Modeling metal cutting processes under consideration of elastic material properties

Most machining models consider the work piece material to exhibit rigid-plastic or, when taking into account the strain rate sensitivity of the flow stress, rigid-viscoplastic behavior. This approach neglects the influence of the elastic material properties of the work piece. Another simplification that is common to many machining models is the assumption of an ideally sharp cutting edge. The main reason for these simplifications is to reduce computation time. Within this work, the influence of the elastic material properties of Ti6Al4V on the two-dimensional simulation of an orthogonal turning process is examined. Based on experimentally determined process forces, rim zone temperatures and residual stresses in the generated surface, the simulation results are evaluated. In order to provide the required experimental data basis, a new orthogonal cutting process based on a helical collar is presented. Unlike the commonly known orthogonal cutting processes, this new process allows the unambiguous identification of process parameters such as cutting velocity and feed rate for each point of the machined surface. The tools utilized were processed by means of drag grinding in order to generate defined cutting edge radii which were then used as input data for the simulation. During the experimental investigation, the occurring process forces and also process temperatures were recorded. Subsequent to the machining experiments, the residual stresses generated in the machined surface were determined by means of X-ray diffraction. The modeling of the cutting process was performed using the finite element code SFTC DEFORM 2D, version 8.1. The simulation results showed a good sensitivity to the variation of the cutting edge radius. The consideration of elastic material properties did not have a significant impact on the modeled process forces. However, contact zone length and strain distribution in chip and work piece are influenced. When introducing shear friction into the elasto-viscoplastic model, the cutting forces fluctuate, which could be interpreted as a pre-stage to chip serration. Cutting forces are overestimated compared to the experiments, while feed forces are underestimated. While the calculated values of the residual stresses deviate from the measurements, the model proves to be sensitive to the process parameters and follows the trends as they can be found in literature. The results are discussed and further steps to be taken in order to improve the simulation quality are pointed out.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2006

Author dc:creator

• Messner, Gregor Franz Ludwig

Contributors dc:contributor

• Klocke, Fritz

• info:eu-repo/classification/ddc/620
• Finite-Elemente-Methode
• Spanende Bearbeitung
• TiAl6V4
• Ingenieurwissenschaften
• Eigenspannungen
• orthogonaler Zerspanprozess
• Zerspansimulation
• Residual Stress
• orthogonal machining
• ZSPNTF100

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-124023%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:62454