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Introduction to Laser-Assisted Machining

Sandip Kunar1*, K. Vijetha1, Jagadeesha T.2, Abhishek Ghosh3, S. Rama Sree4, Prasenjit Chatterjee5, Sreenivasa Reddy Medapati1 and Nabankur Mandal5

1Department of Mechanical Engineering, Aditya Engineering College, Surampalem, India

2Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Howrah, Shibpur, India

3Department of Mechanical Engineering, NIT Calicut, Kozhikode, India

4Department of Computer Science & Engineering, Aditya Engineering College, Surampalem, India

5Department of Mechanical Engineering, MCKV Institute of Engineering, Howrah, India

Abstract

Due to their inherent physical-mechanical qualities, advanced materials such as Ti6Al4V, Inconel, and sophisticated technical materials like composites and ceramics are explored and utilized extensively in biomedicine, nuclear power, etc. However, machining is always involved in turning these novel materials into engineered goods. These substances are regarded as advanced materials due to their machinability features, which include greater machining temperature, reduced surface quality, and less tool life expectancy. These substances are proven to be economically unfeasible to machines using conventional techniques. Recently, there have been numerous attempts to use external energy-aided machining to better these materials' machinability. Scientists in the field of material removal mechanism have recently concentrated their attention on laser-assisted machining (LAM), one of the various externally aided machining methods. The aim of this research article is to explore and describe the prospective applications of LAM for advanced materials, as well as the advantages and drawbacks of this technology.

Keywords: Laser-assisted machining, advanced materials, laser parameters

1.1 Introduction

In the industrial sector, the usage of advanced materials including tool steels, semiconductors, biomaterials, and smart materials is rising [1]. To fulfill the growing demand for greater heat and strength resistance, particularly in the aerospace industry, they are still being investigated and developed [2, 3]. These cutting-edge materials are often machinable because of higher thermal stress of the machining zone. The materials are challenging to manufacture because of characteristics like higher thermal effect and large machining forces. Thus, an innovative approach known as thermally aided machining was established. Plasma-assisted machining, induction and furnace preheating method, and gas torch are a few examples [4].

Although hard-to-cut materials have good qualities, their physical and chemical traits make them challenging to manufacture with standard machinery [5]. A brand-new and cutting-edge method for machining materials with high wear resistance is called laser-assisted machining. For softening the material during the cutting time, the laser is employed as a heating resource with the laser beam directed on the unmachined portion of the job. Heat is added to the substance, softening the surface layer and causing ductile deformation as opposed to delicate deformation during machining [6]. The most significant benefit of laser-aided cutting is its ability to generate job surfaces that are considerably improved compared with those generated by traditional machining, along with a superior material removal rate and low tool erosion [7]. LAM is suitable due to its greater laser beam intensity at less beam power, good concentrating features brought on by extremely brief pulse duration, simplified manufacturing process, eco-friendliness, and improved surface finish [8].

For applications requiring high strength and heat resistance, including those in the aerospace, medical, and electronic industries, advanced materials have been developed in recent decades. These materials include ferrous alloys, cobalt-chromium alloys, and composites [9, 15]. These materials have significant corrosion resistance and the capacity to maintain superior strength at high temperatures. These materials outperform more traditional engineering materials in terms of strength and toughness. However, since converting a final component costs half of the product's final cost, applications of these materials are currently not expanding [9, 10]. Low cutting speed and reduced cut depth because of increased tool wear are to blame for this. As a result, these materials are regarded as being tough to cut. Numerous issues arise during machining, including excessive heat creation during cutting time, a propensity for BUE creation, and catastrophic cutting tool failure [11-14]. Due to these machining processes, poor capability of machinability, higher capital cost, and low efficiency may be substantially affected. The intrinsic properties of hard-to-cut materials make traditional machining techniques like milling or turning ineffective. These materials are currently being machined using a variety of cutting-edge techniques, including electrochemical machining, plasma machining, and thermally aided machining techniques like laser machining. Due to its greater advantages, significant technological advancement, and commercial viability, laser-aided machining (LAM), one of the various techniques, is becoming more and more popular with advanced materials. The current state of LAM and its problems are highlighted in this research with respect to the impact of laser machining factors on the productivity of smart materials.

1.2 Laser-Assisted Machining-Overview

A high-power laser is utilized in laser-aided machining, a hybrid process, to heat the job before material removal using a traditional machine tool. The yield strength of fragile material drops down below its rupture strength at high temperatures, transforming the material's distortion behavior from fragile to ductile. Also, strong, ductile materials lose some of their yield strength at high temperatures, which lowers tool erosion and cutting ability while also enhancing surface quality.

Nd:YAG and CO2 laser are two primary laser sources that are frequently utilized in LAM studies. The latter has superior absorptivity because it has a shorter wavelength. Because the CO2 laser absorbs less laser energy than Nd:YAG, it is less effective in cutting the most advanced materials including titanium and composite materials. Most of the study has addressed the difficulties in traditional machining while concentrating on the advantages of LAM. However, the laser machining factors affect the LAM consequences. Feed rate, spot diameter, and cutting speed are the primary operational aspects associated with LAM. Due to the multiplicity of control factors and how they interact, finding the ideal LAM setting is challenging. Additionally, a numerical analysis based on experimental design is required to explore how the ideal LAM parameter affects other variables and how they interact. Figure 1.1 shows the schematic setup of LAM.

Figure 1.1 Schematic setup of LAM.

1.3 Machining of Advanced Materials

The adoption of advanced materials has accelerated with applications in automotive, shipbuilding, and semiconductors in recent years because they outperform standard metals in terms of high-temperature strength, durability, and corrosion resistance [16-19]. Titanium alloy [20], Inconel 718 alloy [21], compacted graphite iron [22], mullite [23], Si3N4 ceramic [24-26], Waspaloy [27], and A359 aluminum matrix [28] are a few examples of materials that are challenging to cut. Hard-to-cut materials also include magnesium AZ91 [29], stainless steel P550 [30], and AISI D2 steel [31].

1.3.1 Titanium Alloys

This is mainly because titanium alloys have properties like high creep, high wear resistance, fine biocompatibility, and high corrosion resistivity, which make them interesting materials in a variety of manufacturing areas like biomedical, nuclear, etc. Owing to their greater chemical attraction and less heat conductivity, titanium alloys are regarded as advanced materials. The tool life is decreased during the machining of titanium alloys.

S. Sun et al. [32] turned titanium alloy dry at various cutting speeds, feed rates, and cut depths to see how the repeated force frequency altered in relation to the cutting speed and feed rate. With greater cutting speed, the cutting force rises due to the strain rate hardening at higher and lower strain rates correspondingly. Outside of these cutting speed ranges, the cutting force reduces with boosting cutting speed because of the thermal tempering of material. Some investigations on titanium alloys demonstrate that cryogenic machining outperforms dry machining in terms of tool life. The impact of cryogenic machining was examined by M.J. Bermingham et al. [33] using various combinations of feed rate and depth of cut at fixed material removal rate and cutting speed. In dry machining, the combination of lower cutting speed and higher depth of cut improved tool life 1.6 times more than the combined lower depth of cut and higher speed. Tool life at the specified machining conditions is 13 min for dry machining and 20 min for cryogenic machining. Hybrid machining and laser-aided machining (LAM) were utilized to enhance metal removal and tool life. Surface finish, microstructure, and tool...