Space orthogonalization of signal and clutter at a high azimuthal scanning velocity

1993 ◽  
Vol 35 (9-10) ◽  
pp. 521-525
Author(s):  
A. D. Pluzhnikov
Keyword(s):  
Scanning Velocity

Fabrication of SiC Particulates Reinforced MoSi2 Composite Coating by Laser Cladding

2008 ◽  
Vol 373-374 ◽  
pp. 304-307
Author(s):  
Sen Yang ◽  
Ming Run Wang ◽  
Tao Gong ◽  
Wen Jin Liu
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Continuous Wave ◽  
Steel Substrate ◽  
Laser Output Power ◽  
Scanning Velocity ◽  
Sic Particulates ◽  
Metallurgical Bond ◽  
Improve Wear Resistance

In order to improve wear resistance of carbon steel, laser cladding experiments were carried out using a 3kW continuous wave CO2 laser. The diameter of the laser beam was 3-5mm, the scanning velocity was 3-10mm/s, and the laser output power was 1.0-1.3kW. The experimental results showed that MoSi2/SiCP composites coating could be in-situ synthesized from mixture powders of molybdenum, silicon and SiC by laser cladding. A good metallurgical bond between the coating and the substrate could be achieved. The microstructures of the coating were mainly composed of MoSi2, SiC and FeSiMo phases. The average microhardness of the coating was about HV0.21300, about 6.0 times larger than that of steel substrate.

Influence of surface heating level and scanning velocity on the hardened by laser track width

2006 ◽  
Author(s):  
Bogusław Grabas ◽  
Magdalena Najgeburska ◽  
Łukasz Sliwka ◽  
Magdalena Maj
Keyword(s):  
Surface Heating ◽  
Laser Track ◽  
Track Width ◽  
Scanning Velocity

The mechanism of process parameters influencing the AlSi10Mg side surface quality fabricated via laser powder bed fusion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shimin Dai ◽  
Hailong Liao ◽  
Haihong Zhu ◽  
Xiaoyan Zeng
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Process Parameters ◽  
Laser Power ◽  
Side Surface ◽  
Laser Powder Bed Fusion ◽  
Scanning Velocity ◽  
Content Type ◽  
Powder Bed

Purpose For the laser powder bed fusion (L-PBF) technology, the side surface quality is essentially important for industrial applicated parts, such as the inner flow parts. Contour is generally adopted at the parts’ outline to enhance the side surface quality. However, the side surface roughness (Ra) is still larger than 10 microns even with contour in previous studies. The purpose of this paper is to study the influence of contour process parameters, laser power and scanning velocity on the side surface quality of the AlSi10Mg sample. Design/methodology/approach Using L-PBF technology to manufacture AlSi10Mg samples under different contour process parameters, use a laser confocal microscope to capture the surface information of the samples, and obtain the surface roughness Ra and the maximum surface height Rz of each sample after analysis and processing. Findings The results show that the side surface roughness decreases with the increase of the laser power at the fixed scanning velocity of 1,000 mm/s, the side surface roughness Ra stays within the error range as the contour velocity increases. It is found that the Ra increases with the scanning velocity increasing and the greater the laser power with the greater Ra increases when the laser power of contour process parameters is 300 W, 350 W and 400 W. The Rz maintain growth with the contour scanning velocity increasing at constant laser power. The continuous uniform contour covers the pores in the molten pool of the sample edge and thus increase the density of the sample. Two mechanisms named “Active adhesion” and “Passive adhesion” cause sticky powder. Originality/value Formation of a uniform and even contour track is key to obtain the good side surface quality. The side surface quality is determined by the uniformity and stability of the contour track when the layer thickness is fixed. These research results can provide helpful guidance to improve the surface quality of L-PBF manufactured parts.

scholarly journals Experimental Design and Performance Analysis in Plasma Arc Surface Hardening

2012 ◽  
pp. 57-75
Author(s):  
Mohd Idris Shah Ismail ◽  
Zahari Taha ◽  
Mohd Hamdi Abdul Shukor
Keyword(s):  
Surface Roughness ◽  
Experimental Design ◽  
Surface Hardening ◽  
Processing Parameters ◽  
Plasma Arc ◽  
Signal To Noise ◽  
Scanning Velocity ◽  
Hardening Process ◽  
Arc Current ◽  
And Performance

In this paper, the experimental design by using the Taguchi method was employed to optimize the processing parameters in the plasma arc surface hardening process. The evaluated processing parameters are arc current, scanning velocity and carbon content of steel. In addition, the significant effects of the relation between processing parameters were also investigated. An orthogonal array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA) were employed to investigate the effects of these processing parameters. Through this study, not only the increasing in hardened depth and improvement in surface roughness, but the parameters that significantly affect on the hardening performance were also identified. Experimental results showed the effectiveness of this approach. Dalam kertas kerja ini, reka bentuk ujikaji menggunakan kaedah Taguchi digunakan untuk mengoptimumkan parameter pemprosesan dalam proses arka plasma pengerasan permukaan. Parameter pemprosesan yang dinilai adalah arus arka, halaju imbasan dan kandungan karbon dalam keluli. Sebagai tambahan, kesan-kesan penting yang lain seperti hubungan di antara parameter pemprosesan juga diselidiki. Tatasusunan ortogon, nisbah signal to noise (S/N) dan analisis varians (ANOVA) digunakan untuk mengkaji kesan parameter pemprosesan ini. Melalui kajian ini, bukan sahaja kedalaman pengerasan bertambah dan kekasaran permukaan lebih baik, malah parameter pemprosesan yang nyata sekali menpengaruhi prestasi pengerasan dikenal pasti. Hasil percubaan mengesahkan keberkesanan pendekatan ini.

scholarly journals Full Aperture CO2Laser Process to Improve Laser Damage Resistance of Fused Silica Optical Surface

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Wei Liao ◽  
Chuanchao Zhang ◽  
Xiaofen Sun ◽  
Lijuan Zhang ◽  
Xiaodong Yuan
Keyword(s):  
Damage Threshold ◽  
Fused Silica ◽  
Processing Temperature ◽  
Test Results ◽  
Optical Surface ◽  
Improved Method ◽  
Damage Resistance ◽  
Scanning Velocity ◽  
High Laser ◽  
Laser Flux

An improved method is presented to scan the full-aperture optical surface rapidly by using galvanometer steering mirrors. In contrast to the previous studies, the scanning velocity is faster by several orders of magnitude. The velocity is chosen to allow little thermodeposition thus providing small and uniform residual stress. An appropriate power density is set to obtain a lower processing temperature. The proper parameters can help to prevent optical surface from fracturing during operation at high laser flux. S-on-1 damage test results show that the damage threshold of scanned area is approximately 40% higher than that of untreated area.

scholarly journals Stress Rupture Test of MAR-M509 Alloy with Structure Refined by Rapid Resolidification

2012 ◽  
Vol 12 (4) ◽  
pp. 117-120
Author(s):  
M. Mróz ◽  
W. Orłowicz ◽  
M. Tupaj ◽  
A. Trytek
Keyword(s):  
Stress Rupture ◽  
Argon Atmosphere ◽  
Cobalt Alloy ◽  
Scanning Velocity ◽  
Electrical Arc ◽  
Alloy Castings

Abstract This study presents results of stress rupture test of MAR-M-509 cobalt alloy samples, as-cast and after surface refining with a concentrated stream of heat. Tests were conducted on samples of MAR-M-509 alloy castings, obtained using the lost-wax method. Casting structure refining was performed with the GTAW method in argon atmosphere, using the current I = 200 A and electrical arc scanning velocity vs = 100, 150, 200 and 250 mm/min. The effect of rapid resolidification of the MAR-M-509 alloy on the microstructure was examined and significant improvement in stress rupture test was observed

Prediction of Melt-Pool Characteristics in SLM Process for Ti6Al4V Using a Semi-Analytical Model

2021 ◽  
Author(s):  
Shubhra Kamal Nandi ◽  
Rakesh Kumar ◽  
Anubhav ◽  
Anupam Agrawal
Keyword(s):  
Temperature Distribution ◽  
Finite Volume ◽  
Computational Models ◽  
Single Layer ◽  
Layer By Layer ◽  
Scanning Velocity ◽  
Melt Pool ◽  
Alternating Direction ◽  
Volume Method ◽  
Melt Pool Characteristics

Abstract Selective Laser Melting (SLM) is a powder-based layer-by-layer manufacturing technique to produce metallic customized shape components. The exceptionally high thermal gradient induces residual stress and distorts the part geometry affecting the yield quality. Computational models are instrumental in optimizing the process controls to fabricate high-quality components, and hence several such methods have been explored to simulate the thermal behavior of the process and the heat transfer in the melt-pool. Most of the practiced techniques are computationally expensive, making it infeasible to perform a parametric study. Based on closed-form exact heat conduction solution and Finite Volume Method (FVM), a pseudo-analytical thermal modeling approach has been employed to estimate the melt-pool characteristics and temperature distribution of the SLM process. A moving volumetric Gaussian heat source laser model and Green’s function have been adopted to model the heat input by conduction. The heat loss by conduction and convection has been calculated by implementing Finite Volume discretized equations on a 2-dimensional thin-walled domain with appropriate part boundary conditions. Additionally, the Alternating Direction Implicit iterative technique has been implemented for the fast convergence of the simulation. The model is used to demonstrate the influence of the process parameters and non-linear material phase change for a single-line single layer and multilayer part fabrication. The computed melt-pool dimensions and temperature distribution for varying laser-power, scanning velocity, and layer thickness for Ti6Al4V are validated with the experimental data from the literature with fair agreements.

scholarly journals Rapid, Chemical-Free Generation of Optically Scattering Structures in Poly(ethylene terephthalate) Using a CO2 Laser for Lightweight and Flexible Photovoltaic Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Simon D. Hodgson ◽  
Alice R. Gillett
Keyword(s):  
High Speed ◽  
Ethylene Terephthalate ◽  
Fold Increase ◽  
Processing Parameters ◽  
Scanning Velocity ◽  
Average Value ◽  
Free Process ◽  
Poly Ethylene Terephthalate ◽  
Optical Profilometer ◽  
Poly Ethylene

Highly light scattering structures have been generated in a poly(ethylene terephthalate) (PET) film using a CO2 laser. The haze, and in some cases the transparency, of the PET films have been improved by varying the processing parameters of the laser (namely, scanning velocity, laser output power, and spacing between processed tracks). When compared with the unprocessed PET, the haze has improved from an average value of 3.26% to a peak of 55.42%, which equates to an absolute improvement of 52.16% or a 17-fold increase. In addition to the optical properties, the surfaces have been characterised using optical microscopy and mapped with an optical profilometer. Key surface parameters that equate to the amount and structure of surface roughness and features have been analysed. The CO2 laser generates microstructures at high speed, without affecting the bulk properties of the material, and is inherently a chemical-free process making it particularly applicable for use in industry, fitting well with the high-throughput, roll to roll processes associated with the production of flexible organic photovoltaic devices.

Morphological Features of the Solid-Liquid Interface of a Gallium Film

1991 ◽  
Vol 237 ◽  
Author(s):  
Richard D. Robinson ◽  
Ioannis N. Miaoulis
Keyword(s):  
Preliminary Investigation ◽  
Zone Melting ◽  
Liquid Interface ◽  
Silicon Films ◽  
Processing Conditions ◽  
Scanning Velocity ◽  
Solidification Interface ◽  
Solid Liquid Interface ◽  
Solid Liquid

ABSTRACTThis paper presents a new experimental method to investigate solid-liquid interface morphologies during Zone-Melting-Recrystallization at lower than the typical processing temperatures. Gallium films were used as a substitute for silicon films. In situ preliminary investigation identified three phenomena typically occurring during ZMR of silicon films: a) Transition from planar to dendritic to cellular morphologies was observed for different processing conditions; b) cell period proved to be dependant on scanning velocity; c) instabilities at the solidification interface at low heating strip temperatures were caused by supercooling and optical property variations as the material changed phase.

Mechanical and Electrical Properties of Micro-Lines Fabricated by Laser-Assisted Maskless Microdeposition

2008 ◽  
Author(s):  
Hamidreza Alemohammad ◽  
Ehsan Toyserkani
Keyword(s):  
Mechanical Properties ◽  
Laser Radiation ◽  
Laser Scanning ◽  
Processing Parameters ◽  
Electrical Performance ◽  
Nanoindentation Test ◽  
Layer By Layer ◽  
Direct Write ◽  
Effective Energy ◽  
Scanning Velocity

The present paper is concerned with the analysis of the microstructural properties of silver micro-lines produced by Laser-Assisted Maskless Microdeposition (LAMM). LAMM is a laser based direct write method used in microscale layered manufacturing. In LAMM, liquid-suspended nanoparticles of a variety of materials are deposited in a layer-by-layer fashion and cured by a laser radiation. In this work, conductive micro-lines of silver with widths of 20 μm are fabricated, and their microstructures as well as electrical and mechanical properties are studied. Investigations show that the microstructures are affected by the laser power and the laser scanning velocity. To find the effect of laser processing parameters on the electrical performance of the samples, the conductivity of the samples are expressed in terms of the effective energy absorbed during laser radiation. It is shown that the conductivity of the sintered samples is increased up to 2 × 105 S.m−1 by raising the effective energy density. In addition, mechanical properties, i.e. modulus of elasticity of one of the fabricated samples are obtained using the nanoindentation test.

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