But there may be several problems during machining in this case. This need can be satisfied by selection of higher feed velocity, axial and radial depths. Moreover there is a pressing need to maximize the productivity of machining operations. « lessĬritical aerospace components usually require difficult to machine workpiece materials like nickel based alloys.
Extrapolation errors and corrections for workpiece hardness variations are also discussed. As an example application, bar turning force data is used to simulate the torque and thrust force in a combined drilling and reaming process. This approach is shown to accurately predict forces in end turning, bar turning, or fly milling tests on five common tool-work material combinations. Forces in specific processes are then calculated from the empirical equations using geometric transformations. In this method, empirical equations for cutting pressures or forces as a function of the cutting speed, uncut chip thickness, and tool normal rake angle are fit to baseline data from end turning, bar turning, or fly milling tests. This paper describes a unified method for simulating cutting forces in different machining processes from a common set of baseline data. Furthermore, many force more » and pressure equations do not include rake angle effects, so that separate tests are also required for different cutter geometries. The efficiency with which baseline data can be collected is limited by the fact that simulation programs do not use standard force or pressure equations, so that multiple sets of tests must be performed to simulate different machining processes for the same tool-workpiece material combination. Moreover, the testing effort required to generate suitable data for new materials determines whether simulation provides a cost or time advantage over trial-and-error testing. The accuracy of the baseline cutting data determines the accuracy of simulated results. Obtaining accurate baseline force data is often the critical step in applying machining simulation codes. The temperature fields allow us to explain the reduction in the cutting force and the resulting residual stress fields in the workpiece. In particular, it was shown that for LAM the auto-heating of the material in the primary shear zone is less important and that the friction between the tool and chip also generates less heat. The thermo-mechanical model then allowed us to highlight the differences in the temperature fields in the cutting zone with and without the laser.
Experimental tests for the orthogonal cutting of 42CrMo4 steel were used to validate the simulation via the prediction of the cutting force with and without the laser. A thermo-mechanical model for chip formation with and without the laser was also undertaken for different cutting parameters. In order to understand the more » effect of the laser on chip formation and on the temperature fields in the different deformation zones, thermo-mechanical simulation were undertaken. The temperature field in the cutting zone is therefore influenced by many parameters. The laser heat input is essentially superficial and results in non-uniform temperature profiles within the depth of the workpiece. Experimental investigations have confirmed that the cutting force can be decreased, by as much as 40%, for various materials (tool steel, titanium alloys and nickel alloys). The heat input is provided by a high power laser focused several millimeters in front of the cutting tool. Laser Assisted Machining (LAM) improves the machinability of materials by locally heating the workpiece just prior to cutting. international conference on numerical methods in industrial forming processes, Porto (Portugal), 17- Other Information: DOI: 10.1063/1.2740967 (c) 2007 American Institute of Physics Country of input: International Atomic Energy Agency (IAEA) Journal ID: ISSN 0094-243X Country of Publication: United States Language: English Subject: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS 36 MATERIALS SCIENCE CHROMIUM-MOLYBDENUM STEELS COMPUTERIZED SIMULATION CUTTING CUTTING MACHINES CUTTING TOOLS DESIGN MILLING NUMERICAL ANALYSIS = ,
Publication Date: Thu May 17 00:00: OSTI Identifier: 21057342 Resource Type: Journal Article Journal Name: AIP Conference Proceedings Additional Journal Information: Journal Volume: 908 Journal Issue: 1 Conference: NUMIFORM '07: 9. LPMM, ISGMP, Universite Paul Verlaine, Ile du Saulcy, 57000 Metz (France).Institut FEMTO-ST, Departement LMARC, ENSMM, 24 chemin de l'epitaphe, 25000 Besancon (France).