Extrusive Layer Research Articles

Multi-material 3D-Printing Soft Robot Functional Component

—3D printing has a wide range of applications and addresses many challenges inherited from conventional manufacturing techniques. This paper presents a dual-extrusion 3D printing platform capable of printing soft materials for soft robot functional components. Dow Corning-737 and Dragon Skin-0030 materials are used. Single-line experiment is used to determine the optimization parameters of extrusion pressure, printing speed, and layer thickness of the developed multi-material 3D printing platform. A soft valve consisting of two soft materials has been fabricated, and the printed soft valve is verified by a performance experiment. The results indicate that the developed 3D printing platform can fabricate soft robot functional components at high speed with high accuracy.

Quantitative Evaluation of Apically Extruded Debris of Root Canal Dentin Layer with WaveOne, ProTaper Next, ProTaper Gold Rotary File Systems

Endodontic flare-up or post-operative pain occurs when debris such as necrotic pulp tissue, dentin chips, irrigants, and microorganisms are extruded from the apical foramen intraoperatively into the periradicular tissue during root canal instrumentation. This study compared the amount of apical debris extrusion of the root canal dentin layer after using reciprocating and rotary file systems (WaveOne, ProTaper Next and ProTaper Gold). Sixty extracted human maxillary central incisors with one canal and closed apex were included in the study. Samples were randomly and equally divided into three groups (n = 20) according to the file systems used for preparation of the root canal. Teeth in the WO group were instrumented by WaveOne, while the PTN group were instrumented by ProTaper Next, and teeth samples in the PTG group were cleaned and shaped by ProTaper Gold. The mean apically extruded debris weight in grams was estimated using the modified Myers and Montgomery experimental model. Analysis of variance (ANOVA) test was used for the comparison of debris weight in three groups. Post hoc LSD test was applied for pairwise comparison of debris weight. The α value of significance was 0.05. The WO group had significantly lower mean debris weight than the PTN and PTG groups (p = 0.001). Post hoc pairwise comparison revealed that there was a statistically significant difference in mean debris weight between the WO group and PTN group (0.0215 vs. 0.0341, p = 0.001); and the WO group and PTG group (0.0215 vs. 0.0324, p = 0.003). Root canal preparations with different file systems were associated with apical extrusion of the debris from the root canal dentin layer. However, the WaveOne system resulted in a comparatively lower amount of apical debris layer extrusion than the ProTaper Next and ProTaper Gold rotary file systems.

Investigation of the Polymer Coextrusion Process: A Review.

A review of the different coextrusion processes and the related processing problems is presented. A one-dimensional bilayer coextrusion Poiseuille flow model is first developed with Newtonian and shear-thinning rheological behaviors. A transitory computation at the convergence between the two independent polymer layers shows that stationary interface position and velocity profile are established after a short distance of the order of the die gap which justifies the validity of the 1D stationary model. This model is then applied to multilayer temperature dependent coextrusion flows which correspond to realistic industrial coextrusion conditions. Marked interface instabilities may be observed depending on the rheology of the coextruded polymers and of their flow rate ratios. Experiments point clearly out that these instabilities may be amplified along the die land. Convective stability analysis as well as direct numerical computation discriminate flow situations which amplify or damp down instabilities. These 1D models are unable to account for the complex feedblock coat-hanger die geometries. A thin layer coextrusion model is then developed, based on the Hele-Shaw lubrication approximations already used for single layer extrusion problems. It allows to predict the location of the interfaces between the different layers in the whole die, and especially at die exit. This represents a major issue in feedblock die coextrusion. These thin layer approaches are unable to address the encapsulation of one polymer by the other in these complex die geometries with important gap thicknesses. Experiments conducted in dies of square section allow identifying the dynamics of encapsulation. 3D models are required to account for this phenomenon but the management of the sticking contact at the die wall poses difficult numerical problems.

Improving inner structure and properties of additive manufactured amorphous plastic parts: The effects of extrusion nozzle diameter and layer height

Material extrusion is an efficient additive manufacturing process for thermoplastic materials in the field of rapid prototyping, rapid tooling, rapid manufacturing and rapid repair. Parts to be additive manufactured of acrylonitrile butadiene styrene (ABS Terluran GP 35) with mechanical properties close to the data sheet specification of injection molded parts are in the focus of this study. An in-house process chain from the plastic pellets to the finished additive manufactured product is developed to monitor and to define the process parameters for each individual processing step using the terpolymer. By varying the parameters extrusion nozzle diameter and layer height, the production-related internal part structure and the surface topography of the additive manufactured tensile test specimens are improved in such a way that the mechanical property yield strength rises from 55% to 75% of the data sheet specification for injection molded ABS parts. The elongation at break increases from 42% up to 70% of the specified data. The smallest extrusion nozzle diameter in connection with the smallest layer height provide the densest internal part structure, the lowest surface roughness and the best mechanical properties. Especially the ductility was controlled by the manufacturing parameters since the number of pores introduced in the internal part structure determine the number of crazes. Apart from ductility, even with low layer height but larger extrusion nozzle diameter, the resistance to failure of the material extrusion manufactured parts improves significantly and saves manufacturing time by a factor of 10.

Extrusion process simulation and layer shape prediction during 3D-concrete-printing using the Particle Finite Element Method

Product quality and processing of additively manufactured concrete components strongly depend on the flow processes during material extrusion. To control layer deformations and enable purposeful design, numerical analyses with varying process and material parameters were performed to obtain a deeper understanding of flow processes and forces developing in the vicinity of the nozzle using the Lagrangian-based Particle Finite Element Method in association with a Bingham constitutive model. This model was validated by comparing the simulated layer geometries with those obtained from laboratory 3D-printing experiments. Within the investigated parameter range, the forces generated under the extrusion nozzle can be 6 times higher than those induced by self-weight and may cause deformations in substrate layers. Since the distribution of extrusion forces may change substantially under the nozzle for varying parameters, a novel indicator based on the yielding material is introduced to find optimal 3D-printing parameters to prevent plastic deformations in substrate layers.

Bulk-Material Bond Strength Exists in Extrusion Additive Manufacturing for a Wide Range of Temperatures, Speeds, and Layer Times.

Do extrusion temperature, printing speed, and layer time affect mechanical performance of interlayer bonds in material extrusion additive manufacturing (MEAM)? The question is one of the main challenges in 3D printing of polymers. This article aims to analyze the independent effect of printing parameters on interlayer bonding in MEAM. In previous research, printing parameters were unavoidably interrelated, such as printing speed and layer cooling time. Here, original specimen designs allow the effects to be studied independently for the first time to provide new understanding of the effects of a wide range of thermal factors on mechanical properties of 3D-printed polylactide. The experimental approach used direct GCode design to manufacture specially designed single-filament-thick specimens for tensile testing to measure mechanical and thermal properties normal to the interface between layers. In total, five different extrusion temperatures (a range of 60°C), five different printing speeds (a 16-fold change in the magnitude) and four different layer times (an 8-fold change) were independently studied. The results demonstrate interlayer bond strength to be equivalent to that of the bulk material within experimental scatter. This study provides strong evidence about the crucial role of microscale geometry for apparent interlayer bond strength relative to the role of thermal factors. By designing specimens specifically for the MEAM process, this study clearly demonstrates that bulk-material strength can be achieved for interlayer bonds in MEAM even when printing parameters change severalfold. Widespread industrial and academic efforts to improve interlayer bonding should be refocused to study extrusion geometry-the primary cause of anisotropy in MEAM.

Extrusive upper crust formation at slow-spreading ridges: Fault steering of lava flows

The structure of the oceanic upper volcanic crust is less understood at slow-spreading ridges than at faster ones. Its construction is dominated by pillow lavas, reflecting lower effusion rates than those at fast spreading ridges, where sheet and lobate flows are common and flow off-axis while thickening the extrusive volcanic layer. Based on optical and high-resolution bathymetry data from the Lucky Strike segment (Mid-Atlantic Ridge), we document a mode of volcanic emplacement that likely operates at some magmatically robust slow- and ultra-slow spreading ridge segments, in the presence of strong gradients in magma supply. In these settings, sheet flows may efficiently transport melt away from magmatically robust segment centers in the along-axis direction, steered by normal faults, and exploiting along-axis topographic gradients, with limited across-axis flow. Surface lineations of sheet lava flows tend to be subparallel to fault scarps and the overall segment orientation, and show whorls, well-developed lava channels with associated levees, and surface fold structures at flow fronts. This mode of lava emplacement transitions away from the segment center to pillow-dominated seafloor near the segment ends, associated often with hummocks and axial volcanic ridges. This results in local lava emplacement due to a melt supply that is lower than at the segment center. We propose that fault-steering of lava flows along-axis, limiting off-axis transport as observed at fast-spreading systems, may be common at both slow- and ultra-slow spreading ridges with significant along-axis changes in magma supply linked to topographic gradients. As a result, the nature and properties of the extrusive volcanic layer may vary significantly along axis owing to changes in the modes of volcanic emplacement, as transitions from sheet flows to pillow lavas may impact the porosity structure and hence the seismic properties of the extrusive layer in the oceanic upper crust.

Experimental investigations into abrasive flow machining (AFM) of 3D printed ABS and PLA parts

PurposeThe surface roughness of additively manufactured parts is usually found to be high. This limits their use in industrial and biomedical applications. Therefore, these parts required post-processing to improve their surface quality. The purpose of this study is to finish three-dimensional (3D) printed acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) parts using abrasive flow machining (AFM).Design/methodology/approachA hydrogel-based abrasive media has been developed to finish 3D printed parts. The developed abrasive media has been characterized for its rheology and thermal stability using sweep tests, thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The ABS and PLA cylindrical parts have been prepared using fused deposition modeling (FDM) and finished using AFM. The experiments were designed using Taguchi (L9 OA) method. The effect of process parameters such as extrusion pressure (EP), layer thickness (LT) and abrasive concentration (AC) was investigated on the amount of material removed (MR) and percentage improvement in surface roughness (%ΔRa).FindingsThe developed abrasive media was found to be effective for finishing FDM printed parts using AFM. The microscope images of unfinished and finished showed a significant improvement in surface topography of additively manufactures parts after AFM. The results reveal that AC is the most significant parameter during the finishing of ABS parts. However, EP and AC are the most significant parameters for MR and %ΔRa, respectively, during the finishing of PLA parts.Practical implicationsThe FDM technology has applications in the biomedical, electronics, aeronautics and defense sectors. PLA has good biodegradable and biocompatible properties, so widely used in biomedical applications. The ventilator splitters fabricated using FDM have a profile similar to the shape used in the present study.Research limitations/implicationsThe present study is focused on finishing FDM printed cylindrical parts using AFM. Future research may be done on the AFM of complex shapes and freeform surfaces printed using different additive manufacturing (AM) techniques.Originality/valueAn abrasive media consists of xanthan gum, locust bean gum and fumed silica has been developed and characterized. An experimental study has been performed by combining printing parameters of FDM and finishing parameters of AFM. A comparative analysis in MR and %ΔRa has been reported between 3D printed ABS and PLA parts.

Compressive behaviors of 3D printed polypropylene-based composites at low and high strain rates

3D-printed composites have promising potential for applications as structural or functional parts in different engineering fields. However, due to the presence of pores and weak interface interactions, 3D-printed parts have weaker mechanical performance than traditional processed ones. In recent years, polypropylene (PP) emerged as a new 3D printing material with enormous potential. In this work, two PP-based composites (PP/EPR(ethylene-propylene-rubber) and PP/EPDM(ethylene-propylene-diene-monomer)/talc) were chosen to study the effects of extrusion temperature and layer thickness on the quasi-static and dynamic behavior of 3D-printed PP-based composites. The results obtained in this study indicated that the processing induced voids have a significant impact on the mechanical properties of printed specimens as they could cause stress concentration and trigger crack propagation. A smaller layer thickness and a moderate printing temperature could reduce pore size and porosity in the printed parts and consequently increase their mechanical properties. Compared to the response under quasi-static loading, the apparent strength and modulus for both materials under dynamic compression were much higher. Under impact loading, polypropylene-based composites exhibited different rupture characteristics caused by the different reinforcement.

Semisolid heat treatment processing window of Pb-40% Sn alloy for feedstock in the 3D printing thixo-forming process

The 3D printing thixo-forming process is a method that utilizes semisolid thixotropic feedstock for layer extrusion by controlling feedstock viscosity below the complete melting temperature of metallic alloys to form a 3D structure. The process of producing metallic feedstock has a significant impact on alloy microstructure, which is critical for the material’s printability. This study aims to propose a semisolid heat treatment processing window of Pb-40% Sn alloy for use as feedstock billets for a variety of extruder nozzles (sizes 1–3 mm) during the 3D printing thixo-forming process. Firstly, Pb-40% Sn alloys were cold deformed to reduce the specimens’ diameters. Semisolid treatments for deformed specimens were performed at a variety of semisolid heating temperatures and three separate holding times (2, 5, and 10 min). The microstructure of semisolid feedstock specimens was then investigated. The temperature and time of the semisolid heating processing window of Pb- 40% Sn alloy were optimized to feedstock specimens and thixo-extruding processes with different printed output sizes. Therefore, the proposed semisolid heat treatment processing window was a promising approach to pave the way for the low-cost manufacturing of AM, which yields higher printing rates and improved scalability of printed lines. Additionally, this approach allows for a versatile manufacturing route for producing 3D metal parts with maximum density and intricate geometries as a result of the ability to tailor the microstructure.

Influence of ABS print parameters on a 3D open-source, self-replicable printer

PurposeThe purpose of this paper is to investigate and discuss the influence of printing parameters on the mechanical properties of acrylonitrile butadiene styrene (ABS) print by fused deposition modelling (FDM). The mechanical properties of ABS are highly influenced by printing parameters, and they determine the final product quality of printed pieces.Design/methodology/approachFor the paper’s purpose, five main parameters (extrusion temperature, infill pattern, air gap, printing speed and layer thickness) were selected and varied during ABS printing on an open-source and self-replicable FDM printer. Three different colors of commercially available ABS were also used to investigate color and printing parameter’s influence on the tensile strength.FindingsThe research results suggest that two parameters (infill pattern and layer thickness) were most influential on the mechanical properties of print ABS, being able to enhance its tensile strength. Another key influential factor was material color selected prior to printing, which influenced the tensile strength of the print specimen.Originality/valueThis study provides information on print parameters’ influence on the tensile strength of ABS print on replicable open-source three-dimensional (3D) printers. It also suggests the influence of materials’ color on print pieces’ tensile strength, indicating a new parameter for materials selection for 3D printing.

Topology-aware routing of 3D-printed circuits

Abstract Hybrid manufacturing of 3D-printed parts with integrated electronics has made significant progress in recent years. The general idea of depositing conductive material and electronic components during or after the additive manufacturing step was successfully demonstrated for different process types. However, efficient 3D arrangement and wire routing of circuits for seamless integration into the printing process requires the support of appropriate design software. In this paper, we introduce an approach to integrate the wire routing into the slicing software for Fused Filament Fabrication (FFF). This allows us to consider process parameters for each specific print, e.g. extrusion width, layer thickness or shell thickness. The volumetric object model is first converted into a graph data structure which is then used to apply a routing algorithm. The resulting G-code with embedded wires can be directly executed by the printer. The G-code also includes instructions for a pick and place system to automatically produce the entire object, including electronic components, without operator intervention.

Processes of clastic sedimentation associated with Late Cretaceous ophiolite emplacement in the SW segment of the Antalya Complex (S Turkey)

Clastic sediments provide important clues to the timing and processes of ophiolite emplacement, when integrated into the regional temporal and tectonic framework. Four related settings of Late Cretaceous ophiolite-related clastic sediment deposition are exposed in the SW segment of the Antalya Complex, along the western limb of the Isparta Angle, an orocline in SW Turkey. The restored pre-emplacement paleogeography is indicative of a regional-scale Mesozoic carbonate platform, bordered to the east by a Late Triassic volcanic rift that partially infilled with deep-sea sediments, passing eastwards into several Mesozoic carbonate platforms (floored by pre-rift or syn-rift crust) and finally into the South Neotethys. First, emplacement-related sediments unconformably overlie exhumed ultramafic and gabbroic ophiolitic rocks and comprise locally variable mass-flow deposits (up to several-hundred m thick) that are dominated by subaqueous screes and debris-flow deposits. Fossil evidence (benthic and planktic foraminifera, radiolarians and macrofossils) indicates accumulation during the Campanian-Maastrichtian. Much of the coarse talus was derived from weathering and erosion of intrusive ophiolitic rocks (sheeted dykes, gabbro). Petrographic, XRD and whole-rock geochemical analysis of sandstones and igneous clasts indicate additional derivation from basaltic rocks, interpreted as the eroded extrusive layer of the ophiolite. Additional material was derived from Late Triassic-Cretaceous deep-water volcanics and sediments, and also from Late Cretaceous (and older) platform carbonates. The coarse clastics relate to ophiolite emplacement onto the continental margin, rather than forming in an oceanic setting (e.g., rifted ridge or oceanic fracture zone). The emplacement was associated with crustal extension that exposed ultramafic and gabbroic rocks on the seafloor, where they were covered by clastic debris. Secondly, Late Cretaceous calciturbidites and debris-flow deposits depositionally overlie Late Triassic-Late Cretaceous deep-water passive margin sediments. The clastic debris was derived from the emplacing ophiolite and from an adjacent Mesozoic carbonate platform. Thirdly, calciturbidites and debris-flow deposits also depositionally overlie the same carbonate platform. Fourthly, west of the same carbonate platform, ophiolite-derived mass-flow breccias accumulated locally and were then interleaved with previously emplaced ophiolitic plutonic rocks (mainly serpentinite and gabbro), typically at high angles. The four depositional settings relate to ongoing stages of Late Cretaceous ophiolite emplacement in a setting dominated by regional-scale thrusting and strike-slip (i.e., transpression). The latest Cretaceous deformation and related clastic deposition affected part of the northern, active continental margin of the Southern Neotethys, but without reaching more inboard continental crust (regional Tauride platform), a situation that contrasts with more orthogonally emplaced ophiolites.

Inspecting manufacturing precision of 3D printed concrete parts based on geometric dimensioning and tolerancing

The additive manufacture of parts using extrusion-based techniques such as 3D Concrete Printing (3DCP) offers an alternative to traditional moulding processes. The precision to which the desired shape can be produced, however, is limited by the extrusion process and layer thickness, exacerbated by the deformation that occurs in the wet material during manufacture. Quantifying manufacturing precision is a critical part of defining process capability and quality control procedures, but this has yet to be explored for these technologies. To address this, this paper presents the problem of evaluating the geometrical precision of manufactured parts and then proposes an approach based on geometric dimensioning and tolerancing (GD&T), commonly used in manufacturing. This is then applied in a case study in order to demonstrate the application of the technique for understanding and defining process capability, to enable more effective design rules that lead to greater confidence in the viability of part designs, and to provide the reliable performance metrics necessary for process improvement and control. The work concludes that the outlook for such techniques is positive and that the application will be beneficial in the future development of quality control procedures for 3DCP.

Controllable inter-line bonding performance and fracture patterns of continuous fiber reinforced composites by sinusoidal-path 3D printing

In order to improve the inter-line bonding performance of 3D printed continuous fiber reinforced composites, an innovative sinusoidal-path extrusion 3D printing method was proposed. Conventional 3D printing constructs components from stacks of individual extruded straight lines and flat layers, resulting in the relatively weak bonding that occurs between individual lines and layers and is aggravated due to the introduction of continuous fibers. The influence of structural parameters (amplitude & frequency) on the inter-line tensile properties and fracture patterns of sinusoidally 3D printed composites were systematically investigated. The results showed that as the amplitude and frequency of the sinusoidal path increased, the inter-line tensile strength, tensile modulus and fracture energy absorption of CCF/PLA composites increased 95.4%, 57.3% and 165%, respectively. Based on this study, a non-planar sinusoidal layer extrusion 3D printing method of CFRTPCs was proposed, which provides a new idea for comprehensive control of the anisotropy of 3D printed composites.

Modeling and analysis of significant process parameters of FDM 3D printer using ANFIS

Abstract The present work deals with the effects of significant parameters of the Fused Deposition Modeling (FDM) 3D printer on the tensile strength of materials like PETG, ABS and multi-material (60% ABS + 40% PETG). The significant process parameters have been taken as extrusion temperature, layer height and material density. ASTM D638-(IV) standard test specimens have been prepared at different process parameters of the FDM 3D printer to check their tensile strength. UNITEK 94100 Universal testing machine is used to test the tensile strength of test specimens. Thirty experiments have been performed on the UTM machine with various materials and their tensile strength has been recorded as output response. The training between input and output data has been given with ANFIS (Adaptive Neuro-Fuzzy Inference System). It is observed that maximum tensile strength achieved is 0.0405 kN/mm2 for PETG (material density 1.27 g/cm3) when it is fabricated with 0.1 mm layer height and 225 °C extrusion temperature and ANFIS model is successfully performing for giving output on new input parameters with 2.63 percent error.

Additive manufacturing by material extrusion with medical grade silicone elastomers and IR laser curing

PurposeTechniques of extrude and cure additive manufacturing for thermally cured, high viscosity and medical-grade silicone are investigated by using a small ram extruder and a near-infrared (IR) laser. The purpose of this study is to evaluate the process parameter effects on the stiffness of the final products.Design/methodology/approachProcess parameter effects on axial stiffness values and durometer are explored. Parameters such as extrusion layer height, laser speed, laser current, laser raster spacing and multiple laser passes were investigated and compared to traditional cast and cure methods. Dimensional changes were also recorded and compared.FindingsTensile and durometer tests show that certain curing parameters give tensile stress and durometers within 10 per cent of bulk material specifications at 200 per cent strain. Parameters that had the highest impact on tensile stress at 200 per cent strain were layer height (0.73 per cent) followed by laser power (0.69 per cent), and then laser raster spacing (0.45 per cent). Parameters that had the highest impact on durometer were laser power (1.00 per cent), followed by layer height, (0.34 per cent) and then laser raster speed (0.32 per cent). Three-dimensional printed samples had about 11.2 per cent more shrinkage than the bulk cast samples in the longest dimension.Originality/valueThis paper is one of the first that demonstrates near IR laser curing parameter effects on three-dimensional printed, commercial off-the-shelf, medical-grade and viscous silicone. The ability to cure very viscous thermosets locally enables interesting technologies such as wire encapsulation, high voltage actuators and drug delivery devices.

Fabrication and Characterization of High Performance Intermediate Temperature Micro-Tubular Solid Oxide Fuel Cells

A phase inversion-based dual-layer co-extrusion approach was advanced to fabricate micro-channel array structured micro-tubular solid oxide fuel cells (MT-SOFCs). The inner graphite layer was used as a sacrificial layer to eliminate the middle sponge-like layer and inner surface dense skin layer, which were normally formed using the single layer extrusion method. As a result, the micro-channel array generated in the outer layer was a more open structure and facile fuel/gas diffusion was obtained. The fuel/gas permeability of such an anode substrate Ni-Ce0.8Sm0.2O1.9 (Ni-SDC) was ∼9 times that of an anode substrate fabricated using the phase inversion-based single layer extrusion method. The open circuit voltages (OCVs) of the corresponding cell Ni-SDC/SDC/PrBaCo2O5+δ were 0.89 V–0.85 V at 500–600°C, much higher than those of other SDC electrolyte based MT-SOFCs. The peak power density of the cell was ∼1484 mW cm−2 at 600°C, approximately 1.5 times that of a similar cell with an anode substrate fabricated from the single layer extrusion method. This is also the highest performance among the SOFCs with the same material system in open literature. The fuel utilization rate was also significantly improved in different degrees depending on the supplied inlet fuel flow rates.

Evaluation of dimensional accuracy and mechanical behavior of 3D printed reinforced polyamide parts

This paper aims to evaluate the mechanical behavior, dimensional accuracy and total cost of fused deposition modeling (FDM) produced reinforced polyamide (RPA) parts; glass reinforced PA and Kevlar reinforced PA. First of all, the standard specimens are printed by varying three parameters, namely the layer thickness, the print speed and the extrusion temperature. Then, the weight and main dimensions of the obtained samples are measured before the mechanical characterization by tensile test. The results showed the effect of extrusion temperature and layer thickness on material properties is more significant than the impact of print speed. The influence of evaluated factors on the dimensional accuracy and total cost is also observed. Overall, this experimental investigation showed the advantage of reinforcement in enhancing mechanical performance (tensile and fatigue properties) and lead to improving the knowledge about geometrical tolerance of FDM printed reinforced polymer components.

Evaluation of Debris Extrusion and Smear Layer Production Following Preparation Using Three Different Nickel Titanium Files

Objectives: The aim of this study was to compare the amount of apically extruded debris andthe patterns of smear layer formation following the preparation of root canals in extracted humanteeth using ProTaper Next, Twisted file, and a reciprocating single-file system.Material and Methods: Forty-five freshly extracted human single-rooted maxillary incisorswere divided into 3 groups (n=15) then instrumented using Protaper Next, Twisted files, andReciproc. The extruded debris were collected in a pre-weighed Eppendorf tubes. The tubes werestored in an incubator at 70 °C for 2 days before weighing the dry debris using analytical balance.The debris weight was determined by subtracting the initial weight from the final weight. Rootsamples were splitted longitudinally into two halves by making grooves then root halves (cervical,middle and apical) thirds were examined using Environmental Scanning Electron MicroscopeESEM (FEI Quanta 250 FEG, Berlin, Germany) at ×1500 magnification. All the data were subjectedto statistical analysis using Chi-squared, Fisher`s Extract.Results: The three tested rotary nickel titanium files produced comparable amount of debrisextrusion and smear layer patterns covering the root canal dentin walls. Apical third showed theheaviest accumulation of smear layer.