Numerical Analysis of Metal Cutting With Chamfered and Blunt Tools

2002 ◽  
Vol 124 (2) ◽  
pp. 178-188 ◽  
Author(s):  
M. R. Movahhedy, ◽  
Y. Altintas, ◽  
M. S. Gadala,
Keyword(s):  
Formation Process ◽  
Chip Formation ◽  
High Speed ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Cutting Edge ◽  
Hard Materials ◽  
Ale Finite Element Method ◽  
Diffusion Wear ◽  
Process Simulations

In high speed machining of hard materials, tools with chamfered edge and materials resistant to diffusion wear are commonly used. In this paper, the influence of cutting edge geometry on the chip removal process is studied through numerical simulation of cutting with sharp, chamfered or blunt edges and with carbide and CBN tools. The analysis is based on the use of ALE finite element method for continuous chip formation process. Simulations include cutting with tools of different chamfer angles and cutting speeds. The study shows that a region of trapped material zone is formed under the chamfer and acts as the effective cutting edge of the tool, in accordance with experimental observations. While the chip formation process is not significantly affected by the presence of the chamfer, the cutting forces are increased. The effect of cutting speed on the process is also studied.

Numerical Analysis of Cutting With Chamfered and Worn Edge Tools

2000 ◽  
Author(s):  
Mohammad-R. Movahhedy ◽  
Yusuf Altintas ◽  
Mohamed S. Gadala
Keyword(s):  
High Speed ◽  
Cutting Speed ◽  
Cutting Edge ◽  
Maximum Temperature ◽  
Arbitrary Lagrangian Eulerian ◽  
Hard Materials ◽  
Ale Finite Element Method ◽  
Diffusion Wear ◽  
Dead Material ◽  
Chip Removal

Abstract In high-speed machining of hard materials, tools with chamfered edges and tool materials resistant to diffusion wear are commonly used. In this paper, the influence of cutting edge geometry on the chip removal process is studied through numerical simulation of cutting with sharp, chamfered or blunt edges and with carbide or CBN tools. The analysis is based on the use of arbitrary Lagrangian-Eulerian (ALE) finite element method, which makes it possible to analyze the cutting action without having to resort to node separation methods or remeshing. Simulations include cutting with tools of different chamfer angles at a range of cutting speeds and the numerical results are compared with experimental data obtained under similar cutting conditions. The study shows that a region of dead material zone is formed under the chamfer and acts as the effective cutting edge of the tool (in accordance with experimental observations). As a result, the chip formation process is not significantly affected by the presence of the chamfer. However, the forces, the thrust force in particular, are considerably increased. The effect of cutting speed on the process is also studied and is shown to produce a significant increase in maximum temperature on the rake face.

scholarly journals Mechanism of Chip Formation Process at Grinding

2019 ◽  
Vol 297 ◽  
pp. 09002
Author(s):  
Vyacheslav Shumyacher ◽  
Sergey Kryukov ◽  
Olga Kulik ◽  
Xavier Kennedy
Keyword(s):  
Formation Process ◽  
Chip Formation ◽  
High Speed ◽  
Cutting Speed ◽  
Dimensional Accuracy ◽  
Processing Parameters ◽  
Abrasive Grain ◽  
Wave Heating ◽  
High Speed Grinding

The mechanism of chip formation process at grinding is described, which involves a high-speed interaction of abrasive grain and metal, which leads to a concentration of thermal energy in front of the dispersing element (grain), causing a locally concentrated shift in the metal microvolume. In “abrasive grain -metal” contact a dissipative structure is formed which existence is supported by exchange of energy and substance with environment. Due to shock compression of the metal microvolume with abrasive grain, shock-wave heating is realized, initiating emission of electrons ionizing the lubricating cooling fluid in the zone of formation of side micro-scratches left by abrasive. The results obtained in the course of the research can be used to explain the mechanisms of chip formation, as well as the course of the physical and mechanical processes occurring on the surface layers of the grinded workpieces. By controlling chip formation processes at high-speed grinding, by optimally selecting the appropriate ratios between cutting speed and other processing parameters, a reduction in process thermal density can be achieved, which, with the highest productivity, will allow to obtain the required quality of the surface layer of the workpieces and a given dimensional accuracy.

Linear Sawing Apparatus and its Evaluation for Research Into High Speed Bone Sawing

2011 ◽  
Author(s):  
John J. Pearlman ◽  
Anil Saigal ◽  
Thomas P. James
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Cutting Edge ◽  
Material Behavior ◽  
Depth Of Cut ◽  
Cutting Edge Radius ◽  
Edge Radius ◽  
Saw Blade

Previous research into the cutting mechanics of bone sawing has been primarily approached from the perspective of orthogonal metal machining with a single edge cutting tool. This was a natural progression from the larger body of knowledge on the mechanics of metal cutting. However, there are significant differences between typical orthogonal metal cutting parameters and those encountered in bone sawing, such as anisotropic material behavior, depth of cut on the order of cutting edge radius, chip formation mechanism in the context of a saw blade kerf, non-orthogonal considerations of set saw blade teeth, and cutting speed to name a few. In the present study, an attempt is made to overcome these shortcomings by employing a unique sawing fixture, developed to establish cutting speeds equivalent to those of typical sagittal saws used in orthopaedic procedures. The apparatus was developed for research into bone sawing mechanics and is not intended to be a commercial sawing machine. The sawing fixture incorporates the cutting speed possible with lathe operations, as well as the linear cutting capabilities of a milling machine. Depths of cut are on the same order of magnitude as the cutting edge radius typical to saw blade teeth. Initial measurements of cutting and thrust force, obtained with this new experimental equipment, are compared to previous work.

Finite Element Analysis of the Influence of the Material Constitutive Law Formulation on the Chip Formation Process During a High Speed Metal Cutting

2012 ◽  
Author(s):  
Adinel Gavrus ◽  
Pascal Caestecker ◽  
Eric Ragneau
Keyword(s):  
Finite Element ◽  
Formation Process ◽  
Chip Formation ◽  
High Speed ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Constitutive Law ◽  
Cutting Process ◽  
Contact Friction ◽  
Numerical Predictions

During the last decades, the importance of machining in manufacturing industry has required rigorous scientific studies concerning the chip formation process in order to determine optimal speeds, feeds or other technological parameters. For all types of machining including turning, milling, grinding, honing or lapping, the phenomenon of chip formation is similar in terms of the local interaction between the tool and the work piece. Because of the intensive use of CNC machine tools producing parts at ever-faster rates, it has become important to provide analysis of high speed cutting where complex loading conditions occur during the fabrication process: high gradients of the thermo-mechanical variables, strong nonlinearities of the thermo-mechanical coupling, large plastic strains, extremely high strain rates compared to that of other forming processes, important influence of the contact friction and of the microstructure evolution. Today many scientific researches are focalized on finite element analyses of the chip formation and of its morphology evolution during a high speed metals cutting process. To improve the quality of the numerical predictions, a better description of the local shear band formation is needed, using adequate rheological models. On this point of view this paper deals with the influence of the rheological behavior formulation on the morphology and geometry of the chip formation during a finite element simulation of a high speed metal cutting process. Numerical simulations of a high speed orthogonal cutting of special steels are employed to analysis the sensitivity of the numerical results describing the local cutting area with respect to different rheological laws: Norton-Hoff or Cowper-Symonds model, Johnson-Cook one or Zerilli-Armstrong formulation. To obtain a better description of the local material loadings and to take into account the important gradient of the strain rate, plastic strain and temperature values, a more adequate constitutive model is proposed by the author.

Experimental and FEM Study of Serrated Chip Formation in High Speed Turning Processes

2011 ◽  
Vol 264-265 ◽  
pp. 1021-1026
Author(s):  
U. Umer ◽  
Li Jing Xie ◽  
Syed Jawid Askari ◽  
S.N. Danish ◽  
S.I. Butt
Keyword(s):  
Chip Formation ◽  
Cutting Forces ◽  
High Speed ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Serrated Chip ◽  
High Speed Turning ◽  
Serrated Chip Formation

The finite element method (FEM) has been used to model high speed turning processes with orthogonal cutting conditions. In most of the situations, continuous chip formation is used to analyze the turning process due to its stability and allowing many conditions to simplify the process. However with the increasing applications of high speed turning, serrated chip formation is becoming a more common phenomenon in metal cutting. Serrated chips usually occur in machining of difficult to cut materials at or above a threshold speed. An updated Lagrangian formulation has been used in this study which works with element deletion technique based on a failure criterion. The Johnson Cook strain-hardening thermal-softening material model is used to model serrated chip formation. In addition high speed turning experiments were conducted on AISI H13 tubes using PCBN to analyze serrated chip phenomenon. The chips were analyzed after surface treatment using scanning electron microscope. It has been found that the length of cuts in the chip increases with the cutting speed and the chip changes from serrated to discontinuous. Different process variables like cutting forces, chip morphology, stress, strain and temperature distributions are predicted at different process parameters using FEM. The results show cyclic variation in the cutting forces at high cutting speeds due to varying chip load.

scholarly journals Simulation of plastic deformation and destruction in the process of chip formation

2018 ◽  
Vol 211 ◽  
pp. 17007
Author(s):  
Tanel Tärgla ◽  
Jüri Olt ◽  
Olga Liivapuu
Keyword(s):  
Plastic Deformation ◽  
Formation Process ◽  
Chip Formation ◽  
Rheological Model ◽  
Metal Cutting ◽  
Depth Of Cut ◽  
Key Factors ◽  
Local Zone ◽  
Complex Process ◽  
Relaxing Medium

Metal cutting is a complex process in which several mechanisms are at work simultaneously. The mathematical modelling allows carrying out research into the optimization of machining conditions. This work examines the simulation of chip formation during the process of cutting. The studies demonstrated that the chip formation process, taking into account the plastic deformation and destruction of metal in the local zone, is most appropriately represented by a rheological model in the form of a series connection of elasticductile- plastic relaxing medium of Ishlinskiy (reflecting the process of primary deformation of metal from the cut off layer) and the medium of Voigt with two elastic-dissipative elements (representing the process of deformation and frictions from the convergent shaving). The attained complex rheological model served as the basis for constructing a representative dynamic model for the chip formation process. The key factors that govern the chip formation have been taken into account, such as tool vibration frequency and amplitude, depth of cut, feed rate.

Influence of the Process Variables on the Temperature Distribution in AISI 1045 Turning

2012 ◽  
Vol 557-559 ◽  
pp. 1364-1368
Author(s):  
Yong Feng ◽  
Mu Lan Wang ◽  
Bao Sheng Wang ◽  
Jun Ming Hou
Keyword(s):  
Temperature Distribution ◽  
High Speed ◽  
Metal Cutting ◽  
Constitutive Relations ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Fe Model ◽  
Process Variables ◽  
Machined Surface ◽  
Aisi 1045

High-speed metal cutting processes can cause extremely rapid heating of the work material. Temperature on the machined surface is critical for surface integrity and the performance of a precision component. However, the temperature of a machined surface is challenging for in-situ measurement.So, the finite element(FE) method used to analyze the unique nonlinear problems during cutting process. In terms of heat-force coupled problem, the thermo-plastic FE model was proposed to predict the cutting temperature distribution using separated iterative method. Several key techniques such as material constitutive relations, tool-chip interface friction and separation and damage fracture criterion were modeled. Based on the updated Lagrange and arbitrary Lagrangian-Eulerian (ALE) method, the temperature field in high speed orthogonal cutting of carbon steel AISI-1045 were simulated. The simulated results showed good agreement with the experimental results, which validated the precision of the process simulation method. Meanwhile, the influence of the process variables such as cutting speed, cutting depth, etc. on the temperature distribution was investigated.

Development of Cutting Tools With Micro-Textured Surface for High Speed Machining of Ti-6Al-4V

2021 ◽  
Author(s):  
Mitsuru Hasegawa ◽  
Tatsuya Sugihara
Keyword(s):  
Tool Life ◽  
High Speed ◽  
Metal Cutting ◽  
Failure Process ◽  
Cutting Tools ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Cutting Fluid ◽  
Textured Surface ◽  
Textured Surfaces

Abstract In cutting of Ti-6Al-4V alloy, the cutting speed is limited since a high cutting temperature leads to severe tool wear and short tool life, resulting in poor production efficiency. On the other hand, some recent literature has reported that various beneficial effects can be provided by forming micro-textures on the tool surface in the metal cutting process. In this study, in order to achieve high-performance machining of Ti-6Al-4V, we first investigated the mechanism of the tool failure process for a cemented carbide cutting tool in high-speed turning of Ti-6Al-4V. Based on the results, cutting tools with micro textured surfaces were developed under the consideration of a cutting fluid action. A series of experiments showed that the textured rake face successfully decreases the cutting temperature, resulting in a significant suppression of both crater wear and flank wear. In addition, the temperature zone where the texture tool is effective in terms of the tool life in the Ti-6Al-4V cutting was discussed.

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