A friction model for loading and reloading effects in deep drawing processes

Mathematical modelling of an experimental‐analytical method for friction coefficient determination in deep drawing

“…Various experimental tests have been developed to measure the friction coefficient. A few important experimental tests are: tensile strip test, deep drawing, U-shaped strip drawing, rotational friction test, bending under tension, draw-bend simulator test, pin-on-disk and ball-on-disk tests [3][4][5][12][13][14][15][16]. In order to determine the influence of different tool surface roughness (Ra = 2.5 mm, 1.25 mm, 0.63 mm and 0.32 mm) on friction coefficient, bending under tension test was used [4].…”

“…Except surface roughness, contact pressure has a great impact on friction coefficient and most of the mentioned methods are only valid for measuring average friction coefficient over the constant pressure area (rotational friction test, pin-on-disk, draw bend test etc.) [3,[14][15]. By means of the finite element method simulation, in the conventional draw bend simulator test pressure area maps were determined and suggested non-uniform contact pressure [10].…”

“…Also at higher sliding speeds friction coefficient becomes more pressure independent [10]. Furthermore, the friction coefficient also decreases with the increase of contact pressure during loading [14]. Sliding friction model for different modes of surface deformation in boundary lubrication regime was developed.…”

“…Sliding friction model for different modes of surface deformation in boundary lubrication regime was developed. According to the sliding model, where the roughness of both the sheet material and the tool was included, with contact pressure increment the sheet material is subjected to an asperity flattening process which results in friction coefficient decrement [14]. Furthermore, in order to determine friction coefficient on aluminum AA6016 sheet under various surface roughness and pressure the rotating friction tester was used [18].…”

Tool life prediction under multi-cycle loading conditions: A feasibility study

“…It is of great importance to carry out FE simulations for multi-cycle loading to predict the tool life for metal forming processes. Karupannasay et al used a rotational friction tester to simulate the loading and reloading of the workpiece in a deep drawing process [13]. Pan et al investigated a multi-cycle micro-forming process in terms of temperature changes in the die after cycles of loading, in which the heat transfer between the die and workpiece was given as a function of time [14].…”