Laser milling: Modelling crater and surface formation

2006 ◽  
Vol 220 (11) ◽  
pp. 1685-1696 ◽  
Author(s):  
T Dobrev ◽  
S S Dimov ◽  
A J Thomas
Keyword(s):  
Numerical Technique ◽  
Target Material ◽  
Milling Process ◽  
Laser Material ◽  
Surface Formation ◽  
Laser Ablation Process ◽  
Laser Milling ◽  
Change Of State ◽  
Machining Strategies ◽  
Physical Phenomena

In pulsed laser-material removal systems, it is very important to understand the physical phenomena that take place during the laser ablation process. A two-dimensional, theoretical model is developed to investigate the crater formation on a metal target by a microsecond laser pulse. The model takes into account the absorption of the laser light and heating and vapourization of the target, including an adjustment to compensate for the change of state. A simple numerical technique is employed to describe the major physical processes taking part in the laser milling process. The temperature distribution in the target material during the pulse duration is analysed. The effect of the laser fluence on the resulting crater is investigated in detail. The proposed simulation model was validated experimentally for laser-material interactions between a microsecond Nd:YAG laser (λ = 1064 nm) and two different tooling materials. The measured crater depths are in agreement with the model. In addition, an analytical approach is discussed for studying the effects of crater profiles and different machining strategies on the surface formation and the resulting surface quality during the laser milling process. This approach can be employed as a tool for optimizing the process and thus broaden its use in a range of microstructuring applications. The research reported in this paper contributes to a better understanding of microstructuring capabilities of the laser milling process.

Characteristics of Nanopatterns and the Associated Thermal Mechanisms During Near Field Laser-Material Interaction of Nanosecond Laser on Different Targets

2009 ◽  
Author(s):  
Vijay M. Sundaram ◽  
Sy-Bor Wen
Keyword(s):  
Near Field ◽  
Target Material ◽  
Optical Microscope ◽  
Laser Source ◽  
Nanosecond Laser ◽  
Metallic Surfaces ◽  
Experimental Conditions ◽  
Laser Material ◽  
Material Conditions ◽  
Material Interaction

Nano-patterns are generated on semiconducting and metallic surfaces through coupling an apertured near field scanning optical microscope (NSOM) with a pulsed laser source in this study. To understand the dominant mechanisms for the generation of the nano-patterns, a series of experimental measurement of the size and shape of nano-patterns generated on targets under different experimental conditions with different targets is conducted. The characteristic dimensions of nano-patterns show dependence on optical properties of the target material. The qualitative trend of the variation of nano-patterns as a function of laser and material conditions indicates that the dominant mechanisms for the generation of nano-patterns through a combination of nanosecond laser and an apertured NSOM under different conditions studied is near field laser-material interaction.

Optimization Based Geometric Modeling of Nano/Micro Scale Ion Milling of Organic Materials

2009 ◽  
Author(s):  
Jing Fu ◽  
Sanjay B. Joshi
Keyword(s):  
Geometric Modeling ◽  
Focused Ion Beam ◽  
Organic Materials ◽  
Ion Beam ◽  
Target Material ◽  
Milling Process ◽  
Ion Milling ◽  
Flexible Tool ◽  
Water Ice ◽  
Micro Scale

Recently, Focused Ion Beam (FIB) instruments have begun be applied to organic materials such as polymers and biological systems. This provides a novel tool for sectioning biological samples for analysis, or microfabrication with environment friendly materials. The modeling of nano/micro scale geometry accurately sculptured by FIB milling is crucial for generating the milling plan and process control, and for computer simulation for prediction and visualization of the milled geometry. However, modeling of the ion milling process on compound materials, especially for high aspect ratio feature, is still difficult due to the complexity of target material, as well as multiple physical and chemical interactions involved. In this study, a comprehensive model of ion milling with organic targets is presented to address the challenges using a simulation based approach. This platform has also been validated by milling different features on water ice in a cryogenic environment, and the simulation and experiment results show great consistency. With the proliferation of nanotechnology to biomedical and biomaterial domains, the proposed approach is expected to be a flexible tool for various applications involving novel and heterogeneous milling targets.

An Experimental Investigation of the Laser Milling Process for Polycrystalline Diamonds

2011 ◽  
Vol 291-294 ◽  
pp. 810-815 ◽  
Author(s):  
Qi Wu ◽  
Jun Wang
Keyword(s):  
Surface Roughness ◽  
Surface Finish ◽  
Polycrystalline Diamond ◽  
Milling Process ◽  
Depth Of Cut ◽  
Good Surface ◽  
Laser Milling ◽  
Cavity Profile ◽  
Profile Depth ◽  
Good Surface Finish

An experimental study of the pulsed laser milling process for a sintered polycrystalline diamond is presented. The characteristics and quality of the cavities machined with a Yd laser under different pulse energies, pulse overlaps, scan overlaps and numbers of passes are discussed, together with the effects of these parameters on the cavity profile, depth of cut and surface roughness. A statistical analysis is also presented to study the relationship between the process parameters and surface roughness. It shows that the optimum pulse overlap and pulse energy may be used to achieve good surface finish, whereas scan overlap and number of passes can be selected to improve the depth of cut without much effect on the surface finish.

Automatic Characterization of the Material Removal Rate in Laser Manufacturing of TiAl6V4 and Inconel 718

2009 ◽  
Author(s):  
Leonardo Orazi ◽  
Gabriele Cuccolini ◽  
Giovanni Tani
Keyword(s):  
Material Removal Rate ◽  
Inconel 718 ◽  
Material Removal ◽  
Numerical Models ◽  
Removal Rate ◽  
Industrial Applications ◽  
Milling Process ◽  
Laser Source ◽  
Automated Method ◽  
Laser Milling

In this paper a system for the automatic determination of the material removal rate during laser milling process is presented. “Laser milling” can be defined as an engraving process with a strictly controlled penetration depth. In industrial applications, when a new material have to be machined or a change in the system set-up occur the user has to perform a time-consuming experimental campaign in order to determine the correlation between the material removal rate and the process parameters. In these cases the numerical models present some limits due to the elevated calculation time requested to simulate the laser milling of industrial features. In the proposed system, based on a regression model approach, the empirical coefficients, that provide the material removal rate, are automatically generated by a specific software according to the different materials that have to be processed. A description of the automated method and the results obtained in engraving TiAl6V4 and Inconel 718 superalloy with a fiber laser are presented. The system can be adapted to every combination of material/laser source.

Dynamic Simulation of the Micro-Milling Process Including Minimum Chip Thickness and Size Effect

2012 ◽  
Vol 504-506 ◽  
pp. 1269-1274 ◽  
Author(s):  
François Ducobu ◽  
Edouard Rivière-Lorphèvre ◽  
Enrico Filippi
Keyword(s):  
Size Effect ◽  
Cutting Forces ◽  
Mechanistic Model ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Milling Process ◽  
Cutting Conditions ◽  
Micro Milling ◽  
Minimum Chip Thickness ◽  
Physical Phenomena

Micro-milling with a cutting tool is a manufacturing technique that allows production of parts ranging from several millimeters to several micrometers. The technique is based on a downscaling of macroscopic milling process. Micro-milling is one of the most effective process to produce complex three-dimensional micro-parts, including sharp edges and with a good surface quality. Reducing the dimensions of the cutter and the cutting conditions requires taking into account physical phenomena that can be neglected in macro-milling. These phenomena include a size effect (nonlinear rising of specific cutting force when chip thickness decreases), the minimum chip thickness (under a given dimension, no chip can be machined) and the heterogeneity of the material (the size of the grains composing the material is significant as compared to the dimension of the chip). The aim of this paper is to introduce some phenomena, appearing in micromilling, in the mechanistic dynamic simulation software ‘dystamill’ developed for macro-milling. The software is able to simulate the cutting forces, the dynamic behavior of the tool and the workpiece and the kinematic surface finish in 2D1/2 milling operation (slotting, face milling, shoulder milling,…). It can be used to predict chatter-free cutting condition for example. The mechanistic model of the cutting forces is deduced from the local FEM simulation of orthogonal cutting. This FEM model uses the commercial software ABAQUS and is able to simulate chip formation and cutting forces in an orthogonal cutting test. This model is able to reproduce physical phenomena in macro cutting conditions (including segmented chip) as well as specific phenomena in micro cutting conditions (minimum chip thickness and size effect). The minimum chip thickness is also taken into account by the global model. The results of simulation for the machining of titanium alloy Ti6Al4V under macro and micro milling condition with the mechanistic model are presented discussed. This approach connects together local machining simulation and global models.

Producing Three-Dimensional Shapes by Laser Milling

1990 ◽  
Vol 112 (4) ◽  
pp. 375-379 ◽  
Author(s):  
R. K. C. Hsu ◽  
S. M. Copley
Keyword(s):  
Carbon Dioxide ◽  
Laser Beam ◽  
Carbon Dioxide Laser ◽  
Three Dimensional ◽  
Milling Process ◽  
Model Material ◽  
Layer Plane ◽  
Uniform Thickness ◽  
Laser Milling ◽  
Focused Beam

A laser milling process employing a pulsed, carbon dioxide laser has been investigated using graphite as a model material. Material is removed by scanning the focused beam across the surface of the workpiece leaving behind a series of narrow, parallel, overlapping grooves. These grooves, together, constitute the removal of a thin layer of uniform thickness lying parallel to a layer plane. In order to remove layers bounded at the edge by upright walls perpendicular to the layer plane, the laser beam must be tilted with respect to the layer plane. Using this approach, it is possible to produce perpendicular steps and cylindrical surfaces.

scholarly journals The Correlation between Ion Beam/Material Interactions and Practical FIB Specimen Preparation

2003 ◽  
Vol 9 (3) ◽  
pp. 216-236 ◽  
Author(s):  
B.I. Prenitzer ◽  
C.A. Urbanik-Shannon ◽  
L.A. Giannuzzi ◽  
S.R. Brown ◽  
R.B. Irwin ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Target Material ◽  
Beam Current ◽  
Milling Process ◽  
Specimen Preparation ◽  
Analytical Instrument ◽  
Simulation Code ◽  
Raster Pattern

The focused ion beam (FIB) tool has been successfully used as both a stand alone analytical instrument and a means to prepare specimens for subsequent analysis by SEM, TEM, SIMS, XPS, and AUGER. In this work, special emphasis is given to TEM specimen preparation by the FIB lift-out technique. The fundamental ion/solid interactions that govern the FIB milling process are examined and discussed with respect to the preparation of electron transparent membranes. TRIM, a Monte Carlo simulation code, is used to physically model variables that influence FIB sputtering behavior. The results of such computer generated models are compared with empirical observations in a number of materials processed with an FEI 611 FIB workstation. The roles of incident ion attack angle, beam current, trench geometry, raster pattern, and target-material-dependent removal rates are considered. These interrelationships are used to explain observed phenomena and predict expected milling behaviors, thus increasing the potential for the FIB to be used more efficiently with reproducible results.

3-D Modelling of Laser Ablation of Metals in Mould Manufacturing

2006 ◽  
Author(s):  
Giovanni Tani ◽  
Leonardo Orazi ◽  
Alessandro Fortunato ◽  
Gabriele Cuccolini
Keyword(s):  
Laser Ablation ◽  
Numerical Model ◽  
Physical State ◽  
Plasma Plume ◽  
Original Model ◽  
Work Piece ◽  
Heat Distribution ◽  
Liquid Front ◽  
Laser Milling ◽  
Physical Phenomena

An original model for laser milling characterization is presented in this paper. A 3-D numerical model able to simulate the physical phenomena involved in laser ablation of metals was developed where the heat distribution in the work piece, the prediction of velocity of the vapour/liquid front and the physical state of the plasma plume were taken into account. The numerical model was implemented in C++ and an overview of the code capacities is presented.

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