scholarly journals Effect of 3D Printing Parameters on the Refractive Index, Attenuation Coefficient, and Birefringence of Plastics in Terahertz Range

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Alexander T. Clark ◽  
John F. Federici ◽  
Ian Gatley
Keyword(s):  
Refractive Index ◽  
3D Printing ◽  
Attenuation Coefficient ◽  
Refractive Indices ◽  
Attenuation Coefficients ◽  
Layer Height ◽  
Nozzle Size ◽  
3D Printed ◽  
Printing Parameters ◽  
Real Refractive Index

The refractive indices, attenuation coefficients, and level of birefringence of various 3D printing plastics may change depending on the printing parameters. Transmission terahertz time-domain spectroscopy was used to look for such effects in Copolyester (CPE), Nylon, Polycarbonate (PC), Polylactic acid, and Polypropylene. The thickness of each sample was measured using an external reference structure and time-of-flight measurements. The parameters varied were printer nozzle size, print layer height, and print orientation. Comparison of these parameters showed that a printer’s nozzle size and print layer height caused no change in real refractive index or attenuation coefficient. A change in printing orientation from vertical to horizontal caused an increase both in real refractive index and in attenuation coefficient. In vertically printed samples, the increase in birefringence was proportional to the increase in layer height and inversely proportional to nozzle size. There was no measurable intrinsic birefringence in the horizontally printed samples. These effects should be taken into account in the design of FDM 3D printed structures that demand tailored refractive indices and attenuation coefficients, while also providing a foundation for nondestructive evaluation of FDM 3D printed objects and structures.

APPLICATION OF 3D PRINTING TECHNOLOGY FOR RAPID TOOLING IN SHEET METAL FORMING

2020 ◽  
Vol 3 ◽  
pp. 20-30
Author(s):  
M.A. SEREZHKIN ◽  
D.O. KLIMYUK ◽  
A.I. PLOKHIKH
Keyword(s):  
3D Printing ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Rapid Tooling ◽  
Printing Technology ◽  
3D Printing Technology ◽  
3D Printed ◽  
Printed Materials ◽  
Printing Parameters

The article presents the study of the application of 3D printing technology for rapid tooling in sheet metal forming for custom or small–lot manufacturing. The main issue of the usage of 3D printing technology for die tooling was discovered. It is proposed to use the method of mathematical modelling to investigate how the printing parameters affect the compressive strength of FDM 3D–printed parts. Using expert research methods, the printing parameters most strongly affecting the strength of products were identified for further experiments. A method for testing the strength of 3D–printed materials has been developed and tested.

Properties and applications of electrically conductive thermoplastics for additive manufacturing of sensors

2017 ◽  
Vol 84 (9) ◽  
Author(s):  
Benedikt Hampel ◽  
Samuel Monshausen ◽  
Meinhard Schilling
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Electrical Conductance ◽  
Electrically Conductive ◽  
Fused Deposition ◽  
Printing Technique ◽  
Deposition Modeling ◽  
3D Printed ◽  
3D Printing Technique ◽  
Printing Parameters

AbstractIn consequence of the growing diversity of materials in the fused deposition modeling 3D printing technique, electrically conductive materials are commercially available. In this work two filaments based on thermoplastics filled with carbon or metal nanoparticles are analyzed in terms of their electrical conductance. The printing parameters to process the materials with the 3D printer are optimized with the design of experiments (DoE) method. A model to calculate the resistance of such 3D printed structures is presented and a demonstrator as a proof of concept was 3D printed based on these results. In addition, 3D printing of capacitors is investigated.

scholarly journals Modelling and Investigation of Crack Growth for 3D-Printed Acrylonitrile Butadiene Styrene (ABS) with Various Printing Parameters and Ambient Temperatures

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3737
Author(s):  
Yousef Lafi A. Alshammari ◽  
Feiyang He ◽  
Muhammad A. Khan
Keyword(s):  
3D Printing ◽  
Crack Growth ◽  
Three Dimensional ◽  
Acrylonitrile Butadiene Styrene ◽  
Fused Deposition Modelling ◽  
Structural Dynamic ◽  
Fused Deposition ◽  
Nozzle Size ◽  
Printing Parameters ◽  
Butadiene Styrene

Three-dimensional (3D) printing is one of the significant industrial manufacturing methods in the modern era. Many materials are used for 3D printing; however, as the most used material in fused deposition modelling (FDM) technology, acrylonitrile butadiene styrene (ABS) offers good mechanical properties. It is perfect for making structures for industrial applications in complex environments. Three-dimensional printing parameters, including building orientation, layers thickness, and nozzle size, critically affect the crack growth in FDM structures under complex loads. Therefore, this paper used the dynamic bending vibration test to investigate their influence on fatigue crack growth (FCG) rate under dynamic loads and the Paris power law constant C and m. The paper proposed an analytical solution to determine the stress intensity factor (SIF) at the crack tip based on the measurement of structural dynamic response. The experimental results show that the lower ambient temperature, as well as increased nozzle size and layer thickness, provide a lower FCG rate. The printing orientation, which is the same as loading, also slows the crack growth. The linear regression between these parameters and Paris Law’s coefficient also proves the same conclusion.

scholarly journals Printability and properties of 3D-printed poplar fiber/polylactic acid biocomposite

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2774-2788
Author(s):  
Zhaozhe Yang ◽  
Xinhao Feng ◽  
Min Xu ◽  
Denis Rodrigue
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Rheological Properties ◽  
Layer Thickness ◽  
Polylactic Acid ◽  
Physical And Mechanical Properties ◽  
Longitudinal Stripe ◽  
3D Printed ◽  
First Time ◽  
Printing Parameters

To efficiently and economically utilize a wood-plastic biocomposite, an eco-friendly biocomposite was prepared using modified poplar fiber and polylactic acid (PLA) via 3D printing technology for the first time. First, the effects of poplar fiber (0, 1, 3, 5, 7, and 9%) on the mechanical and rheological properties of the printed biocomposites were investigated. Subsequently, the printing parameters, including printing temperature, speed, and layer thickness, were optimized to obtain the biocomposite with superior properties. Finally, four printing orientations were applied to the biocomposite based on the optimized printing parameters to study the effect of filament orientation on the properties of the biocomposite. Favorable printability and mechanical properties of the biocomposite were obtained at 5% poplar fiber. The optimal printing temperature of 220 °C, speed of 40 mm/s, and layer thickness of 0.2 mm were obtained to produce the desired mechanical properties of the biocomposite with the printing orientation in a longitudinal stripe. However, the printing parameters should be chosen according to the applications, where different physical and mechanical properties are needed to achieve efficient and economical utilization of the biocomposites.

Infrared Intensities of Liquids XV: Infrared Refractive Indices from 8000 to 350 cm−1, Absolute Integrated Intensities, Transition Moments, and Dipole Moment Derivatives of Methanol-d, at 25°C

1994 ◽  
Vol 48 (2) ◽  
pp. 176-189 ◽  
Author(s):  
John E. Bertie ◽  
Shuliang L. Zhang
Keyword(s):  
Refractive Index ◽  
Dipole Moment ◽  
Molecular Properties ◽  
Refractive Indices ◽  
The Real ◽  
Transition Moments ◽  
Refractive Index Spectrum ◽  
Integrated Intensities ◽  
Derivatives Of ◽  
Real Refractive Index

This paper reports infrared absorption intensities of liquid methanol- d, CH3OD, at 25°C, between 8000 and 350 cm−1 Measurements were made by multiple attenuated total reflection spectroscopy with the use of the CIRCLE cell, and by transmission spectroscopy with a variable-path-length cell with CaF2 windows. The results of these two methods agree excellently and were combined to yield an imaginary refractive index spectrum, k(ν˜) vs. ν˜, between 6187 and 350 cm−1. The imaginary refractive index spectrum was arbitrarily set to zero between 6187 and 8000 cm−1 where k is always less than 2 × 10−6, in order that the real refractive index can be calculated below 8000 cm−1 by Kramers-Krönig transformation. The results are reported as graphs and as tables of the real and imaginary refractive indices between 8000 and 350 cm−1, from which all other infrared properties of liquid methanol- d can be calculated. The accuracy is estimated to be ± 3% below 5900 cm−1 and ± 10% above 5900 cm−1 for the imaginary refractive index and better than ± 0.5% for the real refractive index. In order to obtain molecular information from the refractive indices, the spectrum of the imaginary polarizability multiplied by wavenumber, ν˜ vs. ν˜, was calculated under the assumption of the Lorentz local field. The area under this ν˜ spectrum was separated into the integrated intensities of different vibrations. Molecular properties were calculated from these integrated intensities—specifically, the transition moments and dipole moment derivatives of the molecules in the liquid, the latter under the harmonic approximation. The availability of the spectra of both CH3OH and CH3OD enables the integrated intensities and the molecular properties of the C-H, O-H, O-D, and C-O stretching and CH3 deformation vibrations to be determined with confidence to a few percent. Further work with isotopic molecules is needed to improve the reliability of the integrated intensities of the C-O-H(D) in-plane bending, H-C-O-H(D) torsion, and CH3 rocking vibrations.

Optimization of Additive Manufacturing for Layer Sticking and Dimensional Accuracy

2019 ◽  
pp. 185-198
Author(s):  
Syed Faiz Ali ◽  
Fasih Munir Malik ◽  
Emin Faruk Kececi ◽  
Burak Bal
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Flow Rate ◽  
Experimental Testing ◽  
Dimensional Accuracy ◽  
Theoretical Modelling ◽  
Bed Temperature ◽  
Nozzle Size ◽  
The Relationship ◽  
Printing Parameters

When the 3D printing process is considered, there are also other parameters, such as nozzle size, flow rate of material, print-speed, print-bed temperature, cooling rate, and pattern of printing. There are also dependencies that will be addressed in between these parameters; for example, if the printing temperature is increased, it is not clear if the viscosity of the material will increase or decrease. This chapter aims to explain the effect of printing temperature on layer sticking while dimensional accuracy is achieved. Theoretical modelling and experimental testing will be performed to prove the relationship. This type of formulation can be later adapted into a slicer program, so that the program automatically selects some of the printing parameters to achieve desired dimensional accuracy and layer sticking.

scholarly journals 3D printed PLA Army-Navy retractors when used as linear retractors yield clinically acceptable tolerances

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Joshua V. Chen ◽  
Alexis B. C. Dang ◽  
Carlin S. Lee ◽  
Alan B. C. Dang
Keyword(s):  
3D Printing ◽  
Polylactic Acid ◽  
Low Cost ◽  
Optimal Designs ◽  
Material Cost ◽  
Resource Poor ◽  
3D Printed ◽  
Strength Material ◽  
Printing Parameters ◽  
Printing Time

Abstract Background Modern low-cost 3D printing technologies offer the promise of access to surgical tools in resource scarce areas, however optimal designs for manufacturing have not yet been established. We explore how the optimization of 3D printing parameters when manufacturing polylactic acid filament based Army-Navy retractors vastly increases the strength of retractors, and investigate sources of variability in retractor strength, material cost, printing time, and parameter limitations. Methods Standard retractors were printed from various polylactic acid filament spools intra-manufacturer and inter-manufacturer to measure variability in retractor strength. Printing parameters were systematically varied to determine optimum printing parameters. These parameters include retractor width, thickness, infill percentage, infill geometry, perimeter number, and a reinforced joint design. Estimated retractor mass from computer models allows us to estimate material cost. Results We found statistically significant differences in retractor strength between spools of the same manufacturer and between manufacturers. We determined the true strength optimized retractor to have 30% infill, 3 perimeters, 0.25 in. thickness, 0.75 in. width, and has “Triangle” infill geometry and reinforced joints, failing at more than 15X the threshold for clinically excessive retraction and costs $1.25 USD. Conclusions The optimization of 3D printed Army-Navy retractors greatly improve the efficacy of this instrument and expedite the adoption of 3D printing technology in many diverse fields in medicine not necessarily limited to resource poor settings.

3D Printed Titanium Dioxide Thin Films for Optoelectronic Applications

2020 ◽  
Vol 843 ◽  
pp. 79-83
Author(s):  
Krairop Charoensopa ◽  
Aran Hansuebsai ◽  
Kazuhiro Manseki
Keyword(s):  
Thin Films ◽  
3D Printing ◽  
Dye Sensitized Solar Cells ◽  
Time Operation ◽  
Nozzle Size ◽  
Deposition Modeling ◽  
Printing System ◽  
3D Printed ◽  
Optoelectronic Applications ◽  
Titanium Dioxide Thin Films

This work focused on the printing of semiconductor TiO2 thin films for solar cell applications by 3D printing system. We demonstrate a Liquid Deposition Modeling (LDM) type for controlling the pattern of TiO2 electrode. The advantage of this type of printer is able to vary the numbers of printed layer as well as different levelling pattern of TiO2 thin films by one time operation. Our aim was to study the effects of operating parameters of the 3D printer, such as nozzle size, speed and pressure on the thickness and uniformity of the printed TiO2 films. Using a commercial TiO2 paste, TiO2 precursor films were deposited on a conductive F-doped SnO2 glass by adjusting nozzle size, speed and pressure. The precursor films with different printed layers and levelling pattern were sintered using oven to produce porous TiO2 electrodes. The thickness and surface roughness of obtained TiO2 electrodes were characterized using Scanning Electron Microscope (SEM) and 3D Measuring Laser Microscope. The printed TiO2 substrates were applied to dye-sensitized solar cells as electrodes. Our LDM type 3D printing will provide a new way of levelling design of device components for versatile optoelectronic applications.

scholarly journals Effects of Printing Parameters on the Fit of Implant-Supported 3D Printing Resin Prosthetics

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2533 ◽  
Author(s):  
Gang-Seok Park ◽  
Seong-Kyun Kim ◽  
Seong-Joo Heo ◽  
Jai-Young Koak ◽  
Deog-Gyu Seo
Keyword(s):  
3D Printing ◽  
Layer Thickness ◽  
Micro Ct ◽  
Marginal Fit ◽  
Dental Model ◽  
Marginal Discrepancy ◽  
3D Printed ◽  
Ct Data ◽  
Internal Gap ◽  
Printing Parameters

The purpose of the study was to investigate the influence of 3D printing parameters on fit and internal gap of 3D printed resin dental prosthesis. The dental model was simulated and fabricated for three-unit prostheses with two implants. One hundred prostheses were 3D printed with two-layer thicknesses for five build orientations using a resin (NextDent C&B; 3D systems, Soesterberg, The Netherlands) and ten prostheses were manufactured with a milling resin as control. The prostheses were seated and scanned with micro-CT (computerized tomography). Internal gap volume (IGV) was calculated from 3D reconstructed micro-CT data. IGV, marginal fit, and lengths of internal gaps were measured, and the values were analyzed statistically. For the 3D printed prostheses, IGV was smaller at 45°, 60°, and 90° compared to other build orientations. The marginal fit evaluated by absolute marginal discrepancy was smaller than other build orientations at 45° and 60°. IGV was smaller at 50 µm layer thickness than at 100 µm layer thickness, but the marginal fit was smaller at 100 µm layer thickness than at 50 µm layer thickness. The 3D printed prosthesis had smaller internal gap than the milled prosthesis. The marginal fit of the 3D printed resin prosthesis was clinically acceptable, and build orientation of 45° and 60° would be recommended when considering fit and internal gap.

scholarly journals Dimensional Stability of 3D Printed Parts: Effects of Process Parameters

2019 ◽  
Vol 119 (2) ◽  
pp. 9 ◽  
Author(s):  
Elizabeth Azhikannickal ◽  
Aaron Uhrin
Keyword(s):  
3D Printing ◽  
Process Parameters ◽  
Dimensional Stability ◽  
Computer Aided Design ◽  
3D Model ◽  
Dimensional Error ◽  
Layer Height ◽  
Fused Deposition ◽  
3D Printed ◽  
Rms Error

The three-dimensional (3D) printing manufacturing process begins with the creation of a 3D model—using computer aided design (CAD) software—of the part to be printed. Using a type of 3D printing known as fused deposition modeling (FDM®), the 3D printer extrudes molten plastic to scan lines to create individual layers (i.e., the infill): one on top of the other. (Note that "scan" in this context refers to the movement of the extruder head, along an x,y coordinate path, while depositing molten plastic.) This process is repeated until the overall geometry, specified by the 3D model, is built. This process is attractive for producing proof of concept or prototype parts in various fields including automotive, aerospace, and medical. However, FDM subjects the material to rapid heating and cooling; therefore, some degree of undesirable warpage of the part occurs post fabrication. The primary objective of this study was to determine the effect of 4 process parameters (i.e., infill shape, infill density, number of perimeters created per layer, and layer height) on the total dimensional error of a representative 3D-printed part. This part (the "simple part"), used in Trials 1 through 3 of this study, was a square acrylonitrile butadiene styrene (ABS) plate having a nominal measurement of 50 mm × 50 mm × 5 mm thick. A residual error (the difference between the measured post-printing dimension and the theoretical CAD file dimension) was calculated along each given direction and for each test print. Finally, a root mean square (RMS) error (i.e., the square root of the average of the squared residual errors along the length, width, and thickness directions) was calculated for each printed part. Three repeat test prints were carried out for each parameter. The number of perimeters played a key role in the dimensional stability of the part. As the number of perimeters increased up to 5, the RMS error decreased. Beyond 5 perimeters, however, the RMS error increased due to excessive warpage/curvature at the corners of the part. Ultimately, when examined individually, a grid infill shape at 100% density, a 0.4 mm layer height, and 5 perimeters each produced the lowest warpage. In combination, these same 4 parameters also produced the lowest RMS error (based on dimensional analysis of 3 test prints) when used to print a more complicated part (the "stacked part") in Trial 4.

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