Investigation on the evolution and distribution of plasma in magnetic field assisted laser-induced plasma micro-machining

Abstract Laser-induced plasma micro-machining (LIPMM) has proven a number of advantages in micro-machining due to reduced thermal defects, smaller heat-affected zones, and larger aspect ratios when compared with conventional laser ablation. The present work explores the use of external magnetic fields to further enhance process outcomes in LIPMM. Specifically, machining characteristics and outcomes including plasma intensity, attainable aspect ratios, and surface quality will be explored through a theoretical and experimental study in different classes of materials in a transverse magnetic field controlled LIPMM. First, process improvement mechanisms are illustrated in terms of plasma confinement and laser absorption in transverse magnetic fields. A magnetic field redistribution analysis is performed to reveal the differences in the achievable enhancements in machining characteristics in terms of material characteristics. Second, a set of single-factor experiments is conducted to investigate the effects of the strength and direction of the magnetic field on machining capabilities in magnetic and nonmagnetic materials (410, 304 stainless steels and silicon). The experimental results show that plasma intensity and aspect ratios can be significantly increased in the presence of transverse magnetic fields. The greatest influence on machining capability is achieved in a magnetic material. In this case, plasma intensity and aspect ratios were increased by about 176% and 160%, respectively, when compared with other materials with a magnetic field strength of 0.1 T and a magnetic field direction parallel to the processing direction. Finally, the morphology and cross-section profiles of micro-channels have been measured for verifying the impact on the surface quality of transverse magnetically controlled LIPMM.

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Unidirectional magnetic field assisted Laser Induced Plasma Micro-Machining

Manufacturing Letters ◽

10.1016/j.mfglet.2014.09.001 ◽

2015 ◽

Vol 3 ◽

pp. 1-4 ◽

Cited By ~ 22

Author(s):

Ishan Saxena ◽

Sarah Wolff ◽

Jian Cao

Keyword(s):

Magnetic Field ◽

Micro Machining ◽

Laser Induced Plasma

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Confinement and re-expansion of laser induced plasma in transverse magnetic field: Dynamical behaviour and geometrical aspect of expanding plume

Physics Letters A ◽

10.1016/j.physleta.2015.04.042 ◽

2015 ◽

Vol 379 (37) ◽

pp. 2215-2220 ◽

Cited By ~ 14

Author(s):

Narayan Behera ◽

R.K. Singh ◽

Ajai Kumar

Keyword(s):

Magnetic Field ◽

Transverse Magnetic Field ◽

Transverse Magnetic ◽

Dynamical Behaviour ◽

Geometrical Aspect ◽

Laser Induced Plasma

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The application of magnetic field at low pressure for optimal laser-induced plasma spectroscopy

Spectrochimica Acta Part B Atomic Spectroscopy ◽

10.1016/j.sab.2015.05.006 ◽

2015 ◽

Vol 110 ◽

pp. 7-12 ◽

Cited By ~ 12

Author(s):

Dae-Hyoung Kim ◽

Yong H. Kihm ◽

Soo-Jin Choi ◽

Jae-Jun Choi ◽

Jack J. Yoh

Keyword(s):

Magnetic Field ◽

Low Pressure ◽

Plasma Spectroscopy ◽

Laser Induced Plasma

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Multi-Material Capability of Laser Induced Plasma Micromachining

Volume 1: Materials; Micro and Nano Technologies; Properties, Applications and Systems; Sustainable Manufacturing ◽

10.1115/msec2014-4142 ◽

2014 ◽

Author(s):

Ishan Saxena ◽

Kornel Ehmann

Keyword(s):

Laser Ablation ◽

Metal Cutting ◽

Medical Engineering ◽

Machining Process ◽

Micro Machining ◽

Promising Alternative ◽

Laser Induced Plasma ◽

Direct Laser ◽

Micro Features ◽

Machining Characteristics

Presently surface micro-texturing has found many promising applications in the fields of tribology, bio-medical engineering, metal cutting, and other functional or topographical surfaces. Most of these applications are material-specific, which necessitates the need for a texturing and machining process that surpasses the limitations posed by a certain class of materials that are difficult to process by laser ablation, owing to their optical or other surface or bulk characteristics. Laser Induced Plasma Micromachining (LIPMM) has emerged as a promising alternative to direct laser ablation for micro-machining and micro-texturing, which offers superior machining characteristics while preserving the resolution, accuracy and tool-less nature of laser ablation. This study is aimed at understanding the capability of LIPMM process to address some of the issues faced by pulsed laser ablation in material processing. This paper experimentally demonstrates machining of optically transmissive, reflective and rough surface materials using LIPMM. Apart from this, the study includes machining of conventional metals (Nickel and Titanium) and polymer (Polyimide), to demonstrate higher obtainable depth and reduced heat affected distortion around micro-features machined by LIPMM, as compared to laser ablation.

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Line-Based Laser Induced Plasma Micro-Machining (L-LIPMM)

Volume 2: Systems; Micro and Nano Technologies; Sustainable Manufacturing ◽

10.1115/msec2013-1153 ◽

2013 ◽

Cited By ~ 1

Author(s):

Rajiv Malhotra ◽

Ishan Saxena ◽

Kornel Ehmann ◽

Jian Cao

Keyword(s):

Laser Ablation ◽

Process Parameters ◽

Ultrashort Pulse ◽

Experimental Setup ◽

Micro Machining ◽

Ultrashort Pulse Laser ◽

Plasma Generation ◽

Laser Induced Plasma ◽

Laser Micro Machining ◽

Wide Range

Recently, the technique of Spot-based Laser Induced Plasma Micro-Machining (Spot-LIPMM) has been developed to address the limitations of conventional ultrashort pulse laser micro-machining. Its main advantages are adaptability to a wide range of materials and superior wall geometries. We propose a variation of the Spot-LIPMM process by creating line plasma instead of spot plasma, with the use of suitable optics. This paper describes the experimental setup used to create line plasma and the process used for micro-machining with L-LIPMM. Optics simulations are developed as a means of guiding the choice of optics to be used for line plasma generation and estimating the energy and shape of the plasma created. It is shown that this Line-based LIPMM (L-LIPMM) process is capable of micromachining channels at a much higher speed than conventional Spot-based laser ablation or spot-based LIPMM. Additionally, the effects of process parameters on machined geometry using L-LIPMM are discussed.

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Simulation of Ultrashort Laser Pulse Absorption At the Water-metal Interface in Laser-Induced Plasma Micro-Machining

Journal of Micro and Nano-Manufacturing ◽

10.1115/1.4049360 ◽

2020 ◽

Author(s):

Jiaxi Xie ◽

Kornel Ehmann ◽

Jian Cao

Keyword(s):

Dielectric Breakdown ◽

Constitutive Relations ◽

Three Dimensional ◽

Optical Breakdown ◽

Micro Machining ◽

Metal Interface ◽

Breakdown Threshold ◽

Laser Induced Plasma ◽

Water Metal ◽

Ultrashort Laser

Abstract This work proposes a physically consistent numerical model to simulate ultrashort laser absorption by a metallic workpiece at the water-metal interface when optical breakdown of the dielectric occurs. The simulation couples the framework of the Finite-Difference Time-Domain method used in computational electromagnetics with the constitutive relation derived from both the model of direct ablation of metals and the first order model of water breakdown. The simulation is used to describe interface ablation processes such as Laser-Induced Plasma Micro-Machining. Applied to the water-aluminum interface, the model is able to describe the metal absorption and the dielectric breakdown threshold in three-dimensional geometry. It is an extensible monolithic approach in which the absorption by different materials can be described by simply changing the constitutive relations.

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