Simulation of Intermittent Turning Processes.

A simulation model is developed to study the dynamic characteristics of intermittent turning operations. Factors such as chip load, free-vibration of the toolpost structure, and nonhomogeneous hardness distribution in the material being cut are incorporated in the model. The principle of superposition is used in the formulation of the simulation algorithm. The impact between the cutting tool and the workpiece at the start of every cutting period during machining is treated as an initial value problem. The simulation model provides a quantitative evaluatior of the tool vibratory motion during the intermittent turning process. Study of the cutting dynamics based on the simulation results not only confirms the experimental findings, but also indicates that increasing the static stiffnes of the toolpost structure is an effective approach to control the tool vibratory motion. The determination of a probability of tool breakage under various spindle speed settings is presented as an example to demonstrate the practical applications of the simulation model developed in this work

Simuiation of Surface Topography Fonned during the Intermittent Turning Processes.

This paper presents a methodology that employs computer simulation to dynamically generate the topography of a surface machined during an intermittent turning process. The methodology is based on a mathematical model that characterizes the intermittent turning process as an alternatiing sequence of forced and free vibratory motion. The simulation of machining workpieces, with discontinuous geometries of arbitrary shape, is facilitated by representing the workpiece surface as a two- dimensional grid, with an index for each cell in the grid accounting fo' the feature boundaries. The tool vibratory motion is integrated with the tool geometric motion to form a basis for the construction of surface texture produced during the machining. The simulation model not only provides for a quantitative evaluation of the surface accuracy through a graphic visualization of the surface topography, but also provides a quantitative estimate of the roughness quality of the machined surface

Simulation of Surface Topography Formed During the Intermittent Turning Processes

[[abstract]]This paper presents a methodology which employs computer simulation to dynamically generate the topography of a surface machined during an intermittent turning process. The methodology is based on a mathematical model that characterizes the intermittent turning process as an alternating sequence of forced and free vibratory motion. The simulation of machining workpieces, with discontinuous geometries of arbitrary shape, is facilitated by representing the workpiece surface as a two-dimensional grid, with an index for each cell in the grid accounting for the feature boundaries. The tool vibratory motion is integrated with the tool geometric motion to form a basis for the construction of surface texture produced during machining. The simulation model not only provides for a qualitative evaluation of the surface accuracy through a graphic visualization of the surface topography, but also provides a quantitative estimate 01 the roughness quality of the machined surface.[[booktype]]紙