Recent advances in plasticity applications in metal machining: slip-line models for machining with rounded cutting edge restricted contact grooved tools

Abstract

This paper presents a summary of new findings on plasticity applications in metal machining, primarily covering the recent efforts on developing new slip-line models for machining with restricted contact grooved tools which involve a finite cutting edge radius. Extended application of the initially developed plane-strain, rigid-plastic slip-line fields to take account of strain, strain-rate and temperature effects is shown to provide non-unique solutions for machining with grooved tools which most commonly incorporate geometric features such as a restricted contact and a rounded cutting edge. Predictions of cutting forces, chip thickness, chip up-curl radius, temperatures and flow stresses at the primary shear zone and at the tool-chip interface, etc. are made for a range of input conditions in orthogonal machining. The practical impact of these new findings on tool-wear and cutting tool design are emphasised in this paper.

Sustainable manufacturing: Modeling and optimization challenges at the product, process and system levels

“…Hence, there is a need for improved predictive process models. Developing predictive models for machining performance measures has been a major focus area for research over the last few decades [15][16][17], with CIRP taking a leading role by establishing an annual international conference series on modeling of machining operations.…”

“…Major research efforts have also been undertaken to develop new and practical slip-line models for machining of ductile materials with rounded cutting edge restricted contact grooved tools [16,17]. The new slip-line model was combined with Oxley's machining theory [23] to predict cutting forces, chip thickness, chip curl radius, strain, strain-rates and temperatures in the shear zone, and at the tool-chip interface [16].…”

Experimental study of Built-Up Layer formation during machining of high strength free-cutting steel

“…Only a few authors led experiments using cutting inserts with chip breaker, for instance Essel (2006) for free cutting steels and Nordgren and Melander (1990) for engineering steels. Chip breaker largely modifies stress distribution at the tool-chip interface (Wang and Jawahir, 2007), and thus BUL location is changed. Sulphide layers were observed in the vicinity of the cutting edge and at the end of the tool-chip contact zone (Nordgren and Melander, 1990) or (Essel, 2006) when BUL is currently observed in the middle of the tool-chip interface with plane rake face.…”

A New Slip-Line Field Modeling of Orthogonal Machining with a Rounded-Edge Worn Cutting Tool

“…But it is known that the cutting edge of a tool cannot be produced perfectly sharp, and the nature radius of cutting edge was estimated as of 0.007 mm (Albrecht, 1960) and a dead metal zone was formed in fornt of the rounded-edge cutting tool (Abdelmoneim, 1980;Abdelmoneim and Scrutton, 1974;Karpat and Ozel, 2008;Waldorf et al, 1998). Various slip-line field analyses were carried out for the rounded-edge cutting tools (Abdelmoneim and Scrutton, 1974;Abdelmoneim, 1980;Karpat and Ozel, 2008;Fang, 2003aFang, , 2003bFang and Fang, 2007;Jin and Altintas, 2011;Waldorf et al, 1998;Wang and Jawahir, 2007). In Fang's (2003aFang's ( , 2003b slip-line field model for a rounded-edge cutting tool, the tool edge roundness was comprehensively defined four variables as tool edge radius, position of the stagnation point on the tool edge, tool-chip frictional shear stress above the stagnation point on the tool edge and tool-chip frictional shear stress below the stagnation point on the tool edge.…”

“…These included cutting forces, ploughing force, chip up-curl radius, chip thickness, tool-chip contact length, thickness of the primary shear zone, average shear strain in the primary shear zone and average shear strain-rate in the primary shear zone. In the some studies (Fang, 2003a(Fang, , 2003bWang and Jawahir, 2007) rounded-edge of cutting tool was divided into two straight chords to simplify the models and the existence of dead metal zone was neglected.…”