ON THE SIMULATION OF CHIP FORMATION PROCESS BY METAL-CUTTING

The central element of a technological system is the process of cutting. For quality control of the process it is necessary to construct chip formation model adequate to real conditions of cutting. The model should be rather simple and at the same time, it should display physical phenomena during chip formation process. In addition, the model should have various dynamic characteristics and correlate with experimental data when varying its parameters.

It is known, that within continuous chip formation parallel processes take place: the processes of elastic and plastic deformation of a cut off layer, deformation of base metal along the hypothetical shear plane, the processes of contact interaction (friction, adhesion, diffusion, etc.) of formed chip with the face of tool, as well as the contact interaction of base metal with the worn place of tool backoff.

Five models of metal cutting process will be considered in the article. The first model is the model with one-surface method of chip formation. Chip formation in this model is described as a process of plastic deformation within a single shear plane.

In the second model chips are formed in the result of successive shift along the plane of elementary volumes of a cut off layer, which is not plastically deformed.

In the third model, it is assumed, that plastic deformation of metal in the shear zone is a result of compression of metal layer, and in this case the friction of chip on the face of tool and the cutting temperature are taken into account.

In the fourth model the shear zone is represented in the form of a plastically deformed wedge bounded by straight glides.

In the fifth model the method of developed deformation zone with out-of-straightness shear surfaces is used.

The analysis of chip formation models and rheological models corresponding to the types of chip formation process showed that the construction of a single universal physical model is improbable. The author suggests a number of rheological models. The worked out models serve as the basis for optimization of automatic cutting process control systems.