scholarly journals Mechanical and Dimensional Investigation of Additive Manufactured Multimaterial Parts

2021 ◽  
Vol 9 ◽  
Author(s):  
Markus Königshofer ◽  
Martin Stoiber ◽  
Ewald Unger ◽  
Christian Grasl ◽  
Francesco Moscato
Keyword(s):  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Tensile Tests ◽  
Biological Tissues ◽  
Test Methods ◽  
Medical Models ◽  
3D Printed ◽  
Eden Prairie ◽  
Design And Manufacture

Additive manufacturing machines, based on the multimaterial jetting technology, are widely used for three-dimensional (3D) printing of sophisticated medical models, which are aimed to be used for preoperative planning and surgical training. Gaining knowledge of process-related influences on mechanical and dimensional properties of 3D-printed parts makes up an essential basis for the design and manufacture of medical models. There are few studies on characterization of multimaterial parts, and those are limited to tests that are not based on standardized methods. Within the scope of this work, mechanical and dimensional investigations were performed on multimaterial parts that were printed using an Objet500–Connex3 3D printer (Stratasys Ltd., Minnesota, Eden Prairie, MN, USA). Among test methods listed in DIN EN ISO 17296-3, tensile tests were chosen for mechanical characterization. In the tensile tests, combinations of four different materials (Tango+, VeroClear, VeroPureWhite, MED610) were tested in three build orientations (XY, YX, ZX). To investigate the orientation-dependent printing accuracy, the tensile specimens were further checked for their dimensional accuracy. Statistically significant variations in the mechanical properties were found between different orientation levels. In general, specimens printed in XY orientation show higher tensile strength than YX- and ZX-oriented specimens. The tensile moduli determined are in the range from 0.2 to 2,500 MPa and compare well with the tensile moduli found in soft biological tissues. Dimensional deviations were found highest for the length of ZX-oriented tensile specimens. For this orientation level, it could be observed that multimaterial specimens, which contain higher percentage of the soft material Tango+, are characterized by higher shrinkage. For tensile specimens printed from the pure photopolymer Tango+, a shrinkage of 4.6% in length was determined. In summary, it was found that with multimaterial jetting technology, the increased shrinkage and lower mechanical strength in the ZX direction must be considered in the design process.

scholarly journals 3D-printed jars for ball-milling experiments monitoredin situby X-ray powder diffraction

2017 ◽  
Vol 50 (4) ◽  
pp. 994-999 ◽  
Author(s):  
Nikolay Tumanov ◽  
Voraksmy Ban ◽  
Agnieszka Poulain ◽  
Yaroslav Filinchuk
Keyword(s):  
Powder Diffraction ◽  
Materials Science ◽  
Three Dimensional ◽  
High Energy ◽  
X Ray ◽  
3D Printed ◽  
Background Absorption ◽  
Design And Manufacture

Mechanochemistry is flourishing in materials science, but a characterization of the related processes is difficult to achieve. Recently, the use of plastic jars in shaker mills has enabledin situX-ray powder diffraction studies at high-energy beamlines. This paper describes an easy way to design and manufacture these jars by three-dimensional (3D) printing. A modified wall thickness and the use of a thin-walled sampling groove and a two-chamber design, where the milling and diffraction take place in two communicating volumes, allow for a reduced background/absorption and higher angular resolution, with the prospect for use at lower-energy beamlines. 3D-printed polylactic acid jars show good mechanical strength and they are also more resistant to solvents than jars made of polymethyl methacrylate. The source files for printing the jars are available as supporting information.

scholarly journals Effects of Raster Orientation, Infill Rate and Infill Pattern on the Mechanical Properties of 3D Printed Materials

2017 ◽  
Vol 69 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Cristian Dudescu ◽  
Laszlo Racz
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Technological Parameters ◽  
Three Dimensional Printing ◽  
3D Printed ◽  
Printed Materials ◽  
Aided Design ◽  
Design And Manufacture

AbstractThree-dimensional printing is an additive manufacturing process that allows rapid design and manufacture of complex component based on computer-aided design models. Compared with some conventional manufacturing processes, additive manufacturing part properties can depend on structural and process parameters rather than purely on material properties. The objectives of the paper are to evaluate the tensile properties of 3D printed components produced using a commercial 3D printer by performing standard tensile tests and to assess the influence of the technological parameters upon mechanical proprieties of printed specimens, considering different printing directions, infill rates and infill patterns. The influence of raster angles is tested through the designed specimens with different transverse plane, they are printed by placing in different angle, including 0°, 30°, 45° and 90°. Specimens with an infill rate varying from 20% to 100% and six different infill patterns has been tested.

Investigation of the Static Behavior and Failure Mechanisms of a 3D Printed Bio-Based Sandwich with Auxetic Core

2020 ◽  
Vol 12 (05) ◽  
pp. 2050051
Author(s):  
Khawla Essassi ◽  
Jean-Luc Rebiere ◽  
Abderrahim El Mahi ◽  
Mohamed Amine Ben Souf ◽  
Anas Bouguecha ◽  
...  
Keyword(s):  
Failure Mechanisms ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Shear Stiffness ◽  
Tensile Tests ◽  
Sandwich Composite ◽  
Static Behavior ◽  
Flax Fibers ◽  
Data Points ◽  
3D Printed

In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the core while bending tests are conducted on the sandwich composite. Those tests are carried out on four different auxetic densities in order to investigate their effect on the mechanical and damage properties of the materials. To monitor the invisible damage and damage propagation, a highly sensitive AE testing method is used. It is found that the sandwich with high core density displays advanced mechanical properties in terms of bending stiffness, shear stiffness, facing bending stress and core shear stress. In addition, the AE data points during testing present an amplitude range of 40–85[Formula: see text]dB that characterizes visible and invisible damage up to failure.

scholarly journals Dimensional Accuracy of Dental Models for Three-Unit Prostheses Fabricated by Various 3D Printing Technologies

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1550
Author(s):  
Soo-Yeon Yoo ◽  
Seong-Kyun Kim ◽  
Seong-Joo Heo ◽  
Jai-Young Koak ◽  
Joung-Gyu Kim
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Dimensional Accuracy ◽  
3D Analysis ◽  
Digital Light Processing ◽  
Test Models ◽  
Reference File ◽  
Significant Difference ◽  
Jet Printing ◽  
3D Printed

Previous studies on accuracy of three-dimensional (3D) printed model focused on full arch measurements at few points. The aim of this study was to examine the dimensional accuracy of 3D-printed models which were teeth-prepped for three-unit fixed prostheses, especially at margin and proximal contact areas. The prepped dental model was scanned with a desktop scanner. Using this reference file, test models were fabricated by digital light processing (DLP), Multi-Jet printing (MJP), and stereo-lithography apparatus (SLA) techniques. We calculated the accuracy (trueness and precision) of 3D-printed models on 3D planes, and deviations of each measured points at buccolingual and mesiodistal planes. We also analyzed the surface roughness of resin printed models. For overall 3D analysis, MJP showed significantly higher accuracy (trueness) than DLP and SLA techniques; however, there was not any statistically significant difference on precision. For deviations on margins of molar tooth and distance to proximal contact, MJP showed significantly accurate results; however, for a premolar tooth, there was no significant difference between the groups. 3D color maps of printed models showed contraction buccolingually, and surface roughness of the models fabricated by MJP technique was observed as the lowest. The accuracy of the 3D-printed resin models by DLP, MJP, and SLA techniques showed a clinically acceptable range to use as a working model for manufacturing dental prostheses

Additive technology applied to the realization of K-band microwave terminations: reproducibility improvement

2018 ◽  
Vol 10 (1) ◽  
pp. 3-8
Author(s):  
Azar Maalouf ◽  
Ronan Gingat ◽  
Vincent Laur
Keyword(s):  
3D Printing ◽  
Frequency Band ◽  
Rectangular Waveguide ◽  
Three Dimensional ◽  
Low Density ◽  
Support Material ◽  
Additive Technology ◽  
3D Printed ◽  
K Band

This study examines K-band rectangular waveguide terminations with three-dimensional (3D)-printed loads, and proposes an Asymmetrical Tapered Wedge topology. This geometry shows a good tradeoff between microwave performance and 3D-printing issues (printing directions and support material requirements), thus improving noticeably the reproducibility of the devices. The effect of the density of the 3D-printed load on the reflection parameter of the termination was investigated. Even for a low density, reflection level remained below −27.5 dB between 18 and 26.5 GHz. Reproducibility was demonstrated by the characterization of six loads that were 3D printed under the same conditions. Measurements demonstrate that a maximum reflection parameter level of −33.5 dB can be ensured over the whole frequency band without any post-machining of the 3D-printed devices.

scholarly journals OSCAR: a framework to identify and quantify cells in densely packed three-dimensional biological samples

2021 ◽  
Author(s):  
Mario ledesma-terron ◽  
Diego perez-dones ◽  
david G Miguez
Keyword(s):  
Biological Samples ◽  
Object Segmentation ◽  
Three Dimensional ◽  
Cell Types ◽  
Biological Tissues ◽  
Nuclear Marker ◽  
Quantitative Characterization ◽  
3D Space ◽  
Immunofluorescence Labeling

We have developed an Object Segmentation, Counter and Analysis Resource (OSCAR) that is designed specifically to quantify densely packed biological samples with reduced signal-to-background ratio. OSCAR uses as input three dimensional images reconstructed from confocal 2D sections stained with dies such as nuclear marker and immunofluorescence labeling against specific antibodies to distinguish the cell types of interest. Taking advantage of a combination of arithmetic, geometric and statistical algorithms, OSCAR is able to reconstruct the objects in the 3D space bypassing segmentation errors due to the typical reduced signal to noise ration of biological tissues imaged in toto. When applied to the zebrafish developing retina, OSCAR is able to locate and identify the fate of each nuclei as a cycling progenitor or a terminally differentiated cell, providing a quantitative characterization of the dynamics of the developing vertebrate retina in space and time with unprecedented accuracy.

scholarly journals Future-Oriented Experimental Characterization of 3D Printed and Conventional Elastomers Based on Their Swelling Behavior

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4402
Author(s):  
Klara Loos ◽  
Vivianne Marie Bruère ◽  
Benedikt Demmel ◽  
Yvonne Ilmberger ◽  
Alexander Lion ◽  
...  
Keyword(s):  
Tensile Tests ◽  
Swelling Behavior ◽  
Uniaxial Tensile ◽  
Stress And Strain ◽  
Experimental Characterization ◽  
Synthetic Fuels ◽  
Fuel Component ◽  
3D Printed ◽  
Fuel Components

The present study investigates different elastomers with regard to their behavior towards liquids such as moisture, fuels, or fuel components. First, four additively manufactured materials are examined in detail with respect to their swelling in the fuel component toluene as well as in water. The chemical nature of the materials is elucidated by means of infrared spectroscopy. The experimentally derived absorption curves of the materials in the liquids are described mathematically using Fick’s diffusion law. The mechanical behavior is determined by uniaxial tensile tests, which are evaluated on the basis of stress and strain at break. The results of the study allow for deriving valuable recommendations regarding the printing process and postprocessing. Second, this article investigates the swelling behavior of new as well as thermo-oxidatively aged elastomers in synthetic fuels. For this purpose, an analysis routine is presented using sorption experiments combined with gas chromatography and mass spectrometry and is thus capable of analyzing the swelling behavior multifacetted. The transition of elastomer constituents into the surrounding fuel at different aging and sorption times is determined precisely. The change in mechanical properties is quantified using density measurements, micro Shore A hardness measurements, and the parameters stress and strain at break from uniaxial tensile tests.

Investigations for Wax Coated 3D Printed Hybrid Patterns for Partial Dentures

2019 ◽  
Author(s):  
Kamaljit Singh Boparai ◽  
Gurpartap Singh ◽  
Rupinder Singh ◽  
Sarabjit Singh
Keyword(s):  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Surface Hardness ◽  
Dimensional Accuracy ◽  
Acrylonitrile Butadiene Styrene ◽  
Processing Technique ◽  
Patient Specific ◽  
Fused Deposition ◽  
3D Printed

Abstract In this work, 3D printed master patterns of acrylonitrile butadiene styrene (ABS) thermoplastic material have been used for the preparation of Ni-Cr based functional prototypes as partial dentures (PD). The study started with patient specific three dimensional (3D), CAD data (fetched through scanning). This data was used for preparation of .STL file for printing of master patterns on fused deposition modeling (FDM) setup. The 3D printed master patterns were further wax coated to reduce the surface irregularities (as cost effective post processing technique). The hybrid patterns were subjected to investment casting for the preparation of Ni-Cr based PD. The finally prepared functional prototypes as PD were optimized for dimensional accuracy, surface finish and surface hardness as responses. The results are visualized and supported by photomicrographs and in-vitro analysis.

Test Methods for Hyperelastic Characterization of Rubber4

2009 ◽  
Vol 37 (3) ◽  
pp. 165-186 ◽  
Author(s):  
R. Kupchella ◽  
J. Kidney ◽  
W. Hutchison
Keyword(s):  
Three Dimensional ◽  
Test Methods ◽  
Biaxial Stress ◽  
Image Correlation ◽  
Optical Methods ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
Stress States ◽  
Property Changes

Abstract Optical methods using digital image correlation (DIC) are utilized in developing rubber constitutive tests. Two and three dimensional DIC systems are employed to measure strains on rubber specimens subjected to uniaxial, planar, and biaxial stress states. A special membrane inflation test was developed and is described for providing the biaxial constitutive data. Deformation-induced material property changes for the three modes of testing are quantified using a concept based on energy dissipation. The constitutive test strain ranges for each of the three modes are separately selected to equalize the material states. The methodology is applied to filled rubber compounds in order to characterize them in terms of hyperelastic behavior. Evaluation and comparison of several common hyperelastic models are given, and application to finite element modeling of a structural rubber specimen is described.

scholarly journals Design of Hybrid Cells to Facilitate Safe and Efficient Human–Robot Collaboration During Assembly Operations

2018 ◽  
Vol 18 (3) ◽  
Author(s):  
Krishnanand N. Kaipa ◽  
Carlos W. Morato ◽  
Satyandra K. Gupta
Keyword(s):  
Three Dimensional ◽  
System State ◽  
Hybrid Cells ◽  
Generation System ◽  
State Monitoring ◽  
Plan Generation ◽  
3D Printed ◽  
Assembly Operations ◽  
Human Robot Collaboration

This paper presents a framework to build hybrid cells that support safe and efficient human–robot collaboration during assembly operations. Our approach allows asynchronous collaborations between human and robot. The human retrieves parts from a bin and places them in the robot's workspace, while the robot picks up the placed parts and assembles them into the product. We present the design details of the overall framework comprising three modules—plan generation, system state monitoring, and contingency handling. We describe system state monitoring and present a characterization of the part tracking algorithm. We report results from human–robot collaboration experiments using a KUKA robot and a three-dimensional (3D)-printed mockup of a simplified jet-engine assembly to illustrate our approach.

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