Dynamics of the Metal-Cutting Process

1965 ◽  
Vol 87 (4) ◽  
pp. 429-441 ◽  
Author(s):  
Paul Albrecht
Keyword(s):  
Dynamic Response ◽  
Cutting Forces ◽  
Metal Cutting ◽  
Dynamic Properties ◽  
Chip Thickness ◽  
Cutting Process ◽  
Uncut Chip Thickness ◽  
Work Surface ◽  
Experimental Approaches ◽  
Inertia Forces

An investigation into the dynamics of the metal-cutting process has been carried out using analytical and experimental approaches. An exploratory analysis into the dynamic behavior of the cutting process revealed such dynamic properties as a loop response of the cutting forces caused by the waviness of the work surface. This finding indicates the possibility of unstable behavior of the cutting process in itself. It was possible to describe analytically the phase between the force response and fluctuations of uncut chip thickness for the case of a wavy work surface. Effects of the magnitude of the shear angle as well as of its fluctuations have been studied which make it possible to correlate the instability within the cutting process to the properties of the work material. Apart from the configuration of the cutting process, its physical properties, such as inertia forces in chip formation, have been introduced into the analysis because inertia forces, negligible at steady state, may grow significant if cutting conditions are fluctuating at higher frequencies. An experimental setup has been devised and built featuring a special design of a tool dynamometer particularly suitable for the measurement of dynamic response of the cutting forces. In the setup, a cutting tool activated by a hydraulic shaker is controlled in an average position by a feedback loop mechanism. This setup makes it possible to obtain a record of the dynamic response of cutting forces caused by the fluctuation of uncut chip thickness produced by an oscillating tool in the frequency range up to about 400 cps.

Forces in Green Micromachining of Ceramics: An Experimental Investigation on Micromachining of Aluminum Nitride

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Recep Onler ◽  
Sundar V. Atre ◽  
O. Burak Ozdoganlar
Keyword(s):  
Cutting Forces ◽  
Metal Cutting ◽  
Diamond Tool ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Powder Injection ◽  
Uncut Chip Thickness ◽  
Green State ◽  
Single Crystal Diamond ◽  
Thrust Forces

This paper presents an investigation of green micromachining (GMM) forces during orthogonal micromachining green-state AlN ceramics. Green-state ceramics contain ceramic powders within a binder; processed samples are subsequently debound and sintered to obtain solid ceramic parts. An effective approach to create microscale features on ceramics is to use mechanical micromachining when the ceramics are at their green state. This approach, referred to as GMM, considerably reduces the forces and tool wear with respect to micromachining of sintered ceramics. As such, fundamental understanding on GMM of ceramics is critically needed. To this end, in this work, the force characteristics of powder injection molded AlN ceramics with two different binder states were experimentally investigated via orthogonal cutting. The effects of micromachining parameters on force components and specific energies were experimentally identified for a tungsten carbide (WC) and a single crystal diamond tools. As expected, the thrust forces were seen to be significantly larger than the cutting forces at low uncut chip thicknesses when using the carbide tool with its large edge radius. The cutting forces are found to be more sensitive to uncut chip thickness than the thrust forces are. When a sharp diamond tool is used, cutting forces are significantly larger than the thrust forces even for small uncut chip thicknesses. The specific energies follow an exponential decrease with increasing uncut chip thickness similar to the common trends in metal cutting. However, due to interaction characteristics between cutting edge and ceramic particles in the green body, evidence of plowing and rubbing along the cutting region was observed even with a sharp diamond tool.

Electrical Current at Metal Cutting Process: A Literature Review

2015 ◽  
Vol 808 ◽  
pp. 40-47 ◽  
Author(s):  
Raluca Daicu ◽  
Gheorghe Oancea
Keyword(s):  
Literature Review ◽  
Cutting Forces ◽  
Metal Cutting ◽  
Electrical Current ◽  
Cutting Edge ◽  
Cutting Process ◽  
Metallic Materials ◽  
Cutting Zone

Processing metallic materials by cutting using good electricity conductor cutting edges it appears an electrical current due mainly to the temperature in the cutting zone. Analyzing of the electrical current the information about the unfolding mode of the cutting process can be obtained. The cutting electrical current can be used in several applications: the estimation of the temperature in the cutting zone, the estimation of the cutting forces, the identification of the wear state of the cutting edge etc. The first researches were started in Russia and they were based on the utilization of the cutting electrical current to measure the temperature in the cutting zone. Afterwards, other applications were identified in the literature and the researches were extended in other countries like India, Japan, USA, Brazil, France, Bangladesh and Romania. This paper presents a review of the researches about the electrical current which appears at cutting process.

Experimental Study of the Dynamic Behavior of Thin-Walled Tubular Workpieces in Turning Cutting Process

2020 ◽  
pp. 1-19
Author(s):  
Zied Sahraoui ◽  
Kamel Mehdi ◽  
Moez Ben Jaber
Keyword(s):  
Dynamic Behavior ◽  
Cutting Forces ◽  
Chip Thickness ◽  
Cutting Process ◽  
Machining Process ◽  
Structural Damping ◽  
Turning Process ◽  
Manufactured Products ◽  
Thin Walled ◽  
The Stability

Nowadays, industrialists, especially those in the automobile and aeronautical transport fields, seek to lighten the weight of different product components by developing new materials lighter than those usually used or by replacing some massive parts with thin-walled hollow parts. This lightening operation is carried out in order to reduce the energy consumption of the manufactured products while guaranteeing optimal mechanical properties of the components and increasing quality and productivity. To achieve these objectives, some research centers have focused their work on the development and characterization of new light materials and some other centers have focused their work on the analysis and understanding of the encountered problems during the machining operation of thin-walled parts. Indeed, various studies have shown that the machining process of thin-walled parts differs from that of rigid parts. This difference comes from the dynamic behavior of the thin-walled parts which is different from that of the massive parts. Therefore, the purpose of this paper is to first highlight some of these problems through the measurement and analysis of the cutting forces and vibrations of tubular parts with different thicknesses in AU4G1T351 aluminum alloy during the turning process. The experimental results highlight that the dynamic behavior of turning process is governed by large radial deformations of the thin-walled workpieces and the influence of this behavior on the variations of the chip thickness and cutting forces is assumed to be preponderant. The second objective is to provide manufacturers with a practical solution to the encountered vibration problems by improving the structural damping of thin-walled parts by additional damping. It is found that the additional structural damping increases the stability of the cutting process and reduces considerably the vibrations amplitudes.

Investigation of effect of uncut chip thickness to edge radius ratio on nanoscale cutting behavior of single crystal copper: MD simulation approach

2020 ◽  
pp. 251659842093763
Author(s):  
A. Sharma ◽  
P. Ranjan ◽  
R. Balasubramaniam
Keyword(s):  
Molecular Dynamics ◽  
Single Crystal ◽  
Material Removal ◽  
Chip Thickness ◽  
Cutting Process ◽  
Uncut Chip Thickness ◽  
Edge Radius ◽  
Nanoscale Cutting ◽  
Cutting Behavior ◽  
Subsurface Defects

Extremely small cutting depths in nanoscale cutting makes it very difficult to measure the thermodynamic properties and understand the underlying mechanism and behavior of workpiece material. Highly precise single-crystal Cu is popularly employed in optical and electronics industries. This study, therefore, implements the molecular dynamics technique to analyze the cutting behavior and surface and subsurface phenomenon in the nanoscale cutting of copper workpieces with a diamond tool. Molecular dynamics simulation is carried out for different ratios of uncut chip thickness ( a) to cutting edge radius ( r) to investigate material removal mechanism, cutting forces, surface and subsurface defects, material removal rate (MRR), and stresses involved during the nanoscale cutting process. Calculation of forces and amount of plowing indicate that a/ r = 0.5 is the critical ratio for which the average values of both increase to maximum. Material deformation mechanism changes from shear slip to shear zone deformation and then to plowing and elastic rubbing as the cutting depth/uncut chip thickness is reduced. The deformation during nano-cutting in terms of dislocation density changes with respect to cutting time. During the cutting process, it is observed that various subsurface defects like point defects, dislocations and dislocation loops, stacking faults, and stair-rod dislocation take place.

Cutting Dynamics in Machine Tool Chatter: Contribution to Machine-Tool Chatter Research—3

1965 ◽  
Vol 87 (4) ◽  
pp. 464-470 ◽  
Author(s):  
R. L. Kegg
Keyword(s):  
Machine Tool ◽  
Metal Cutting ◽  
Chip Thickness ◽  
Cutting Process ◽  
Dynamic Force ◽  
General Technique ◽  
Cross Sensitivity ◽  
Machine Tool Chatter ◽  
Measuring Techniques ◽  
Tool Chatter

This is one of four papers presented simultaneously on the general subject of chatter. This work is concerned with finding a representation of the dynamic metal-cutting process which is suitable for use in a linear closed-loop theory of stability of the system composed of the machine tool structure, the cutting process, and their means of combining. Measuring techniques for experimentally determining this behavior are discussed and some problems in the dynamic measurement of forces are explored. It is found that it is not at all sufficient to simply build a dynamometer whose lowest natural frequency is well beyond the range of interest. It is also shown that dynamic cross sensitivity can far exceed static cross sensitivity so that a more general technique for data correction developed in the present work must be used to calibrate dynamic force data. Results obtained to date with an oscillating tool and a flat uncut surface show that some phase, increasing with frequency, is always present between the dynamic cutting forces and the oscillatory uncut chip thickness. This phase is different for the two components of the resultant cutting force. It is felt that two mechanisms, both associated with the tool clearance flank, can explain most of the dynamic cutting effects found in testing.

Influence of Reground Tool Sharpness on Micro-Cutting Process

2010 ◽  
Vol 37-38 ◽  
pp. 550-553
Author(s):  
Xin Li Tian ◽  
Zhao Li ◽  
Xiu Jian Tang ◽  
Fang Guo ◽  
Ai Bing Yu
Keyword(s):  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Cutting Tools ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Cutting Process ◽  
Micro Cutting ◽  
Temperature Distributions ◽  
Edge Radius ◽  
1045 Steel

Tool edge radius has obvious influences on micro-cutting process. It considers the ratio of the cutting edge radius and the uncut chip thickness as the relative tool sharpness (RST). FEM simulations of orthogonal cutting processes were studied with dynamics explicit ALE method. AISI 1045 steel was chosen for workpiece, and cemented carbide was chosen for cutting tool. Sixteen cutting edges with different RTS values were chosen for analysis. Cutting forces and temperature distributions were calculated for carbide cutting tools with these RTS values. Cutting edge with a small RTS obtains large cutting forces. Ploughing force tend to sharply increase when the RTS of the cutting edge is small. Cutting edge with a reasonable RTS reduces the heat generation and presents reasonable temperature distributions, which is beneficial to cutting life. The force and temperature distributions demonstrate that there is a reasonable RTS range for the cutting edge.

An Integral Method to Determine Workpiece Flow Stress and Friction Characteristics in Metal Cutting

2015 ◽  
Vol 9 (6) ◽  
pp. 775-781
Author(s):  
Norfariza Wahab ◽  
◽  
Yumi Inatsugu ◽  
Satoshi Kubota ◽  
Soo-Young Kim ◽  
...  
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Cutting Forces ◽  
High Speed ◽  
Metal Cutting ◽  
Cutting Edge ◽  
Cutting Process ◽  
Machining Parameters ◽  
Friction Characteristics ◽  
High Speed Cutting

In recent times, numerical simulation techniques have been commonly used to estimate and predict machining parameters such as cutting forces, stresses, and temperature distribution. However, it is very difficult to estimate the flow stress of a workpiece and the friction characteristics at a tool/chip interface, particularly during a high-speed cutting process. The objective of this study is to improve the accuracy of the present method and simultaneously determine the characteristics of the flow stress of a workpiece and friction at the cutting edge under a high strain rate and temperature during the cutting process. In this study, the Johnson-Cook (JC) flow stress model is used as a function of strain, strain rate, and temperature. The friction characteristic was estimated by minimizing the difference between the predicted and measured results of principal force, thrust force, and shear angle. The shear friction equation was used to estimate the friction characteristics. Therefore, by comparing the measured values of the cutting forces with the predicted results from FEM simulations, an expression for workpiece flow stress and friction characteristics at the cutting edge during a high-speed cutting process was estimated.

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.

Analysis of Oblique Cutting Forces

1967 ◽  
Vol 89 (2) ◽  
pp. 347-355 ◽  
Author(s):  
Russell F. Henke
Keyword(s):  
Steady State ◽  
Cutting Force ◽  
Cutting Forces ◽  
Metal Cutting ◽  
Single Point ◽  
Orthogonal Cutting ◽  
Cutting Process ◽  
Chip Area ◽  
Oblique Cutting ◽  
The Stability

This paper is the latest of a continuing series on the subject of self-excited machine tool chatter. The representation of the metal cutting process as required by the previously developed closed-loop chatter theory is extended to oblique cutting with tools of practical shape and geometry. The cutting process parameters essential to proper application of the stability theory are found by an analytical formulation leading to a classical eigenvalue problem. Techniques are developed to determine the steady-state constant of proportionality between resultant cutting force and uncut chip area, the direction of resultant cutting force, and the direction of maximum cutting stiffness for any single-point cutting operation. In the process, a general method to predict steady-state oblique cutting forces is evolved. The method depends on certain experimentally justifiable assumptions and utilizes previously compiled orthogonal cutting data.

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