Dynamic Behavior of a Thin-Walled Cylindrical Workpiece During the Turning Process, Part 1: Cutting Process Simulation

2002 ◽  
Vol 124 (3) ◽  
pp. 562-568 ◽  
Author(s):  
K. Mehdi ◽  
J.-F. Rigal ◽  
D. Play
Keyword(s):  
Dynamic Behavior ◽  
Process Simulation ◽  
Point Of View ◽  
Cutting Process ◽  
Natural Phenomenon ◽  
Chatter Vibration ◽  
Turning Process ◽  
Chatter Vibrations ◽  
Cylindrical Workpiece ◽  
Thin Walled

From a practical point of view, in machining applications, chatter vibration constitutes a major problem during the cutting process. It is becoming increasingly difficult to suppress chatter during cutting at high speeds. Many investigators have regarded chatter vibrations as a “natural” phenomenon during the cutting process and a part of the process itself. In classical machining operations with thick-walled workpieces chatter vibrations occur when the cutting depth exceeds stability limits dependent on the machine tool. On the other hand, in the case of thin-walled cylindrical workpieces, chatter vibration problems are not so simple to formulate. The main purpose of this study is to qualify the dynamic behavior of a thin-walled workpiece during the turning process. It contains two parts: the cutting process simulation and the definition of experimental stability criteria. In the first part, a numerical model, which simulates the turning process of thin-walled cylindrical workpieces, is proposed. This model also permits obtaining workpiece responses to excitation generated by cutting forces. Finally, the stability of the process is discussed.

Dynamic Behavior of a Thin-Walled Cylindrical Workpiece During the Turning-Cutting Process, Part 2: Experimental Approach and Validation

2002 ◽  
Vol 124 (3) ◽  
pp. 569-580 ◽  
Author(s):  
K. Mehdi ◽  
J.-F. Rigal ◽  
D. Play
Keyword(s):  
Dynamic Behavior ◽  
Experimental Approach ◽  
Element Model ◽  
Central Place ◽  
Operating Conditions ◽  
Cutting Process ◽  
Turning Process ◽  
Cylindrical Workpiece ◽  
Thin Walled ◽  
The Stability

Chatter vibrations in the cutting process have a central place in many machining applications. A numerical and theoretical approach of self-excited vibrations during the turning process of thin-walled hollow workpieces has been presented in the accompanying paper. Furthermore, a finite element model has been proposed to simulate the dynamics of the system. The response to a Dirac excitation, presented as Nyquist curves, is proposed in order to characterize the dynamics of the turning process and the stability criterion. In this the second part of two related papers, the main objective is to validate the simulated dynamic behavior by using the experimental approach. The results of machining tests performed on thin-walled tubes with steel and aluminum alloys, using different operating conditions (dimensions, geometry and setting conditions) are presented and discussed.

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.

scholarly journals Analytical modeling of a thin-walled cylindrical workpiece during the turning process. Stability analysis of a cutting process

2017 ◽  
Vol 19 (8) ◽  
pp. 5825-5841 ◽  
Author(s):  
Artem Gerasimenko ◽  
Mikhail Guskov ◽  
Alexander Gouskov ◽  
Philippe Lorong ◽  
Alexander Shokhin
Keyword(s):  
Stability Analysis ◽  
Analytical Modeling ◽  
Cutting Process ◽  
Turning Process ◽  
Process Stability ◽  
Cylindrical Workpiece ◽  
Thin Walled

Error Source Diagnostics Using a Turning Process Simulator

1998 ◽  
Vol 120 (2) ◽  
pp. 409-416 ◽  
Author(s):  
Sung-Gwang Chen ◽  
A. Galip Ulsoy ◽  
Yoram Koren
Keyword(s):  
Process Simulation ◽  
Cutting Process ◽  
Force Model ◽  
Error Source ◽  
Turning Process ◽  
Cutting Force Model ◽  
Cnc Lathe ◽  
Computer Numerically Controlled ◽  
Simulation Results ◽  
Process Simulator

To improve productivity and quality in machining, it is necessary to understand the interactions among machine tool components and the cutting process. This paper presents a model that characterizes interactions among the subsystems of a computer numerically controlled (CNC) lathe. The model is combined with a cutting force model to obtain a comprehensive turning simulator that simulates the cutting forces and part dimensions. A series of calibration experiments are proposed and implemented for process simulation. The simulation results are good when compared with experimental measurements. The interactions among the subunits of a CNC lathe and the cutting process are found to be potentially important.

scholarly journals Experimental Study on Application of Tuned Mass Dampers for Chatter in Turning of a Thin-Walled Cylinder

2021 ◽  
Vol 11 (24) ◽  
pp. 12070
Author(s):  
Yutaka Nakano ◽  
Tsubasa Kishi ◽  
Hiroki Takahara
Keyword(s):  
Small Mass ◽  
Turning Process ◽  
Tuned Mass Dampers ◽  
Suppression Effect ◽  
Chatter Suppression ◽  
Cylindrical Workpiece ◽  
Thin Walled ◽  
Different Characteristics ◽  
Tool Damage ◽  
Walled Cylinder

Chatter is more likely to occur during the turning process of a thin-walled cylindrical workpiece owing to the low rigidity of such workpieces. Chatter causes intensive vibration, deterioration of the surface finish accuracy, tool damage, and tool wear. Tuned mass dampers (TMD) are usually applied as a passive damping technique to induce a large damping effect using a small mass. This study experimentally investigated the effect of the mounting arrangement and tuning parameters of the TMDs on the production of chatter during the turning process of a thin-walled cylinder, wherein multiple TMDs with extremely small mass ratios were attached to the rotating workpiece. The results of the cutting tests performed by varying the circumferential and axial mounting positions of the TMDs exhibited different characteristics of the chatter suppression effect. Conclusively, the TMDs could suppress the chatter generated by the vibration mode with circumferential nodes if they were mounted on the workpiece to avoid the coincidence of the circumferential arrangement with the pitch of the vibration nodes, regardless of the extremely small mass of the TMDs.

scholarly journals Numerical and Experimental Investigation on Dynamic Behavior in Turning Process of Thin-walled Workpieces made of 42CrMo4 Steel Alloy

2021 ◽  
Author(s):  
Zied Sahraoui ◽  
Nawel Glaa ◽  
Kamel MEHDI
Keyword(s):  
Finite Element ◽  
Dynamic Behavior ◽  
Feed Rate ◽  
Cutting Forces ◽  
Metal Cutting ◽  
Numerical Study ◽  
Steel Alloy ◽  
Turning Process ◽  
42Crmo4 Steel ◽  
Thin Walled

Abstract Machining thin-walled parts is generally cumbersome due to their low structural rigidity. Thus, to better understand the dynamic behavior of thin-walled parts during machining, various engineers and researchers in the field of metal cutting employ the Finite Element Method (FEM) due to its ability to highlight the physics involved in chip formation and the range of force generated in the cutting zone. The results of numerical simulations are evaluated using comparison with experimental data. In this paper, we study the effect of feed rate as well as the thickness of the wall part made of 42CrMo4 steel alloy on the cutting forces and workpiece displacements both experimentally and numerically during roughing and finishing turning process. The numerical study is based on the development of a three-dimensional (3D) Finite Element Model (FEM) in Abaqus/Explicit frame. In the model, the workpiece material is governed by a behavior law of Johnson-Cook. The detachment of the chip is simulated by a ductile fracture law also of Johnson-Cook. Numerical and experimental results show that the cutting forces and the quality of the machined surface depend not only on the choice of cutting parameters but also on the dynamic behavior of thin-walled parts due to their low rigidity and low structural damping during of the machining operation. Indeed, cutting forces are proportional to the feed rate and inversely proportional to the thickness of the part. The largest displacements recorded on the part are mainly along the direction of the tangential component of the cutting force. The flexibility of the part generates instability in the cutting process, but the frequencies of the vibrations are higher than the frequency of rotation of the part.

Effects of deep cryogenic treatment on machinability, hardness and microstructure in dry turning process of tempered steels

2020 ◽  
pp. 095440892097944
Author(s):  
Menderes Kam
Keyword(s):  
Cryogenic Treatment ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Point Of View ◽  
Turning Process ◽  
Deep Cryogenic Treatment ◽  
Dry Turning ◽  
Control Factors ◽  
Heat Treated ◽  
Hardness Values

This study investigated the effects of Deep Cryogenic Treatment (DCT) on machinability, hardness, and microstructure in dry turning process of AISI 4140 (48-51 HRc) tempered steels with ceramic cutting tools on the surface roughness (Ra). DCT process of steels has shown significant improvement in their mechanical properties. In this context, experiments were made with Taguchi L16 method and optimum values were determined. Three different values for each control factors as: different heat treated samples, cutting speeds (160, 200, 240, 280 m/min), feed rates (0.08, 0.12, 0.16, 0.20 mm/rev) were selected. As a result, the lowest Ra value was found to be 0.159 µm for the DCTT36 sample at a cutting speed of 240 m/min, a feed rate of 0.08 mm/rev. The optimum Ra value was the lowest for the DCTT36 sample compared to the other samples as 0.206 µm. The hardness values of the micro and macro were highest for the DCTT36 sample. Microstructural point of view Scanning Electron Microscopy (SEM) point of view, the DCCT36 sample showed that best results owing to its homogeneity. It was concluded that lower Ra values can be obtained with ceramic cutting tool in dry turning experiments according to the studies in the literature review. It is thought to be preferred as an alternative to cylindrical grinding process due to lower cost.

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