Laser Beam Milling of Alumina Ceramics - The Impact on Material Removal Efficiency and Machined Surface Morphology

2017 ◽  
Vol 261 ◽  
pp. 143-150 ◽  
Author(s):  
Peter Šugár ◽  
Martin Frnčík ◽  
Jana Šugárová ◽  
Miroslav Sahul
Keyword(s):  
Laser Beam ◽  
Removal Efficiency ◽  
Material Removal ◽  
Scanning Speed ◽  
Fibre Laser ◽  
Machining Processes ◽  
Machined Surface ◽  
Machine Surface Quality ◽  
Mechanical Devices ◽  
The Impact

Laser machining is one of the most widely used advanced noncontact machining processes used for creating new surfaces, structures, cavities and also complex electro-mechanical devices, usually with very small dimensions, by laser radiation. It is the process in which the material’s thermophysical properties rather than mechanical properties determine the machinability. Design of process parameters is highly critical for successful material removal and high machine surface quality. In the paper the laser beam milling is experimentally studied applying the nanosecond pulse fibre laser and alumina ceramic as working material. The influence of pulse energy, pulse repetition rate, scanning speed and tracks displacement on material removal efficiency and the quality of machined surface is reported.

scholarly journals Laser surface texturing of tool steel: textured surfaces quality evaluation

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Peter Šugár ◽  
Jana Šugárová ◽  
Martin Frnčík
Keyword(s):  
Laser Beam ◽  
Tool Steel ◽  
Surface Texturing ◽  
Scanning Speed ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Fibre Laser ◽  
Textured Surfaces ◽  
Machined Surface ◽  
Ytterbium Fibre Laser

Abstract In this experimental investigation the laser surface texturing of tool steel of type 90MnCrV8 has been conducted. The 5-axis highly dynamic laser precision machining centre Lasertec 80 Shape equipped with the nano-second pulsed ytterbium fibre laser and CNC system Siemens 840 D was used. The planar and spherical surfaces first prepared by turning have been textured. The regular array of spherical and ellipsoidal dimples with a different dimensions and different surface density has been created. Laser surface texturing has been realized under different combinations of process parameters: pulse frequency, pulse energy and laser beam scanning speed. The morphological characterization of ablated surfaces has been performed using scanning electron microscopy (SEM) technique. The results show limited possibility of ns pulse fibre laser application to generate different surface structures for tribological modification of metallic materials. These structures were obtained by varying the processing conditions between surface ablation, to surface remelting. In all cases the areas of molten material and re-cast layers were observed on the bottom and walls of the dimples. Beside the influence of laser beam parameters on the machined surface quality during laser machining of regular hemispherical and elipsoidal dimple texture on parabolic and hemispherical surfaces has been studied.

Effects of the Laser Beam Interaction with the Workpiece Material

2012 ◽  
Vol 504-506 ◽  
pp. 1207-1212
Author(s):  
Margareta Coteaţă ◽  
Laurenţiu Slătineanu ◽  
Irina Grigoraş (Beşliu) ◽  
Nicolae Pop
Keyword(s):  
Laser Beam ◽  
Material Removal ◽  
Machining Parameters ◽  
Workpiece Material ◽  
Laser Beam Machining ◽  
Workpiece Surface ◽  
Physical Effects ◽  
Beam Interaction ◽  
The Impact ◽  
Experimental Researches

The laser beam machining uses the effects generated at the impact of the workpiece surface with a laser beam that has adequate energetically and spatial - temporal characteristics. It is known that, as result of the laser beam impact with the workpiece material, local chemical and physical effects are signalized. In order to study such effects and simultaneously the technological possibilities of laser beam equipment, some experimental researches were developed on an Ytterbium fiber laser equipment of 300 W. Movements of the laser spot along established trajectories were ensured, changing the sizes of the machining parameters. The influence exerted by the machining parameters and by the materials characteristics on the material removal from the test piece was highlighted. The surface layer modifications were also studied.

scholarly journals Molecular Dynamics Simulation Study of Liquid-Assisted Laser Beam Micromachining Process

2018 ◽  
Vol 2 (3) ◽  
pp. 51 ◽  
Author(s):  
Vivek Menon ◽  
Sagil James
Keyword(s):  
Molecular Dynamics ◽  
Laser Beam ◽  
Material Removal ◽  
Md Simulation ◽  
Bubble Formation ◽  
Machining Process ◽  
Dynamics Simulation ◽  
Dynamic Mode ◽  
Machining Processes ◽  
Static Mode

Liquid Assisted Laser Beam Micromachining (LA-LBMM) process is an advanced machining process that can overcome the limitations of traditional laser beam machining processes. This research involves the use of a Molecular Dynamics (MD) simulation technique to investigate the complex and dynamic mechanisms involved in the LA-LBMM process both in static and dynamic mode. The results of the MD simulation are compared with those of Laser Beam Micromachining (LBMM) performed in air. The study revealed that machining during LA-LBMM process showed higher removal compared with LBMM process. The LA-LBMM process in dynamic mode showed lesser material removal compared with the static mode as the flowing water carrying the heat away from the machining zone. Investigation of the material removal mechanism revealed the presence of a thermal blanket and a bubble formation in the LA-LBMM process, aiding in higher material removal. The findings of this study provide further insights to strengthen the knowledge base of laser beam micromachining technology.

A Metric for Defining the Energy Efficiency of Thermally-Assisted Machining

2006 ◽  
Author(s):  
Frank Pfefferkorn ◽  
Shuting Lei
Keyword(s):  
Energy Efficiency ◽  
Silicon Nitride ◽  
Thermal Energy ◽  
Material Removal ◽  
End Milling ◽  
Removal Rate ◽  
Operating Conditions ◽  
The Body ◽  
Machining Processes ◽  
The Impact

A significant amount of work has been conducted on thermally-assisted machining with a great deal being focused on laser-assisted machining. The body of work has shown that preheating of the workpiece (usually localized heating) makes it possible to machine certain structural ceramics with a conventional cutting tool, improves the machinability of superalloys, and improves the micro-end milling of metals. A variety of metrics have been used to ascertain the impact of thermal assistance on the machining of these materials including: specific cutting energy, tool wear rate, surface roughness, residual stress, material removal rate, material removal mechanism, cost, and surface integrity. Combined, these quantities provide a good but incomplete description of the process and efficacy of thermal assistance. This manuscript looks at the flow of energy in thermally-assisted machining in an attempt to determine how beneficial preheating is. Some efficiency metrics are suggested and used to study the data that has been collected to date. The total thermal energy deposited in the workpiece is compared to the theoretical minimum required to heat the removed material in order to determine what percentage of the deposited (i.e. absorbed) energy is actually used in assisting the cutting process. This enables a comparison between cutting processes (e.g. end milling and turning) and operating conditions to determine how efficiently the added thermal energy is being used. Compared with other machinability metrics the thermal energy efficiency is used to evaluate how beneficial preheating is to the machining processes studied. Two sets of data are studied: laser-assisted turning of silicon nitride and partially-stabilized zirconia. The specific energy for LAM of silicon nitride is compared to that for grinding of silicon nitride. It is hoped that this presentation will spark debate in the manufacturing community and provide more insight into thermally-assisted manufacturing.

Improving the Surface Finish and other Properties of Engineering Metal Parts

2019 ◽  
Vol 813 ◽  
pp. 197-202
Author(s):  
Muhannad A. Obeidi ◽  
Eanna McCarthy ◽  
Inam Ul Ahad ◽  
Dermot Brabazon
Keyword(s):  
Laser Beam ◽  
Processing Time ◽  
Dimensional Accuracy ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Laser Surface ◽  
Beam Power ◽  
Metal Parts ◽  
Surface Polishing ◽  
The Impact

The manufacture of metal parts requires post processing in most cases. These processes include heat treatment for releasing of the residual stresses resulting on the metal surface due to the excessive mechanical forces applies to cut the metal during machining, i.e. milling, turning and drilling. Another example would be the polishing of parts using different techniques. In predominant, polishing is used enhance the part’s roughness to improve the friction coefficient, to give the parts a better view and most important is to adjust the final dimensional accuracy in the microns and sub-microns scale. Traditional polishing methods include the mechanical polishing by using abrasive media or grinding machines, chemical polishing which has the benefit of reaching the inaccessible features although this method requires longer processing time in addition to the impact on environment. Sometimes the thermal deburring method is also applied for the chamfer of sharp edges and corners. In the recent years, the laser polishing technique exhibits interesting efforts and results regarding reproducibility, high control over the processing parameters which allow for the processing of different metals and non-metals materials in addition to the ultrashort processing time. This study is focusing on the laser surface polishing of metal parts, its potentials and limitations. In this study, laser surface polishing using CO2 laser beam irradiation was implemented on stainless steel Additive Manufactured produced surfaces. Two design of experiment models were implemented for the optimization of the main laser input processing parameters. The processing parameters examined were the laser beam power, the scanning speed, the number of laser scan passes, the percentage overlap of the laser tracks between the consecutive passes and the laser beam focal position. The characterization of the measured surface roughness and the modified layer microstructure were carried out using scanning electron microscopy (SEM) and 3D optical.

scholarly journals Optimization of Laser Engraving of Acrylic Plastics from the Perspective of Energy Consumption, CO2 Emission and Removal Rate

2021 ◽  
Vol 5 (3) ◽  
pp. 78
Author(s):  
Mohammad Muhshin Aziz Khan ◽  
Shanta Saha ◽  
Luca Romoli ◽  
Mehedi Hasan Kibria
Keyword(s):  
Energy Consumption ◽  
Production Rate ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Scanning Speed ◽  
Gas Emissions ◽  
Laser Engraving ◽  
Co2 Gas ◽  
Optimal Set

This paper focuses on optimizing the laser engraving of acrylic plastics to reduce energy consumption and CO2 gas emissions, without hindering the production and material removal rates. In this context, the role of laser engraving parameters on energy consumption, CO2 gas emissions, production rate, and material removal rate was first experimentally investigated. Grey–Taguchi approach was then used to identify an optimal set of process parameters meeting the goal. The scan gap was the most significant factor affecting energy consumption, CO2 gas emissions, and production rate, whereas, compared to other factors, its impact on material removal rate (MRR) was relatively lower. Moreover, the defocal length had a negligible impact on the response variables taken into consideration. With this laser-process-material combination, to achieve the desired goal, the laser must be focused on the surface, and laser power, scanning speed, and scan gap must be set at 44 W, 300 mm/s, and 0.065 mm, respectively.

EDM with USM Combination Process of Sintered NdFeB Permanent Magnet

2010 ◽  
Vol 44-47 ◽  
pp. 1066-1069
Author(s):  
Li Li ◽  
Li Ling Qi ◽  
Zong Wei Niu
Keyword(s):  
Permanent Magnet ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Dielectric Fluid ◽  
Machined Surface ◽  
Combination Process ◽  
Electro Discharge Machining ◽  
Ndfeb Permanent Magnet ◽  
Machining Characteristics

This paper presents an experimental investigation of the machining characteristics of sintered NdFeB permanent magnet using a combination process of electro-discharge machining (EDM) with ultrasonic machining (USM). Concentration of abrasive in the dielectric fluid is changed to explore its effect on the material removal rate (MRR). MRR of EDM /USM, conventional EDM are compared, machined surface characteristics are also compared between them. It is concluded that the combination EDM/USM process can increase the MRR and decrease the thickness of the recast layer. In the combination process, an appropriate abrasive concentration can improve its machining efficiency.

Study of the Removal of Boron from Metallurgical Grade Silicon by Oxidation Slagging Method

2010 ◽  
Vol 156-157 ◽  
pp. 882-885 ◽  
Author(s):  
Yu Yan Hu ◽  
Dong Liang Lu ◽  
Tao Lin ◽  
Yu Liu ◽  
Bo Wang ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Orthogonal Experiment ◽  
Slag System ◽  
Refining Process ◽  
Impact Factors ◽  
Metallurgical Grade Silicon ◽  
Optimum Parameters ◽  
Grade Silicon ◽  
Refining Time ◽  
The Impact

Refining of solar grade silicon by metallurgical method is the research hotspot of polycrystalline field. Slagging method is benefit to the removal of the impurities especially to boron exsisted in the raw silicon. In this study, the influence of the density, the viscosity and liquidus temperature of the slag components on the refining process were discussed, and then the slag system SiO2-Na2CO3 was choosed as the slagging agents. And then the impact factors on the removal efficiency of boron such as the composition of SiO2 and Na2CO3, the ratio of slag to silicon and the refining time were investigated by the orthogonal experiment. The results showed that the optimum parameters of the oxidation refining for removing boron were as follows: the main composition of the oxidant is “SiO2 : Na2CO3 = 60% : 40%”; the slag/silicon ratio is 0.5; time for refining is 60min at 1550 . The results indicated that the removal efficiency of boron was 88.28%, and the content of boron in MG-Si can be reduced to 7ppmw under the best refining process¬.

Evaluation and defense of light commands attacks against voice controllable systems in smart cars

2021 ◽  
pp. 095745652110015
Author(s):  
Zhijian Xu ◽  
Guoming Zhang ◽  
Xiaoyu Ji ◽  
Wenyuan Xu
Keyword(s):  
Laser Beam ◽  
Success Rate ◽  
Incidence Angle ◽  
Attack Angle ◽  
Light Transmittance ◽  
Controllable System ◽  
Lower Light ◽  
Controllable Systems ◽  
Smart Cars ◽  
The Impact

The in-car voice controllable system has become an almost standard feature in smart cars. Prior work shows that the voice controllable system is vulnerable to light commands attack which uses the laser as the medium to inject voice commands. In this article, we first reproduced the light commands attack on acoustic isolated in-car voice controllable system under several scenarios with a lightweight solution. We validate the feasibility of injecting the malicious voice command through a window into the microphone by modulating a laser beam. Then, we tested a variety of mainstream countermeasures such as placing sunscreen film on the glass panel to see whether it can protect the microphone from being attacked. Surprisingly, we find that the lower light transmittance of sunscreen film is the lower the success rate of the attack. Experiment results also show that when the transmittance rate of sun film is 50% which is the darkest sunscreen film that can be applied, the attacking success rate decreased by up to 0.4. We also explore the impact of attack angle by changing the incidence angle of the laser beam and the results demonstrate that light commands is sensitive to attack angle and the successful angle range is ± 15°. Finally, we propose a series of hardware-based protection schemes against light commands attacks.

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