せん断形切りくず生成機構の塑性学的解析(第2報)

Abstract

The visioplasticity technique which was presented in a concrete form in the previous paper is applied to the analysis of discontinuous and continuous chip formations.The plastic deformation at the initial stage of discontinuous chip formation is essentially E.H. Lee's type pseudo-steady plastic flow although the flow does not last so long as to show any practical importance.Variation of plastic deformation, slip line field and its hodograph with cutting time during a cycle of producing discontinuous chip segment are obtained with the aid of grid lines engraved on a side of the workpiece. The plastic flow, slip line field and its hodograph for continuous chip formation are also obtained using the same technique and compared with the results for discontinuous chip formation. The comparison shows a great resemblance in slip line field and hodograph as well for the both types of chip formation although the grid line deformations are entirely different. This means that instantaneous properties of the each plastic field are es sentially the same, and transition between the two types of chip formation appears to be quite smooth.Under a very high friction condition on tool-face, built-up edge is sometimes formed from half-way of discontinuous chip formation. The possibility of the formation is discussed with the properties of slip line, and hodograph.