scholarly journals The influence of printing parameters on multi-material two-photon polymerisation based micro additive manufacturing

2021 ◽  
pp. 102575
Author(s):  
Qin Hu ◽  
Graham A. Rance ◽  
Gustavo F. Trindade ◽  
David Pervan ◽  
Long Jiang ◽  
...  
TEM Journal ◽  
2020 ◽  
pp. 966-970
Author(s):  
Damir Hodžić ◽  
Adi Pandžić ◽  
Ismar Hajro ◽  
Petar Tasić

Widely used additive manufacturing technique for plastic materials is Fused Deposition Modelling (FDM). The FDM technology has gained interest in industry for a wide range of applications, especially today when large number of different materials on the market are available. There are many different manufacturers for the same FDM material where the difference in price goes up to 50%. This experimental study investigates possible difference in strength of the 3D printed PLA material of five different manufacturers. All specimens are 3D printed on Ultimaker S5 printer with the same printing parameters, and they are all the same colour.


2021 ◽  
Vol 15 (4) ◽  
pp. 491-497
Author(s):  
Tomislav Breški ◽  
Lukas Hentschel ◽  
Damir Godec ◽  
Ivica Đuretek

Fused filament fabrication (FFF) is currently one of the most popular additive manufacturing processes due to its simplicity and low running and material costs. Support structures, which are necessary for overhanging surfaces during production, in most cases need to be manually removed and as such, they become waste material. In this paper, experimental approach is utilised in order to assess suitability of recycling support structures into recycled filament for FFF process. Mechanical properties of standardized specimens made from recycled polylactic acid (PLA) filament as well as influence of layer height and infill density on those properties were investigated. Optimal printing parameters for recycled PLA filaments are determined with Design of Experiment methods (DOE).


Science ◽  
2019 ◽  
Vol 366 (6461) ◽  
pp. 105-109 ◽  
Author(s):  
Sourabh K. Saha ◽  
Dien Wang ◽  
Vu H. Nguyen ◽  
Yina Chang ◽  
James S. Oakdale ◽  
...  

High-throughput fabrication techniques for generating arbitrarily complex three-dimensional structures with nanoscale features are desirable across a broad range of applications. Two-photon lithography (TPL)–based submicrometer additive manufacturing is a promising candidate to fill this gap. However, the serial point-by-point writing scheme of TPL is too slow for many applications. Attempts at parallelization either do not have submicrometer resolution or cannot pattern complex structures. We overcome these difficulties by spatially and temporally focusing an ultrafast laser to implement a projection-based layer-by-layer parallelization. This increases the throughput up to three orders of magnitude and expands the geometric design space. We demonstrate this by printing, within single-digit millisecond time scales, nanowires with widths smaller than 175 nanometers over an area one million times larger than the cross-sectional area.


Author(s):  
Austin C. Hayes ◽  
Gregory L. Whiting

Abstract Additive manufacturing enables the production of complex geometries extremely difficult to create with conventional subtractive methods. While good at producing complex parts, its limitations can be seen through its penetration into everyday manufacturing markets. Throughput limitations, poor surface roughness, limited material selection, and repeatability concerns hinder additive manufacturing from revolutionizing all but the low-volume, high-value markets. This work characterizes combining powder-binder jetting with traditional casting techniques to create large, complex metal parts. Specifically, we extend this technology to wind turbine generators and provide initial feasibility of producing complex direct-drive generator rotor and stator designs. In this process, thermal inkjet printer heads selectively deposit binder on hydroperm casting powder. This powder is selectively solidified and baked to remove moisture before being cast through traditional methods. This work identifies a scalable manufacturing process to print large-scale wind turbine direct drive generators. As direct-drive generators are substantially larger than their synchronous counterparts, a printing process must be able to be scaled for a 2–5 MW 2–6m machine. For this study, research on the powder, binder, and printing parameters is conducted and evaluated for scalability.


2020 ◽  
Vol 10 (12) ◽  
pp. 4148
Author(s):  
Rodrigo Cézar da Silveira Romero ◽  
André Argueso Machado ◽  
Kliftom Amorim Costa ◽  
Paulo Henrique Rodriguês Guilherme Reis ◽  
Pedro Paiva Brito ◽  
...  

This work aims to develop a low-cost human hand prosthesis manufactured through additive manufacturing. The methodology used for the development of the prosthesis used affordable and low-cost materials in the market. Tensile testing was performed to estimate the mechanical properties in order to verify the resistance of the printing material used. Afterwards, the mechanical feasibility study executed on the device was performed using finite element method. In conclusion, we can observe fundamental factors that influence the 3D printing process, especially in relation to its printing parameters and mechanical properties. Maximum stress, yield stress, modulus of elasticity, elongation, and hardness are the prominent properties that should be considered when choosing the polymeric material. The numerical simulation showed that the structure of the prosthesis did not present plastic deformations to the applied loads, proving its mechanical viability.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Juan Manuel Vázquez Martínez ◽  
David Piñero Vega ◽  
Jorge Salguero ◽  
Moises Batista

Purpose The evaluation of novel materials such as the acrylonitrile styrene acrylate (ASA) for tribological and mechanical conditions can provide a structural protection against the environmental and wear effects that results in the long-term integrity of the 3 D printed parts. Results of the experimental stage are intended to identify the influence of the printing conditions on the functional characteristics of ASA parts that results in variations of the friction coefficient, wear rate and tensile response. In addition, this study aims to highlight the relevance of printing parameters to avoid the use of chemical post-processing stages, increasing the performance and sustainability of the process. Design/methodology/approach In this research, an evaluation of the influence of printing parameters of layer thickness and temperature on the mechanical and tribological response have been carried out for ASA specimens manufactured by fused filament fabrication technology. For this purpose, a range of three different values of thickness of fused layer and three different printing temperatures were combined in the manufacturing process of tests samples. Mechanical behavior of the printed parts was evaluated by standard tensile tests, and friction forces were measured by pin-on-disk tribological tests against steel spheres. Findings Higher layer thickness of the printed parts shows lower resistance to tribological wear effects; in terms of friction coefficient and wear rate, this type of parts also presents lower tensile strength. It has been detected that mechanical and tribological behavior is highly related to the micro-geometrical characteristics of the printed surfaces, which can be controlled by the manufacturing parameters. Under this consideration, a reduction in the coefficient of friction near to 65% in the average value was obtained through the variation of the layer thickness of printed surfaces. Originality/value This research aims to fill a gap in the scientific literature about the use of specific additive manufacturing materials under dynamic contact. This paper is mainly focused on the influence of the manufacturing parameters on the tribological and mechanical behavior of a weather resistant polymer (ASA).


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3961 ◽  
Author(s):  
Hong Xiao ◽  
Wei Han ◽  
Yueke Ming ◽  
Zhongqiu Ding ◽  
Yugang Duan

Three-dimensional printing of continuous carbon fiber/epoxy composites (CCF/EPCs) is an emerging additive manufacturing technology for fiber-reinforced polymer composites and has wide application prospects. However, the 3D printing parameters and their relationship with the mechanical properties of the final printed samples have not been fully investigated in a computational and quantifiable way. This paper presents a sensitivity analysis (SA)-based parameter optimization framework for the 3D printing of CCF/EPCs. A surrogate model for a process parameter–mechanical property relationship was established by support vector regression (SVR) analysis of the experimental data on flexural strength and flexural modulus under different process parameters. An SA was then performed on the SVR surrogate model to calculate the importance of each individual 3D printing parameter on the mechanical properties of the printed samples. Based on the SA results, the optimal 3D printing parameters and the corresponding flexural strength and flexural modulus of the printed samples were predicted and verified by experiments. The results showed that the proposed framework can serve as a high-accuracy tool to optimize the 3D printing parameters for the additive manufacturing of CCF/EPCs.


Author(s):  
Sourabh K. Saha ◽  
Chuck Divin ◽  
Jefferson A. Cuadra ◽  
Robert M. Panas

Two-photon lithography is a direct laser write process that enables fabrication of millimeter scale 3D structures with nanoscale building blocks. In this technique, writing is achieved via a nonlinear two-photon absorption process during which two photons are near-simultaneously absorbed at high laser intensities. Due to the high laser intensities, it is essential to carefully select the incident power so that two-photon polymerization (TPP) occurs without any laser damage of the resist. Currently, the feasible range of laser power is identified by writing small test patterns at varying power levels. Herein, we demonstrate that the results of these tests cannot be generalized because the damage threshold power is dependent on the proximity of features and reduces by as much 37.5% for overlapping features. We have identified that this reduction occurs due to a combination of reduced TPP for overlapping features and increased single-photon absorption of the resin after curing. We have captured the damage arising out of this proximity effect via 3D computed tomography images of a non-homogenous part that has varying feature density. Part damage manifests in the form of internal spherical voids that arise due to boiling of the resist at high laser intensities. Herein, we have empirically quantified this proximity effect by identifying the damage threshold power at different writing speeds and feature overlap spacings. In addition, we present a first-order analytical model that captures the scaling of this proximity effect. The scaling laws and the empirical data generated here can be used to select the appropriate writing process parameters so as to correct for proximity effects and prevent part damage during sub-micron additive manufacturing of parts with closely spaced features.


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