Mechanisms of formation of different types of metal chips

The aim of the work is to determine the cause-and-effect relationships of the formation of different types of chips during the processing of metal alloys.The research methodology involved the use of both experimental work and Finite Element Analysis.Deformations during the cutting of steels AISI 1045 and AISI 321 were studied.It was established that during cutting, depending on the ratio of compression and bending deformations, three types of chips are formed: solid, segmented, and fragmented.Finite element calculations prove that regardless of the properties of the material being processed, the maximum stresses in the workpiece arise near the cutting edge, which is a stress concentrator.Subsequently, if the tool contacts a brittle material, a crack appears in front of the cutting edge.If the material demonstrates plastic properties, a zone of increased plasticity is formed.In both cases, a console is formed, which creates bending deformation in the cutting zone.Analysis of the distribution of deformations in the cutting zone showed that the formation of chips during the cutting of elastic-plastic materials can occur either as a result of simultaneous fracture along the shear plane and the surface between the allowance and the workpiece, or exclusively along the surface between the allowance and the workpiece.In the first case, a segmented chip is formed, and in the second -a solid one.When a crack forms near the cutting edge, further bending destroys the console, and fragmented chips appear.If bending is impossible, a compression fracture occurs, and small fragments and dust are formed.Controlling the chip formation mechanism by adjusting the parameters of the cutting mode and using cooling allows for improving its transportation, increasing the safety of equipment operation, and the quality of the machined surface.