The optimal die semi-angle concept in wire drawing, examined using automatic optimization techniques

Abstract

International audienceCoupling of evolutionary algorithms (EA) with meta-models (MM) is used to investigate the concept of the optimal die semi-angle in wire drawing. Traditional process design by minimization of the wire drawing force highlights an optimal die angle which increases with friction factor and reduction ratio. When wire drawing optimization is applied on the Latham and Cockcroft damage criterion, an optimal die semi-angle no longer appears: in this mono-objective optimization, the lowest industrially achievable die angle is recommended. Thanks to EA-MM coupling, multi-objective optimizations have been performed and the Pareto optimal front has been precisely plotted so as to find the best compromise. Simultaneous optimization of damage and wire drawing force suggests a refined vision of the optimal die semi-angle concept. Choosing a lower angle than the traditional optimum allows damage to be decreased without a significant increase of the drawing force. However, it is shown that a die semi-angle slightly above the optimum should be selected, for fear of friction drift; this explains the rather high traditional value of the angle

Comparison of reduction ability between multi-stage cold drawing and rolling of stainless steel wire – Experimental and numerical investigations of damage

“…Although successful applications were obtained with above-mentioned studies, few of these results were validated by experiments. Massé et al (2013) performed an optimization on a single drawing pass to deduce an optimal die angle to minimize drawing force and damage using the Latham-Cockcroft fracture criterion (Cockcroft and Latham, 1968). Based on multi-objective optimization, the authors showed that for the range of industrially used angles, a strong decrease of damage could be obtained at the expense of small increase of drawing force.…”

Effects of Process Conditions, Material Properties, and Initial Shape of Flaw on the Deformation Behavior of Surface Flaw during Wire Drawing

“…Die angle is important parameter in wire drawing process since it strongly affects homogeneity of mechanical properties of drawn wire along the radial direction as well as drawing force. [18][19][20] Figure 4 shows the deformation behaviors of surface flaw of drawn wire with die angle and total RA. The depth of surface flaw decreased with increasing total RA, but the deformed shape of surface flaw was different with die angle.…”

Impact of Die Radius in a Streamlined Die during Wire Drawing

“…Although the properties of the drawn wire have complex interactions with several process parameters, three process parameters in particular can affect the abovementioned four issues during wire drawing: reduction of area (RA) per pass, die angle, and friction at the wire-die interface. Therefore, many researchers have investigated the influence of RA per pass [6,12,13], die angle [14][15][16], and friction at the wire-die interface [17,18] on the drawing force, strain inhomogeneity, defects, and die life.…”