Prediction of serrated chip formation in orthogonal metal cutting by advanced adaptive 2D numerical methodology

2011 ◽  
Vol 9 (3/4) ◽  
pp. 295 ◽  
Author(s):  
Mazen Issa ◽  
Khemais Saanouni ◽  
Carl Labergere ◽  
Alain Rassineux
Keyword(s):  
Chip Formation ◽  
Metal Cutting ◽  
Serrated Chip ◽  
Orthogonal Metal Cutting ◽  
Serrated Chip Formation

Finite Element Analysis of Adiabatic Shear Band Formation during Orthogonal Metal Cutting

2007 ◽  
Vol 345-346 ◽  
pp. 885-888 ◽  
Author(s):  
Sung Han Rhim ◽  
Hyung Wook Park ◽  
Soo Ik Oh
Keyword(s):  
Chip Formation ◽  
Metal Cutting ◽  
Adiabatic Shear Band ◽  
Adiabatic Shear ◽  
Shear Band Formation ◽  
Serrated Chip ◽  
Band Formation ◽  
Adiabatic Shear Band Formation ◽  
Serrated Chip Formation ◽  
Flow Stress Model

In serrated chips of difficult-to-machining materials such as medium carbon steel and titanium alloy during metal cutting process at high strain rates, the fine grain structure of the narrow shear bands which results from thermal softening due to severe deformation have been observed. However, the theories which have been developed to analyze continuous chip formation and most FEM analyses based on the conventional models such as Johnson-Cook and Zerilli-Armstrong flow stress model fail to explain the adiabatic shear band formation and the serrated chip formation. This paper discusses the characteristic of the new flow stress model in the previous investigation [1,2] and FEM simulation results to predict the serrated chip formation results are shown.

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.

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