Experimental Analysis of Process and Laser Parameters in Laser Marking

2008 ◽  
Author(s):  
Jean-Pierre Kruth ◽  
Evren Yasa
Keyword(s):  
Laser Power ◽  
Pump Current ◽  
Pulse Frequency ◽  
Laser Melting ◽  
Molten Material ◽  
Chemical Methods ◽  
Laser Marking ◽  
New Process ◽  
Product Identification ◽  
Scan Speed

Laser marking is a relatively new process to produce a mark on a product by the energy of a laser beam, mostly for the purpose of product identification and traceability. Compared to other techniques such as ink-marking, mechanical engraving and electro-chemical methods, laser marking has many advantages. In this study, laser marking is done with the laser of a standard RP/RM machine, i.e. a selective laser melting machine. This makes laser marking especially suited for marking parts produced by laser RP/RM techniques. On the other hand, the major difficulty in the process is the number of parameters and their complex relations which have not yet been investigated thoroughly. In the current study, the influences of scan speed, laser pump current (laser power) and pulse frequency of a Q-switched Nd:YAG laser on the mark qualities were investigated by single-factor experiments on stainless steel parts. It was found that these parameters substantially affect mark width, depth and rim formation which is caused by the expelled molten material due to the recoil pressure during the marking process. In order to investigate the influence of cross interactions, a design of experiment methodology was used to evaluate the effects of the same parameters on the success of the laser marking process in terms of removed material and clarity of the mark (visibility, sharpness, etc.).

Influence of Selective Laser Melting Process Parameters on Densification Behavior, Surface Quality and Hardness of 18Ni300 Steel

2020 ◽  
Vol 861 ◽  
pp. 77-82
Author(s):  
Gan Li ◽  
Cheng Guo ◽  
Wen Feng Guo ◽  
Hong Xing Lu ◽  
Lin Ju Wen ◽  
...  
Keyword(s):  
Energy Density ◽  
Relative Density ◽  
Maraging Steel ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Laser Power ◽  
Densification Behavior ◽  
Laser Melting ◽  
Scan Speed

This study investigated the effect of laser power (P), scan speed (v) and hatch space (h) on densification behavior, surface quality and hardness of 18Ni300 maraging steel fabricated by selective laser melting (SLM). The results indicated that the relative density of the SLMed samples has a shape increase from 73% to 97% with the laser energy density increasing from 0.5 to 2.2 J/mm2. The relative density ≥ 99% was achieved at the energy density in the range of 2.2~5.9 J/mm2. The optimum process parameters were found to be laser power of 150~200 W, scan speed of 600mm/s and hatch space of 0.105mm. In addition, it was found that the hardness increased initially with the increasing relative density up to relative density of 90% and then little relationship, but finally increase again significantly. This work provides reference for determining process parameters for SLMed maraging steel and the development of 3D printing of die steels.

Experimental Investigation of Selective Laser Melting of Lunar Regolith for In-Situ Applications

2013 ◽  
Author(s):  
Miranda Fateri ◽  
Andreas Gebhardt ◽  
Maziar Khosravi
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Lunar Regolith ◽  
Laser Melting ◽  
Manufacturing Method ◽  
3D Objects ◽  
Scan Speed ◽  
Manufacturing Methods ◽  
Object Layer

Selective Laser Melting (SLM) is a powder based Additive manufacturing (AM) technology which builds an object layer wise using a laser beam to melt the powder on an elevated platform. Thus far numerous studies have investigated lunar manufacturing methods and construction but little is known about applicability of SLM of lunar regolith. As most lunar construction proposals require transportation of essential materials from Earth, using an in-situ manufacturing method with indigenous material would be considerably more economical. Fabrication of parts with SLM using various metals and ceramics has already been presented. As such, the feasibility of using lunar regolith mixture to create functional parts with SLM process is investigated. Variation of process parameters such as laser power, scan speed, and scan strategies is investigated and multiple 3D objects are successfully created and presented.

Effect of processing parameters on forming defects during selective laser melting of AlSi10Mg powder

2020 ◽  
Vol 26 (5) ◽  
pp. 871-879 ◽  
Author(s):  
Haihua Wu ◽  
Junfeng Li ◽  
Zhengying Wei ◽  
Pei Wei
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Argon Pressure ◽  
Powder Layer ◽  
Laser Melting ◽  
Content Type ◽  
Scan Speed ◽  
Forming Defects

Purpose To fabricate a selective laser melting (SLM)-processed AlSi10Mg part with almost full density and free of any apparent pores, this study aims to investigate the effect of ambient argon pressure and laser scanning speed on the particles splash during the AlSi10Mg powder bed laser melting. Design/methodology/approach Based on the discrete element method (DEM), a 3D model of random distribution of powder particles was established, and the 3D free surface of SLM forming process was dynamically tracked by the volume of fluid, where a Gaussian laser beam acts as the energy source melting the powder bed. Through the numerical simulation and process experimental research, the effect of the applied laser power and scanning speed on the operating laser melting temperature was studied. Findings The process stability has a fundamental role in the porosity formation, which is process-dependent. The effect of the processing conditions on the process stability and the resultant forming defects were clarified. Research limitations/implications The results shows that the pores were the main defects present in the SLM-processed AlSi10Mg sample, which decreases the densification level of the sample. Practical implications The optimal processing parameters (argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm ) applied during laser melting can improve the quality of selective laser melting of AlSi10Mg, Social implications It can provide a technological support for 3D printing. Originality/value Based on the analysis of the pore and balling formation mechanisms, the optimal processing parameters have been obtained, which were argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm. Then, a near-fully dense sample free of any apparent pores on the cross-sectional microstructure was produced by SLM, wherein the relative density of the as-built samples is larger than 97.5%.

scholarly journals Optimisation of selective laser melting for a high temperature Ni-superalloy

2015 ◽  
Vol 21 (4) ◽  
pp. 423-432 ◽  
Author(s):  
Luke N. Carter ◽  
Khamis Essa ◽  
Moataz M Attallah
Keyword(s):  
High Temperature ◽  
Response Surface ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Laser Power ◽  
Surface Model ◽  
Good Prediction ◽  
Laser Melting ◽  
Content Type ◽  
Scan Speed

Purpose – The purpose of this paper is to optimise the selective laser melting (SLM) process parameters for CMSX486 to produce a “void free” (fully consolidated) material, whilst reducing the cracking density to a minimum providing the best possible fabricated material for further post-processing. SLM of high temperature nickel base superalloys has had limited success due to the susceptibly of the material to solidification and reheat cracking. Design/methodology/approach – Samples of CMSX486 were fabricated by SLM. Statistical design of experiments (DOE) using the response surface method was used to generate an experimental design and investigate the influence of the key process parameters (laser power, scan speed, scan spacing and island size). A stereological technique was used to quantify the internal defects within the material, providing two measured responses: cracking density and void per cent. Findings – The analysis of variance (ANOVA) was used to determine the most significant process parameters and showed that laser power, scan speed and the interaction between the two are significant parameters when considering the cracking density. Laser power, scan speed, scan spacing and the interaction between power and speed, and speed and spacing were the significant factors when considering void per cent. The optimum setting of the process parameters that lead to minimum cracking density and void per cent was obtained. It was shown that the nominal energy density can be used to identify a threshold for the elimination of large voids; however, it does not correlate well to the formation of cracks within the material. To validate the statistical approach, samples were produced using the predicted optimum parameters in an attempt to validate the response surface model. The model showed good prediction of the void per cent; however, the cracking results showed a greater deviation from the predicted value. Originality/value – This is the first ever study on SLM of CMSX486. The paper shows that provided that the process parameters are optimised, SLM has the potential to provide a low-cost route for the small batch production of high temperature aerospace components.

Direct Selective Laser Sintering of WC-Co Cemented Carbide by Premixing of Additives

2012 ◽  
Author(s):  
Hideki Kyogoku ◽  
Takeshi Uemori ◽  
Akihiko Ikuta ◽  
Kenichi Yoshikawa ◽  
Hitoshi Ohmori
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Smooth Surface ◽  
Laser Scanning ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Cemented Carbides ◽  
Sintering Process ◽  
Laser Melting ◽  
Scan Speed

In this study, the fabrication conditions of WC cemented carbides by direct selective laser melting were investigated. The effects of additives, such as Co, Cu-20%Sn and Cu powders, and laser scanning conditions on laser sintering process were examined to fabricate a sound laser-scanned body of WC cemented carbides. The optimum laser power, scan speed and scan pitch were found out by experiments. It was found that the continuously smooth single-scan track can be obtained at a lower laser power and a higher scan speed by the addition of 30% Cu powder. The smooth surface of the laser-scanned body could be fabricated at a laser power of 9 W, a scan speed of 20 mm/s and a scan pitch of 0.05 mm.

Coloration of Stainless Steel Utilizing Fiber Laser Oxidation

2011 ◽  
Vol 121-126 ◽  
pp. 70-74
Author(s):  
Chin Lung Chang ◽  
Jyun Wei Wu ◽  
Chia Yen Lee
Keyword(s):  
Stainless Steel ◽  
Fiber Laser ◽  
Laser Power ◽  
Processing Parameters ◽  
Pulse Frequency ◽  
Optical Microscope ◽  
Laser Marking ◽  
Polished Stainless Steel ◽  
Oxidation Layers ◽  
Stainless Steel 316

This paper presents a novel technique for coloring stainless steel utilizing a fiber laser. This study develops a processing technology that uses a fiber laser as a laser marking tool, and varies processing parameters such as pre-surface-processing conditions, stainless steel type, line distance, laser power, engraving speed, and laser pulse frequencies to achieve different results. This study investigates the results of the stainless workpiece coloring using optical microscope (OM). This study shows that polished stainless steel 316 exhibits the best engraving effect. With this material, the line distance, laser power, engraving speed, and pulse frequency of the laser change the oxidation thickness. The color of the processed workpiece also changes as the oxidation thickness changes due to the interference caused by the different thicknesses of the oxidation layers. Results prove that fiber laser processing of stainless steel is a promising and efficient technique for coloring stainless steel.

scholarly journals Parametric Influences on Heat Affected Zone in Micro-channel Milling Process of Zirconia Ceramic

2021 ◽  
Author(s):  
Omar Faruk Biswas ◽  
Abhishek Sen ◽  
Ishwer Shivakoti ◽  
Golam Kibria
Keyword(s):  
Heat Affected Zone ◽  
Laser Power ◽  
Laser System ◽  
Average Power ◽  
High Hardness ◽  
Pulse Frequency ◽  
Zirconia Ceramic ◽  
Micro Channel ◽  
Scan Speed ◽  
Haz Width

Zirconia, a bio-ceramic, is widely utilized in bioengineering, biomedical implants, dentistry, and the automotive industry due to high hardness, excellent wear resistance, etc. However, it is difficult to attain micro features on zirconia utilizing a laser machining system for the aforesaid properties. The paper deals with the study of the Heat Affected Zone (HAZ) formation during the micro-channel milling (V-shaped cross-sections) of zirconia utilizing a nanosecond fiber laser system. Experiments are accomplished to examine the consequence of control variables namely transverse feed, pulse frequency, laser power, scan number, and scan speed. The influence of each of the laser process variables on response parameter are studied in order to get the significant trends of laser parameters. With the increment of laser power, the number of pass and transverse feed, HAZ width dimensions tend to increase. The reverse phenomena are observed for pulse frequency and scan speed. The lower HAZ width which is achieved as 31.74 μm at a parametric setting of average power at 10 W, pulse frequency at 65 kHz, scanning speed at 11 mm/s, a number of pass at 1, transverse feed at 0.005 mm.

Melt Pool and Single Track Formation in Selective Laser Sintering/Selective Laser Melting

2014 ◽  
Vol 933 ◽  
pp. 196-201 ◽  
Author(s):  
Mohd Rizal Alkahari ◽  
Tatsuaki Furumoto ◽  
Takashi Ueda ◽  
Akira Hosokawa
Keyword(s):  
Laser Beam ◽  
Layer Thickness ◽  
Laser Power ◽  
Selective Laser Sintering ◽  
Single Track ◽  
Laser Melting ◽  
Consolidation Process ◽  
Melt Pool ◽  
Track Formation ◽  
Scan Speed

Selective Laser Sintering/Selective Laser Melting (SLS/SLM) is one of Additive Manufacturing (AM) processes that utilize layer by layer powder deposition technique and successive laser beam irradiation based on Computer Aided Design (CAD) data. During laser irradiation on metal powders, melt pool was formed, which then solidified to consolidated structure. Therefore, melt pool is an important behavior that affects the final quality of track formation. The study investigates the melt pool behavior through visualization of the consolidation process during the single track formation on the first layer. In order to understand the transformation process of metal powder to consolidated structure and mechanism involved, high speed camera was used to monitor the process. Yb:fiber laser beam was irradiated on metal powder at maximum power of 150W. The laser processing parameters such as laser power, scan speed and layer thickness were varied in order to investigate their influence on the consolidation process. The result shows the size of melt pool increased with laser power and decreasing with increment in scan speed. Furthermore, with the increase of layer thickness, melt pool formation was unstable with chaotic movement. Significant amount of molten powder splattering was recorded from the melt pool. At high layer thickness also, the molten powder formed spherical shaped and the solidified molten powder failed to wet with the substrate.

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