. In this work, a bench-top powder melt extrusion (PME) 3D printer head was designed and fabricated to print parts directly from powder-based materials rather than filament. The final design of the PME printer head evolved from the Rich Rap Universal Pellet Extruder (RRUPE) design and was realized through an iterative approach. The PME printer was made possible by modifications to the funnel shape, pressure applied to the extrudate by the auger, and hot end structure. Through comparison of parts printed with the PME printer with those from a commercially available fused filament fabrication (FFF) 3D printer using common thermoplastics poly(lactide) (PLA), high impact poly(styrene) (HIPS), and acrylonitrile butadiene styrene (ABS) powders (< 1 mm in diameter), evaluation of the printer performance was performed. For each build material, the PME printed objects show comparable viscoelastic properties by dynamic mechanical analysis (DMA) to those of the FFF objects. However, due to a significant difference in printer resolution between PME (X–Y resolution of 0.8 mm and a Z-layer height calibrated to 0.1 mm) and FFF (X–Y resolution of 0.4 mm and a Z-layer height of 0.18 mm), as well as, an inherently more inconsistent feed of build material for PME than FFF, the resulting print quality, determined by a dimensional analysis and surface roughness comparisons, of the PME printed objects was lower than that of the FFF printed parts based on the print layer uniformity and structure. Further, due to the poorer print resolution and inherent inconsistent build material feed of the PME, the bulk tensile strength and Young’s moduli of the objects printed by PME were lower and more inconsistent (49.2 ± 10.7 MPa and 1620 ± 375 MPa, respectively) than those of FFF printed objects (57.7 ± 2.31 MPa and 2160 ± 179 MPa, respectively). Nevertheless, PME print methods promise an opportunity to provide a platform on which it is possible to rapidly prototype a myriad of thermoplastic materials for 3D printing.

Axiomatic design and solution variants applied to a modular 3D printing head based in material extrusion

This paper presents a design procedure based on integration of the solution variants method and axiomatic design as choice criteria during the conceptual design phase. In order to evaluate the design procedure was choice a real problem related to the transmission system of a vertical twin screw head applied to a desktop experimental 3D printer. The main technical and research opportunities of the case study (3D printer head) include the use of powder as raw material in small quantities (around 200 g) for exploration of 4D printing through formulating of compounds and polymer blends, as well filament generation. To be compact due small work envelope; provide to access to fast assembly, disassembly, and maintenance and generate a torque next to 15 N.m are the main technical characteristics required for driven system of 3D head. Considering the different gears geometry and configuration including flexible transmissions options, the solution variants method was choice as screening criteria to ranking the feasible solutions. Based on weighting order, method allowed establishing multifactorial criteria, organized in a hierarchical tree. According this method, the conceptual design option obtained higher value was a worm screw gear for use as power transmission in case study. The use of axiomatic design allowed exploring the relations between functional and technical domains of the driven system. In order to measure the robustness of the conceptual solution obtained through this design procedure was estimated the indices of reangularity and semangularity from axiom of the independence whose value were 0.838 and 0.500.

On-demand-like FDM 3D printhead consideration

On-demand-like FDM 3D printhead consideration

On-demand-like FDM 3D printhead consideration

HIT Research Corp, the research and development arm of HIT Devices Ltd., has been studying the feasibility of utilizing the patented on-demand and temperature-controllable heating device for various applications. One field identified and focused has been the fast growing three dimensional (3D) printing technology. There are several different methods of 3D printing, but the technology compatible with our device and also most widely used process is known as Fused Deposition Modelling (FDM). An FDM 3D printer uses a thermoplastic filament, which is heated to its melting point by a heating device and then extruded through a small hole, layer by layer, to create a three dimensional object. The traditional 3D extruder (or printhead as we refer to) heating section has a discrete heating element and temperature sensor which makes it large and bulky. We integrated them on a single ceramic substrate so it will be more efficient, compact, lighter and easier to maneuver for the three dimensional head movement. Unlike many existing printheads which incorporate a substantial size cooling fan or some cooling devices in order to bleed off the excess heat which is not used for melting the material, the excess heat of the new heating head is minimal and cooling requirement is substantially reduced. The most significant benefit for the new configuration is the ability to be made into a multi-nozzle line-type printhead due to the size and thermal efficiency. This will be left for the future report, the preliminary study indicates that there will be a serious impact on the process time when it becomes an actual product.