scholarly journals Three-Dimensional (3D) Printing Implemented by Computer-Generated Holograms for Generation of 3D Layered Images in Optical Near Field

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 286
Author(s):  
Chung-Fei Lee ◽  
Wei-Feng Hsu ◽  
Tzu-Hsuan Yang ◽  
Ren-Jei Chung
Keyword(s):  
3D Printing ◽  
Incident Light ◽  
Near Field ◽  
Three Dimensional ◽  
Angular Spectrum ◽  
Initial Study ◽  
Layer By Layer ◽  
Light Modulator ◽  
Lateral Direction ◽  
Printing System

Photocurable three-dimensional (3D) printing is a stepwise layer-by-layer fabrication process widely used in the manufacture of highly specialized objects. Current 3D printing techniques are easily implemented; however, the build rate is slow and the surface quality is less than ideal. Holographic 3D display (3DHD) technology makes it possible to reform planar wavefronts into a 3D intensity distribution, which appears as a 3D image in space. This paper examined the application of holographic imaging technology to 3D printing based on photocurable polymers. The proposed system uses a 3DHD diffractive optics system based on a liquid-crystal-on-silicon spatial light modulator (LCoS-SLM), wherein a 3D layered image is created in the optical near field, based on a computer-generated hologram (CGH) optimized using the iterative angular spectrum algorithm (IASA) and a circular IASA. From a single CGH, multiple 2D sliced images are created in space to form a 3D optical image used to initiate the photopolymerization of photocurable resin to form 3D objects. In experiments, the proposed 3D printing system was used to create five polymer objects with a maximum axial length of 25 mm and minimum feature width of 149 μm. The phase-only CGH reformed the incident light into a distribution of optical intensity with high diffraction efficiency suitable for photocuring. Despite limitations pertaining to fabrication area and axial complexity in this initial study, the proposed method demonstrated high light efficiency, high resolution in the lateral direction, rapid fabrication, and good object continuity.

Multiphoton Polymerization Using Femtosecond Bessel Beam for Layerless Three-Dimensional Printing

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Xiaoming Yu ◽  
Meng Zhang ◽  
Shuting Lei
Keyword(s):  
3D Printing ◽  
Bessel Beam ◽  
Three Dimensional ◽  
Average Diameter ◽  
Laser Exposure ◽  
Layer By Layer ◽  
Light Modulator ◽  
Aspect Ratios ◽  
Printing Method ◽  
Printing Speed

Photopolymerization enables the printing of three-dimensional (3D) objects through successively solidifying liquid photopolymer on two-dimensional (2D) planes. However, such layer-by-layer process significantly limits printing speed, because a large number of layers need to be processed in sequence. In this paper, we propose a novel 3D printing method based on multiphoton polymerization using femtosecond Bessel beam. This method eliminates the need for layer-by-layer processing, and therefore dramatically increases printing speed for structures with high aspect ratios, such as wires and tubes. By using unmodulated Bessel beam, a stationary laser exposure creates a wire with average diameter of 100 μm and length exceeding 10 mm, resulting in an aspect ratio > 100:1. Scanning this beam on the lateral plane fabricates a hollow tube within a few seconds, more than ten times faster than using the layer-by-layer method. Next, we modulate the Bessel beam with a spatial light modulator (SLM) and generate multiple beam segments along the laser propagation direction. Experimentally observed beam pattern agrees with optics diffraction calculation. This 3D printing method can be further explored for fabricating complex structures and has the potential to dramatically increase 3D printing speed while maintaining high resolution.

scholarly journals A guideline for 3D printing terminology in biomedical research utilizing ISO/ASTM standards

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Amy E. Alexander ◽  
Nicole Wake ◽  
Leonid Chepelev ◽  
Philipp Brantner ◽  
Justin Ryan ◽  
...  
Keyword(s):  
3D Printing ◽  
Medical Literature ◽  
Three Dimensional ◽  
Physical Object ◽  
Medical Community ◽  
Layer By Layer ◽  
Digital File ◽  
Standardized Terminology ◽  
Standard Terms ◽  
The Impact

AbstractFirst patented in 1986, three-dimensional (3D) printing, also known as additive manufacturing or rapid prototyping, now encompasses a variety of distinct technology types where material is deposited, joined, or solidified layer by layer to create a physical object from a digital file. As 3D printing technologies continue to evolve, and as more manuscripts describing these technologies are published in the medical literature, it is imperative that standardized terminology for 3D printing is utilized. The purpose of this manuscript is to provide recommendations for standardized lexicons for 3D printing technologies described in the medical literature. For all 3D printing methods, standard general ISO/ASTM terms for 3D printing should be utilized. Additional, non-standard terms should be included to facilitate communication and reproducibility when the ISO/ASTM terms are insufficient in describing expository details. By aligning to these guidelines, the use of uniform terms for 3D printing and the associated technologies will lead to improved clarity and reproducibility of published work which will ultimately increase the impact of publications, facilitate quality improvement, and promote the dissemination and adoption of 3D printing in the medical community.

scholarly journals Three-dimensionally printed polycaprolactone/multicomponent bioactive glass scaffolds for potential application in bone tissue engineering

2020 ◽  
Vol 6 (1) ◽  
pp. 57-69
Author(s):  
Amirhosein Fathi ◽  
Farzad Kermani ◽  
Aliasghar Behnamghader ◽  
Sara Banijamali ◽  
Masoud Mozafari ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
3D Printing ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Three Dimensional ◽  
Layer By Layer ◽  
Composite Scaffolds ◽  
3D Printed ◽  
Co Doped

AbstractOver the last years, three-dimensional (3D) printing has been successfully applied to produce suitable substitutes for treating bone defects. In this work, 3D printed composite scaffolds of polycaprolactone (PCL) and strontium (Sr)- and cobalt (Co)-doped multi-component melt-derived bioactive glasses (BGs) were prepared for bone tissue engineering strategies. For this purpose, 30% of as-prepared BG particles (size <38 μm) were incorporated into PCL, and then the obtained composite mix was introduced into a 3D printing machine to fabricate layer-by-layer porous structures with the size of 12 × 12 × 2 mm3.The scaffolds were fully characterized through a series of physico-chemical and biological assays. Adding the BGs to PCL led to an improvement in the compressive strength of the fabricated scaffolds and increased their hydrophilicity. Furthermore, the PCL/BG scaffolds showed apatite-forming ability (i.e., bioactivity behavior) after being immersed in simulated body fluid (SBF). The in vitro cellular examinations revealed the cytocompatibility of the scaffolds and confirmed them as suitable substrates for the adhesion and proliferation of MG-63 osteosarcoma cells. In conclusion, 3D printed composite scaffolds made of PCL and Sr- and Co-doped BGs might be potentially-beneficial bone replacements, and the achieved results motivate further research on these materials.

scholarly journals Porous PLAs with Controllable Density by FDM 3D Printing and Chemical Foaming Agent

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 866
Author(s):  
A. R. Damanpack ◽  
André Sousa ◽  
M. Bodaghi
Keyword(s):  
3D Printing ◽  
Flow Rate ◽  
Three Dimensional ◽  
Poly Lactic Acid ◽  
Layer By Layer ◽  
Printing Technology ◽  
Material Density ◽  
Foaming Agent ◽  
3D Printing Technology ◽  
Fabrication Parameters

This paper shows how fused decomposition modeling (FDM), as a three-dimensional (3D) printing technology, can engineer lightweight porous foams with controllable density. The tactic is based on the 3D printing of Poly Lactic Acid filaments with a chemical blowing agent, as well as experiments to explore how FDM parameters can control material density. Foam porosity is investigated in terms of fabrication parameters such as printing temperature and flow rate, which affect the size of bubbles produced during the layer-by-layer fabrication process. It is experimentally shown that printing temperature and flow rate have significant effects on the bubbles’ size, micro-scale material connections, stiffness and strength. An analytical equation is introduced to accurately simulate the experimental results on flow rate, density, and mechanical properties in terms of printing temperature. Due to the absence of a similar concept, mathematical model and results in the specialized literature, this paper is likely to advance the state-of-the-art lightweight foams with controllable porosity and density fabricated by FDM 3D printing technology.

Three-Dimensional Finite-Difference Time-Domain Method Modeling of Nanowire Optical Probe

2014 ◽  
Vol 602-605 ◽  
pp. 3359-3362
Author(s):  
Chun Li Zhu ◽  
Jing Li
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Incident Light ◽  
Near Field ◽  
Three Dimensional ◽  
Polarization Direction ◽  
Near Field Imaging ◽  
Difference Time ◽  
Field Imaging

In this paper, output near fields of nanowires with different optical and structure configurations are calculated by using the three-dimensional finite-difference time-domain (3D FDTD) method. Then a nanowire with suitable near field distribution is chosen as the probe for scanning dielectric and metal nanogratings. Scanning results show that the resolution in near-field imaging of dielectric nanogratings can be as low as 80nm, and the imaging results are greatly influenced by the polarization direction of the incident light. Compared with dielectric nanogratings, metal nanogratings have significantly enhanced resolutions when the arrangement of gratings is perpendicular to the polarization direction of the incident light due to the enhancement effect of the localized surface plasmons (SPs). Results presented here could offer valuable references for practical applications in near-field imaging with nanowires as optical probes.

Algorithm to Reduce Leading and Lagging in Conformal Direct-Print

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Morteza Vatani ◽  
Faez Alkadi ◽  
Jae-Won Choi
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
3D Model ◽  
Three Dimensional ◽  
Motion Direction ◽  
B Spline ◽  
And Topology ◽  
Printing System ◽  
3D Printed ◽  
Printed Patterns

A novel additive manufacturing algorithm was developed to increase the consistency of three-dimensional (3D) printed curvilinear or conformal patterns on freeform surfaces. The algorithm dynamically and locally compensates the nozzle location with respect to the pattern geometry, motion direction, and topology of the substrate to minimize lagging or leading during conformal printing. The printing algorithm was implemented in an existing 3D printing system that consists of an extrusion-based dispensing module and an XYZ-stage. A dispensing head is fixed on a Z-axis and moves vertically, while the substrate is installed on an XY-stage and moves in the x–y plane. The printing algorithm approximates the printed pattern using nonuniform rational B-spline (NURBS) curves translated directly from a 3D model. Results showed that the proposed printing algorithm increases the consistency in the width of the printed patterns. It is envisioned that the proposed algorithm can facilitate nonplanar 3D printing using common and commercially available Cartesian-type 3D printing systems.

scholarly journals Rapid and Inexpensive Fabrication of Multi-Depth Microfluidic Device using High-Resolution LCD Stereolithographic 3D Printing

2019 ◽  
Vol 3 (1) ◽  
pp. 26 ◽  
Author(s):  
Mohamed Mohamed ◽  
Hitendra Kumar ◽  
Zongjie Wang ◽  
Nicholas Martin ◽  
Barry Mills ◽  
...  
Keyword(s):  
High Resolution ◽  
3D Printing ◽  
Soft Lithography ◽  
Liquid Crystal Display ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Single Step ◽  
Droplet Generator ◽  
Rapid Fabrication ◽  
Printing System

With the dramatic increment of complexity, more microfluidic devices require 3D structures, such as multi-depth and -layer channels. The traditional multi-step photolithography is time-consuming and labor-intensive and also requires precise alignment during the fabrication of microfluidic devices. Here, we present an inexpensive, single-step, and rapid fabrication method for multi-depth microfluidic devices using a high-resolution liquid crystal display (LCD) stereolithographic (SLA) three-dimensional (3D) printing system. With the pixel size down to 47.25 μm, the feature resolutions in the horizontal and vertical directions are 150 μm and 50 μm, respectively. The multi-depth molds were successfully printed at the same time and the multi-depth features were transferred properly to the polydimethylsiloxane (PDMS) having multi-depth channels via soft lithography. A flow-focusing droplet generator with a multi-depth channel was fabricated using the presented 3D printing method. Experimental results show that the multi-depth channel could manipulate the morphology and size of droplets, which is desired for many engineering applications. Taken together, LCD SLA 3D printing is an excellent alternative method to the multi-step photolithography for the fabrication of multi-depth microfluidic devices. Taking the advantages of its controllability, cost-effectiveness, and acceptable resolution, LCD SLA 3D printing can have a great potential to fabricate 3D microfluidic devices.

Axial Control of Two-Photon Polymerization With Femtosecond Bessel Beam

2017 ◽  
Author(s):  
Xiaoming Yu ◽  
Meng Zhang ◽  
Shuting Lei
Keyword(s):  
3D Printing ◽  
Bessel Beam ◽  
Average Diameter ◽  
Axial Direction ◽  
Polymerization Process ◽  
Layer By Layer ◽  
Light Modulator ◽  
Simultaneous Generation ◽  
Two Photon ◽  
Two Photon Polymerization

Stereolithography of three-dimensional, arbitrarily-shaped objects is achieved by successively curing photopolymer on multiple 2D planes and then stacking these 2D slices into 3D objects. Often as a bottleneck for speeding up the fabrication process, this layer-by-layer approach originates from the lack of axial control of photopolymerization. In this paper, we present a novel stereolithography technology with which two-photon polymerization can be dynamically controlled in the axial direction using Bessel beam generated from a spatial light modulator (SLM) and an axicon. First, we use unmodulated Bessel beam to fabricate micro-wires with an average diameter of 100 μm and a length exceeding 10 mm, resulting in an aspect ratio > 100:1. A study on the polymerization process shows that a fabrication speed of 2 mm/s can be achieved. Defect and deformation are observed, and the micro-wires consist of multiple narrow fibers which indicate the existence of the self-writing effect. A test case is presented to demonstrate fast 3D printing of a hollow tube within one second. Next, we modulate the Bessel beam with an SLM and demonstrate the simultaneous generation of multiple focal spots along the laser propagation direction. These spots can be dynamically controlled by loading an image sequence on the SLM. The theoretical foundation of this technology is outlined, and computer simulation is conducted to verify the experimental results. The presented technology extends current stereolithography into the third dimension, and has the potential to significantly increase 3D printing speed.

scholarly journals Layered 3D Printing by Tethered Pyro-Electrospinning

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Sara Coppola ◽  
Giuseppe Nasti ◽  
Veronica Vespini ◽  
Pietro Ferraro
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
Multiwall Carbon Nanotubes ◽  
Processing Parameters ◽  
Layer By Layer ◽  
Biocompatible Polymer ◽  
Intrinsic Factors ◽  
Electric Effect ◽  
Mild Temperature

Nowadays it is easy to imagine that the exploitation of different additive manufacturing approaches could find use in regenerative medicine and frontiers nanotechnology with a strong interest in the development of in vivo bio-incubators that better replicate the tissue environment. Various electrospinning technologies have been exploited for the fabrication of composite polymeric architectures, where fibers have been used for the construction layer by layer of micro-architectures. Unfortunately, in case of processing biomaterials, the intrinsic factors of the materials could become obstacles when considering such advanced engineering methods. Here, for the first time, we use the pyro-EHD process for the fabrication of layered three-dimensional architectures made using a biodegradable and biocompatible polymer. The proposed approach for layered 3D printing works at mild temperature allowing deposition at high resolution and great flexibility in manufacturing, avoiding high voltage generators, and nozzles. The layered 3D printing, activated by the pyro-electric effect, is discussed and characterized in terms of geometrical features and processing parameters. Different geometries and micro-architecture (wall, square, triangle, and hybrid structures) have been demonstrated and over printing of composite polymer, obtained by mixing multiwall carbon nanotubes and fluorochrome, has been discussed, focusing on the use of a biodegradable and biocompatible polymer.

Steel Parts with Tailored Material Gradients by 3D-Printing Using Nano-Particulate Ink

2005 ◽  
Vol 492-493 ◽  
pp. 679-684 ◽  
Author(s):  
Dirk Godlinski ◽  
Stéphane Morvan
Keyword(s):  
3D Printing ◽  
Solid Freeform Fabrication ◽  
Three Dimensional ◽  
Material Design ◽  
Nano Particles ◽  
Layer By Layer ◽  
Steel Matrix ◽  
Local Composition ◽  
Composition Control ◽  
Halftone Image

It is difficult to generate any user-defined three dimensional gradient to tailor the functional properties of a component. Problems are not only the lack of local material design tools, but also a suitable manufacturing process. The implementation of the concept of local composition control into the Solid Freeform Fabrication (SFF) process 3D-Printing is described, which leads to geometrical complex parts out of tailored materials. Suspensions of different functional inks containing a binder and carbon black nano-particles are dispensed into droplets through multiple jets – like inkjet printing a halftone image on a paper – but into a metal powder bed to generate layer by layer graded green parts. In this case the tailored preforms are then sintered, while the nano-particle additions from the functional ink act locally as alloying elements in the steel matrix to combine e.g. both, toughness and hardness in the part. This work concentrates on the realisation of the new process and shows first results taking the generation of carbon-graded steel parts as an example.

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