Effect of side edge angle and effective rake angle on top burrs in micro-milling

2012 ◽  
Vol 36 (3) ◽  
pp. 444-450 ◽  
Author(s):  
Kushendarsyah Saptaji ◽  
Sathyan Subbiah ◽  
Jaspreet Singh Dhupia
Keyword(s):  
Rake Angle ◽  
Micro Milling ◽  
Edge Angle ◽  
Side Edge ◽  
Effective Rake Angle

Impact of Spindle Speed on Micro-Milling Stability

2012 ◽  
Author(s):  
Eric B. Halfmann ◽  
C. Steve Suh
Keyword(s):  
Slip Line ◽  
Chip Thickness ◽  
Rake Angle ◽  
Micro Milling ◽  
Work Piece ◽  
Formation Mechanisms ◽  
Lumped Mass ◽  
Effective Rake Angle ◽  
Helical Angle ◽  
Force Mechanism

Milling efficiency is hampered by excessive tool vibrations that negatively impact the work-piece quality. This is more of a concern in micro-milling where sudden tool breakage occurs before the operator can adjust cutting parameters. Due to different chip formation mechanisms in micro-milling, an increased tool-radius to feed-rate ratio, and higher spindle speeds, micro-milling is a highly non-linear process which can produce multiple and broadband frequencies which increase the probability of tool failure. Micro-milling is studied through the development and analysis of a 3-D nonlinear micro-milling dynamic model. A lumped mass, spring, damper system is assumed for modeling the dynamic properties of the tool. The force mechanism utilized is a slip-line field model that provides the advantages of being highly dynamic by accounting for the constantly changing effective rake angle and slip-line variables. Accurate prediction of the chip thickness is important in correctly predicting the dynamics of the system since the force mechanism and its variables are a function of the chip thickness. A novel approach for calculating the instantaneous chip thickness which accounts for the tool jumping out of the cut and elastic recovery of the work-piece is presented. The effective rake angle and helical angle is accounted for resulting in a 3-D micro-milling model. The model is shown to resolve the high frequency force components that are seen in experimental data available in literature. Also, exciting the system at various spindle speeds results in dynamic states of motion that negatively impact the process through increased vibration amplitude and a broad frequency bandwidth.

scholarly journals Experimental Study on the Minimum Undeformed Chip Thickness Based on Effective Rake Angle in Micro Milling

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 924
Author(s):  
Xian Wu ◽  
Li Liu ◽  
Mingyang Du ◽  
Jianyun Shen ◽  
Feng Jiang ◽  
...  
Keyword(s):  
Averaging Method ◽  
Chip Thickness ◽  
Rake Angle ◽  
Cutting Process ◽  
Micro Milling ◽  
Undeformed Chip Thickness ◽  
Effective Rake Angle ◽  
Force Signal ◽  
Micro Parts ◽  
Tool Cutting

Micro milling is widely used to manufacture micro parts due to its obvious advantages. The minimum undeformed chip thickness, the effective rake angle, and size effect are the typical characteristics and closely related to each other in micro milling. In this paper, the averaging method is proposed to quantitatively estimate the effective rake angle in the cutting process. The minimum undeformed chip thickness is explained based on the effective rake angle and determined to be 0.17 rn (tool cutting edge radius). Then, micro milling experiment was conducted to study the effect of the minimum undeformed chip thickness. It is found that the minimum undeformed chip thickness results in the unstable cutting process, the uneven peaks on cutting force signal, and the dense characteristic frequency distribution on frequency domain signal. The dominant ploughing effect induces the great specific cutting energy and the deteriorated surface roughness due to the minimum undeformed chip thickness.

High Speed Non-Linear Micro-Milling Dynamics

2012 ◽  
Author(s):  
Eric B. Halfmann ◽  
C. Steve Suh
Keyword(s):  
Slip Line ◽  
Chip Thickness ◽  
Rake Angle ◽  
Micro Milling ◽  
Work Piece ◽  
Formation Mechanisms ◽  
Effective Rake Angle ◽  
Non Linear ◽  
Force Mechanism ◽  
Milling Dynamics

The efficiency of the milling process is limited due to excessive vibrations that negatively impact the tool and work-piece quality. This becomes even more of a concern in micro-milling where sudden tool breakage occurs before the operator can adjust cutting parameters. Due to different chip formation mechanisms in micro-milling, an increased tool-radius to feed-rate ratio, and higher spindle speeds, micro-milling is a highly non-linear process which can produce multiple and broadband frequencies which increase the probability of tool failure. This paper investigates micro-milling through the development and analysis of a 3-D nonlinear micro-milling dynamic model. A lumped mass, spring, damper system is assumed for modeling the dynamic properties of the tool. The force mechanism utilized is a slip-line field model that provides the advantages of being highly dynamic by accounting for the constantly changing effective rake angle and slip-line variables. Accurate prediction of the chip thickness is important in correctly predicting the dynamics of the system since the force mechanism and its variables are a function of the chip thickness. A novel approach for calculating the instantaneous chip thickness which accounts for the tool jumping out of the cut and elastic recovery of the work-piece is presented. The derivation for the effective rake angle is given and the helical angle is accounted for resulting in a 3-D micro-milling model. The results of simulating the model demonstrate its capability of producing the high frequency force components that are seen in experimental data available in literature. The advantages of using this approach over the constant empirical force coefficient approach when studying micro-milling dynamics is discussed and the instability of the system is investigated utilizing instantaneous frequency.

Study on Machining Mechanism of Glass Using Discrete Element Method

2014 ◽  
Vol 577 ◽  
pp. 108-111 ◽  
Author(s):  
Ying Qiu ◽  
Mei Lin Gu ◽  
Feng Guang Zhang ◽  
Zhi Wei
Keyword(s):  
Discrete Element Method ◽  
Element Model ◽  
Discrete Element ◽  
Rake Angle ◽  
Milling Process ◽  
Micro Milling ◽  
Discrete Element Model ◽  
Machined Surface ◽  
Damage Depth ◽  
Element Method

The discrete element method (DEM) is applied to glass micromachining in this study. By three standard tests the discrete element model is established to match the main mechanical properties of glass. Then, indentating, cutting, micro milling process are simulated. Results show that the vertical damage depth is prevented from reaching the final machined surface in cutting process. Tool rake angle is the most remarkable factor influencing on the chip deformation and cutting force. The final machined surface is determined by the minimum cutting thickness per edge. Different cutting thickness, cutter shape and spindle speed largely effect on the mechanism of glass.

scholarly journals Microstructure-Based 3D FE Modeling for Micro Cutting Ferritic-Pearlitic Carbon Steels

2014 ◽  
Author(s):  
M. Abouridouane ◽  
F. Klocke ◽  
D. Lung
Keyword(s):  
Size Effects ◽  
Chip Thickness ◽  
Rake Angle ◽  
Carbon Steels ◽  
Micro Milling ◽  
Fe Model ◽  
Two Phase ◽  
Workpiece Material ◽  
Micro Cutting ◽  
Feed Force

The mechanics of the cutting process on the microscopic level differ fundamentally from the conventional macro cutting. For example, the tool edge radius influences the cutting mechanism in micro machining significantly with regard to the effective rake angle, the minimum chip thickness, the dominance of ploughing, and the related elasto-plastic deformation of the workpiece material. These phenomena, known as size effects, have a profound impact on the cutting force, process stability, and resulting surface finish in micro cutting. Therefore, microstructural effects in microscale cutting require quite different assumptions to be made concerning underlying material behaviour during micro cutting and have led to the need for new modeling approaches to account for such effects. This paper presents a three-dimensional finite element approach to incorporate microstructure into micro cutting simulation based on the concept of a representative volume element (RVE) and constitutive material modeling as well as using the Lagrangian formulation proposed in the implicit FE code Deform 3D™. Micro drilling and micro milling tests using solid carbide tools with different diameters (d = 50 μm − 1 mm) were performed on ferrite-pearlite two-phase steel AISI 1045 for the verification of the developed 3D multiphase FE computation model regarding chip formation, feed force, and torque. The developed 3D multiphase FE model was successfully used to predict size effects in micro cutting.

The Effect of Cut Tool Geometric Parameters on Tool Tear of Machining Nickel-Base GH4169 Super Alloys

2010 ◽  
Vol 37-38 ◽  
pp. 1457-1461 ◽  
Author(s):  
Zhao Peng Hao ◽  
D. Gao ◽  
R.D. Han
Keyword(s):  
Tool Life ◽  
Cutting Speed ◽  
High Strength ◽  
Rake Angle ◽  
Geometric Parameters ◽  
Cutting Edge ◽  
Factors Affecting ◽  
Edge Angle ◽  
Coated Tools ◽  
Nickel Base

Nickel-based super alloy GH4169 has been widely used in aerospace industry because of its good mechanical properties under high temperature. However, it is difficult to machine for its high strength, poor thermal conductivity and serious work-hardening. The effects of tool geometric parameters on tool life are studied by machining experiments using YG8 tools with different cutting edge angle in this paper. The tool with cutting edge angle 45°has longer tool life than 75°. The cutting experiments have been carried out using TiAlN (PVD) coated tools (AC520U) with different rake angle. It shows that the tool life with rake angle 9° were increased by 50% and 25% compared to tool with rake angle 3°and 6° when cutting speed is 30m/min. The tool with rake angle 9° is not suitable for cutting GH4169 when cutting speed is more than 35m/min. The results show that geometric parameter of cutting tool is one of the important factors affecting tool life.

On the Effects of a Built-Up Edge on Acoustic Emission in Metal Cutting

1990 ◽  
Vol 112 (2) ◽  
pp. 184-189 ◽  
Author(s):  
D. V. Hutton ◽  
Qinghuan Yu
Keyword(s):  
Acoustic Emission ◽  
Experimental Evidence ◽  
Deformation Zone ◽  
Metal Cutting ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Rake Angle ◽  
Shear Angle ◽  
Cutting Conditions ◽  
Effective Rake Angle

Experimental evidence is presented which indicates that the presence of a built-up edge can significantly affect the generation of acoustic emission in metal cutting. Results for machining SAE 1018 and 4140 steels show that the built-up edge can mask the generally accepted AE-cutting speed relation when cutting tools having small rake angles are used. Under cutting conditions conducive to development of a built-up edge, it is shown that increased acoustic emission is generated as a result of increased effective rake angle and corresponding increase of shear angle in the primary deformation zone. Three distinct types of built-up edge have been observed and classified as immature, periodic, or developed, according to effect on acoustic emission.

Experimental Study on the Chip Geometry and Shear Angle in Micro-Cutting Aluminum 7050-T7451

2010 ◽  
Vol 443 ◽  
pp. 657-662
Author(s):  
Jun Zhou ◽  
Jian Feng Li ◽  
Jie Sun
Keyword(s):  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Shear Angle ◽  
Micro Scale ◽  
Effective Rake Angle ◽  
Al 7075 ◽  
Chip Geometry ◽  
Cutting Experiments ◽  
Machining Characteristics

In this paper, the micro-scale machining characteristics of a non-ferrous structural alloy, aluminum 7050-T7451 is investigated through a series of cutting experiments. The effects of cutting speed and undeformed chip thickness on the chip geometry, cutting ratio, effective rake angle and shear angle in orthogonal micro-scale cutting of Al 7075-T7451 are presented. Explanations for the observed trends are also given.

Basic Study on Micro V-Groove Cutting of Tungsten Carbide Using Diamond Tools

2012 ◽  
Vol 565 ◽  
pp. 517-522 ◽  
Author(s):  
Takayuki Kitajima ◽  
Shigeki Okuyama ◽  
Akinori Yui
Keyword(s):  
Tool Wear ◽  
Tungsten Carbide ◽  
Rake Angle ◽  
Basic Study ◽  
Diamond Tools ◽  
Diamond Crystals ◽  
Effective Rake Angle ◽  
The Relationship ◽  
Groove Cutting ◽  
Poly Crystalline Diamond

Micro V-groove cutting of cobalt-free tungsten carbide using two types of V-shaped diamond tools is performed using mist of zinc dialkyl-dithiophosphate (ZnDDP) as lubricant. The two types of tool tested are 1) mono-crystalline diamond and 2) poly-crystalline diamond made of approximately 30 nm-sized diamond crystals. The geometry of the V-groove-cutting process is theoretically investigated and the relationship between V-groove angle, original rake angle, and effective rake angle is clarified. Through the cutting experiments, the effects of diamond types and rake angle on tool-wear characteristics are explained. When rake angle is set at zero degrees, tool chipping frequently occurs for both types of diamond tools even when ZnDDP is supplied. However, when rake angle is set at -30 degrees for poly-crystalline diamond, tool wear is minimized.

Chatter Stability Model of Micro-Milling With Process Damping

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Xiaoliang Jin ◽  
Yusuf Altintas
Keyword(s):  
Finite Element ◽  
Cutting Speed ◽  
Rake Angle ◽  
Micro Milling ◽  
Piezo Actuator ◽  
Chatter Stability ◽  
Line Field ◽  
Process Damping ◽  
Aisi 1045 Steel ◽  
1045 Steel

This paper presents the prediction of cutting forces and chatter stability of micro-milling operations from the material's constitutive flow stress and structural dynamics of the micro-end mill. The cutting force coefficients are identified either using previously presented slip-line field or finite element methods by considering the effects of chip size, cutting edge radius, rake angle and cutting speed. The process damping caused by the plowing of round edge is modeled by finite element method. The frequency response function of the fragile micro-mill is measured through specially devised piezo actuator mechanism. Dynamic model of micro-milling with the velocity dependent process damping mechanism is presented, and the chatter stability is predicted in frequency domain. The proposed models have been experimentally verified in micro-milling of AISI 1045 steel.

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