Three Dimensional Microstructures from Metal Carbonyls

1998 ◽  
Vol 542 ◽  
Author(s):  
Jan-Erik Lind ◽  
Olli Nyrhila ◽  
Juha Kotila ◽  
Tatu Syvanen
Keyword(s):  
Laser Power ◽  
Growth Parameters ◽  
Three Dimensional ◽  
Spot Size ◽  
Layer By Layer ◽  
Metal Carbonyls ◽  
Power Laser ◽  
Iron Carbonyls ◽  
Scan Speed ◽  
Gas Pressures

Abstract3D-LCVD of nickel and iron carbonyls was studied in order to grow 3-D metal forms under static or scanning Nd:YAG-laser beam. In addition to growth, emphasis was also placed on the prevention of the simultaneous decomposition of carbon monoxide, which interferes with the metal growth process. This was essential, because the fairly high precursor gas pressures of the metal carbonyls are very tempting for the 3D-LCVD. Parameters to be optimized included precursor pressure, laser power, laser scan speed and spot size. In order to optimize the growth parameters, the microstructures of the resulting forms were studied using SEM. Comparison between static and scanning growth is presented with the building philosophy in mind, e.g. whether to build structures layer by layer, from modules or in conjunction with another process to compensate for their shortcomings. The substrates used included steel, graphite and porous bronze.The results indicated different microstructures for iron and nickel, which were dependent on the total/precursor pressure. In the scanning experiments, nickel produced very thin films of high reflectivity, whereas iron produced a structure which could be described as a crystalline spider's web. The static experiments produced solid rods in the case of nickel, whereas with iron, the rods were hollow, even with same spot sizes. Moreover, an evident change in the microstructure of the nickel forms as a function of pressure was observed. The 3-D growth rate of the static experiments seemed very promising for the forthcoming scanning experiments.

Study on Numerical Simulation of Laser Quenching Based on ANSYS

2012 ◽  
Vol 538-541 ◽  
pp. 1862-1865
Author(s):  
Jian Lai Wang ◽  
Jian Cao ◽  
Qian Kai Lin ◽  
Hui Feng ◽  
Hai Hua Shen
Keyword(s):  
Laser Power ◽  
Field Model ◽  
Spot Size ◽  
Laser Beams ◽  
Ansys Software ◽  
Power Laser ◽  
Laser Quenching ◽  
Surface Temperature Distribution ◽  
Temperature Field Model ◽  
Scan Speed

In this paper, a temperature field model of 45 steel shafts during the laser quenching was built and simulated by using ANSYS software. Its surface temperature distribution of the shaft during the laser beams scanning was simulated. Their effects of different laser power, laser beams spot size and scan speed on part’s quenching performance were analyzed.

Simulation and Experimental Study on Temperature Fields for Laser Assisted Machining of Silicon Nitride

2009 ◽  
Vol 419-420 ◽  
pp. 521-524
Author(s):  
Xue Feng Wu ◽  
Hong Zhi Zhang ◽  
Yang Wang ◽  
Chao Xie
Keyword(s):  
Silicon Nitride ◽  
Laser Heating ◽  
Laser Power ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Transfer Model ◽  
Beam Diameter ◽  
Power Laser ◽  
Laser Assisted Machining ◽  
Translational Speed

Laser assisted machining (LAM) is an effective method machining difficult-to-machine materials such as ceramics which uses a high power laser to focally heat a workpiece prior to material removal with a traditional cutting tool. A laser assisted machining experiment system was set up and a transient, three-dimensional heat transfer model was developed for LAM of silicon nitride using Finite Element Method to understand the thermal process of laser heating. The model was based on temperature-dependent thermophysical properties and the heat generated was neglected due to cutting which is assumed to be small compared to the heat generated by laser heating. The experiments were carried out to investigate the effects of operating parameters, such as laser power, laser translational speed, rotational speed, laser beam diameter and preheating time on temperature distribution. An infrared radiation thermometer was used to measure the surface temperature histories and the experimental results were in good agreement with predictions. The laser power and laser translational speed have the greatest influence on the temperature.

scholarly journals Optimization of SLM process parameters for Ti6Al4V medical implants

2019 ◽  
Vol 25 (3) ◽  
pp. 433-447 ◽  
Author(s):  
Mahmoud Elsayed ◽  
Mootaz Ghazy ◽  
Yehia Youssef ◽  
Khamis Essa
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Process Parameters ◽  
Laser Power ◽  
Medical Implants ◽  
Power Laser ◽  
Porosity Level ◽  
Content Type ◽  
Scan Speed ◽  
Hatch Spacing

PurposeTi6Al4V alloy has received a great deal of attention in medical applications due to its biomechanical compatibility. However, the human bone stiffness is between 10 and 30 GPa while solid Ti6Al4V is several times stiffer, which would cause stress shielding with the surrounding bone, which can lead to implant and/or the surrounding bone’s failure.Design/methodology/approachIn this work, the effect of selective laser melting (SLM) process parameters on the characteristics of Ti6Al4V samples, such as porosity level, surface roughness, elastic modulus and compressive strength (UCS), has been investigated using response surface method. The examined ranges of process parameters were 35-50 W for laser power, 100-400 mm/s for scan speed and 35-120 µm for hatch spacing. The process parameters have been optimized to obtain structures with properties very close to that in human bones.FindingsThe results showed that the porosity percentage of a SLM component could be increased by reducing the laser power and/or increasing the scan speed and hatch spacing. It was also shown that there was a reverse relationship between the porosity level and both the modulus of elasticity and UCS of the SLM part. In addition, the increased laser power was resulted into a substantial decrease of the surface roughness of SLM parts. Results from the optimization study revealed that the interaction between laser process parameters (i.e. laser power, laser speed, and the laser spacing) have the most significant influence on the mechanical properties of fabricated samples. The optimized values for the manufacturing of medical implants were 49 W, 400 mm/s and 99 µm for the laser power, laser speed and laser spacing, respectively. The corresponding porosity, surface roughness, modulus of elasticity and UCS were 23.62 per cent, 8.68 µm, 30 GPa and 522 MPa, respectively.Originality/valuePrevious investigations related to additive manufacturing of Ti alloys have focused on producing fully dense and high-integrity structures. There is a clear gap in literature regarding the simultaneous enhancement and adjustment of pore fraction, surface and mechanical properties of Ti6Al4V SLM components toward biomedical implants. This was the objective of the current study.

scholarly journals Simulation of the Thermal Aberration of Fused Silica Reflective Optics Under High-power Laser Irradiation

2021 ◽  
Author(s):  
Yuan Li ◽  
HongMing Yu ◽  
XinQi Yin ◽  
Juan Wu ◽  
Feng Wang ◽  
...  
Keyword(s):  
High Power ◽  
Laser Power ◽  
Beam Quality ◽  
Spot Size ◽  
Fused Silica ◽  
Incident Power ◽  
High Power Laser ◽  
Incident Laser ◽  
Power Laser ◽  
Incident Laser Power

Abstract The output beam quality of high-power laser systems is limited by laser-induced thermal aberration of fused silica reflective optics. A numerical model for the simulation of thermal aberration was proposed and verified by the experimental results. Simulations on the thermal aberration of fused silica optics under 3~10 kW laser irradiation with laser beam diameters of 5 mm ~ 45 mm were carried out with the verified model. The simulation results showed that the peak-valley (PV) value of thermal aberration increases with increasing incident laser power under the same incident laser spot size and reduces with increasing incident laser spot size under the same incident laser power. There are the same PV values of thermal aberration under different incident power or power densities. An analytic formula of thermal aberration PV as a function of incident laser power and beam spot size was proposed. The analytic results are in good agreement with the simulations. With these conclusions, the thermal aberration of fused silica optics under high incident power and power density can be evaluated by that under low incident power and power density. It is helpful for the design of high-power laser systems to obtain reasonable output beam quality.

scholarly journals 3D Printing of High Viscosity Reinforced Silicone Elastomers

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2239
Author(s):  
Nicholas Rodriguez ◽  
Samantha Ruelas ◽  
Jean-Baptiste Forien ◽  
Nikola Dudukovic ◽  
Josh DeOtte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
New Technologies ◽  
Three Dimensional ◽  
High Viscosity ◽  
Layer By Layer ◽  
Silicone Elastomers ◽  
Uv Curable ◽  
Octet Truss ◽  
Tunable Mechanical Properties

Recent advances in additive manufacturing, specifically direct ink writing (DIW) and ink-jetting, have enabled the production of elastomeric silicone parts with deterministic control over the structure, shape, and mechanical properties. These new technologies offer rapid prototyping advantages and find applications in various fields, including biomedical devices, prosthetics, metamaterials, and soft robotics. Stereolithography (SLA) is a complementary approach with the ability to print with finer features and potentially higher throughput. However, all high-performance silicone elastomers are composites of polysiloxane networks reinforced with particulate filler, and consequently, silicone resins tend to have high viscosities (gel- or paste-like), which complicates or completely inhibits the layer-by-layer recoating process central to most SLA technologies. Herein, the design and build of a digital light projection SLA printer suitable for handling high-viscosity resins is demonstrated. Further, a series of UV-curable silicone resins with thiol-ene crosslinking and reinforced by a combination of fumed silica and MQ resins are also described. The resulting silicone elastomers are shown to have tunable mechanical properties, with 100–350% elongation and ultimate tensile strength from 1 to 2.5 MPa. Three-dimensional printed features of 0.4 mm were achieved, and complexity is demonstrated by octet-truss lattices that display negative stiffness.

scholarly journals Modeling of three-dimensional exciplex pumped fluid Cs vapor laser with transverse and longitudinal gas flow

2021 ◽  
Vol 9 ◽  
Author(s):  
Chenyi Su ◽  
Xingqi Xu ◽  
Jinghua Huang ◽  
Bailiang Pan
Keyword(s):  
Wall Temperature ◽  
Laser Power ◽  
Gas Flow ◽  
Particle Density ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Heat Accumulation ◽  
Vapor Laser ◽  
Output Laser Power ◽  
Output Laser

Abstract Considering the thermodynamical fluid mechanics in the gain medium and laser kinetic processes, a three-dimensional theoretical model of an exciplex-pumped Cs vapor laser with longitudinal and transverse gas flow is established. The slope efficiency of laser calculated by the model shows good agreement with the experimental data. The comprehensive three-dimensional distribution of temperature and particle density of Cs is depicted. The influence of pump intensity, wall temperature, and fluid velocity on the laser output performance is also simulated and analyzed in detail, suggesting that a higher wall temperature can guarantee a higher output laser power while causing a more significant heat accumulation in the cell. Compared with longitudinal gas flow, the transverse flow can improve the output laser power by effectively removing the generated heat accumulation and alleviating the temperature gradient in the cell.

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.

Assessment of mechanical and biocompatible performance of ultra-large nitinol endovascular devices fabricated via a low-energy laser joining process

2021 ◽  
pp. 088532822110195
Author(s):  
Moataz Elsisy ◽  
Mahdis Shayan ◽  
Yanfei Chen ◽  
Bryan W Tillman ◽  
Catherine Go ◽  
...  
Keyword(s):  
Laser Power ◽  
In Vitro Study ◽  
Spot Size ◽  
Laser Joining ◽  
Study Results ◽  
Energy Laser ◽  
Joining Process ◽  
Endovascular Devices ◽  
Low Energy Laser

Nitinol is an excellent candidate material for developing various self-expanding endovascular devices due to its unique properties such as superelasticity, biocompatibility and shape memory effect. A low-energy laser joining technique suggests a high potential to create various large diameter Nitinol endovascular devices that contain complex geometries. The primary purpose of the study is to investigate the effects of laser joining process parameters with regard to the mechanical and biocompatible performance of Nitinol stents. Both the chemical composition and the microstructure of the laser-welded joints were evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). In vitro study results on cytotoxicity demonstrated that the joining condition of 8 Hz frequency and 1 kW laser power showed the highest degree of endothelial cell viability after thermal annealing in 500°C for 30 min. Also, in vitro study results showed the highest oxygen content at 0.9 kW laser power, 8 Hz frequency, and 0.3 mm spot size after the thermal annealing. Mechanical performance test results showed that the optimal condition for the highest disconnecting force was found at 1 Hz frequency and 1 kW power with 0.6 mm spot size. Two new endovascular devices have been fabricated using the optimized laser joining parameters, which have demonstrated successful device delivery and retrieval, as well as acute biocompatibility.

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 Non-isothermal phase-field simulations of laser-written in-plane SiGe heterostructures for photonic applications

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ozan Aktas ◽  
Yuji Yamamoto ◽  
Mehmet Kaynak ◽  
Anna C. Peacock
Keyword(s):  
Quantum Wells ◽  
Phase Field ◽  
Silicon Germanium ◽  
Phase Segregation ◽  
Layer By Layer ◽  
Beam Position ◽  
Graded Index ◽  
Semiconductor Alloy ◽  
Scan Speed ◽  
Growth Methods

AbstractAdvanced solid-state devices, including lasers and modulators, require semiconductor heterostructures for nanoscale engineering of the electronic bandgap and refractive index. However, existing epitaxial growth methods are limited to fabrication of vertical heterostructures grown layer by layer. Here, we report the use of finite-element-method-based phase-field modelling with thermocapillary convection to investigate laser inscription of in-plane heterostructures within silicon-germanium films. The modelling is supported by experimental work using epitaxially-grown Si0.5Ge0.5 layers. The phase-field simulations reveal that various in-plane heterostructures with single or periodic interfaces can be fabricated by controlling phase segregation through modulation of the scan speed, power, and beam position. Optical simulations are used to demonstrate the potential for two devices: graded-index waveguides with Ge-rich (>70%) cores, and waveguide Bragg gratings with nanoscale periods (100–500 nm). Periodic heterostructure formation via sub-millisecond modulation of the laser parameters opens a route for post-growth fabrication of in-plane quantum wells and superlattices in semiconductor alloy films.

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