Zazuli Mohid

Laser Assisted Machining of Titanium Alloys

Laser assisted machining is categorized in preheat machining process. The laser beam used to heat up work materials is very flexible in providing a localized heat area. However the combination between two processes which has totally different fundamental has contributed to complex processing characteristics. In the case of hard to machined metal processing, problems in surface integrity and accuracy are frequently arise. Tool ware and work material properties changes are some of the issue that drove engineers and researchers to seek for optimized processing parameters. This chapter introduces resent finding in research done on laser assisted machining (LAM). Focus is given on laser assisted mechanical machining consist of laser assisted milling (LAM) and laser assisted turning (LAT).

Thermal-Assisted Machining of Nickel-based Alloy

Nickel-based alloy can be found in different industrial applications especially in aircraft engines and hot end components of various types of gas turbines with its high strength, strong corrosion resistance and excellent thermal fatigue properties and thermal stability compared to conventional materials. However, nickel-based alloy is one of the extremely difficult-to-cut materials. During the machining process, the interaction between the tool and the workpiece causes severe plastic deformation and intense friction at the tool-workpiece interface. Because of the increasing demands in industries, any improvement of conventional machining processes or any other deployment of additional technique is directly related to higher productivity. Thermal-assisted machining (TAM) has become an effective alternative to the conventional machining of these difficult-to-cut materials. Various types of heating methods and the beneficial effects on machining of nickel-based alloys are discussed in this chapter. Finally, TAM was proven as an efficient technique to increase the machinability of nickel-based alloys in terms of tool life, surface roughness and cutting force.

Numerical Analysis of Laser Heating for Laser Assisted Micro Milling Application

The promising processing techniques of micro scale parts are very important in products miniaturization and functions enhancement. Combination of two or more processing techniques gives better processing performance especially when dealing with difficult-to-cut materials. For that reason, the combination of laser beam and micro milling process has been widely studied and proven efficient in reducing cutting force and tool life extension. However, this process needs a precise temperature control in order to eliminate heat effect generated by laser beam irradiation. In this study, temperature distributions are determined numerically to characterize the melted zone and heat affected zone geometry. From the results, the estimation of tool and micro milling cutter distance together with the allowable depth of cut are determined.

Numerical analysis of laser preheating for laser assisted micro milling of Inconel 718

Micro milling of super alloy materials such as nickel based alloys such as Inconel 718 is challenging due to the excellent of its mechanical properties. Therefore, new techniques have been suggested to enhance the machinability of nickel based alloys by pre-heating the workpiece’s surface to reduce its strength and ductility. The prediction of fluctuated temperature distribution generated by pulsed wave laser in laser assisted micro milling (LAMM) is crucial. The selection of processing parameter by minimize the effect on the processing characteristic is decisive to ensure the machining quality is high. Determining the effect of heat generated in underneath surface is important to make sure that the cutting tools are able to cut the material with maximum depth of cut and minimum defects in terms of tool wear and tool life. In this study the simulation was carried by using Ansys APDL. In order to confirm the actual and distribution irradiation of temperature from simulation, an experimental was done to validate the results. The experiment was conducted by using Nd:YAG laser with wavelength 1064 nm.

Dissimilar Materials Laser Welding Characteristics of Stainless Steel and Titanium Alloy

Welding parameters are directly influenced by the work material properties. Thermal properties such as thermal conductivity and melting point are very important to estimate the range of power required and the allowable scanning speed. However, when two or more different materials are involved, modifying lasing parameters are not enough to counter the problems such as imbalance melting region and weak adhesion of contact surface. To counter this problem, the characteristics of welding beads formation for both materials need to be clarified. In this study, comparison of welding beads constructed using the same scanning parameters were done to understand the different and similarity of melted region for the both materials. Actual welding of the both materials were done under different offset distance to obtain a balanced melting area and well mixed melting region.

Effect of GMAW-CMT heat input on weld bead profile geometry for freeform fabrication of aluminium parts

In developing a new method for weld based freeform fabrication, parameter affecting the geometry of single-pass need to be determined as it has great influence on dimensional accuracy and mechanical property of metallic part. In this paper, profile geometry and microstructure of single pass weld bead developed using Gas Metal Arc Welding Cold Metal Transfer (GMAW-CMT) was investigated. Observation on cross sectional weld bead indicates GMAW-CMT has capability to produce free spatter and crack defect weld bead. Profile geometry measurement shows weld bead develop at higher heat input has width size larger than the weld bead develop at lower heat input. Microstructure examination in the substrate reveals formation of columnar dendritic, cellular and planar structure while at buildup layer exhibit equiaxed dendritic structure

Tribological evaluation on various formulation of modified rbd palm olein as sustainable metalworking fluids for machining process

Sustainable manufacturing has become popular among manufacturers and industrialists due to the increase in environmental issues, health impacts and stringent law enforcement. The use of vegetable oils as metalworking fluids is one way to implement manufacturing sustainability. Palm oils are commonly used as cooking oils. Further, palm oil is also the main oil sources in Southeast Asia besides petroleum. Therefore, the potential use of palm oil as functional lubricant for future replacement of petroleum-based oil is indeed important. In this study, the refined, bleached and deodorized (RBD) palm olein has been formulated into various properties of modified RBD palm oil (MRPO) by transesterification process at different molar ratio of RBD methyl ester (FAME) with trimethylolpropane (TMP). Next, the MRPOs are compared with synthetic ester on lubrication and tribology tests according to standard based on American Society for Testing and Materials (ASTM). The results observed that MRPO have outstanding performance in lubrication and tribological behavior. MRPO2 recorded the highest viscosity index and the lowest coefficient of friction which are 496 and 0.06, respectively. MRPO2 showed to be an alternative biodegradable cutting fluid in promoting sustainable manufacturing activities by reducing the bad impact on environment and health.

Investigation on Laser Assisted Micro Ball Milling of Inconel 718

Micro milling of super alloy materials such as nickel based alloys is challenging due to the excellent of its mechanical properties. Therefore, new techniques have been suggested to enhance the machinability of nickel based alloys by pre-heating the workpiece’s surface to reduce its strength. Determining the processing parameters and their effects to the processing characteristics are crucially important. However, not only the micro-milling parameters need to be considered, but the pre-heating parameters are also need to take into consideration as well. These parameters are expected to improve the machinability. In this study, the experiment of LAMM in Inconel 718 was conducted with considering laser power, cutting speed, depth of cut, feed rate and laser-to-cutting tool distance. From the result, the effectiveness of laser assisted and cutting parameter in term of cutting force and tool wear was identified by comparing between conventional and LAMM. Finally, the optimum range of machining parameters can be determined.

Laser Assisted Micro-Groove Ball Milling of Ti6Al4V

In micro scale, the size of cutting tool and shape significantly contributed to the machining performance. Many studies have been done to improve the cutting tool life and machined surface quality. Problems could become more severe when the workpiece has a low thermal conductivity while having high level of ductility such as titanium alloy. In this study, micro ball mill cutting tool is selected to produce a linear groove on a titanium alloy plate. The process is integrated with a laser source as a pre-heating element on the work piece surface. The condition of the flank surface of the tools and cutting force were observed and discussed. The influence of tool orientation and laser heating parameters in laser assisted micro ball milling (LAMM) were also discussed. It was found out that adhesion is the dominant tool wear mechanism thus fluctuate the cutting force value.

Determination of Heat Flux Intensity Distribution and Laser Absorption Rate of AISI D2 Tool Steel

The prediction of fluctuated temperature distribution generated by pulsed wave laser in laser assisted micro milling (LAMM) is crucial. The selection of processing parameter by minimize the effect on the processing characteristic is decisive to ensure the machining quality is high. Determining the effect of heat generated in underneath surface is important to make sure that the cutting tools are able to cut the material with maximum depth of cut and minimum defects in term of tool wear and tool life. In this study the simulation was carried by using Ansys APDL. In order to confirm the actual and distribution irradiation of temperature from simulation, an experimental was done to validate the results. The experiment was conducted by using Nd:YAG laser with wavelength 1064 nm.