Study of the Mechanics of the Micro-Groove Cutting Process

2011 ◽  
Author(s):  
Keith A. Bourne ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor
Keyword(s):  
Thin Film ◽  
High Speed ◽  
Single Point ◽  
Chip Thickness ◽  
Cutting Process ◽  
Burr Formation ◽  
Workpiece Surface ◽  
Process Mechanics ◽  
Exit Burr ◽  
Groove Cutting

In an earlier paper, a high-speed micro-groove cutting process that makes use of a flexible single-point cutting tool was presented. In this paper, 3D finite element modeling of this cutting process is used to better understand process mechanics. The development of the model, including parameter estimation and validation, is described. Validation experiments show that on average the model predicts side burr height to within 2.8%, chip curl radius to within 4.1%, and chip thickness to within 25.4%. The model is used to examine chip formation, side burr formation, exit burr formation, and the potential for delamination of a workpiece consisting of a thin film on a substrate. Side burr formation is shown to primarily occur ahead of a tool and is caused by expansion of material compressed after starting to flow around a tool rather than becoming part of a chip. Exit burr formation is shown to occur when a thin membrane of material forms ahead of a tool and splits into two side segments and one bottom segment as the tool exits a workpiece. Lastly, examination of the stresses below a workpiece surface shows that film delamination can occur when the depth of a groove cut into a thin film is large relative to the film thickness.

Finite Element-Based Study of the Mechanics of Microgroove Cutting

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Keith A. Bourne ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Cutting Tool ◽  
Single Point ◽  
Chip Thickness ◽  
Cutting Process ◽  
Burr Formation ◽  
Process Mechanics ◽  
Exit Burr ◽  
Validation Experiments

In an earlier paper, a high-speed microgroove cutting process that makes use of a flexible single-point cutting tool was presented. In this paper, 3D finite element modeling of this cutting process is used to better understand process mechanics. The development of the model, including parameter estimation and validation, is described. Validation experiments show that on average the model predicts side burr height to within 2.8%, chip curl radius to within 4.1%, and chip thickness to within 25.4%. The model is used to examine chip formation, side burr formation, and exit burr formation. Side burr formation is shown to primarily occur ahead of a tool and is caused by expansion of material compressed after starting to flow around a tool rather than becoming part of a chip. Exit burr formation is shown to occur when a thin membrane of material forms ahead of a tool and splits into two side segments and one bottom segment as the tool exits a workpiece.

scholarly journals Phenomenological Study of Multivariable Effects on Exit Burr Criteria During Orthogonal Cutting of AlSi Alloys Using Principal Components Analysis

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Tristan Régnier ◽  
Guillaume Fromentin ◽  
Alain D'Acunto ◽  
José Outeiro ◽  
Bertrand Marcon ◽  
...  
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
Phenomenological Study ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Cutting Parameters ◽  
Experimental Methodology ◽  
Burr Formation ◽  
Tool Geometry ◽  
Exit Burr

During machining, burrs are produced along a part's edges, which can affect a final product lifetime or its efficiency. Moreover, time-consuming and expensive techniques are needed to be applied to remove such burrs. Therefore, companies attempt to reduce burrs formation during machining by manipulating the cutting conditions. This study aims to analyze and quantify the effect of a wide number of parameters on burr formation, resulting from different mechanisms, during orthogonal cutting of AlSi alloys. A highly developed experimental methodology combining high-speed camera recording, laser scanning, and in situ deburring system is used for this study. A statistical analysis is then applied to evaluate relations between controlled parameters and the occurrence of exit burrs morphologies. The results show that the uncut chip thickness influences burr types distribution along the exit edge and chamfer geometry. Among the cutting parameters and tool geometry, tool rake angle is the main parameter affecting burr height. Finally, it is found that none of the burrs geometrical characteristics ranges are piloted by cutting parameters or tool geometry. The assumption of a possible microstructural influence on these outputs is made.

Ultra High-Speed Micro-Milling of Aluminum Alloy

2015 ◽  
Author(s):  
Said Jahanmir ◽  
Michael J. Tomaszewski ◽  
Hooshang Heshmat
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Micro Milling ◽  
Burr Formation ◽  
Ultra High Speed ◽  
Cut Quality ◽  
Tool Diameter ◽  
Cutting Speeds

Small precision parts with miniaturized features are increasingly used in components such as sensors, micro-medical devices, micro-fuel cells, and others. Mechanical micromachining processes, e.g., turning, drilling, milling and grinding are often used for fabrication of miniaturized components. The small micro-tools (50 μm to 500 μm diameter) used in micromachining limit the surface speeds achieved at the cutting point, unless the rotational speeds are substantially increased. Although the cutting speeds increase to 240 m/min with larger diameter tools (e.g., 500 μm) when using the highest available spindle speed of 150,000 rpm, the cutting speed with the smaller 50 μm tools is limited to 24 m/min. This low cutting speed at the tool tip is much smaller than the speeds required for efficient cutting. For example, in macro-milling of aluminum alloys the recommended speed is on the order of 60–200 m/min. The use of low cutting speeds limits the production rate, increases tool wear and tendency for burr formation, and limits the degree of dimensional tolerance and precision that can be achieved. The purpose of the present paper is to provide preliminary results that show the feasibility of ultra high-speed micro-milling of an aluminum alloy with respect to surface quality and burr formation. A new ultra high-speed spindle was used for micro-milling of an aluminum alloy with micro-end-mills ranging in diameter from 51 μm to 305 μm. Straight channels were machined to obtain an array of square patterns on the surface. High surface cutting speeds up to 340 m/min were achieved at 350,000 rpm. Inspection of the machined surfaces indicated that edge quality and burr formation tendency are related to the undeformed chip thickness, and therefore the cutting speed and feed rate. The quantity of burrs observed on the cut surfaces was generally small, and therefore, the burr types were not systematically determined. Cutting with the 305 μm tool at a cutting speed of 150 m/min produced an excellent cut quality using a chip thickness of 0.13 μm. However, the cut quality deteriorated as the chip thickness was decreased to 0.06 μm by increasing the cutting speed to 340 mm/min. This result is consistent with published data that show the dependence of bur formation on ratio of chip thickness to tool tip radius. The channel widths were also measured and the width of channels cut with the small diameter tools became larger than the tool diameter at higher speeds. The dependence of the channel widths on rotational speed and the fact that a similar variation was not observed for larger diameter tools, suggested that this phenomena is related to dynamic run-out of the tool tip, which increases the channel width at higher speeds.

Finite Element Analysis of Cutting Forces in High Speed Machining

2006 ◽  
Vol 532-533 ◽  
pp. 753-756 ◽  
Author(s):  
Jun Zhao ◽  
Xing Ai ◽  
Zuo Li Li
Keyword(s):  
Finite Element ◽  
Cutting Force ◽  
Cutting Forces ◽  
High Speed ◽  
Fem Simulation ◽  
Chip Thickness ◽  
Cutting Conditions ◽  
Cutting Process ◽  
Undeformed Chip Thickness ◽  
High Speed Cutting

The Finite Element Method (FEM) has proven to be an effective technique to investigate cutting process so as to improve cutting tool design and select optimum cutting conditions. The present work focuses on the FEM simulation of cutting forces in high speed cutting by using an orthogonal cutting model with variant undeformed chip thickness under plane-strain condition to mimic intermittent cutting process such as milling. High speed cutting of 45%C steel using uncoated carbide tools are simulated as the application of the proposed model. The updated Lagrangian formulation is adopted in the dynamic FEM simulation in which the normalized Cockroft and Latham damage criterion is used as the ductile fracture criterion. The simulation results of cutting force components under different cutting conditions show that both the thrust cutting force and the tangential cutting force increase with the increase in undeformed chip thickness or feed rate, whereas decrease with the increase in cutting speed. Some important aspects of modeling the high speed cutting are discussed as well to expect the future work in FEM simulation.

A Study of Exit-Burr Formation Mechanism Using the Finite Element Method in Micro-Cutting of Aluminum Alloy

2008 ◽  
Vol 375-376 ◽  
pp. 470-473 ◽  
Author(s):  
Dong Lu ◽  
Jian Feng Li ◽  
Yi Ming Rong ◽  
Jie Sun ◽  
Jun Zhou ◽  
...  
Keyword(s):  
Cutting Speed ◽  
Chip Thickness ◽  
Burr Formation ◽  
Uncut Chip Thickness ◽  
Micro Cutting ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Tool Edge ◽  
Speed Effect ◽  
Exit Burr

A burr formation process in micro-cutting of Al7075-T7451 was analyzed. Three stages of burr formation including steady-state cutting stage, pivoting stage, and burr formation stage are investigated. And the effects of uncut chip thickness, cutting speed and tool edge radius on the burr formation are studied. The simulation results show that the generation of negative shear zone is one of the prime reasons for burr formation. Uncut chip thickness has a significant effect on burr height; however, the cutting speed effect is minor. Unlike in conventional cutting, in micro-cutting the effect of tool edge radius on the burr geometry can no longer be neglected.

Experimental Research on Microburrs of High Speed Drilling of PCB Using Microdrill

2012 ◽  
Vol 497 ◽  
pp. 215-219 ◽  
Author(s):  
Xiao Hu Zheng ◽  
Zhi Qiang Liu ◽  
Cheng Yong Wang ◽  
Qing Long An ◽  
Ming Chen
Keyword(s):  
High Speed ◽  
Copper Foil ◽  
Great Influence ◽  
Burr Formation ◽  
Drilling Process ◽  
Fiber Plastic ◽  
High Speed Drilling ◽  
Micro Hole ◽  
Three Stages ◽  
Exit Burr

Microburrs have great influence on printed circuit board’s quality. PCB is composed of glass fiber plastic reinforcement material and copper foil. The PCB microburrs are generated in copper foil drilling process. These burrs are generated by copper extrusion and accumulation around the micro-hole. Enter burr and exit burr is quite different. Enter burrs are lower than exit burrs. The burr formation experienced three stages: First, Copper foil extrudes with the feed of microdrill; Second, Most of the Materials are cut off by drill tip and the rest of material; At last, rollover burrs appear when drill enters or exits uncut chip rolls.

scholarly journals Study on the Cutting Efficiency of High-Speed Band Saw Blade by Taylor Tool Life and Fractal Equations

2018 ◽  
Vol 201 ◽  
pp. 01001 ◽  
Author(s):  
Sung-Hua Wu ◽  
Ming-Shyan Huang ◽  
Cheng-En Jhou ◽  
Chin-Chung Wei
Keyword(s):  
Tool Life ◽  
Chip Formation ◽  
High Speed ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Local Stress ◽  
Cutting Process ◽  
Cutting Efficiency ◽  
Improvement Rate ◽  
Sawing Process

The study proposed the chip formation steady-state model and cutting efficiency model for multi-cutters by Taylor tool life and fractal equation according to uniform chip thickness in high-speed band sawing process. Furthermore, a kind of new hook-tooth can be successfully applied on continuously uniformed chip formation in order to raise the production precision. The study developed MDOF cutting dynamics, which can be applied on multi-cutting process by Taylor tool life and fractal equations. Factors of affecting band-sawing included the cutting force, the cutting geometry, the cutting heat, the local stress-strain and the chip thickness formation uniformity. These factors had an important influence on tool wear, surface roughness, production precision and cutting efficiency in high-speed sawing process. The simulated results shown that, the wear resistance property is better at coating TiN 0.6 μm. In high-speed cutting process, the cutting improvement rate can be increased at least 13%. While the hook-tooth cutting speed achieved 120 m/min, comparing with non-coating cutting tooth, coating 0.6μm coating-layer can make the temperature decreased, obviously.

Improving Formability in SPIF Processes through High Speed Rotating Tool: Experimental and Numerical Analysis

2013 ◽  
Vol 549 ◽  
pp. 156-163 ◽  
Author(s):  
Gianluca Buffa ◽  
Davide Campanella ◽  
Rossano Mirabile ◽  
Livan Fratini
Keyword(s):  
High Speed ◽  
Single Point ◽  
Sheet Forming ◽  
Effect Of Temperature ◽  
Cnc Machine ◽  
Forming Process ◽  
New Approach ◽  
Process Mechanics ◽  
Forming Angle ◽  
Complex Parts

Single-point incremental forming (SPIF) is a quite new sheet-forming process which offers the possibility to deform complex parts without dedicated dies using a single-point tool and a standard three-axis CNC machine. Although the process mechanics enables higher strains with respect to traditional sheet-forming processes, research has been focused on further increasing the maximum forming angle. In the paper, a new approach is used to enhance the material formability through a localized sheet heating as a consequence of the friction work caused by high speed rotating tool. Numerical simulation was utilized to relate the effect of temperature with the main field variables distribution in the sheet.

scholarly journals Evaluating Hole Quality in Drilling of Al 6061 Alloys

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2443 ◽  
Author(s):  
Mohammad Uddin ◽  
Animesh Basak ◽  
Alokesh Pramanik ◽  
Sunpreet Singh ◽  
Grzegorz M. Krolczyk ◽  
...  
Keyword(s):  
High Speed ◽  
Removal Rate ◽  
Chip Thickness ◽  
High Speed Steel ◽  
Spindle Speed ◽  
Burr Formation ◽  
Dominant Factor ◽  
Hole Quality ◽  
Maximum Increase ◽  
Dimensional Error

Hole quality in drilling is considered a precursor for reliable and secure component assembly, ensuring product integrity and functioning service life. This paper aims to evaluate the influence of the key process parameters on drilling performance. A series of drilling tests with new TiN-coated high speed steel (HSS) bits are performed, while thrust force and torque are measured with the aid of an in-house built force dynamometer. The effect of process mechanics on hole quality, e.g., dimensional accuracy, burr formation, surface finish, is evaluated in relation to drill-bit wear and chip formation mechanism. Experimental results indicate that the feedrate which dictates the uncut chip thickness and material removal rate is the most dominant factor, significantly impacting force and hole quality. For a given spindle speed range, maximum increase of axial force and torque is 44.94% and 47.65%, respectively, when feedrate increases from 0.04 mm/rev to 0.08 mm/rev. Stable, jerk-free cutting at feedrate of as low as 0.04 mm/rev is shown to result in hole dimensional error of less than 2%. A low feedrate along with high spindle speed may be preferred. The underlying tool wear mechanism and progression needs to be taken into account when drilling a large number of holes. The findings of the paper clearly signify the importance and choice of drilling parameters and provide guidelines for manufacturing industries to enhance a part’s dimensional integrity and productivity.

scholarly journals Numerical Modeling the Effects of Chamfer and Hone Cutting Edge Geometries on Burr Formation

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Numerical Model ◽  
High Speed ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Cutting Edge ◽  
Machining Process ◽  
Burr Formation ◽  
Machining Processes ◽  
Tool Edge ◽  
Exit Burr

A finite element based numerical model to simulate orthogonal machining process and associated burr formation process has been developed in the presented work. To incorporate simultaneous effects of mechanical and thermal loadings in high speed machining processes, Johnson and Cook`s thermo-visco-plastic flow stress model has been adopted in the conceived numerical model. A coupled damage-fracture energy approach has been used to observe damage evolution in workpiece and to serve as chip separation criterion. Simulation results concerning chip morphology, nodal temperatures, cutting forces and end (exit) burr have been recorded. Model has been validated by comparing chip morphology and cutting force results with experimental findings in the published literature. Effects of cutting edge geometries [Hone and Chamfer (T-land)] on burr formation have been investigated thoroughly and discussed in length. To propose optimum tool edge geometries for reduced burr formation in machining of an aerospace grade aluminum alloy AA2024, numerical analyses considering multiple combinations of cutting speed (two variations), feed (two variations) and tool edge geometries [Hone edge (two variations), Chamfer edge (four variations)] have been performed. For chamfer cutting edge, the “chamfer length” has been identified as the most influential macro geometrical parameter in enhancing the burr formation. Conversely, “chamfer angle” variation has been found least effecting the burr generation phenomenon.

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