scholarly journals Increasing of Strength of FDM (FFF) 3D Printed Parts by Influencing on Temperature-Related Parameters of the Process

2018 ◽  
Author(s):  
Vladimir E. Kuznetsov ◽  
Alexey N. Solonin ◽  
Azamat G. Tavitov ◽  
Oleg D. Urzhumtsev ◽  
Anna H. Vakulik
Keyword(s):  
Bulk Material ◽  
Sample Surface ◽  
Fracture Load ◽  
Material Strength ◽  
Thermal Imager ◽  
Fused Filament Fabrication ◽  
Printing Process ◽  
Temperature Conditions ◽  
Two Factors ◽  
Related Stress

This work investigates how the user-controlled parameters of the 3D printing process define temperature conditions on the boundary between layers of the part being fabricated and how these conditions influence the structure and strength of the part. The process studied is fused filament fabrication with a desktop 3D printer and the material utilized is PLA (polylactic acid). As a characteristic of the part strength the fracture load in the case of a three-point bend and calculated related stress were used. During the printing process parts were oriented with the long side along the Z axis, thus, in the bend tests, the maximum stress occurred orthogonally to the layers. During the fabrication process, temperature distribution on the sample surface was monitored with thermal imager. Sample mesostructure was analyzed using SEM. The influence of the extrusion temperature, the intensity of part cooling, the printing speed and the time between printing individual layers were considered. The influence of all the parameters can be expressed through two generalizing factors: the temperature of the previous layer and the flow efficiency, determining the ratio of the amount of extruded plastic to the calculated. A regression model was proposed that describes the effect of the two factors on the printed part strength. Along with interlayer bonding strength, these two factors determine the formation of the part mesostructure (the geometry of the boundaries between individual threads). It is shown that the optimization of the process parameters responsible for temperature conditions makes it possible to approximate the strength of the interlayer cohesion to the bulk material strength.

scholarly journals Increasing of Strength of FDM (FFF) 3D Printed Parts by Influencing on Temperature-Related Parameters of the Process

2018 ◽  
Author(s):  
Vladimir E. Kuznetsov ◽  
Alexey N. Solonin ◽  
Azamat G. Tavitov ◽  
Oleg D. Urzhumtsev ◽  
Anna H. Vakulik
Keyword(s):  
Bulk Material ◽  
Fracture Load ◽  
Material Strength ◽  
Thermal Imager ◽  
Fused Filament Fabrication ◽  
Printing Process ◽  
Temperature Conditions ◽  
Two Factors ◽  
Related Stress ◽  
Point Bend

Current work investigates how user-controlled parameters of 3D printing process define temperature conditions on the boundary between layers of the part being fabricated and how these conditions influence structure and strength of the part. The process studied is fused filament fabrication with a desktop 3D printer and the material utilized is PLA (polylactic acid). As a characteristic of the part strength the fracture load in the case of a three-point bend and calculated related stress were used. During the printing process parts were oriented the long side along the Z axis, thus, in the bend tests, the maximum stress occurred orthogonally to the layers. During the fabrication process temperature distribution on the samples surface was monitored with thermal imager. Sample mesostructure was analyzed using SEM. The influence of the extrusion temperature, the intensity of part cooling, the printing speed and the time between printing individual layers were considered. The influence of all the parameters can be expressed through two generalizing factors: the temperature of the previous layer and the flow efficiency, determining the ratio of the amount of extruded plastic to the calculated. A regression model was proposed that describes the effect of the two factors on the printed part strength. Along with interlayer bonding strength, these two factors determine the formation of the part mesostructure (the geometry of the boundaries between individual threads). It is shown that the optimization of the process parameters responsible for temperature conditions makes it possible to approximate the strength of the interlayer cohesion to the bulk material strength.

scholarly journals Increasing strength of FFF three-dimensional printed parts by influencing on temperature-related parameters of the process

2020 ◽  
Vol 26 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Vladimir E. Kuznetsov ◽  
Alexey N. Solonin ◽  
Azamat Tavitov ◽  
Oleg Urzhumtsev ◽  
Anna Vakulik
Keyword(s):  
Bulk Material ◽  
Three Dimensional ◽  
Fracture Load ◽  
Bending Test ◽  
Material Strength ◽  
Thermal Imager ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Temperature Conditions ◽  
Two Factors

Purpose This paper aims to investigate how the user-controlled parameters of the fused filament fabrication three-dimensional printing process define temperature conditions on the boundary between layers of the part being fabricated and how these conditions influence the structure and strength of the polylactic acid part. Design/methodology/approach Fracture load in a three-point bending test and calculated related stress were used as a measure. The samples were printed with the long side along the z-axis, thus, in the bend tests, the maximum stress occurred orthogonally to the layers. Temperature distribution on the sample surface during printing was monitored with a thermal imager. Sample mesostructure was analyzed using scanning electron microscopy. The influence of the extrusion temperature, the intensity of part cooling, the printing speed and the time between printing individual layers were considered. Findings It is shown that the optimization of the process parameters responsible for temperature conditions makes it possible to approximate the strength of the interlayer cohesion to the bulk material strength. Originality/value The novelty of the study consists in the generalization of the outcomes. All the parameters varied can be expressed through two factors, namely, the temperature of the previous layer and the extrusion efficiency, determining the ratio of the amount of extruded plastic to the calculated. A regression model was proposed that describes the effect of the two factors on the printed part strength. Along with interlayer bonding strength, these two factors determine the formation of the part mesostructure (the geometry of the boundaries between individual threads).

scholarly journals Fused filament fabrication: comparison of methods for determining the interfacial strength of single welded tracks

2021 ◽  
Vol 8 ◽  
pp. 32
Author(s):  
Anselm Heuer ◽  
Jonas Huether ◽  
Wilfried V. Liebig ◽  
Peter Elsner
Keyword(s):  
Bulk Material ◽  
Tensile Load ◽  
Interfacial Strength ◽  
Interfacial Area ◽  
Accurate Method ◽  
Material Strength ◽  
Optimal Conditions ◽  
Fused Filament Fabrication ◽  
Nozzle Temperature

The mechanical properties of plastic-based additively manufactured specimens have been widely discussed. However, there is still no standard that can be used to determine properties such as the interfacial strength of adjacent tracks and also to exclude the influence of varying manufacturing conditions. In this paper, a proposal is made to determine the interfacial strength using specimens with only one track within a layer. For this purpose, so-called single-wall specimens of polylactide were characterised under tensile load and the interfacial area between the adjacent layers was determined using three methods. It turned out that the determination of the interfacial area via the fracture surface is the most accurate method for determining the interfacial strength. The measured interfacial strengths were compared with the bulk material strength and it was found that the bulk material strength can be achieved under optimal conditions in the FFF process. It was also observed that with increasing nozzle temperature, the simultaneous printing of specimens influences the interfacial strength. To conclude, this method allows to measure the interfacial strength without superimposing the influence of voids. However, for example, the interfacial strength within a layer cannot be determined.

Temperature-compensated constitutive model of fused filament fabrication 3D printed PLA materials with full extrusion temperatures

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kaiyang Zhu ◽  
Zichen Deng ◽  
Shi Dai ◽  
Yajun Yu
Keyword(s):  
Mechanical Properties ◽  
Thermal Decomposition ◽  
Constitutive Model ◽  
Polylactic Acid ◽  
Extrusion Temperature ◽  
Fused Filament Fabrication ◽  
Printing Process ◽  
Content Type ◽  
3D Printed ◽  
Interlayer Bonding

Purpose This study aims to focus on the effect of interlayer bonding and thermal decomposition on the mechanical properties of fused filament fabrication-printed polylactic acid specimens at high extrusion temperatures. Design/methodology/approach A printing process, that is simultaneous manufacturing of contour and specimen, is used to improve the printing accuracy at high extrusion temperatures. The effects of the extrusion temperature on the mechanical properties of the interlayer and intra-layer are evaluated via tensile experiments. In addition, the microstructure evolution affected by the extrusion temperature is observed using scanning electron microscopy. Findings The results show that the extrusion temperature can effectively improve the interlayer bonding property; however, the mechanical properties of the specimen for extrusion temperatures higher than 270°C may worsen owing to the thermal decomposition of the polylactic acid (PLA) material. The optimum extrusion temperature of PLA material in the three-dimensional (3D) printing process is recommended to be 250–270°C. Originality/value A temperature-compensated constitutive model for 3D printed PLA material under different extrusion temperatures is proposed. The present work facilitates the prediction of the mechanical properties of specimens at an extrusion temperature for different printing temperatures and different layers.

scholarly journals Effect of Marginal Designs on Fracture Strength of High Translucency Monolithic Zirconia Crowns

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Niwut Juntavee ◽  
Sasiprapa Kornrum
Keyword(s):  
Bearing Capacity ◽  
Testing Machine ◽  
Fracture Load ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Two Factors ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
Bonferroni Test ◽  
Inclined Planes

Introduction. Monolithic zirconia is able to achieve certain aesthetic, but its durability in resisting fracture has been questioned, as fractures often originate from margins of restoration. This study determined fracture resistance of highly translucent monolithic zirconia crowns with different margin designs in terms of marginal thickness and collar height. Materials and Methods. Zirconia blanks (Ceramill® Zolid HT+) were selected for the fabrication of zirconia crowns according to different designs, including varying margin thicknesses (light chamfer, CL; heavy chamfer, CH) and collar heights (no collar, NC; low collar, LC; high collar, HC), which resulted in CLNC, CLLC, CLHC, CHNC, CHLC, and CHHC groups (15 crowns each). The crowns were seated on a metal die and loaded vertically through round end punch (θ = 10 mm), contacting with inclined planes of cusp in a testing machine with crosshead speed of 0.2 mm/min until fracture. Videos with a rate of 50 frames/second were used to record fracture. Fracture load (N) and durable period (s) were compared for significant differences using ANOVA and Bonferroni test (α = 0.05). Results. The mean ± sd of fracture load (N) and durable time (s) were 3211 ± 778 and 212 ± 47 for CLNC; 3041 ± 1370 and 188 ± 53 for CLLC; 2913 ± 828 and 192 ± 27 for CLHC; 4226 ± 905 and 245 ± 35 for CHNC; 4486 ± 807 and 228 ± 29 for CHLC; and 4376 ± 1043 and 227 ± 37 for CHHC. This indicated that marginal thickness had a significant influence on load-bearing capacity and durable time (p<0.05). No significant impact of collar height was shown, either on load-bearing capacity or durable time (p>0.05). No interaction between two factors was presented (p>0.05). Conclusions. Heavy chamfer margin provided stronger zirconia crown than light chamfer, but both were capable of withstanding fracture load higher than maximum masticatory force. Neither presence nor absence of collar indicated any impact on strength. Fabrication of zirconia crowns with either heavy or light chamfer margin and either presence or absence of collar, with the consideration of emergence profile, should be considered.

scholarly journals Interlayer bonding has bulk-material strength in extrusion additive manufacturing: New understanding of anisotropy

2020 ◽  
Vol 34 ◽  
pp. 101297 ◽  
Author(s):  
James Allum ◽  
Amirpasha Moetazedian ◽  
Andrew Gleadall ◽  
Vadim V. Silberschmidt
Keyword(s):  
Additive Manufacturing ◽  
Bulk Material ◽  
Material Strength ◽  
Interlayer Bonding

ZAF, PAP, Φ(ρz), α-FACTOR..: A Comparison of the Relative Accuracies of The Alphabet Soup of Correction Factors for “Non-Optimized” Samples

1996 ◽  
Vol 54 ◽  
pp. 470-471
Author(s):  
John T. Armstrong
Keyword(s):  
Bulk Material ◽  
Analytical Data ◽  
Sample Surface ◽  
Beam Current ◽  
Correction Factors ◽  
Correction Procedure ◽  
Data Set ◽  
Quantitative Analyses ◽  
Relative Errors ◽  
Very High

The ultimate practical test of the utility of a correction procedure for quantitative x-ray microanalysis is how well the analyses of standards of interest conform to their known compositions. Many papers have been published testing various correction algorithms by processing data from sets of quantitative analyses through the corrections and then comparing the resulting error histograms {e.g., Fig. 1). The best correction procedure is usually considered to be the method that results in error histograms with the minimum mean relative error and the smallest standard deviation for the distribution of relative errors. Such evaluations can be misleading for a number of reasons: (1) the correction procedure may have been “adjusted” by adding empirical factors to produce superior results for a particular type of specimen. If the test data either include these data or include samples of similar composition to those employed for the refinement, the results may appear artificially good and may not work nearly as well for other types of specimens. (2) The analytical data used for testing may itself be flawed, either because the samples were not actually the compositions they were thought to be (or the sample surface analyzed was not the same composition as that published for the bulk material); or because the surface or the sample was contaminated, rough or charging; or because the analytical conditions were not well controlled. (Many of the published k-factors used in evaluating correction procedures [e.g., ref. 1] were obtained in the early days of microbeam analysis, using instruments having poor control over high voltage and beam current stability with low spectrometer take-off angles.) (3) The analytical data may contain specimens analyzed under unusual conditions {e.g,, very high or veiy low accelerating potentials) that may have very large corrections dominating the data set that may never be encountered in normal analysis.

Health Monitoring Using Acoustic Emission Technique During Fused Filament Fabrication Printing Process

2021 ◽  
Author(s):  
Ke Xu ◽  
Souran Manoochehri
Keyword(s):  
Acoustic Emission ◽  
Real Time ◽  
In Situ Monitoring ◽  
Fused Filament Fabrication ◽  
Printing Process ◽  
Process Reliability ◽  
Ae Signal ◽  
The Time Domain ◽  
Manufacturing Technologies ◽  
Key Indicators

Abstract Fused Filament Fabrication (FFF) is one of the most popular additive manufacturing technologies for manufacturing prototypes with various complex geometries. However, current commercial FFF machines have limitations in terms of process reliability and product quality. In order to overcome these limitations and improve the accuracy and reliability of these machines, a real-time monitoring system is needed to make sure that any part defects can be detected during the printing process and printing parameters can be identified that can be modified to resolve the printing anomalies resulting in minimization of waste and improvement of efficiency. In this study, a method for in-situ monitoring of FFF machine conditions is proposed utilizing an acoustic emission (AE) technology. The AE sensor is used to monitor the vibration signals generated during the whole printing process in real-time. The AE signal is then analyzed and processed, and categorized according to the selected objective characteristics. The proposed method can be utilized to identify the abnormal states of machine conditions. The time-domain features of AE hits after post-processing are used as key indicators. Experimental results show that this method has the potential to be used as a non-invasive diagnostic and prognostic tool for FFF machine maintenance and process control.

Dynamical Nonlinearities in Piezoelectric Materials

2007 ◽  
Vol 1034 ◽  
Author(s):  
Eira Seppälä ◽  
Virpi Korpelainen ◽  
Kari Ojasalo ◽  
Matti Sarjala ◽  
Mikko Alava ◽  
...  
Keyword(s):  
Bulk Material ◽  
Piezoelectric Materials ◽  
Hysteresis Loops ◽  
Sample Surface ◽  
Electric Polarization ◽  
Ferroelectric Materials ◽  
Laser Vibrometer ◽  
Ginzburg Landau ◽  
Atomic Force ◽  
Quenched Randomness

AbstractDynamical nonlinearities in piezoelectric materials have been investigated over different time and frequency scales using four different methods; measurements of displacement and electric polarization of bulk material, measurements of nanometer scale surface structure of the material by an atomic force microscope (AFM), and numerical modelling of ferroelectric materials with quenched randomness. Laser vibrometer measurements of the deformations of piezoelectric materials, d31 type PZT and PMN-PT sheets, have been done under sinusoidal voltage loading with different frequencies. This yields information about the dynamical hysteresis behavior, such as the area of the hysteresis loops as a function of the applied frequency f and voltage amplitude. Similarly the hysteresis loops have been measured for the electric polarization of the same samples. Relaxation behaviors of the same materials have been measured by an AFM. Topography of the piezo sheets was measured after applied DC voltage, indicating slow collective changes in the polarization close and at the sample surface. To investigate the time-dependent hysteresis, we have studied numerically a Ginzburg-Landau-Devonshire (GLD) model for ferroelectric materials including dilution type quenched randomness. Quantities studied include the area of the hysteresis loop, of the polarization in the material, and the coercive electric field Ec as a function of the frequency f, both as a function of the disorder strength.

Effects of SiC on Oxidation Behavior of ZrB2-Based Composites with MoSi2 and SiC Additives

2014 ◽  
Vol 602-603 ◽  
pp. 457-462 ◽  
Author(s):  
Shu Qi Guo
Keyword(s):  
Weight Gain ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Bulk Material ◽  
Sample Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scale Layer ◽  
Exposure Temperature ◽  
Reactive Mixture

In this study, oxidation behavior of ZrB2-MoSi2-SiC composite was investigated in the hot-pressed 5-20 vol% SiC-containing ZrB2-20 vol% MoSi2-based composites which were exposed to dry air between 1100°C and 1500°C up to 10 hours. The effects of SiC additive on the oxidation behavior were assessed. Experimental results showed that the weight gain due to oxidation exposure in air increased with increasing exposure temperature and exposure time. Parabolic oxidation behavior was observed for all the compositions composites. On the other hand, the weight gain decreased with increasing amount of SiC added. The addition of SiC improved the oxidation resistance of the composites, and the improvement was enhanced with increasing amount of SiC added. In addition, X-ray diffraction was used to identify major crystalline phases present in both the as-received and the post-oxidized composites. The oxidized sample surface was characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The microstructure of the post-oxidized composites consisted of two characteristic regions: oxidized reactive region and unreactive bulk material region. Furthermore, the oxidized reactive region divided into an outermost dense silica-rich scale layer and oxidized reactive mixture layer. The improvement of the oxidation resistance due to the addition of SiC is associated with the presence of the thicker dense outermost scale layer which inhibited inward diffusion of oxygen through it.

Sign in / Sign up

Export Citation Format

Share Document