Laser Assisted Milling Device: A Review

이춘만,김동현,백종태,김은정 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.3 No.2

Laser-Assisted milling is a type of thermally-assisted machining process in which a workpiece is locally softened by a laser heat source before machining. This method is effective solution for machining materials such as Inconel series alloys, titanium alloy, and ceramics, which are more difficult to machine compared with conventional materials. It is also a green machining process, because it saves energy by reducing the cutting force. Laser-Assisted milling has only been used in limited fields including single-direction machining of flat surfaces. When the laser-assisted milling has a complex tool-path, it is difficult to control the heat source and cutting tool simultaneously. To apply the process in industrial field studies of workpieces having various shapes are needed. This paper provides a review of current laser-assisted milling devices, and then develops a three-dimensional laser-assisted milling device for complex tool-path machining. A high-power diode laser with additional axes was retrofit to the spindle of a five-axis machining center. The device could be used in industrial fields whose machined products have complicated shapes.

Characteristics of laser assisted machining for silicon nitride ceramic according to machining parameters

Kim, Jong-Do,Lee, Su-Jin,Suh, Jeong 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.4

This paper describes the Laser Assisted Machining (LAM) that cuts and removes softened parts by locally heating the ceramic with laser. Silicon nitride ceramics can be machined with general machining tools as well, because YSiAlON, which was made up ceramics, is soften at about $1,000^{\circ}C$. In particular, the laser, which concentrates on highly dense energy, can locally heat materials and very effectively control the temperature of the heated part of specimen. Therefore, this paper intends to propose an efficient machining method of ceramic by deducing the machining governing factors of laser assisted machining and understanding its mechanism. While laser power is the machining factor that controls the temperature, the CBN cutting tool could cut the material more easily as the material gets deteriorated from the temperature increase by increasing the laser power, but excessive oxidation can negatively affect the quality of the material surface after machining. As the feed rate and cutting depth increase, the cutting force increases and tool lifespan decreases, but surface oxidation also decreases. In this experiment, the material can be cut to 3mm of cutting depth. And based on the results of the experiment, the laser assisted machining mechanism is clarified.

Laser-Assisted Milling of Turbine Blade Using Five-Axis Hybrid Machine Tool with Laser Module

Wan-Sik Woo,이춘만 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.3

Laser-assisted machining (LAM) is known to be an innovative hybrid technique to enhance the machinability of difficult-to-cut materials. LAM is a method of machining with cutting tools after the machinability is improved by laser preheating. Most studies of LAM have focused mainly on turning methods. Laser-assisted milling (LAMill) processes, including grinding and drilling, are still in the early stages of research and are limited, as the laser heat source must be able to move continuously ahead of the tool. In recent years, some research has concentrated on processing simple three-dimensional (3D) shapes using LAMill, but more innovative research must be done before this method can be commercialized. Therefore, the objective of this study is to manufacture a turbine blade using a five-axis hybrid machine tool with a laser module to make progress toward the goal of the commercialization of LAMill. The manufacturing of the turbine blade using a five-axis LAMill method is attempted for the first time in this study. A thermal analysis was conducted to determine the cutting depth for LAMill. The machining procedure was divided into roughing and finishing steps in order to process the rectangular titanium alloy specimens into a blade shape. The experiments were performed under identical conditions to verify the effectiveness of LAMill compared to CM. The cutting force, surface roughness and hardness were measured and a surface analysis was conducted to compare the machining characteristics after machining.

A study on the machining characteristics of specimens with spherical shape using laser-assisted machining

Kim, I.W.,Lee, C.M. Pergamon ; Elsevier Science Ltd 2016 Applied thermal engineering Vol.100 No.-

Materials such as nickel-based alloys have high strength and excellent resistance to many corrosive environments, and are widely used in various industrial fields, but are difficult to machine using conventional machining. To machine difficult-to-cut materials, thermally enhanced machining (TEM) has been developed internationally. One of the currently applied thermally enhanced machining methods, laser assisted machining (LAM), uses laser preheating to locally soften materials ahead of the cutting tool before machining. There have been no research works by LAM for three-dimensionally shaped specimens. Compared to a plate shape, it is more difficult to predict the optimum LAM preheating temperature for a three-dimensional shape, because with a 3D surface, the shape of the preheated spot changes continuously during machining. In this study, LAM was applied to spherical shaped specimens of three different materials, AISI 1045, Inconel 718 and titanium alloy for three dimensional machining. Before the machining experiments, thermal analysis was carried out by finite element analysis (FEA) to determine the optimum preheating temperature. A contouring machining method was used in the experiments. Cutting force and surface roughness were measured to analyze machining characteristics, and were found to be improved by LAM. These results can be applied to similar machining of difficult-to-cut materials.

레이저 보조선삭 중 주철환봉 내부의 온도분포 예측에 관한 연구

김관우(Kwan-Woo Kim),조해용(Hae-Yong Cho),이제훈(Jae-Hoon Lee),서정(Jeong Suh),신동식(Dong-Sig Shin) 한국레이저가공학회 2010 한국레이저가공학회지 Vol.13 No.2

Laser-assisted machining is dependent on absorbed energy density into workpiece. Generally, the absorptivity of laser beam is dependent on wave length of laser, materials, surface roughness, etc. Various shapes and energy densities for beam irradiation can be used to laser-assisted machining. In this thesis, efficient method of heat source modeling was developed and designed by using one fundamental experimental trials. And then, laser-assisted machining of rod-shaped cast iron was simulated by using commercial FEM code MARC. Simulations and experiments with various conditions were carried out to determine suitable condition of pre-heating for laser-assisted turning process. Temperature distribution of cutting zone could be predicted by simulation

Investigation into the Machining Characteristics of AISI 1045 Steel and Inconel 718 for an Ellipsoidal Shape using Laser-Assisted Contouring and Ramping Machining

김인우,이춘만 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.9

Laser assisted machining (LAM) is a thermally assisted machining (TAM) method that softens difficult-to-cut materials by laser preheating. Laser assisted turning (LAT) is easy to keep the shape of the laser heat source to be circle because the laser heat source is irradiated to the workpiece surface at a fixed position. So, commercial LAT devices have been developed in some countries. However, it is difficult to apply laser assisted milling (LAMill) to three-dimensionally shaped workpieces, because it is not easy to control laser preheating according to the change of workpiece shape. In this study, LAMill was newly applied to two materials having an ellipsoidal shape as a curved 3D example. Effective depth of cut and the optimum preheating temperature were obtained by a transient thermal analysis. Contouring and ramping machining were employed in the experiments. Machining characteristics were investigated by analyzing the cutting force, surface roughness and tool condition, and it has been found that they are enhanced by LAMill. The research results can be used further to processing of other difficult-to-cut materials.

Eco-Friendly Face Milling of Titanium Alloy

Park, Kyung-Hee,Yang, Gi-Dong,Lee, Myung-Gyu,Jeong, Hoon,Lee, Seok-Woo,Lee, Dong Yoon 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.6

Recently, a use of difficult to cut materials including titanium alloy has been substantially increasing in aerospace and automotive industries. Eco-friendly machining technology, which eliminates or minimizes cutting fluids in machining fields, has been emerged in compliance with green manufacturing trend. In this regard, machining technologies, such as hard milling, laser assisted machining (LAM), and enhanced lubrication/cooling method, have been adapted by the industries. Among the technologies, cryogenic machining has been considered for a viable solution for the materials without any environmental problems. LAM and minimum quantity lubrication (MQL) can be useful method to cut these materials with an appropriate use. In this study, machining performance of eco-friendly machining techniques was compared experimentally for the titanium alloy (Ti-6Al-4V). The machining performance was evaluated in terms of tool wear and cutting force. From experimental results, coated cutting tool with flood cooling condition was not recommended in titanium machining. The cryogenic, MQL, LAM showed outstanding machining performance than dry and flood cooling. Especially MQL machining was superior with relatively simple system setup. In addition, lubrication and cooling mechanism by combination of MQL and cryogenic reduced cutting force and tool wear. For energy consumption, MQL and cryogenic methods can be a sustainable solution.

레이저 보조가공을 이용한 Si 광학부품의 초정밀 가공에 관한 연구

김대호(Dae Ho Kim),홍준희(Jun Hee Hong) 한국생산제조학회 2021 한국생산제조학회지 Vol.30 No.5

The performance of optical components is sensitive to the surface roughness; hence, ultra-precision machining technique is significantly important. In this paper, ultra-precision machining and laser-assisted machining was performed; We evaluated them as methods for machining of silicon, an infrared optical component material. Machining brittle material by a diamond turning machine is challenging; laser-assisted machining resolves this issue. For instance, Si is an optical material with superior optical characteristics; however, Si usage is limited due to poor machinability. In contrast, Si can be machined with good surface roughness using laser-assisted machining. We obtained a surface roughness under Ra 10 nm, form accuracy under Pt 250 nm at the found optimal machining condition.

Machining characteristics of micro lens mold in laser-assisted micro-turning

김종수,강봉철 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.4

Laser-assisted machining (LAM) is a type of hybrid material removal process, which is used for locally and instantaneously decreasing the hardness of materials, such as ceramics and hard composites, by irradiating the material with a focused laser during mechanical cutting. LAM, which has been studied primarily for the macro-machining of the hard materials, was applied to the micro-turning process of high hardness steel for a micro-lens mold in this research. The laser-assisted micro-turning (LAμT) process was analyzed using finite element modeling to predict the thermal effects and temperature distributions induced by irradiation of a focused laser and to determine critical cutting parameters, such as spot size, heading distance, and feeds. The effects of the LAμT were verified by an in-situ comparison with conventional micro-turning method, and the cutting conditions were optimized to maximize the cutting performances in terms of cutting force, surface finish, and chip exhaust. Consequently, a lower cutting force and better surface finish was demonstrated compared to the conventional method for the optimized LAμT condition. Therefore, this study showed that the LAμT can be successfully applied to the micro-machining of hard molds.

Laser-assisted machining에서 질화규소 시편의 표면온도와 절삭특성에 관한 연구

임세환,이제훈,신동식,김종도,김주현 한국레이저가공학회 2009 한국레이저가공학회지 Vol.12 No.1

In laser-assisted machining (LAM), laser beam is used to locally increase the temperature of a workpiece and thus to enhance the machinability. In order to set the temperature of the material removal area of a workpiece at an optimal value, process parameters, such as laser power, feed rate, and rotational velocity, have to be carefully controlled. In this work, the effects of laser power and feed rate on the temperature distribution of a silicon nitride rotating at a constant velocity were experimentally investigated. Using a pyrometer, temperatures at various locations of the silicon nitride were measured both in circumferential and axial directions. The measured temperatures were fitted to a quadratic equation to approximate the temperature at the cutting location. The machining results showed that cutting force and tool wear were decreased when the temperature at the cutting location was increased.