Conventional Fused Deposition Modeling Research Articles

A 4-Axis Technique for Three-Dimensional Printing of an Artificial Trachea.

Several types of three-dimensional (3D)-printed tracheal scaffolds have been reported. Nonetheless, most of these studies concentrated only on application of the final product to an in vivo animal study and could not show the effects of various 3D printing methods, materials, or parameters for creation of an optimal 3D-printed tracheal scaffold. The purpose of this study was to characterize polycaprolactone (PCL) tracheal scaffolds 3D-printed by the 4-axis fused deposition modeling (FDM) method and determine the differences in the scaffold depending on the additive manufacturing method. The standard 3D trachea model for FDM was applied to a 4-axis FDM scaffold and conventional FDM scaffold. The scaffold morphology, mechanical properties, porosity, and cytotoxicity were evaluated. Scaffolds were implanted into a 7 × 10-mm artificial tracheal defect in rabbits. Four and 8weeks after the operation, the reconstructed sites were evaluated by bronchoscopic, radiological, and histological analyses. The 4-axis FDM provided greater dimensional accuracy and was significantly closer to CAD software-based designs with a predefined pore size and pore interconnectivity as compared to the conventional scaffold. The 4-axis tracheal scaffold showed superior mechanical properties. We suggest that the 4-axis FDM process is more suitable for the development of an accurate and mechanically superior trachea scaffold.

3D-printed polymer antiresonant waveguides for short-reach terahertz applications.

In this work, we present a 3D-printed waveguide that provides effective electromagnetic guidance in the THz regime. The waveguide is printed using low-cost polycarbonate and a conventional fused deposition modeling printer. Light guidance in the hollow core is achieved through antiresonance, and it improves the energy effectively transported to the receiver compared to free space propagation. Our demonstration adds to the field of 3D-printed terahertz components, providing a low-cost way of guiding terahertz radiation.

Model-guided design and characterization of a high-precision 3D printing process for carbohydrate glass

Water-soluble glass patterned by 3D printing is a versatile tool for tissue engineering and microfluidics. Glasses can be patterned layer-by-layer as in conventional fused deposition modeling but also along 3D, “freeform” paths. In the latter approach, extruding heated material through a nozzle translating in 3D space allows for fabrication of sparse, freestanding networks of cylindrical filaments. These freeform structures are suitable for sacrificial molding with a variety of media, leaving complex microchannel networks. However, 3D printing carbohydrate glass in this way presents several unique challenges: 1) the material must resist degradation and crystallization during printing, 2) the glass must be hot enough to flow freely during extrusion and fuse to the printed construct, while cooling rapidly to retain its shape upon exiting the nozzle, 3) the extruder needs to apply high pressure, with rapid stop and start times and 4) the net force that acts on the filament during extrusion must be minimized so that the filament shape is predictable, i.e., coincides with the path taken by the nozzle. First, we review the properties of commercially available carbohydrate glasses and provide a guide for processing isomalt, our material of choice, to achieve the best printing performance. A pressure-controlled, piston-driven extruder is then described which allows for rapid responses and precise control over the material flow rate. We then analyze the heat transfer within the filament and the forces that contribute to the filament’s final shape. We find that the dominant force is due to the radial flow of the molten glass as it exits the nozzle. This analysis is validated on a purpose-built isomalt 3D printer, which we utilize to characterize relationships between extrusion pressure, translation speed, filament diameter, and viscous force. The insights of the physics of the printing process enable fabrication of intricate freeform prints as well as layer-by-layer designs. The practical and theoretical considerations should facilitate adoption of additive manufacturing of carbohydrate glasses with applications to a wide variety of fields, including tissue engineering and microfluidics.

Developing enhanced carbon nanotube reinforced composites for full-scale 3D printed components

Recent research has developed a range of novel nano-enhanced 3D Printer filaments for high-end structural applications. In this research, an enhanced carbon nanotube filament has been formulated with different concentrations of graphitized multiwalled carbon nanotubes. These have been dispersed into an acrylonitrile butadiene styrene polymer matrix under a process of high sheer mixing. This formulation was extruded to form a 1.75 mm diameter filament that was used to 3D print custom full size aerospace components that were later tested and displayed mechanical strength enhancement. In this article the process is detailed which show a method to manufacture 3D printed nanocomposite structures. These polymer filaments can be used on any conventional fused deposition modeling 3D Printing machine for the fabrication of scale components that require mechanical enhancement.

A Portable 3D Printer System for the Diagnosis and Treatment of Multidrug-Resistant Bacteria

Summary Multidrug-resistant bacteria are a major threat to human health, but broad-spectrum antibiotics are losing efficacy. There is a need to screen a given drug against a bacterial infection outside of the laboratory. To address this need, we have designed and built an inexpensive and easy-to-use 3D-printer-based system that allows easily readable quantitative tests for the performance of antibacterial drugs. The platform creates a sterile diagnostic device by using 3D printing, and the device is filled automatically with growth medium, and then antibiotics are sprayed onto the medium by ink-jet technology. The sample for testing can be introduced via a fluid port, and the printer hot bed is used to incubate the device, allowing operation in the field. Combining advantages from various established tests of antibacterial performance, this allows the comparison of a specific antibiotics and bacteria. Also, this system can create and test several antibiotic formulations for therapeutic use, and we demonstrate this potential by investigating a mixture of pathogens that are only killed by a mixture of drugs.

개인안전 제품을 위한 3 차원 다공성 폴리머 프린팅의 최적화 공정조건에 대한 연구

In this paper, a fundamental experiment regarding the formation of porous 3D structures for personal safety products using 3D PPP (Porous Polymer Printing) was introduced for the first time. The filament was manufactured by mixing PP (Polypropylene) and CBA (Chemical Blowing Agent) with polymer extruder, and the diameter of the filament was approximately 1.75mm. The proposed 3D PPP method, combined with the conventional FDM (Fused Deposition Modeling) procedure, was influenced by process parameters, such as the nozzle temperature, printing speed and CBA density. In order to verify the best processing conditions, the depositing parameters were experimentally investigated for the porous polymer structure. These results provide parameters under which to form a multiple of 3D porous polymer structures, as well as various other 3D structures, and help to improve the mechanical shock absorption for personal safety products.

자동공구교환장치를 이용한 융합 FDM 공정 및 장치개발에 관한 연구

The purpose of this study is an attempt to improve the functionality of a conventional Fused Deposition Modeling (FDM) process using the Automatic Tool Changer (ATC) to perform multi-material production and post-processing. Hybrid-FDM means a fusion of an Additive Manufacturing process and grinding process using the ATC system. In order to enhance the potentiality of production capacity for multi-material fabrication and surface roughness improvement, two extrusion tools and one grinding tool system are suggested. A pneumatic chuck is attached on a moving platform in the XY axes plane and an extrusion head and grinding head are placed in a docking station, allowing for a quick changeover with each other. Therefore, the manufacturing lead time can be reduced efficiently for the fabrication of a product.

Printing Three-Dimensional Electrical Traces in Additive Manufactured Parts for Injection of Low Melting Temperature Metals

While techniques exist for the rapid prototyping of mechanical and electrical components separately, this paper describes a method where commercial additive manufacturing (AM) techniques can be used to concurrently construct the mechanical structure and electronic circuits in a robotic or mechatronic system. The technique involves printing hollow channels within 3D printed parts that are then filled with a low melting point liquid metal alloy that solidifies to form electrical traces. This method is compatible with most conventional fused deposition modeling and stereolithography (SLA) machines and requires no modification to an existing printer, though the technique could easily be incorporated into multimaterial machines. Three primary considerations are explored using a commercial fused deposition manufacturing (FDM) process as a testbed: material and manufacturing process parameters, simplified injection fluid mechanics, and automatic part generation using standard printed circuit board (PCB) software tools. Example parts demonstrate the ability to embed circuits into a 3D printed structure and populate the surface with discrete electronic components.

Influence of Fill Gap on Flexural Strength of Parts Fabricated by Curved Layer Fused Deposition Modeling

Rapid Prototyping Techniques (RPT) have evolved over the last decade. Novel RP techniques are being developed to improve the overall properties of parts manufactured using RPT. One such technique is the Curved layer fused deposition modeling (CLFDM) which has been developed based on the conventional Fused Deposition Modeling (FDM) technique. The CLFDM technique has gained significant amount of attention as a result of its advantages such as increased flexural strength, reduction of the stair-stepping effect and the reduction in the number of layers, especially for thin shell-like structures. This paper studies the effects of fill gap (FG) on flexural strength and bead dimension, middle-plane cross section profiles and the fracture surface and compares the results to parts made using the traditional planar layer-by-layer approach. Also, in the end some meaningful and interesting future study areas both in hardware design and software development for the CLFDM are proposed.

Process and material behavior modeling for a new design of micro-additive fused deposition

The aim of this paper is to explore the limits and special requirements for additive manufacturing using polymer extrusion with a nozzle diameter much smaller than the conventional one: 0.050 mm diameter. This work is focused on the nozzle design and analyzes the effect of such a reduced diameter on the extrusion process and on the cooling of material while being deposited on the part. The approach is based on experimental and theoretical studies starting from conventional fused deposition modeling technology where the study tested swelling and cooling of filament material during deposition. Experimental work was used to assess the validity of the theoretical model and the first normal stress equation which estimated a swelling factor (diameter) of 1.249 at 0.087 g/h mass rate. The convection coefficient (h) on the plastic part was estimated as7 W/m2 K on the first deposited layer; considerably lower than some references show.