Surface texture characterization of selective laser melted Ti-6Al-4V components using fractal dimension and lacunarity analysis

2020 ◽  
pp. 095440542097108
Author(s):  
Akhil V ◽  
Arunachalam N ◽  
Raghav G ◽  
Sivasrinivasu Devadula
Keyword(s):  
Surface Roughness ◽  
Fractal Dimension ◽  
Additive Manufacturing ◽  
Surface Texture ◽  
Surface Characterization ◽  
Transform Method ◽  
Study Results ◽  
Lacunarity Analysis ◽  
Surface Images

The Selective Laser Melting (SLM) process based additive manufacturing has wide applications in medical, aerospace, defense, and automotive industries. To qualify the components for certain tribological applications, the characterization of surface texture is very important. But the applicability of traditional methods and parameters to characterize the surface texture were under evaluation. As the nature manufacturing the components were very different and complex, the unconventional surface characterization methods also under evaluation to reveal much more meaningful information. This study demonstrates the surface characterization of Ti-6Al-4V SLM components using fractal analysis of the surface images. The computed fractal dimension using the Fourier transform method showed a strong correlation of more than 0.8 with the measured 3D surface roughness parameters. The change in anisotropic nature of the surface images with the process parameter variation is studied and found that the surface textures showed a weaker anisotropic nature at lower laser power ranges, high scanning speed, and high hatch distance values. The lacunarity analysis is carried out using the gliding box algorithm to study the homogeneity nature of the surface texture and found that the surface texture is more homogeneous at higher surface roughness conditions. The study results can be utilized for the development of a quick, low-cost surface monitoring system in real-time for additive manufacturing industries.

scholarly journals Evaluating the Quality Surface Performance of Additive Manufacturing Systems: Methodology and a Material Jetting Case Study

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 995 ◽  
Author(s):  
Razvan Udroiu ◽  
Ion Braga ◽  
Anisor Nedelcu
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Manufacturing Systems ◽  
Statistical Design ◽  
Statistical Design Of Experiments ◽  
Systems Methodology ◽  
Study Results ◽  
Materials Used

The performance characterization of the manufacturing processes for additive manufacturing (AM) systems is a significant task for their standardization and implementation in the industry. Also, there is a large diversity of materials used in different AM processes. In the present paper, a methodology is proposed to evaluate, in different directions, the performance of an AM process and material characterization in terms of surface quality. This methodology consists of eight steps, based on a new surface inspection artifact and basic artifact orientations. The proposed artifact with several design configurations fits different AM systems sizes and meets the needs of customers. The effects of main factors on the surface roughness of up-facing platens of the artifacts are investigated using the statistical design of experiments. The proposed methodology is validated by a case study focused on PolyJet material jetting technology. Samples are manufactured of photopolymer resins and post-processed. Three factors (i.e., artifact orientation, platen orientation, and finish type) are considered for the investigation. The case study results show that the platen orientation, finish type, and their interaction have a significant influence on the surface roughness (Ra). The best Ra roughness results were obtained for the glossy finish type in the range of 0.5–4 μm.

scholarly journals Post-Processing and Surface Characterization of Additively Manufactured Stainless Steel 316L Lattice: Implications for BioMedical Use

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1376
Author(s):  
Alex Quok An Teo ◽  
Lina Yan ◽  
Akshay Chaudhari ◽  
Gavin Kane O’Neill
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Surface Characterization ◽  
High Surface ◽  
Surface Characteristics ◽  
Post Processing ◽  
Stainless Steel 316L ◽  
Processing Methods ◽  
Particulate Debris

Additive manufacturing of stainless steel is becoming increasingly accessible, allowing for the customisation of structure and surface characteristics; there is little guidance for the post-processing of these metals. We carried out this study to ascertain the effects of various combinations of post-processing methods on the surface of an additively manufactured stainless steel 316L lattice. We also characterized the nature of residual surface particles found after these processes via energy-dispersive X-ray spectroscopy. Finally, we measured the surface roughness of the post-processing lattices via digital microscopy. The native lattices had a predictably high surface roughness from partially molten particles. Sandblasting effectively removed this but damaged the surface, introducing a peel-off layer, as well as leaving surface residue from the glass beads used. The addition of either abrasive polishing or electropolishing removed the peel-off layer but introduced other surface deficiencies making it more susceptible to corrosion. Finally, when electropolishing was performed after the above processes, there was a significant reduction in residual surface particles. The constitution of the particulate debris as well as the lattice surface roughness following each post-processing method varied, with potential implications for clinical use. The work provides a good base for future development of post-processing methods for additively manufactured stainless steel.

Tubing String Thread Sealing Surfaces Damage Evaluation Based on Acoustic Elasticity Theory

2019 ◽  
Vol 944 ◽  
pp. 828-834 ◽  
Author(s):  
Jian Jun Wang ◽  
Jian Hua Sun ◽  
Shang Yu Yang ◽  
Yao Rong Feng ◽  
Kai Lin
Keyword(s):  
Surface Roughness ◽  
Elasticity Theory ◽  
Contact Stress ◽  
Surface Characterization ◽  
Surface Damage ◽  
Center Frequency ◽  
Sealing Performance ◽  
Tubing String ◽  
Acoustic Elasticity

During the processing of tubing premium threaded made up, the degree of the thread sealing surface intactness will directly affect the sealing performance of the string. Nevertheless, there are some difficulties to detect the damage of the engaged sealing surface effectively. In the present study the sealing surface damage was judged by the sealing surface contact stress’s relative changes according to the acoustic elasticity theory,. At the same time, the wear defects generated at the tubing sealing surface, during the tubing made up, contrasted with the wear and unworn surface roughness of coupling ultrasonic detected about the sealing surface. The results showed that with the acoustic amplitude evaluated the sealing contact stress was susceptible to the influence of surface roughness of coupling. But the reflection wave with the center frequency on the sealing surface characterization of the contact stress could avoid this problem effectively.

scholarly journals Characterization of additively manufactured AlSilOMg cubes with different porosities

2021 ◽  
Vol 121 (4) ◽  
Author(s):  
C. Taute ◽  
H. Möller ◽  
A. du Plessis ◽  
M. Tshibalanganda ◽  
M. Leary
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Structural Integrity ◽  
Lead Times ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Sample Characteristics

SYNOPSIS Additive manufacturing can be used to produce complex and custom geometries, consolidating different parts into one, which in turn reduces the required number of assemblies and allows distributed manufacturing with short lead times. Defects, such as porosity and surface roughness, associated with parts manufactured by laser powder bed fusion, can severely limit industrial application. The effect these defects have on corrosion and hence long-term structural integrity must also be taken into consideration. The aim of this paper is to report on the characterization of porosity in samples produced by laser powder bed fusion, with the differences in porosity induced by changes in the process parameters. The alloy used in this investigation is AlSi10Mg, which is widely used in the aerospace and automotive industries. The sample characteristics, obtained by X-ray tomography, are reported. The design and production of additively manufactured parts can be improved when these defects are better understood. Keywords: additive manufacturing, L-PBF, AlSi10Mg, porosity, surface roughness, density.

Fractal Dimension and Multifractal Spectra of INGAN/GAN Self-Assembled Quantum Dots Films

2008 ◽  
Author(s):  
K. T. Lam
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Fractal Dimension ◽  
High Speed ◽  
Surface Characterization ◽  
Chemical Vapor ◽  
Surface Shape ◽  
Root Mean Square Roughness ◽  
Multifractal Spectra ◽  
Self Assembled

The surface shape and microstructure of semiconductor thin films, especially nanometer thin films, greatly influence such physical characteristics as the electricity, magnetic and optics nature to the thin films, etc. In this work, we use the fractal dimension and multifractal spectra to study the surface morphology of annealed InGaN/GaN self-assembled quantum dot (SAQD) films. Samples used in this study were grown on (0001)-oriented sapphire (Al2O3) substrates in a vertical low-pressure metalorganic chemical vapor deposition (MOCVD) reactor with a high-speed rotation disk. The fractal dimension and multifractal spectra can be used to describe the influence of different annealing conditions on surface characterization. Fractal analysis reveals that both the average surface roughness and root-mean-square roughness of nanostructure surfaces decreased after thermal annealing. It can be seen that a smoother surface was obtained after an annealing temperature of 800°C, and it implies that the surface roughness of this case is minimum in all tests. The results of this paper also include a mathematical model to describe the observation of fractal and multifractal characteristics in semiconductor nanostructure films.

A MULTIFUNCTIONAL AND PORTABLE OPTICAL SENSOR FOR QUANTITATIVE CHARACTERIZATION OF 3D SURFACE TEXTURE PROPERTIES

2010 ◽  
Vol 07 (04) ◽  
pp. 269-284
Author(s):  
YANTAO SHEN ◽  
YONGXIONG WANG ◽  
NING XI
Keyword(s):  
Mechanical Properties ◽  
Surface Texture ◽  
Surface Characterization ◽  
Texture Features ◽  
Mechanical Impedance ◽  
Quantitative Characterization ◽  
Texture Properties ◽  
Surface Patterns ◽  
3D Surface Texture

Surface characterization technologies are generally sorted into two categories: noncontact and contact-based technologies. Among these technologies, no one can stand out to simultaneously and rapidly measure both surface patterns/textures and mechanical properties such as softness, friction, and mechanical impedance. In this paper, we have addressed this problem and developed a multifunctional and portable surface texture sensor through combination of both contact and noncontact optical surface profiling mechanisms. The developed sensor relying on an optomechanical principle can be efficiently used for quantitative characterization of surface texture properties including 3D texture pattern, roughness, and even mechanical properties like softness, etc. As one of the important applications, we have used the sensor to measure and analyze texture properties of extensive automotive interior leather sample surfaces. The results demonstrate that the sensor can effectively assist the interior designer to quantify and classify essential texture features of automobile interior surfaces.

scholarly journals Simplified micrometric surface characterization of different implant surfaces available on the Brazilian market

2018 ◽  
Vol 17 ◽  
pp. 1-9
Author(s):  
Luiz Carlos do Carmo Filho ◽  
Ana Paula Pinto Martins ◽  
Amália Machado Bielemann ◽  
Anna Paula da Rosa Possebon ◽  
Fernanda Faot
Keyword(s):  
Surface Roughness ◽  
Chemical Composition ◽  
Surface Treatment ◽  
Rough Surface ◽  
Surface Characterization ◽  
Implant Surface ◽  
Treatment Techniques ◽  
Surface Contaminants ◽  
Cervical Portion

Aim: This study characterized the implant surfaces available on the Brazilian market in terms of topography, chemical composition, and roughness. Methods: The following brands were selected according to their surfaces: Kopp (Ko), Signo Vinces (Sv), Neodent (Ne), Osseotite (Os) NanoTite (Nt), SIN (Si), Titanium Fix (Tf), conventional Straumann (Str), Active SLA (SLA). The morphological analysis and the alloy impurities and implant surface contaminants were analyzed by SEM-EDS. Surface roughness parameters and 3-D reconstructions were obtained by laser microscopy (20x). Two distinct areas were evaluated: i) the cervical portion (no surface treatment), and ii) the middle third (treated surface). Results: The characterization of the implant surfaces by SEM showed morphological differences between the thread geometries and surface morphology at 800x and 2000x magnification. The EDS elemental analysis showed a predominance of titanium (Ti) for all implants. The SLA surface showed only peaks of Ti while other implants brands showed traces of impurities and contaminants including Al, C, PR, F, Mg, Na, Ni, O, P, and SR. The implant surface roughness in the cervical portion did not exceed Ra 0.5–1.0 μm, constituting a minimally rough surface and obtaining acceptable standards for this region. Only Nt, Str, and SLA presented Ra above 2 μm in the middle third area showing a rough surface favorable for osseointegration. Conclusion: This study concluded that there is no established standard for morphology, chemical composition and implant surface roughness that allows a safe comparison between the available dental implant surfaces. National implant brands generally contain more impurities and surface contaminants than their international counterparts and were consequently more sensitive to the surface treatment techniques.

Fractal-Based Characterization of Surface Texture

1992 ◽  
Vol 35 (3) ◽  
pp. 37-44
Author(s):  
Ken Grosser ◽  
Stephen Chesters ◽  
Hwa-Chi Wang ◽  
Gerhard Kasper
Keyword(s):  
Surface Roughness ◽  
Quality Assurance ◽  
Test Data ◽  
Surface Texture ◽  
High Purity ◽  
Measurement Method ◽  
Manufacturing Processes ◽  
Surface Finishes ◽  
Gas System

The surface roughness of high purity gas system distribution materials is a matter of concern for many critical manufacturing processes. Control of this roughness is thus much in demand and requires a sensitive measurement method. A refined fractal-based characterization is presented as a possible solution. Test data that use this method to compare various surface finishes and correlate roughness with surface cleanability are offered with explanations. This could become an effective quality assurance tool in those applications where surface roughness is important.

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