Print Head Research Articles

‘5D PRINTING’ -THE NEW ERA IN DENTISTRY! -A NARRATIVE REVIEW

3D printing technology has a wide range of applications in various industries. It is widely used to produce complex 3D structures, but it has some limitations such as a limited amount of material, etc., which have been overcome with the introduction of 4D printing technology. In 4D printing, which involves time as a function and the combination of smart materials, this enables properties such as changing form and function.[1]Five-dimensional (5D) printing is a new branch of additive manufacturing (AM) with great potential to solve problems in engineering, medicine, dentistry and other related fields. It is the latest technological advancement used to produce complex and intricately shaped products, implants and devices with much better physical properties than those obtained by three-dimensional (3D) printing. The concept of 5D printing originated from William Yerazunis of the American University of Mitsubishi Electric Research Laboratories (MERL). In 5D printing, the printing plate also moves with the printing head during the printing process. in 3D printing techniques.[1]four-dimensional (4D) printing is the concept of using a smart material that can change the shape of a printed object over time as the temperature changes. [2] One of the advantages of 5D printing is the use of 25% less material than 3D printing. Five-dimensional printing is all about efficiently manufacturing this complex and curved structure with maximum strength. Using computer-aided design (CAD) data to produce super strong dental implants, orthodontic brackets, crowns, aligners, bridges and appliances. This CAD data is created using the dentist's 3D scanner / different design software.[1] 5D printing of five axes: [1], 1.X-axis ;2. Y-axis;3. Z axis; 4. Movable print head and 5. Movable printing base.5D printing is an advanced manufacturing technology that builds on the concept of 3D printing and adds customization options and features. While 3D printing requires the creation of three-dimensional objects layer by layer, 5D printing allows additional functions or features to be added to a printable object, often dynamically or responsively. its role in dentistry may be limited due to the newness of the technology.

A vibrating membrane ejector for direct ink writing of printed electronics

Direct ink writing (DIW) represents a technical branch of additive manufacturing technology, particularly suitable for prototyping or small-batch printing production of printed electronic components. However, the existing print heads required for near or sub-100 μm line width are quite sophisticated, limiting the accessibility and application of the DIW method. This paper reports the use of the vibrating membrane ejector (VME) as a new option for the print head of DIW. The structure of the VME-based print head was specially designed for this purpose. Finite element modeling and analysis of the VME’s vibration characteristics were performed to provide insights into the ejection conditions and behaviors. The factors influencing the size of printed structures were identified and analyzed through the printing of a metal–organic complex silver (Ag) ink. After optimizing several operational parameters to limit the spreading effects and suppress the satellite droplets, the DIW printed line width has reached about 100 μm. The effectiveness of the VME-based print head was further demonstrated through the DIW fabrication of interdigitated electrodes and microstrip transmission lines. This highlights the versatility of the VME-based print head as a practical tool for device prototyping and ink development in the field of printed electronics.

Transfer of a rational formulation and process development approach for 2D inks for pharmaceutical 2D and 3D printing

The field of pharmaceutical 3D printing is growing over the past year, with Spitam® as the first 3D printed dosage form on the market. Showing the suitability of a binder jetting process for dosage forms. Although the development of inks for pharmaceutical field is more trail and error based, focusing on the Z-number as key parameter to judge the printability of an ink. To generate a more knowledgeable based ink development an approach from electronics printing was transferred to the field of pharmaceutical binder jetting. Therefore, a dimensionless space was used to investigate the limits of printability for the used Spectra S Class SL-128 piezo print head using solvent based inks. The jettability of inks could now be judged based on the capillary and weber number. Addition of different polymers into the ink narrowed the printable space and showed, that the ink development purely based on Z-numbers is not suitable to predict printability. Two possible ink candidates were developed based on the droplet momentum which showed huge differences in process stability, indicating that the used polymer type and concentration has a high influence on printability and process stability. Based on the study a more knowledgeable based ink design for the field of pharmaceutical binder jetting is proposed, to shift the ink design to a more knowledgeable based and process-oriented approach.

Binder-jet 3D printing of pea-based snacks with modulated texture

This paper demonstrates, for the very first time, 3D printing of pea-based snacks with tunable texture using the binder jetting (BJT) method, pea flour as the print powder, and an aqueous binder solution. The binding mechanism was studied by performing both Hele-Shaw cell experiments and confocal microscopy on the printed samples. As the pea flour was exposed to an aqueous binder, the starch granules swelled. These granules remained swollen but were further joined by a network of protein-rich bridges as the sample dried. Inclusion of sugar and post-printing baking tended to strengthen the as-printed samples, and the resultant mechanical properties were on par with commercial snacks that are not 3D printed. By controlling the amount of aqueous binder dispensed from the inkjet print heads, more than one order of magnitude differences in compressive strength and modulus were achieved, demonstrating the exciting potential of using 3D printing for texture modulation of plant-based snacks.

3D printing path method for multi-tow continuous carbon fiber

Carbon fiber composite materials have many excellent characteristics such as high temperature resistance, friction resistance, thermal conductivity and corrosion resistance, so carbon fiber composite materials have become the first choice for printing materials. In order to improve the printing efficiency of carbon fiber 3D printing technology, it has been expanded to four side-by-side nozzles based on traditional single nozzles, and four nozzles are bound to print side by side. The four-nozzle side-by-side printing path has the problem of coordinating the motion planning of each nozzle, controlling the squeezing difference of each nozzle, and adjusting the angle of the print head, so it is necessary to reasonably control the squeezing amount of each nozzle and the angle of the print head. After the slicing processing based on the existing model, the Gcode code of the model is obtained. The Gcode code of the model is processed through the multi-tow continuous carbon fiber 3D printing path planning algorithm. The movement trajectory of each nozzle of the printer is reasonably planned based on the outer wall coordinates and the extrusion amount of each nozzle is controlled. Finally, the snipping instruction is executed after a circle of trajectory to print the next layer of motion trajectory, which ultimately improves the 3D printing while ensuring the accuracy of multi-beam model 3D printing.

Using Own Algorithms to Increase the Quality and Fatigue Resistance of FDM Printing for Use in Drones and Small Aircraft

Abstract The present article discusses the three-dimensional (3D) printing process in the fused deposition modeling (FDM) or the fused filament fabrication (FFF) technique using the author’s own philosophy of shaping the printing head path. The main requirements are the possibility of eliminating supports and reducing or even eliminating the need for the mechanical processing of 3D prints before their final assembly. The presented methodology was implemented in a computer program written by the author and was used to print typical parts used in aviation. Individual methods of shaping parts typical for the construction of small flying models, such as wings and fuselages, and methods of strengthening and connecting them have been discussed. The proposed solutions are illustrated with photos of readymade prints. This article also discusses the issues that printing high-quality parts may encounter and how to avoid them. Some attention has also been paid to the materials used for printing and their suitability in the construction of aircraft and their fatigue strength.

Multi-Sensor Origami Platform: A Customizable System for Obtaining Spatiotemporally Precise Functional Readouts in 3D Models.

Bioprinting technology offers unprecedented opportunities to construct in vitro tissue models that recapitulate the 3D morphology and functionality of native tissue. Yet, it remains difficult to obtain adequate functional readouts from such models. In particular, it is challenging to position sensors in desired locations within pre-fabricated 3D bioprinted structures. At the same time, bioprinting tissue directly onto a sensing device is not feasible due to interference with the printer head. As such, a multi-sensing platform inspired by origami that overcomes these challenges by "folding" around a separately fabricated 3D tissue structure is proposed, allowing for the insertion of electrodes into precise locations, which are custom-defined using computer-aided-design software. The multi-sensing origami platform (MSOP) can be connected to a commercial multi-electrode array (MEA) system for data-acquisition and processing. To demonstrate the platform, how integrated 3D MEA electrodes can record neuronal electrical activity in a 3D model of a neurovascular unit is shown. The MSOP also enables a microvascular endothelial network to be cultured separately and integrated with the 3D tissue structure. Accordingly, how impedance-based sensors in the platform can measure endothelial barrier function is shown. It is further demonstrated the device's versatility by using it to measure neuronal activity in brain organoids.

Numerical simulation of 3D concrete printing derived from printer head and printing process

Ensuring the repeatability and stability of printing process is significant for the 3D Concrete Printing (3DCP). However, the diversity of printers often leads to unpredictable printing journeys. Hence, in this study the printer head was dimensionally characterized by three factors: channel diameter, neck height, and nozzle diameter. The effects of printer head and process parameters (travel speed, extrusion flow rate, and nozzle height) on the geometry stability and shape of printed filament were investigated with computational fluid dynamics method. The results indicated that, for printing materials without coarse aggregates, extrusion methods had a negligible impact on 3DCP process. For the printer head, the nozzle diameter dominated the geometry stability while the neck height and channel diameter had little effects. A dimensionless parameter φ was proposed to quantitatively analyze the influences of travel speed, extrusion flow rate, and nozzle diameter. The systematic mechanical analysis indicated that the geometry instability (tearing and meandering) was controlled by the φ and nozzle height. Based on the above analysis, the selection principle for printing parameters was proposed to ensure a stable and repeatable printing. The research results regarding printer heads and printing parameters can greatly promise the large-scale application of 3DCP.

3D Printed Cement Composites Testing

Testing of the properties of cement mortars for 3D printing has not been standardized yet. Manufacturers of dry mixes declares tensile strength and compressive strength, but these properties are determined on standard beams for cement mortars, and their values may differ from the material actually formed by the 3D printing method. Another factor affecting strength is the printing process itself, where different printing machines require different consistencies and therefore different amount of water. Last but not least, it is necessary to take into account the different properties of the printed material depending on the direction of testing. Presented article brings results of determination the compressive strength, flexural tensile strength, splitting tensile strength and uniaxial tensile strength of the cement mortar from 3D printing loaded in different directions in relation to the axis of the print and comparing them with the parameters determined on standard beams made of the same material. A commercially produced dry mixture was used. Rectangular object was printed. Before the actual printing and also the fresh mixture was taken from the print head directly into the molds for the production of standard beams 40×40×160 mm. The printed object and the beams were placed in a water environment after 24 hours and the properties were determined at the age of 28 days. Cubes with dimensions of 40×40×40 mm and beams of 40×40×160 mm were subsequently cut from the printed object. The results of the testing point to a relatively large variability of the strength characteristics not only according to the direction of the load forces, but also in different places of the printed object (samples were taken in the bottom part, in the middle and in top of the printed object). Strengths of the standard beams were significantly higher than strengths of samples cut out from 3D printed object.

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.

Numerical study of the heat transfer characteristics of wide-format thermal print head

Thermal printing technology has achieved remarkable success in the realm of portable printing due to its advantages such as high printing speed, easy maintenance, and energy efficiency. Nevertheless, there have been no reports on the application of thermal print technology in the booming field of wide-format printing. This article presents the design and construction of a primordial wide-format thermal printer. The corresponding heat transfer model used to design it is proposed subsequently, and the accuracy of the model is validated through experimental methods. The heat transfer characteristics of the wide-format thermal printer during operation are investigated using the model, providing essential technical support for the advancement and proliferation of thermal printing technology in the wide-format printing domain. The findings demonstrate that, during stable operation of the wide-format thermal printer, 84.7% of the heat generated by the heat generator is effectively transferred to the protective film for dye melting, while 13.3% of the heat is dissipated as waste heat to the glass substrate. The temperature distribution in the splicing area is greatly affected due to the non-working heat generation dots. Furthermore, the heat flux between adjacent heat generation dots is nonnegligible and exerts a mutual effect on the respective temperatures.

Theoretical and experimental research on the mechanical tests of 3D printed samples from various materials

At this moment, a real industrial, scientific and technological revolution is being discussed worldwide, consisting in the development of Additive Manufacturing AM technologies through the use of 3D printing. The FDM (Fused Deposition Modelling) 3D printing technology consists in the deposition of fusible material layer by layer in the XOY plane, the thickness of the 3D printed layer is g = 0.12 ÷ 0.24 mm, the resolution of 3D printing is r = 0.1mm, while the print head advances vertically on the OZ axis. The purpose of the work is to determine the breaking moment through destructive mechanical bending tests of some samples made by 3D printing from the following materials: ABS+, PETG and PLA. 5 samples were made in 3 printing directions: horizontal, vertical and lateral, resulting in 15 samples for each material. The total number of samples used is 45. Knowing these values, depending on the requirements of the specifications, a certain material and a certain printing position can be used.

Problems and Handling Methods of Laser Printers

A laser printer is a common office and personal printing equipment widely welcomed for high-speed, high-quality print output. The high temperature usually causes the printer nozzle temperature to be too high, affecting the printing quality and even damaging the printer. This is because the laser printer works by attaching the toner to the paper through high-temperature sintering, hence the print head’s temperature. Maintaining a suitable temperature environment is crucial for the normal operation and life of the laser printer. In addition, If the position and thickness of the black and white tendons change, it may affect the uneven distribution of the ink when printing, resulting in patches or blur of the printed image. In the printer’s cartridges, the black and white bars are separated, ensuring that the ink in the cartridge is evenly distributed when printing. If the position and thickness of the black and white tendons change, it may affect the uneven distribution of the ink when printing, resulting in patches or blur of the printed image. Therefore, when replacing ink cartridges or resetting or modifying some settings of the printer, be careful to be sure not to damage the printer. This study aims to solve the technical defects of laser printers, improve the level of printing technology, and improve the user experience.

A correlation study on piezo-embedded carbon fibre reinforced polylactic acid composite: Experimental and numerical modelling

In this research work, a piezoelectric sensor and actuator model was designed. Carbon fibre-reinforced polylactic acid (CF/PLA) composites were fabricated using the fused deposition modelling (FDM) technique using many parameters to achieve this goal. For instance, the primary key parameters were 0.1 mm (layer height) and 25 mm/s (print head). Besides, the fabricated samples were subjected to a tensile study. Besides, MATLAB® Partial Differential Equation (PDE) tool was used to develop a finite element analysis (FEA) model for the piezoelectric actuator using the experimentally tested results. The MATLAB® was also used to examine the geometry and tip deflection. The experimental works were carried out to measure the sample’s strain using piezoelectric sensors. This approach could be used to establish the accuracy of the model. The CF/PLA composites were fabricated using 20 wt.% of reinforcements. The experimental results and finite element simulation were good agreement on results. Results reported that the deflections of 6.5765 mm, 5.197 mm, and 7.6328 mm, respectively embedded with PZT 5J, PZT 5H, and PZT 5A.

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.

New Designs and Manufacturing Possibilities for Inkjet Print Head Nozzle Plates

New Designs and Manufacturing Possibilities for Inkjet Print Head Nozzle Plates

The effect of selected process parameters on shape fidelity in extrusion-based bioprinting of natural and synthetic hydrogels

Recently application of 3D bioprinting to bioengineering has gained interest for the availability of advanced biomaterials with promising properties for regenerative medicine and drug delivery. In particular, extrusion-based bioprinting has the possibility to use a wide range of hydrogels of natural and synthetic origin. One of the most critical weaknesses of bioprinting is the poor post-printing shape fidelity of 3D scaffold possibly due to the porous-viscoelastic nature and swelling behavior of extruded polymers through the printing head. In this work, a quantitative index, termed shape fidelity index, is proposed to evaluate the discrepancy between ideal and real printed scaffolds. Scaffolds were printed with natural polysaccharides, such as alginate and cellulose (Xplore®), and synthetic polymers, such as polyethylene glycol (START®). Four process parameters on 2 levels were selected for the study according to a DOE analysis: inlet pressure, printing speed, temperature and type of biomaterial. 16 experiments were performed with an extrusion-based bioprinter to produce 3D porous scaffolds, the shape and surface areas of which were characterized with optical microscopy and image analysis. Shape fidelity indices were characterized to guide the optimization of the bioprinting process. The proposed approach permits also to determine the process parameter influencing the most the printing outcome and to rank the parameter importance for optimizing the shape fidelity of the bioprinted manufacts with soft biomaterials.

A decision support system for the selection of FDM process parameters using MOORA

Additive Manufacturing (AM) is an automated process of fabricating three-dimensional (3D) physical objects from a 3D-CAD data by adding layers of materials one upon another through a print head or nozzle without using any tooling components or machining environments. Due to freedom in design, any complex shape can be produced using this process. Fused Deposition Modeling (FDM) is one such AM technology that is commonly used for its simplicity, environment friendliness and low requirement for process monitoring. However, this technology is limited only to small-scale production due to high cost and high build time. The present work focuses on the development of a framework for parametric optimization of the FDM process using multi-objective optimization based on ratio analysis (MOORA). A CAD model of the cam follower mechanism has been prepared in the Solidworks platform and used in this experiment for optimization of build time and cost which have been considered as response variables of the experiment. The experiment has been conducted following the full factorial design of experiment (DoE) method.

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.

Exploring the Potential of Residual Aspergillus Mycelium as a Sustainable Material for Additive Biomanufacturing

Non-degradable materials are responsible for a variety of negative socio-environmental effects. In order to realize a sustainable bioeconomy a circular design of production systems based on biogenic resources is inevitable. Consequently, the recycling of residual and side-streams is becoming increasingly relevant. In this paper, we investigate the potential of using sterilized mycelium from Aspergillus niger, which occurs as a residual-product from the citric acid production, as a sustainable material for additive biomanufacturing by using the Liquid Deposition Modeling technology. The mycelium-based material is extruded through a specially designed printer head, enabling a multi-layered fabrication of complex structures. In combination with additives such as fibers the mycelium can lead to materials with promising mechanical characteristics and shows good properties for its use as an innovative material to be applied in additive manufacturing processes. We conclude that additive biomanufacturing with mycelium from Aspergillus is a sustainable alternative for traditional materials. Its biodegradability characteristic makes it a promising material for various applications and circular products. Finally, we outline further research and development issues to enable the transformation into industrial applications.