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Using multi-axis material extrusion to improve mechanical properties through surface reinforcement
Virtual and Physical Prototyping
Abstract
Due to the layer stacking inherent in traditional three-axis material extrusion (ME) additive manufacturing processes, a part's mechanical strength is limited in the print direction due to weaker interlayer bond strength. Often, this requires compromise in part design through either adding material in critical areas of the part, reducing end-use loads or forgoing ME as a manufacturing option. To address this limitation, the authors propose a multi-axis deposition technique that deposits material along a part's surface to improve mechanical performance. Specifically, the authors employ a custom 6 degree of freedom robotic arm ME system to create a surface reinforcing ‘skin’, similar to composite layup, in a single manufacturing process. In this paper, vertical tensile bars are fabricated through stacked XY layers, followed by depositing material directly onto the printed surface to evaluate the effect of the skinning approach on mechanical properties. Experimental results demonstrate that surface-reinforced interlayer bonds provide increased yield strength.
... Incorporating additional DoF into the deposition system would enable other strategies (e.g., Fig. 1(b)) by allowing the tool head and part to reorient relative to each other, as with the authors' 6-DoF robotic arm ME system shown in Fig. 2. Specifically, this would allow for better alignment of the material in regards to the applied loads and reduce the need for design compromises in order to maintain part performance [8]. Referred to here as multi-axis (MA) ME, these strategies have been used to improve the performance of hemispherical pressure caps [9], tensile bars through conformal surface reinforcement [10], and optimized 2.5D surface geometries [11] relative to geometrically similar parts printed with XY-planar layers. ...
... As described in Sec. 1, there are existing techniques for generating MA toolpaths (e.g., Refs. [9,11,10]), but they are restricted to the fabrication of geometries with deposition directions that lie on stratified surfaces (i.e., geometries with orientation fields that can be decomposed into a series of surfaces). The results demonstrated in this work do not have orientation fields that are easily decomposed into surfaces. ...
... For the sake of brevity, the specific forms of the gradient equations (given in general form in Eqs. (10) and (11)) are only shown for the Euler angle parameterization, but all parameterizations follow the same structure. ...
The layer-by-layer deposition process used in material extrusion (ME) additive manufacturing results in inter- and intra-layer bonds that reduce mechanical performance. Multi-axis ME techniques have shown potential for mitigating this issue by enabling tailored deposition directions based on loading conditions in three dimensions (3D). Planning deposition paths leveraging this capability remains a challenge, as an intelligent method for assigning these directions does not exist. Existing literature introduced topology optimization (TO) methods that assign material orientations to discrete regions of a part by simultaneously optimizing material distribution and orientation. These methods are insufficient for multi-axis ME, as the process offers additional freedom in varying material orientation that is not available to those methods. Additionally, optimizing orientation design spaces is difficult, and this issue is amplified with increased flexibility; the chosen orientation parameterization heavily impacts the algorithm's performance. Therefore, the authors i) present a TO method to solve the simultaneous problem with considerations for 3D material orientation variation and ii) establish a suitable parameterization of the orientation design space. Three parameterizations are explored in this work: Euler angles, explicit quaternions, and natural quaternions. The parameterizations are compared using two benchmark minimum compliance problems: a 2.5D Messerschimitt-Böolkow-Blohm beam and a 3D Wheel. For the Wheel, the presented algorithm demonstrated a 38% improvement in compliance over an algorithm that only allowed planar orientation variation. Additionally, natural quaternions maintain the well-shaped design space of explicit quaternions without unit length constraints, which lowers computational costs.
... The composite parts have much higher specific strength and stiffness along the fibre direction than parts made with polymers alone while remaining lightweight (Sieberer et al. 2022;Bhatt et al. 2020;Hou et al. 2020). At present, various types of CFRP-AM processes have been developed, such as laser-assisted tape placement (LATP) (Parandoush et al. 2017), laminated object manufacturing (LOM) (Bhatt et al. 2019), and material extrusion (MEX) (Matsuzaki et al. 2016;Billah et al. 2020;Kubalak, Wicks, and Williams 2018). In comparison, the MEX has gained the most widespread attention due to its lower cost and better controllability on fibre layouts (Dickson et al. 2017;van de Werken et al. 2021). ...
... The performance improvement of fabricated parts by the conformal CFRP-AM process is rarely reported. Moreover, the multi-DoF motion allows the toolpaths to be set along any desired direction rather than being limited to two dimensions to strengthen the model (Pedersen et al. 2016;Kubalak, Wicks, and Williams 2018). Therefore, generating desired conformal toolpaths becomes another great challenge for the development of CFRP-AM. ...
The advents in continuous fibre-reinforced polymer additive manufacturing (CFRP-AM) present unprecedented opportunities for the rapid development of next-generation high-performance composites with selectively and spatially distributed reinforcement. However, the widely adopted 3-degree-of-freedom motion configuration in current CFRP-AM systems hinders the exploration of composite structures with non-planar fibre layouts. This work presents a novel conformal CFRP-AM system to fabricate grid-stiffened shell structures leveraging its multi-DoF motion to pattern spatial features. The system integrates a 6-axis robot with an optimally designed co-extrusion module and operates through a design-to-manufacturing workflow. The proposed workflow includes three steps: system calibration, conformal toolpath generation, and process implementation. The conformal toolpath generation is a surface-mapping-based method that allows a simultaneous exploration of various geometric designs and their toolpaths. Experimental comparisons were made between parts fabricated by different processes, i.e., planar and conformal based, with different toolpaths, i.e., shells filled with zigzag and arc-offset patterns, and with various geometric designs, i.e., stiffener ribs with different crossline angles. The results manifest that the proposed system can significantly improve the compression strength and stiffness of grid-stiffened shell structures. Meanwhile, the additional design freedom on process and structure opens up a new possibility to customise their mechanical performance.
... Tam and Mueller printed optimized 2.5D surface geometries using a 6-DoF robotic arm, demonstrating a 76% improvement in ultimate compressive load over similar geometries fabricated using strictly XY-planar layers [12]. Previous work from the authors investigated the effects of conformal surface printing, similar to a composite layup process, facilitated by a 6-DoF robotic arm [13]. Tensile specimens fabricated with the surface reinforcement outperformed specimens without reinforcement by 59% in yield tensile stress. ...
... Analysis tools determined lines of principal stresses and deposition paths were propagated along those lines. For [13], the orientation field was not explicitly created, as the load paths were simplified in the tensile specimen geometry, but the expected load paths still informed the toolpath. ...
The thermal characteristics of the material extrusion additive manufacturing (AM) process produce weak bonds between layers and adjacent depositions, resulting in an overall anisotropic mechanical performance. Design for AM guidelines advise printing load-bearing parts such that load is applied strictly along the deposition paths, but this can be difficult to achieve with complex loading conditions. Recent works have explored toolpath generation techniques capable of generating deposition paths that are aligned with complicated load paths, but the methods rely on assumptions about the shape of the load paths relative to the geometry. In this paper, the authors present an algorithm for generating deposition paths for any arbitrary geometry and anticipated load paths. Deposition paths are planned using a streamline placement algorithm - commonly used for visualizing fluid flow fields - that treats the load paths as a velocity field. The algorithm is demonstrated on an example geometry, and the volumetric coverage of the resulting toolpath is compared to a toolpath generated using a standard toolpath planning technique. Through this comparative study, it is demonstrated that the toolpath resulting from the authors' proposed algorithm is able to follow the load paths while still achieving similar volumetric coverage to the standard toolpath.
... By aligning roads with principal stress lines, the optimized surface geometries outperformed similar, unoptimized XY-planar geometries. In the authors' previous work, the tensile performance of printed specimens was improved by depositing a conformal surface reinforcement with a robotic arm (Kubalak et al., 2017). The yield tensile strength exhibited by vertically oriented tensile bars improved by 59 per cent with the addition of the surface reinforcement. ...
... The build directions are assigned on the criterion of minimizing support material, but there is no control over the direction of Figure 1 Robotic ME platform deposition within each region. Others (Tam and Mueller, 2017;Kubalak et al., 2017) are used to improve mechanical performance and enable control over the deposition direction, but they are only applicable to surface geometries, making it difficult to extract generalizable mechanical properties. ...
Purpose
Material extrusion (ME) suffers from anisotropic mechanical properties that stem from the three degree of freedom (DoF) toolpaths used for deposition. The formation of each layer is restricted to the XY-plane, which produces poorly bonded layer interfaces along the build direction. Multi-axis ME affords the opportunity to change the layering and deposition directions locally throughout a part, which could improve a part’s overall mechanical performance. The purpose of this paper is to evaluate the effects of changing the layering and deposition directions on the tensile mechanical properties of parts printed via multi-axis ME.
Design/methodology/approach
A multi-axis toolpath generation algorithm is presented and implemented on a 6-DoF robotic arm ME system to fabricate tensile specimens at different global orientations. Specifically, acrylonitrile butadiene styrene (ABS) tensile specimens are printed at various inclination angles using the multi-axis technique; the resulting tensile strengths of the multi-axis specimens are compared to similarly oriented specimens printed using a traditional 3-DoF method.
Findings
The multi-axis specimens had similar performances regardless of orientation and were equivalent to the 3-DoF specimens printed in the XYZ orientation (i.e. flat on the bed with roads aligned to the loading condition). This similarity is attributed to those sets of specimens having the same degree of road alignment.
Practical implications
Parts with out-of-plane loads currently require design compromises (e.g. additional material in critical areas). Multi-axis deposition strategies could enable local changes in layering and deposition directions to more optimally orient roads in critical areas of the part.
Originality/value
Though multi-axis ME systems have been demonstrated in literature, no prior work has been done to determine the effects of the deposition angle on the resulting mechanical properties. This work demonstrates that identical mechanical properties can be obtained irrespective of the build direction through multi-axis deposition. For ABS, the yield tensile strength of vertically oriented tensile bars was improved by 153 per cent using multi-axis deposition as compared to geometrically similar samples fabricated via 3-DoF deposition.
... Thus, by controlling the orientation of the extruder, a part with a better surface finish, structural qualities, and less residual stress can be fabricated. In certain conditions, it may also eliminate the need for support for part fabrication through AM [14,15]. Bhatt et al. [16] have shown that the robotic sheet lamination-based AM process offers several benefits over other AM processes such as direct energy deposition and stereolithography. ...
div>This work aims to define a novel integration of 6 DOF robots with an extrusion-based 3D printing framework that strengthens the possibility of implementing control and simulation of the system in multiple degrees of freedom. Polylactic acid (PLA) is used as an extrusion material for testing, which is a thermoplastic that is biodegradable and is derived from natural lactic acid found in corn, maize, and the like. To execute the proposed framework a virtual working station for the robot was created in RoboDK. RoboDK interprets G-code from the slicing (Slic3r) software. Further analysis and experiments were performed by FANUC 2000ia 165F Industrial Robot. Different tests were performed to check the dimensional accuracy of the parts (rectangle and cylindrical). When the robot operated at 20% of its maximum speed, a bulginess was observed in the cylindrical part, causing the radius to increase from 1 cm to 1.27 cm and resulting in a thickness variation of 0.27 cm at the bulginess location. However, after optimizing the speed at 35% of its maximum speed, 100% dimensional accuracy was achieved. The integration resulted in collision-free robot and extrusion movement, flexibility, capability of making large parts, and enhanced dimensional accuracy.</div
... Even though there are solutions that allow for 3D printing using machines with 6 degrees of freedom [20], most available 3D printing solutions are based on fibre placement on a flat layer (XY-plane) -the 3D object is divided into flat 2D layers along the Z axis and then created by successively adding material layer-by-layer, as shown in Figure 1. The problem of stacking flat layers is not trivial and is well described in papers by Opalach et al. [14], Peeters et al. [21] and Le-Manh and Lee [22]. ...
The increasing popularity of continuous fibre 3D-printing brings new challenges to the composite design process. Usually, composite parts include physical obstacles: holes for bearings, inserts, bolts, external shape limitations, or exclusion zones. For such parts the well-known types of in-plane reinforcements – classical unidirectional infill, spiral reinforcement of holes, and generalised perimeters – do not provide satisfactory solutions. This article describes a completely new, specialised type of reinforcement based on the generalised belt-and-pulleys transmission principle, where the pulleys are generalised to any convex obstacles and the belt shows the fibre path connecting them. This type of fibre reinforcement provides an intuitive curvilinear connection between the obstacles and optimises the fibre direction in the most common case, when a load is applied to the obstacles. The developed algorithm has been implemented and is now an integral part of fibrify® Design Suite by 9T Labs.
... Robots can adapt to curved or irregular geometries, enabling the printing Kraiburg TPE (Waldkraiburg, Germany) [53] of complex shapes that would be challenging or impossible with gantry-based printers (Figure 4(b)). Kubalak et al. introduced an algorithm that automates the generation of multi-degree-of-freedom (DoF) tool paths for applying a reinforcing skin onto AM parts [60]. The efficacy of this skinning approach was demonstrated by comparing skinned tensile bars to similar bars without the skin. ...
Large-format 3D printing for polymers enables cost-effective mass customisation and production of structurally robust, large-scale components for industries like aerospace and automotive. This review analyses additive manufacturing scalability, including throughput, volume, and essential criteria for 3D printing techniques. Challenges in large-scale polymer additive manufacturing are explored, including material selection, interlayer bonding, surface quality versus production speed, recyclability of materials, and post-processing. Materials development is found to be crucial for addressing thermal shrinkage issues, with solutions involving process control and fibre reinforcement while considering rheological properties and nozzle clogging. Balancing production speed and surface finishing in material extrusion 3D printing involves factors like print speed, nozzle size, and innovative designs to optimise throughput and surface quality. In large-format 3D printing, meticulous process control and quality assurance are vital to ensure the expected printing outcomes and defect-free parts, given the substantial material and energy investment.
... Trumph 1000W CW laser and a coaxial powder head mounted on Kuba robot (Pinkerton, 2010) and 6-axis robotic-end effector and KUKA robot arm for ABS printing (Shi, 2014)). Especially, robotic arms have the benefits of speed, agility and flexibility in printing (Ding et al., 2015;Vasiliadis et al., 2022;Kubalak et al., 2018) and their control is already known before the advent of 3-, 5-or 6D printing concepts. ...
Additive manufacturing gained popularity in the 2000s and is now considered a new or emerging technology of the 21st century. However, the origin of the process is much older and has existed for several decades, more precisely since the 19th century, when it appeared in small science fiction novels. In addition to these layer-by-layer approaches, there are also additive tomographic or volumetric approaches that allow the 3D object to be printed in a single step. These approaches, along with 3D printing of smart materials, are not so popular and consequently not fully understood or utilised. Thus, the paper briefly outlines the history of the transition from classical 2.5D printing, to 3D or non-planar printing, to 4D printing (with smart materials), to 5D printing (on equipment with more than three degrees of freedom), to 6D printing (a combination of 4D and 5D printing) and finally to volumetric printing. The future perspective of this technology are briefly presented with some application and examples.
... To examine the effects of infill line direction and interface type on interlayer performance, a multi-axis toolpath planning algorithm is required to control the printing toolpath. Although various algorithms described in the existing literature can control the deposition direction of the tool, they are only applicable to surface geometries and are difficult to print standard interlayer fracture test specimens with a BISI [59][60][61]. In the algorithm adopted in this paper, the workpiece was first oriented to align its build direction with the global Z-axis, and then slicing was performed, similar to typical 3D printing deposition. ...
The weak layer interfaces of 3D-printed short carbon fiber (SCF) reinforced polymer composites have remained an issue due to planar layer printing by traditional 3D printers. Recently, multi-axis 3D printing technology which can realize non-planar layer printing has been developed. This study’s aim was to evaluate and compare the bonding performance of non-planar interfaces produced by multi-axis 3D printing with that of planar interfaces. The tested non-planar interfaces were designed as bio-inspired structured interfaces (BISIs) based on microstructural interfacial elements in biological materials. The standard specimens with the 0°/90° and 0° infill line directions were printed by a robotic arm multi-axis 3D printer. Double cantilever beam (DCB) and end-notched flexure (ENF) tests were conducted to obtain Mode Ⅰ and Mode Ⅱ interlaminar toughness of SCF-reinforced composites. Test results showed that the critical energy release rates of the integrally formed BISI were significantly improved compared with the planar interface (PLAI) for both Mode I and Mode II delamination. In particular, the BISI with 0° infill line direction exhibited the greatest increase in critical energy release rate, and the damaged areas were spatially swept through the curved interfaces of the BISI with different infill line directions by scanning electron microscopy (SEM) and computed tomography (CT), which showed that the higher critical energy release rate was always accompanied with a larger damaged area. In addition, the tensile and flexural properties of 0°-infilled PLAI and BISI specimens were also measured. This work provides an in-depth investigation of the PLAI and BISI properties of SCF-reinforced composites, demonstrating the potential benefits of integrally formed BISI by multi-axis 3D printing and fostering new perspectives to enhance layer interfaces of 3D printed composites.
https://authors.elsevier.com/c/1iIj37tcTWlOKr
... But self-collision and displacement between different non-planar surfaces is somehow the main problem. In general, non-planar layers are strongly affected by stair-stepping for flat surfaces [7,8]. This research work discusses experimental studies on product surface quality that were not possible for the planner tool path. ...
Fused deposit modeling (FDM) technology is one of the unique integration manufacturing processes in the engineering and biomedical sectors. However, surface finishing in the FDM process is a measure of concern mainly when the surface is either curved or irregular. Generally non-planar surfaces are usually reduced these tasks, but prototypes of an object are first introduced to create tool paths. So, the combination of non-planar and planar layers provides a smooth surface and the object is created through a FDM 3D printer. It always helps to increase the usability of an open-source slicer by adding the power needed to print a non-planar surface layer. Non-planar tool paths have been used to create a three-dimensional object and explain it with a slicer that helps it. The original print layers are formed by moving the bottom surfaces of the non-planar surface from their original position to the top, and the toolpaths protrude downward along the mesh of the original surface. Non-planar surfaces are not very good because the layers collide with the printhead in any complex object so a special printhead is designed for non-planar printing so that the layers do not collide with the printhead in any way when printing non-planar surfaces. This paper discusses experimental studies on product surface quality that were not possible for the planner tool path. It has been observed that the slicing time, printing time, and printing cost of 3D printed object using non-planar method are similar to planar layer method with an improved surface quality.KeywordsPlanar-layer printingNon-planar layer printingCurved layer printing
... Departing from the layer-by-layer approach, FFF systems were also developed to enable non-planar deposition for curved parts and aligning deposition of layers with predicted local stress tensors to enhance structural performance of the parts in out of plane directions [16,17]. A deposition system with six degrees of freedom that can effectively deposit material across multiple planes on the surface of the part with improved interlayer strength was also developed recently [18,19]. ...
... This hybrid process can provide high-quality items. To create high-quality sculptures, material is removed with the milling tool as it is deposited in layers by the FDM printer (Kubalak et al., 2018). A method for the FDM process that uses a six-axis industrial robot to deposit material on an item to enhance its mechanical qualities. ...
In this chapter, six axis robots-integrated fused deposition modelling (FDM) processes have been used to fabricate the polymer three-dimensional (3D) printing objects. A unique method of printing 3D things uses an industrial robot with an FDM extruder as its end-effector. This robot is controlled by sophisticated controller technology and Robot Ware control software. The robot's end effector will travel along the designed toolpath as it is modelled by Robot Studio software. Printing a cube serves as a demonstration of the methods used to combine the FDM process with a six-axis industrial robot. This demonstrates how components can be produced using additive manufacturing and robotics. By applying different process parameters of the innovative system, the tensile and flexural strengths of printed specimens have been optimised using the Taguchi method.
... In our case, this can be observed with the 0°/90°rectilinear path, in which an improved mechanical behavior was achieved (Figure 8). In addition, the incorporation of reinforcement shells around the printed object act to reduce the stair-stepping effect and to improve the mechanical performance by shifting the stress away from the interfaces between layers (Kubalak et al., 2018;Huang and Singamneni, 2015). This was indeed the case for the 0°/90°c ases with shells ( Figure 9). ...
Purpose
Mechanical anisotropy associated with material extrusion additive manufacturing (AM) complicates the design of complex structures. This study aims to focus on investigating the effects of design choices offered by material extrusion AM – namely, the choice of infill pattern – on the structural performance and optimality of a given optimized topology. Elucidation of these effects provides evidence that using design tools that incorporate anisotropic behavior is necessary for designing truly optimal structures for manufacturing via AM.
Design/methodology/approach
A benchmark topology optimization (TO) problem was solved for compliance minimization of a thick beam in three-point bending and the resulting geometry was printed using fused filament fabrication. The optimized geometry was printed using a variety of infill patterns and the strength, stiffness and failure behavior were analyzed and compared. The bending tests were accompanied by corresponding elastic finite element analyzes (FEA) in ABAQUS. The FEA used the material properties obtained during tensile and shear testing to define orthotropic composite plies and simulate individual printed layers in the physical specimens.
Findings
Experiments showed that stiffness varied by as much as 22% and failure load varied by as much as 426% between structures printed with different infill patterns. The observed failure modes were also highly dependent on infill patterns with failure propagating along with printed interfaces for all infill patterns that were consistent between layers. Elastic FEA using orthotropic composite plies was found to accurately predict the stiffness of printed structures, but a simple maximum stress failure criterion was not sufficient to predict strength. Despite this, FE stress contours proved beneficial in identifying the locations of failure in printed structures.
Originality/value
This study quantifies the effects of infill patterns in printed structures using a classic TO geometry. The results presented to establish a benchmark that can be used to guide the development of emerging manufacturing-oriented TO protocols that incorporate directionally-dependent, process-specific material properties.
... So far, the most convenient and efficient way is to create dedicated paths to given shapes with regard to the application. The final decision may be influenced by aesthetics, printing time, the need to use support structures or mechanical strength required [18]. Some of the published works focus on cutting 3D models for non-planar printing based on decomposing and regrouping of the shape of the model to create sections that are 3D printed in different orientations [19]. ...
An attempt was made to build a simple and low-cost device capable of positioning 3D prints for the process of additive manufacturing to conveniently allow the desired extend of the existing 3D printing capabilities. 3D printing with the use of increased number of axes, as compared to the standard approach, can eliminate such disadvantages of FDM technology as orthotropy of prints, surface roughness, and the consumption of both time and material devoted to make support structures. A CAD design of a parallel manipulator, used as a positioning table (platform), was developed, which was used for numerical simulations, and then a physical manipulator was made. The table was tested independently, i.e., as a stand-alone device, and, next, in cooperation with a 3D printer which allowed to obtain non-planar prints. The obtained results allowed for both the identification of problems related to multi-axis 3D FDM printing and an attempt to formulate concepts enabling to overcome them via adequate design and control modifications. The raised conclusions will be used to further development and more comprehensive understanding the phenomena that are present during the investigated manufacturing process.
... The mechanisms of this printer is shown in Figure 9 In 2018, Dai et al. (2018) presented a six-DOF printer that can deposit material along curved layers, thus achieving zero support usage (see Figure 10). Kubalak, Wicks, and Williams (2018) proposed a six-DOF AM system to fabricate parts with improved mechanical properties. De ...
Currently, additive manufacturing (AM) technology has received significant attention from both academia and industry. AM is characterized by fabricating geometrically complex components in a layer-by-layer manner, and greatly reduces the geometric complexity restrictions compared with traditional manufacturing. As AM is no longer limited to the normal three degrees of freedom (DOF) (three-axis) systems, there are many new multi-DOF AM machines been developed with various aims. It is, therefore, necessary that a review of the topic with regard to multi-DOF AM is performed for future AM system development. This paper, focuses on reviewing publications related to multi-DOF AM according to the number of DOF on an AM machine. The major part of the paper aims to inspire both researchers and engineers to further develop and improve multi-DOF AM systems to achieve different goals. The final part of the paper discusses the findings together with future research directions.
... However, it is still an immature technology, and the effects of bead-bead bonding, bead-pin bonding needs to be investigated for further improvement. Another exciting addition in FFF technology is the six degrees of freedom (DOF) FFF extrusion system [195,196]. This multi-DOF extrusion system may give the flexibility to align beads with a preferred direction (x, y, and z) with the part's stress contours to arrest the inter-layer delamination like the Z-pinning. ...
This paper presents the state-of-the-art of additive manufacturing of composites for processing functional, load-bearing components. A general overview of different additive manufacturing methods is provided, and specific attention is focused on fused filament fabrication-based composites processing. Different process modeling strategies are summarized, and key aspects of these models are discussed. Significant results such as thermal and fluid flow characteristics, effects of nozzle geometry on melt flow, fiber orientation, bead spreading, and solidification, the formation of residual stresses, and deformation behavior are discussed from computational modeling perspective. The scientific advancement, model limitations, and future modeling needs are prescribed reviewing the current works. A general overview of material development in nano-micro-macro-scale reinforcement is also presented. Different length-scales of reinforcement has its own challenges and promises. The continuous fiber reinforcement has a great potential for being the next-generation composites manufacturing technology. However, the challenges in reducing the void content, better bonding between the fiber–matrix, and layer-layer adhesion, and process uncertainty are some of the key areas yet to advance. Based on the current limitations on computational modeling, materials development, and process modeling studies, future research needs and recommendations are provided.
... The first step before slicing is to orientate the part, which means how to place the part referred to the printer axis (X, Y, and Z). The orientation affects the surface roughness and/or dimensional accuracy [2][3][4][5][6][7][8][9][10], printing time [4][5][6], and part strength [7,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. ...
In this paper, the fatigue response of fused filament fabrication (FFF) Acrylonitrile butadiene styrene (ABS) parts is studied. Different building parameters (layer height, nozzle diameter, infill density, and printing speed) were chosen to study their influence on the lifespan of cylindrical specimens according to a design of experiments (DOE) using the Taguchi methodology. The same DOE was applied on two different specimen sets using two different infill patterns—rectilinear and honeycomb. The results show that the infill density is the most important parameter for both of the studied patterns. The specimens manufactured with the honeycomb pattern show longer lifespans. The best parameter set associated to that infill was chosen for a second experimental phase, in which the specimens were tested under different maximum bending stresses so as to construct the Wöhler curve associated with this 3D printing configuration. The results of this study are useful to design and manufacture ABS end-use parts that are expected to work under oscillating periodic loads.
... At the end, one more point worth mentioning is that five-axis filament deposition (Song, Pan, and Chen 2015; Wu et al. 2017a;Dai et al. 2018;Kubalak, Wicks, and Williams 2018) has been widely investigated. By rotating the part orientation or the printing nozzle direction, overhangs can be manufactured which totally eliminates the need of overhang-free constraints. ...
In recent years, additive manufacturing technology has been highly focused on its strong capability in complex geometry manufacturing and great suitability for customised product fabrication. Researchers have recognised the key role of additive manufacturing in leading the next-generation manufacturing, and have conducted extensive research from different aspects, including product design, process development, material modelling and many others. Several design-for-additive manufacturing methods have been proposed, specifically about design, and different computer-aided programmes have been developed, such as geometric modelling-based design, bio-inspired design, evolutionary algorithm-driven design and topology optimisation. However, authors have observed that many of these methods are named ‘design for additive manufacturing’ without specifying the exact additive manufacturing process. This could be problematic since a general design method cannot reflect the best practice given a specific additive manufacturing process. In this review paper, material extrusion polymer 3D printing is focused specifically. The motive of this paper is to conduct a literature survey about design methods for material extrusion polymer 3D printing, summarising the state of the art and pointing out the underdeveloped research topics; more importantly, some general design-for-additive manufacturing methods will be discussed, especially for their adaption to the material extrusion process.
... Custom mechanism 3 + 2 ✓ Material extrusion ABS/Nylon/Polyester Chen et al. [124] Custom mechanism 5 ✓ VAT photopolymerization Resin Peng et al. [125] Custom mechanism 5 ✓ Material extrusion ABS Kubalak et al. [126] Manipulator 6 ✓ Material extrusion ABS ...
Robots are versatile machines that can perform complex manipulation operations. Recent advances in industrial robotics make robots useful in a wide variety of manufacturing processes. Several recent efforts have demonstrated how robots can be used in additive manufacturing (AM) processes. This paper surveys the work focused on expanding the functional capabilities of AM processes using robots. We identify the following main capabilities realized by performing AM using robots: (1) multi-directional fabrication, (2) conformal deposition, (3) assembling prefabricated components in AM, (4) supportless AM, and (5) large-scale AM. We classify the recent literature in this area in terms of mechanisms, kinematic degrees of freedom (DOF) of the system, types of AM process, and materials. Finally, we discuss the limitations of the current work and the opportunities for future research in this area.
... Flexibility, productivity and agility are the key elements of today's competitive manufacturing environment [80]. With the development of automation technologies, multiple degree of freedom robots are promising systems for the implementation of flexible, productive and reconfigurable manufacturing methods, performing several tasks from basic handling operations to grinding, cutting, drilling, welding and polishing [81]. Moreover, current additive manufacturing systems have great potential to reduce time to market, increasing customisation, widening the design option compared to traditional methods. ...
The additive manufacturing and the robotic applications are tremendously increasing in the manufacturing field. This review paper discusses the concept of robotic-assisted additive manufacturing. The leading additive manufacturing methods that can be used with a robotic system are presented and discussed in detail. The information flow required to produce an object from a CAD model through a robotic-assisted system, different from the traditional information flow in a conventional additive manufacturing approach is also detailed. Examples of the use of robotic-assisted additive manufacturing systems are presented.
... Nonplanar printed parts where both stronger and stiffer than their regular printed counterparts. Kubalak et al. [22] showed that the layer bonding can be increased by printing a reinforcement shell onto the outer surface of the object to shift the mechanical stress away from the layer bondings. ...
... Nonplanar printed parts where both stronger and stiffer than their regular printed counterparts. Kubalak et al. [22] showed that the layer bonding can be increased by printing a reinforcement shell onto the outer surface of the object to shift the mechanical stress away from the layer bondings. ...
Additive manufacturing processes are inherently subject to discretization effects. For most technologies, stair-stepping artifacts impair the surface quality of 3D printed objects, especially when the surface slope is close to horizontal. In this paper we propose a novel Fused Deposition Modeling (FDM) slicing approach that combines nonplanar and planar layers, increasing printing quality and resulting in smoother, stronger object surfaces. Our slicing algorithm automatically detects which parts of the object should be printed with nonplanar layers and uses a geometric model of the printhead and extruder to generate collision-free toolpaths. Our open source implementation is based on the popular Slic3r tool and can be used on all common three-axis 3D printers. We present typical printing results and compare surface quality as well as slicing and printing times with traditional and adaptive planar slicing.
... To improve the mechanical properties along the printing axis, [Kubalak et al., 2018] printed a reinforced surface onto a regularly printed core with a six-axis robotic arm printing system. The idea is to shift the stress from the layer bonding to the shell of the object which is printed in a different direction as the core. ...
Stair stepping artifacts reduce the surface quality of 3D printed objects, especially when the slope is close to horizontal. Previous researchers showed that nonplanar surfaces could reduce these artifacts but only presented prototypes for the toolpath generation. The combination of nonplanar and planar layers results in smoother surfaces and the object is still printable on a three-axis 3D printer. Adding the ability to print nonplanar surfaces to an open-source slicer increases the usabil-ity and provides a general-purpose approach. This work presents a slicer that is capable of generating nonplanar toolpaths from any object. While printing, the printhead does not collide with the object since this is checked beforehand. The surface quality of objects with nonplanar layers is significantly better than with planar layers only.
... Flexibility, productivity and agility are the key elements of today's competitive manufacturing environment [80]. With the development of automation technologies, multiple degree of freedom robots are promising systems for the implementation of flexible, productive and reconfigurable manufacturing methods, performing several tasks from basic handling operations to grinding, cutting, drilling, welding and polishing [81]. Moreover, current additive manufacturing systems have great potential to reduce time to market, increasing customisation, widening the design option compared to traditional methods. ...
OBJECTIVES. We aimed to identify a mechanism for statin-induced myopathy which explains its prevalence and selectivity for skeletal muscle, and to understand its interaction with moderate exercise. BACKGROUND. Statin-associated adverse muscle symptoms reduce adherence to statin therapy and this limits the effectiveness of statins in reducing cardiovascular risk. The issue is further compounded by perceived interactions between statin treatment and exercise. METHODS. We studied muscles from individuals taking statins and rats treated with statins for 4 weeks. RESULTS. In skeletal muscle, statin treatment caused dissociation of the stabilizing protein FKBP12 from the sarcoplasmic reticulum (SR) Ca2+ release channel, the ryanodine receptor 1 (RyR1), which was associated with pro-apoptotic signaling and reactive nitrogen/oxygen species (RNS/ROS)-dependent spontaneous SR Ca2+ release events (Ca2+ sparks). Statin treatment had no effect on Ca2+ spark frequency in cardiac myocytes. Despite potentially deleterious effects of statins on skeletal muscle, there was no impact on force production or SR Ca2+ release in electrically-stimulated muscle fibers. Statin-treated rats with access to a running wheel ran further than controls and this exercise normalized FKBP12 binding to RyR1, preventing the increase in Ca2+ sparks and pro-apoptotic signaling. CONCLUSIONS. Statin-mediated RNS/ROS-dependent destabilization of SR Ca2+ handling has the potential to initiate skeletal (but not cardiac) myopathy in susceptible individuals. Importantly, although exercise increases RNS/ROS, it did not trigger deleterious statin effects on skeletal muscle; indeed our results indicate that moderate exercise may benefit individuals who take statins.
... FFF systems are using a similar approach for non-planar deposition on a curved surface to shift stress from planar interfaces into the primary structure [22,23]. A six degree of freedom deposition system is also being developed that can deposit material across multiple planes on the surface of parts -effectively creating a "skin" on the part exterior to improve inter-layer strength [24,25]. ...
Conventional 3D printing approaches are restricted to building up material in a layer-by-layer format, which is more appropriately considered “2.5-D” printing. The layered structure inherently results in significant mechanical anisotropy in printed parts, causing the tensile strength in the build direction (z-axis) to be only a fraction of the in-plane strength – a decrease of 50–75% is common. In this study, a novel “z-pinning” approach is described that allows continuous material to be deposited across multiple layers within the volume of the part. The z-pinning process is demonstrated using a Fused Filament Fabrication (FFF) printer for polylactic acid (PLA) and carbon fiber reinforced PLA. For both materials, z-pinning increased the tensile strength and toughness in the z-direction by more than a factor of 3.5. Direct comparisons to tensile strength in the x-axis showed a significant decrease in mechanical anisotropy as the volume of the pin was increased relative to the void in the rectilinear grid structure. In fact, the PLA sample with the largest pin volume demonstrated mechanically isotropic properties within the statistical uncertainty of the tests. Tensile test results were also analyzed relative to the functional area resisting deformation for each sample.
... Whereas conventional 3axis AM strategies slice geometry into simplified 2D tool paths, 5-axis tool path generation becomes dynamic, requiring specialist software not usually associated with AM. Curved layer Material Extrusion (CLME) is an AM process which has been developed over the past decade and presented by a number of authors [3,4,8]. A ME machine is typically modified with an additional axis of rotational movement in the substrate allowing the tool movement required to deposit curved layers. ...
A link to the conference paper is in the comments.
Mechanical properties of parts fabricated via the Material Extrusion (ME) process can be improved by optimising process settings, however, their properties are strongly influenced by build orientation due to the stair-stepping effect initiating cracks whilst under load. 5-axis ME enables the fabrication of parts without the layer-by-layer restrictions that conventional 3-axis strategies impose. By aligning extrusion direction with high stress tensors, 5-axis tool paths can be used to reduce the effects of weak inter-layer bonds.
To establish performance differences between parts manufactured by either strategy, wave spring-inspired geometry was selected for production, due to the multi-directional tensile loads acting throughout the material. 5-axis and 3-axis tool paths were generated via the Grasshopper 3D virtual environment within Rhinoceros 3D and MakerBot Desktop, and manufactured using a 5AXISMAKER and a MakerBot Replicator 2, respectively. To evaluate performance differences between the two strategies, compression tests were conducted on the parts.
... The first step before slicing is to orientate the part, which means how to place the part referred to the printer axis (X, Y, and Z). The orientation affects the surface roughness and/or dimensional accuracy [2][3][4][5][6][7][8][9][10], printing time [4][5][6], and part strength [7,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. ...
In this paper, the fatigue response of fused filament fabrication (FFF) Acrylonitrile butadiene styrene (ABS) parts is studied. Different building parameters (layer height, nozzle diameter, infill density, and printing speed) were chosen to study their influence on the lifespan of cylindrical specimens according to a design of experiments (DOE) using the Taguchi methodology. The same DOE was applied on two different specimen sets using two different infill patterns-rectilinear and honeycomb. The results show that the infill density is the most important parameter for both of the studied patterns. The specimens manufactured with the honeycomb pattern show longer lifespans. The best parameter set associated to that infill was chosen for a second experimental phase, in which the specimens were tested under different maximum bending stresses so as to construct the Wöhler curve associated with this 3D printing configuration. The results of this study are useful to design and manufacture ABS end-use parts that are expected to work under oscillating periodic loads.
... The first step before slicing is to orientate the part, which means how to place the part referred to the printer axis (X, Y and Z). The orientation affects surface roughness and/or dimensional accuracy [2][3][4][5][6][7][8][9][10], printing time [4][5][6] and part strength [7,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. ...
In this paper, the fatigue response of Fused Filament Fabrication (FFF) Acrylonitrile butadiene styrene (ABS) parts is studied. Different building parameters (layer height, nozzle diameter, infill density, and printing speed) were chosen to study their influence on the lifespan of cylindrical specimens according to a design of experiments (DOE) using the Taguchi methodology. The same DOE was applied on two different specimen sets using two different infill patterns: rectilinear and honeycomb. The results show that infill density is the most important parameter for both studied patterns. The specimens manufactured with the honeycomb pattern show longer lifespans. The best parameter set associated to that infill was chosen for a second experimental phase, in which the specimens were tested under different maximum bending stresses to construct the Wöhler curve associated to this 3D printing configuration. The results of this study are useful to design and manufacture ABS end-use parts that are expected to work under oscillating periodic loads.
Purpose
Material extrusion (MEX) additive manufacturing often requires support structures to enable manufacture of steep overhanging features. Multi-axis deposition (often enabled by a robotic arm) offers novel toolpath planning methods that can significantly reduce or eliminate supports. However, there is currently a lack of established design guidelines for the process.
Design/methodology/approach
This study investigates the relationship between achievable, support-free overhangs and the multi-axis build direction. Although altering build directions mid-print can increase the layer-to-layer overlap of an overhanging feature, the deposition paths on the overhanging surface may be less supported with respect to gravity. To interrogate these effects, a 6-degree-of-freedom robotic arm MEX platform printed test pieces with overhang angles (relative to the build direction) increasing from 0° to 75° at build directions varying from 0° (i.e., XY-planar) to 60° with respect to the global Z-axis.
Findings
Characterization of printed surface quality revealed no statistically significant difference in the fidelity of the overhanging surface as the build direction was changed. These results suggest that the overhang threshold observed in traditional XY-planar printing (typically 45°) remain consistent regardless of build direction (e.g. a build direction of 60° successfully printed a relative overhang of 45°), indicating that deposition quality was not negatively impacted by gravitational forces.
Originality/value
This study provides insight into how tool orientation can be optimized to maximize part accuracy and minimize support material requirements; after quickly screening for the XY-planar overhang threshold, designers can freely select multi-axis build directions throughout part geometries, provided the overhanging surfaces are below that relative threshold.
High-performance insulation materials are used in transformers, generators, and closed-loop lines for high-speed trains and aviation. Traditional artificial materials have weak mechanical and dielectric characteristics and for obtaining better properties high processing cost of fibre is involved. In order to overcome this problem an effect was made in this study by manually fabricating the insulation sheet by utilizing high-performance industrial spinning waste of p-aramid fibres and cigarette filter fibres. The fabricated insulation sheets were tested for its thermal and mechanical properties, such as tensile strength, thermal conductivity, contact heat transmission, and flammability. It was found that the sample prepared with equal weight percentage of p-aramid waste fibres and cigarette filter fibres had 2.5kgf tensile strength. Additionally, the sample required 105 s for 10 °C rise in temperature while tested at 100 °C as per ISO 12127-1.KeywordsCigarette filterThermal insulationP-aramid fibreInsulation sheet
Numerical experimentation is performed to investigate the steady-state flow and heat transfer phenomenon over a solid sphere at medium range of Reynolds number (0.1 ≤ Re ≤ 100) and Peclet number (0.1 ≤ Pe ≤ 200). The Navier–Stokes equation of the spherical polar coordinate system in stream function and vorticity formulation is used to capture the momentum transfer while the temperature equation of the spherical polar coordinate system is utilized for heat transport. The finite difference method is applied to discretize the governing equations, and the successive over-relaxation method is used to solve the discretized sets of algebraic equations. The momentum transfer section of the simulation is validated by comparing the vortex separation angle, vortex width, and the total drag coefficients with the existing works. Moreover, the heat transfer phenomenon is authenticated by comparing the average Nusselt number with literature. The outcome of this study is presented in terms of streamline and vorticity contour, the drag coefficients, isotherm contour, and local and average Nusselt numbers (Nu) at various Re and Pe. While performing this numerical experimentation, it is observed that a vortex ring at the downstream location of the sphere first appears at Re equal to 22. Moreover, at low Re, the vorticity contour exists in the whole computational domain, and with increase in Re, the vorticity fields start to diffuse toward the rear section of the sphere. In addition, for the case of heat transfer occurrence, the Re has significant influence on Nu at relatively higher Pe only.
Rapid Prototyping (RP) technologies provide the ability to fabricate initial prototypes from various model materials. Stratasys Fused Deposition Modeling (FDM) is a typical RP process that can fabricate prototypes out of ABS plastic. To predict the mechanical behavior of FDM parts, it is critical to understand the material properties of the raw FDM process material, and the effect that FDM build parameters have on anisotropic material properties. This paper characterizes the properties of ABS parts fabricated by the FDM 1650. Using a Design of Experiment (DOE) approach, the process parameters of FDM, such as raster orientation, air gap, bead width, color, and model temperature were examined. Tensile strengths and compressive strengths of directionally fabricated specimens were measured and compared with injection molded FDM ABS P400 material. For the FDM parts made with a 0.003 inch overlap between roads, the typical tensile strength ranged between 65 and 72 percent of the strength of injection molded ABS P400. The compressive strength ranged from 80 to 90 percent of the injection molded FDM ABS. Several build rules for designing FDM parts were formulated based on experimental results. Electronic access The research register for this journal is available at http://www.emeraldinsight.com/researchregisters The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/1355-2546.htm 1.
Purpose
This paper aims to investigate the deposited structure and mechanical performance of printed materials obtained during initial development of the Big Area Additive Manufacturing (BAAM) system at Oak Ridge National Laboratory. Issues unique to large-scale polymer deposition are identified and presented to reduce the learning curve for the development of similar systems.
Design/methodology/approach
Although the BAAM’s individual extruded bead is 10-20× larger (∼9 mm) than the typical small-scale systems, the overall characteristics of the deposited material are very similar. This study relates the structure of BAAM materials to the material composition, deposition parameters and resulting mechanical performance.
Findings
Materials investigated during initial trials are suitable for stiffness-limited applications. The strength of printed materials can be significantly reduced by voids and imperfect fusion between layers. Deposited material was found to have voids between adjacent beads and micro-porosity within a given bead. Failure generally occurs at interfaces between adjacent beads and successive layers, indicating imperfect contact area and polymer fusion.
Practical implications
The incorporation of second-phase reinforcement in printed materials can significantly improve stiffness but can result in notable anisotropy that needs to be accounted for in the design of BAAM-printed structures.
Originality/value
This initial evaluation of BAAM-deposited structures and mechanical performance will guide the current research effort for improving interlaminar strength and process control.
In common thermoplastic additive manufacturing (AM) processes, a solid polymer filament is melted, extruded though a rastering nozzle, welded onto neighboring layers and solidified. The temperature of the polymer at each of these stages is the key parameter governing these non-equilibrium processes, but due to its strong spatial and temporal variations, it is difficult to measure accurately. Here we utilize infrared (IR) imaging - in conjunction with necessary reflection corrections and calibration procedures - to measure these temperature profiles of a model polymer during 3D printing. From the temperature profiles of the printed layer (road) and sublayers, the temporal profile of the crucially important weld temperatures can be obtained. Under typical printing conditions, the weld temperature decreases at a rate of approximately 100°C/s and remains above the glass transition temperature for approximately 1 s. These measurement methods are a first step in the development of strategies to control and model the printing processes and in the ability to develop models that correlate critical part strength with material and processing parameters.
This book covers in detail the various aspects of joining materials to form parts. A conceptual overview of rapid prototyping and layered manufacturing is given, beginning with the fundamentals so that readers can get up to speed quickly. Unusual and emerging applications such as micro-scale manufacturing, medical applications, aerospace, and rapid manufacturing are also discussed. This book provides a comprehensive overview of rapid prototyping technologies as well as support technologies such as software systems, vacuum casting, investment casting, plating, infiltration and other systems. This book also: Reflects recent developments and trends and adheres to the ASTM, SI, and other standards Includes chapters on automotive technology, aerospace technology and low-cost AM technologies Provides a broad range of technical questions to ensure comprehensive understanding of the concepts covered.
Fused Filament Fabrication (FFF) is an additive manufacturing (AM) method that relies on the thermal extrusion of a thermoplastic feedstock from a mobile deposition head. Conventional FFF constructs components from stacks of individual extruded layers using tool paths with fixed z-values in each individual layer. Consequently, the manufactured components often contain inherent weaknesses in the z-axis due to the relatively weak thermal fusion bonding that occurs between individual layers, as well as poor surface finish in shallow sloped contours. This study demonstrates the use of Curved Layer FFF (CLFFF) tool paths in tandem with a commercially available parallel, or delta, style FFF system to allow the deposition head to follow the topology of the component. By incorporating a delta robot and CLFFF tool paths in this way, improvements in the surface finish of the manufactured parts has been observed, and time costs associated with Cartesian robot based CLFFF manufacturing have been notably reduced. Furthermore, employing a delta robot provides additional flexibility to CLFFF manufacturing and increases the feasibility of its application for advanced manufacturing. The study has also demonstrated a viable approach to multi-material FFF by decoupling support structure and part manufacture into regions of CLFFF and static z tool pathing in an appropriate fashion.
Purpose
– This paper aims to develop a new slicing method for fused deposition modelling (FDM), the curved layer adaptive slicing (CLAS), combining adaptive flat layer and curved layer slicing together.
Design/methodology/approach
– This research begins with a review of current curved layer and adaptive slicing algorithms employed in the FDM and further improvement of the same, where possible. The two approaches are then integrated to develop the adaptive curved layer slicing based on the three-plane intersection method for curved layer offsetting and consideration of facet angles together with the residual heights for adaptive slicing. A practical implementation showed that curved layer adaptive layers respond in similar lines to the flat layer counterparts in terms of the mechanical behaviour of FDM parts.
Findings
– CLAS is effective in capturing sharply varying surface profiles and other finer part details, apart from imparting fibre continuity. Three-point bending tests on light curved parts made of curved layers of varying thicknesses prove thicker curved layers to result in better mechanical properties.
Research limitations/implications
– The algorithms developed in this research can handle relatively simple shapes to develop adaptive curved slices, but further developments are necessary for more complex shapes. The test facilities also need further improvements, to be able to programmatically implement adaptive curved layer slicing over a wide range of thicknesses.
Practical implications
– When fully developed and implemented, CLAS will allow for better FDM part construction with lesser build times.
Originality/value
– This research fills a gap in terms of integrating both curved layer and adaptive slicing techniques to better slice and build a part of given geometry using FDM.
Building end-use functional parts with additive manufacturing (AM) technologies is a challenging task. Several factors influence their surface finish, dimensional accuracy, mechanical properties and cost. Their orientation inside the building chamber is one of the most significant factors in AM processes. When using Fused Deposition Modeling (FDM) to build such parts, additional factors must be considered.
This paper aims to accomplish two purposes: finding a good model to simulate FDM parts and correlating a finite element analysis (FEA) simulation with physical testing.
The first objective was achieved by experimental tensile test of specimens to determine the nine mechanical constants that defines the stiffness matrix of an orthotropic material. Three Young’s modulus, three Poisson’s ratio and three shear modulus were experimentally obtained as well as yield tensile and ultimate strength of each specimen.
A simple part was designed and manufactured in different orientations to be physically tested and simulated to achieve the second objective. Polycarbonate (PC) was used as part material. Combined loading including bending and torsion was used. Differences on mechanical response were observed during the physical test of the parts depending on the building direction. Conclusions comment results and the convenience of using a different constitutive model depending on the design and use specifications
Through the method of fiber lamination, carbon fiber preforms with different orientation angles of 30°, 45°, 60° and 90° were prepared, and 2D-Cf/Al composites were fabricated by liquid–solid extrusion following the vacuum infiltration technique (LSEVI). Through mechanical properties test of the above composites, it showed that ultimate tensile strength (UTS) of the obtained Cf/Al composite was improved more than that of the matrix alloy. It was found that the volume fraction of four kinds of preform was about 45%. Fibers were arranged according to a certain direction, and this was very helpful in improving the performances of composites. In the preparation process, squeeze pressure was far greater than theoretical calculated value, and this was because many infiltration factors had been simplified and ignored in the theoretical calculation model. Infiltration of composites was sufficient and uniform and obvious defects could not be found. Tensile fracture was uneven, indicating that fibers played the reinforced role effectively, which also improved the properties of the composites greatly. Meanwhile, the increased rates of composites׳ UTS with different angles had large differences. When the angles were 45° and 90°, the increased rates were 112.5% and 63.9%, respectively. Through theoretical analysis and experimental comparison, it was concluded that the total fiber bearing capacities were the key dominant factor.
Fused deposition modeling (FDM), one of the rapid prototyping techniques is a promising technology for rapid manufacture of end use parts direct from CAD files and with the proliferation of cheaper machines, is likely to play a vital role in future polymer processing, challenging traditional processes such as injection moulding in some cases. Research evidence suggests that the road and layer structures would have significant influences on the mesostructure and consequent mechanical behaviour of the resulting polymer part. While adaptive slicing and other deposition schemes have been attempted for different reasons, it is believed that an appropriate deposition scheme is essential to ensure the best inter-road and interlayer connectivity, resulting in a continuous network of polymer chains, as in the case of the traditional processes. The current research proposes the curved layer deposition for FDM, in particular for thin shell-like parts, to ensure fibre continuity. Mathematical models are developed for curved slicing, implemented in a few case studies, parts are printed, and test results suggest marked improvement in the mechanical characteristics of curved layer parts.
Rapid Prototyping (RP) technologies provide the ability to fabricate initial prototypes from various model materials. Stratasys Fused Deposition Modeling (FDM) is a typical RP process that can fabricate prototypes out of ABS plastic. To predict the mechanical behavior of FDM parts, it is critical to understand the material properties of the raw FDM process material, and the effect that FDM build parameters have on anisotropic material properties. This paper characterizes the properties of ABS parts fabricated by the FDM 1650. Using a Design of Experiment (DOE) approach, the process parameters of FDM, such as raster orientation, air gap, bead width, color, and model temperature were examined. Tensile strengths and compressive strengths of directionally fabricated specimens were measured and compared with injection molded FDM ABS P400 material. For the FDM parts made with a 0.003 inch overlap between roads, the typical tensile strength ranged between 65 and 72 percent of the strength of injection molded ABS P400. The compressive strength ranged from 80 to 90 percent of the injection molded FDM ABS. Several build rules for designing FDM parts were formulated based on experimental results. Electronic access The research register for this journal is available at http://www.emeraldinsight.com/researchregisters The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/1355-2546.htm 1.
5980 Series -Dual Column Floor Model
- Instron
Instron, "5980 Series -Dual Column Floor Model." [on-line] Available
from:
http://www.instron.us/en-us/products/testing-systems/universal-testingsystems/electromechanical/5900/5980-floor-model [Accessed 8 June 2017], 2017.
Design and realization of a 6 degree of freedom robotic extrusion platform
- J R Kubalak
Oak Ridge National Lab, Oak Ridge, TN. Manufacturing Demonstration Facility, 1-11. Available from: https://www.osti.gov/scitech
- L J Love
- C Duty
Honeycomb Filaments: Drone Line
- Reprap
RepRap, "Honeycomb Filaments:
Drone Line." [on-line] Available from:
http://reprap.org/wiki/Honeycomb Filaments: Drone Line [Accessed 27 September 2017], 2017.
Strengthening ABS, Nylon, and Polyester 3D Printed Parts by Stress Tensor Aligned Deposition Paths and Five-Axis Printing
- W S Yerazunis
- J C I Barnwell
- D N Nikovski
W. S. Yerazunis, J. C. I. Barnwell, and D. N. Nikovski, "Strengthening ABS, Nylon, and
Polyester 3D Printed Parts by Stress Tensor Aligned Deposition Paths and Five-Axis
Printing," Solid Freeform Fabrication Symposium, pp. 1259-1271, 2016.
The Effect of Fiber Orientation and Laminate Layup on Fiber-Reinforced Polymer Composite
- I Sharma
- P D Kumar
- P R Maiti
I. Sharma, P. D. Kumar, and P. R. Maiti, "The Effect of Fiber Orientation and Laminate
Layup on Fiber-Reinforced Polymer Composite," Journal of Structural Engineering,
pp. 49-70, 2015.
Manufacturing Demonstration Facility, 1-11
- L J Love
- C Duty
Cincinnati big area additive manufacturing (BAAM)
- L J Love
- C Duty
L. J. Love and C. Duty, "Cincinnati big area additive manufacturing (BAAM)," pp. 1-11, 2015.
Design and Realization of a 6 Degree of Freedom Robotic Extrusion Platform
- J R Kubalak
- C D Mansfield
- T H Pesek
- Z K Snow
- E B Cottiss
- O D Ebelingkoning
- M G Price
- M H Traverso
- L D Tichnell
- C B Williams
- A L Wicks
J. R. Kubalak, C. D. Mansfield, T. H. Pesek, Z. K. Snow, E. B. Cottiss, O. D. Ebelingkoning, M. G. Price, M. H. Traverso, L. D. Tichnell, C. B. Williams, and A. L. Wicks,
"Design and Realization of a 6 Degree of Freedom Robotic Extrusion Platform," Solid
Freeform Fabrication Symposium, pp. 1314-1332, 2016.
D638-14 Standard Test Method for Tensile Properties of Plastics
ASTM, "D638-14 Standard Test Method for Tensile Properties of Plastics, ASTM International, West Conshohocken, PA," 2014.