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

Abstract

Influence of the contact pressure in the deep drawing processes is a very actual research topic in the metal forming technology. Within this research the tribological model of the strip sliding in the flat die was developed. The original experimental computerized apparatus for testing of the strip sliding in the variable contact pressure conditions was developed, as well. The complex, multi-factor experiment was performed by application of the Al thin sheet, with the contact elements of various roughnesses, with different lubricants application and with the variable contact pressure. Besides the description of the developed apparatus, the theoretical way for determination of the pressure dependences was also presented. Based on the theoretical changes of pressure, set in advance, the real influence of the contact pressure was obtained, for each of the given conditions. That makes possible to determine the influence of the tribological factors on the actual pressure. The obtained real contact pressure has verified the reliability of the experimental apparatus, namely the degree of the theoretical pressure dependences deviation from the real ones.

Influence of TiN Coating on the Drawing Force and Friction Coefficient in the Deep Drawing Process of AlMg4.5Mn0.7 Thin Sheets

“…The force is transferred to the exchangeable elements (ma the alloyed tool steel X37CrMoV5-1), which hold the thin sheet strip of AlMg4.5M (Figure 4). Since the surfaces are different, the surface roughness values of the elem were determined as well (Table 1) [28]. 3 [27].…”

“…The force is transferred to the exchangeable elements (made of the alloyed tool steel X37CrMoV5-1), which hold the thin sheet strip of AlMg4.5Mn0.5 (Figure 4). Since the surfaces are different, the surface roughness values of the elements were determined as well (Table 1) [28]. Prior to the start of the test, it was necessary to determine and define four dependencies of the contact pressure according to which the experiment was to be performed.…”

“…Prior to the start of the test, it was necessary to determine and define four dependencies of the contact pressure according to which the experiment was to be performed. Those non-linear functions (P1 to P4), presented in Figure 5a,b, were defined based on empirical values of the minimum and maximum pressure (0 to 20 MPa) [28,29]. The pressure variation step is 60 mm, corresponding to the laboratory press properties [30].…”

“…The friction coefficients were calculated for each of the mentioned conditions based on the obtained values of traction forces, actual contact pressures and the known contact area between the sheet metal strip and the sliding elements. Diagrams of the actual contact pressures are presented in detail in [28].…”

“…Four variable dependencies of the contact pressure in terms of time were predefined for the needs of the planned experiment [28].…”