Stress Distribution at the Interface Between Tool and Chip in Machining

Abstract

Stress distribution along a tool rake face were measured directly in the orthogonal machining of various metals. The method of measurement was based on the use of a composite tool which was divided into two parts parallel to a cutting edge in order to measure separately the force acting on one section of the tool. The stress distributions under actual cutting conditions were revealed, and the relationship between the nature of stress distribution and the mechanical properties of work material was clarified. It was ascertained that the nature of stress distribution was closely connected with the strain hardening index of work material and the frictional coefficient between tool and material.

Numerical and analytical modeling of orthogonal cutting: The link between local variables and global contact characteristics

“…17a that l c =t 1 % 1:9. This value is quite close to those of the model proposed by Toropov and Ko [37] and Kato et al [38], Eq. (22).…”

“…Empirical formulations for l c were given by Abuladze [34], Poletika [35], and Marinov [36]. Of note is the simple relationship proposed by Toropov and Ko [37] and Kato et al [38]:…”

State-dependent distributed-delay model of orthogonal cutting

“…Whereas τ is the regenerative delay, which is now equal to the rotation period and can be expressed with the angular velocity Ω of the workpiece: τ = 2π/Ω. Experiments show [24,39] that the chip thicknessh(t, θ) along the rake face (also called the deformed chip thickness) is proportional to the shifted uncut chip thickness h(t + θ) (also called undeformed chip thickness):h(t, θ) = Ch(t + θ), where 1 < C < 10 is a constant depending primarily on the workpiece material and the rake angle. Thus,…”

“…Now we improve his model by recognizing that the size l of the chip-tool interface is not constant, but is a function of the time-varying uncut chip thickness h. According to experimental results presented in [24,42,44,39], the relation between the contact length and chip thickness can be described using a linear (or shifted linear) function in a wide range of uncut chip thickness values. Therefore, we assume that the contact length is proportional to the uncut chip thickness at the tool tip:…”

“…According to experiments [24,42,44,39], the length and the shape of the force distribution depends on the chip thickness, which implies that the corresponding distributed delay in the model equation is state-dependent. The scope of this paper is to explore whether this state-dependent delay affects the linear and the global stability properties of the machining operation compared to the same model with distributed delay of constant length.…”