The formation of the cutting tool microgeometry by pulsed laser ablation (original) (raw)
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This paper focuses on modelling and optimizing process parameters in pulsed laser micro-machining. Use of continuous wave or pulsed lasers to perform micro-machining of 3-D geometrical features on difficult-to-cut metals is a feasible option due the advantages offered such as tool-free and high precision material removal over conventional machining processes. Despite these advantages, pulsed laser micro-machining is complex, highly dependent upon material absorption reflectivity, and ablation characteristics. Selection of process operational parameters is highly critical for successful laser micro-machining. For this reason, it is necessary to clearly understand the process parameter influence on material removal in complex 3-D geometrical features. A set of designed experiments are carried in a pulsed Nd:YAG laser system using H13 hardened tool steel as work material. Several T-shaped deep features with straight and tapered walls have been machining as representative mold cavities ...
Theoretical aspects of Laser micro machining and its role in new industrial revolution
CETMIE-2017, 2017
A laser micro machining is becoming popular in the industrial world due to its unique characteristics. Miniaturization has changed the path of machining of various materials. The various properties such as high peak intensity, precision, non-thermal interaction and flexibility make micro-laser machining a well accepted tool of machining. The major advantage of laser micro machining is lower aspect ratio, precise laser cutting zone, flexibility and fast processing. The objective of this review article is to analyze the various laser micromachining techniques, challenges in application, research carried out and their characteristics. This article also depicts the comparison between different laser micro-machining sources which have direct impact on the quality of machined surfaces. A comparison between pico-second, micro-second and nano-second laser has been explained with respect to fluence ablation in the machining zone.
Micromachining of cold-worked tool steel by nanosecond laser
IOP Conference Series: Materials Science and Engineering
The paper brings the results of experimental study of the laser beam milling applying the industrial grade fiber nanosecond laser operating at wavelength of 1064 nm and 62SiMnCr4 cold-work tool steel as working material. The laser pulse intensity and both lateral and transverse pulse overlaps influence on the material removal rate (MRR) and surface roughness are analysed and discussed. The experimental results reveal that for high ablation efficiency in combination with good surface finish the higher values of laser pulse intensities and lower to moderate lateral pulse overlap distances should be applied.
Short pulse laser milling effects on surface integrity
Laser milling of engineering materials is a viable alternative to conventional methods for machining complex micro components. The laser source employed to perform such micro structuring has a direct impact on achievable surface integrity. At the same time, the trade offs between high removal rates and the resulting surface integrity should be taken into account when selecting the most appropriate ablation regime for performing laser milling. In this paper the effects of pulse duration on surface quality and material microstructure are investigated when ablating a material commonly used for manufacturing micro tooling inserts. When performing ultra short pulsed laser ablation some heat is dissipated into the bulk but not sufficient to trigger significant structural changes.
Laser milling: Pulse duration effects on surface integrity
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture
Laser milling of engineering materials is a viable alternative to conventional methods for machining complex microcomponents. The laser source employed to perform such microstructuring has a direct impact on achievable surface integrity. At the same time, the trade-offs between high removal rates and the resulting surface integrity should be taken into account when selecting the most appropriate ablation regime for performing laser milling. In this paper the effects of pulse duration on surface quality and material microstructure are investigated when ablating a material commonly used for manufacturing microtooling inserts. For both micro- and nanosecond laser regimes, it was estimated that the heat-affected zone on the processed surface is within 50 μm. When performing ultra-short pulsed laser ablation, the effects of heat transfer are not as evident as they are after processing with longer laser pulse durations. Although some heat is dissipated into the bulk when working in pico- ...
Analysis of Shape Geometry and Roughness of Ti6Al4V Parts Fabricated by Nanosecond Laser Ablation
Micromachines
Laser milling is a micro-machining process that uses a laser beam as a tool to remove material through the layer-by-layer ablation mechanism. Generally in laser ablation, the quality of parts is reduced by melt accretions and thermal damage; therefore, this problem is reduced with shorter pulse duration, although ablation efficiency decreases as well. Thus, laser ablation in the nanosecond range still offers a good compromise between process quality and efficiency. Therefore, laser milling with nanosecond laser ablation requires an accurate study to reduce geometric defects induced by the process. The aim of this paper was to study the shape geometry and roughness of Ti6Al4V parts fabricated by laser milling using a nanosecond Nd:YAG laser source. The impact of the laser processing parameters on machining outcomes was studied in order to determine the optimized processing conditions for reducing geometrical defects and improving surface quality. In particular, the influence of average laser power, frequency, and scanning speed was investigated. The geometry of micro-parts was revealed using a 3D digitizing system, the Optimet Mini Conoscan 4000, which combines a non-contact, single-point measuring sensor based on conoscopic holography technology. The use of this measurement technology yielded complete information of the shape geometry and dimensions of the built parts. In addition, the roughness of manufactured surfaces was assessed to complete the analysis.
INVESTIGATION AND ANALYSIS OF LASER BEAM MACHINING
BEST Journal, 2014
The high intensity which can be obtained by focusing the pulsed energy emitted by a LASER can offer potential as a tool for nearly forceless machining. The method can be used on any material, regardless of thermal properties, which can be evaporated without decomposition, including almost all ceramics and metals. With most substances, almost all of the material removed by LASER machining leaves in the liquid state. Only a small fraction is vaporized, and the high rate of the vaporization exerts forces which expel the liquid metal. All features of LASER beam machining improve with increased intensity. The higher the intensity, the less heat is resonant in the uncut material, an important consideration with materials which are sensitive to heat shock, and the more efficient the process is in terms of volume of material removed per unit of energy. The intensities which are available with the LASER are high enough so that the heat affected zone (HAZ) on a cut surface is too small to be detected and there is no solidified liquid film residue on the cut surface. In this paper Laser micromachining of an aluminum film on a glass substrate is investigated using atime-resolved transmission imaging technique with nanosecond resolution.
Application Features of the Cutting Tool, Hardened by Laser Pulsed Radiation
2016
The performed studies of the application features of the cutting tool, hardened by laser pulsed radiation are based on the comprehensive cutting process analysis. In this approach, the modeling results of the cutting process with hardened tool allowing to define the area of the effective use of laser treatment (LT). In particular, the increase in the tool life only for the certain values of the cut depth at the fixed irradiation energy was observed. The causes of the observed phenomena were determined based on durometric researches and studies of the microstructure in the contact zone. The measurements were performed for the cutters (steel R18) after turning structural steel 12Kh2N4A under various cutting modes. It was found that the processes of tool material softening, observed at turning with high feed values, limits the scope of cutting conditions by hardened tool. It is shown that LT leads to increased tool life, operating at the cutting conditions when the growth of tension thermodynamic in the cutting zone does not result in the development of softening processes. It is established that the area cutting modes are restricted to the values of cut depth not exceeding 1.5 mm (V=42.5 m/min, s=0.2 mm/rev) for the investigated pair of tool-workpiece (R18-12Kh2N4A). Tool life increases by more than 4 times compared to the durability of the non-irradiated tool provided the optimal combination of laser processing and hardened tool cutting modes is achieved.
Machining performance of laser surface micro-textured drilling tools
International Journal of Surface Science and Engineering, 2011
Surface modification of high-speed steel drills using laser has been proposed as a step before physical vapour deposition in order to increase the adhesion of the titanium nitride coating on the tool substrate. A copper vapour laser and a scanning-head system were used to produce highly controlled laser ablation on the surface. In the current work, the laser average power varied from 0.5 to 6 W and the laser shots were applied next to one another. After laser surface modification and coating, the drills were used to machine low-alloy carbon steel and stainless steel in a CNC machine. The tool lives were then compared to those obtained with the same kind of tool but whose substrate was prepared conventionally. The laser-treated drills had a longer lifetime than conventional ones. Under the conditions of this study, the laser-treated drills presented a 40% higher performance than conventional drills for carbon steel machining. The increase in performance reached 400% in stainless steel drilling. In general, laser processing with an average power of 1 W yielded the best results.