Experimental-numerical analysis of contact conditions influence on the ironing strip drawing process

Abstract

Purpose The purpose of this paper is comparison of experimental values of the drawing forces to numerical values in different contact conditions, taking into account the appearance of galling which occurs due to of difficult drawing process conditions. Design/methodology/approach The following two research approaches are used in this paper – the physical modeling, realized by the laboratory experiment, and the numerical simulation of the ironing drawing process. By analyzing the obtained results, the technique of physical modeling, with help of the laboratory equipment and numerical simulation by application of the finite element method, can be successfully used in studying the thin sheet ironing – strip drawing process. Findings It is significant to compare values of the deformation forces obtained by physical experiment to values obtained by the numerical simulation. In that way, it is possible to compare applied contact conditions (four lubricants in that case) and estimate matching of experimentally and numerically obtained results of the deformation forces. Presented results point out very good technological characteristics of ecologically friendly lubricant (single-bath) and grease based on MoS2. Significant decrease of the deformation force was achieved by its application, as well as maintaining of the lubricant’s layer during the forming process and almost complete elimination of galling on the contact. Practical implications Numerical analysis of stresses in the working piece wall, during the thin sheet strip drawing, requires precise values of the friction coefficient. It is an important indicator because one can define the contact conditions as the input data for the numerical simulation, based on its values for each type of lubricants and each value of the compressive lateral force. Originality/value The environmentally friendly lubricant tested exhibits a more favorable distribution of the drawing force during the process, mainly in experimental case. Grease based on MoS2 has good lubricating properties but that lubricant is conventional and environmentally unacceptable. Ecologically friendly lubricant can be successfully used in real ironing strip drawing process especially for high values of holding force achieving an increased tool life.

Simulation of Flat Die Deep Drawing Process by Variable Contact Pressure Sliding Model

“…Changes on the contact surfaces (wear, glued particles) can disturb the stable course of the sliding process. Otherwise, the failure of the drawed part can occur [13], [14].…”

The Possibilities for Application of Numerical Simulation in the Ironing Process of Thin Sheets

“…A special device that models the symmetrical contact between the thin sheet and the die in strip deep drawing was constructed for experimental investigations in this work, Figure 1, [10,11]. The sheet strip is being placed into the clamping jaws 12 (Figure 1).…”

“…The physical model, used in this experiment, was realized based on previous research [10]. The applied model enables realization of high contact pressures.…”

New Method of Defining of Process Parameters in Double Side Thinning Strip Ironing Test

“…Main reason is probably great appliance of ironing forming process in modern industry. It is sufficiently to notice that industry produce by ironing process only, more than two hundred billions pieces yearly of well known product: beverage cans [5,7,9] or other products .…”