FE Simulation on Blank Holder Control Using Friction Reducing Algorithm in Deep Drawing Process

Abstract

Recent global efforts to resolve environmental issues are required in sheet metal forming. For this reason, some research projects have been focused on unlubricated processes as well as on the use of volatile lubricants. However, low formability due to poor lubrication conditions is still a matter of concern. In this study, in order to improve the friction conditions, a new algorithm for controlling blank holding force (BHF) and punch speed (SPD) was proposed. The concept is to separate the wrinkle eliminating process from drawing process. That is, the process proceeds with an extremely low BHF until a wrinkle sufficiently grows, and the wrinkle is eliminated by BHF loading without punch penetration. Its effectiveness was investigated by finite element (FE) simulation, in which two blank models (0.5 mm and 1.0 mm thickness) were used. As a result, the maximum forming forces decreased by 5.33% (0.5 mm) and 1.55% (1.0 mm) compared with those of the uncontrolled model at a constant minimum BHF. In addition, a thinner blank sheet is better for the algorithm on the basis of the result that cup height decreases and thickness distribution increases in the case of 0.5 mm thickness.

Effect of alternating blank holder motion of drawing and wrinkle elimination on deep-drawability

“…The effectiveness of the present blank holder control method has been demonstrated [7]. However, the effect on formability was not investigated in detail.…”

“…In order to improve the formability of thin blanks, an algorithm for controlling blank holder motion has been proposed by us [7]. Blank holder motion control is based on the status of wrinkling.…”

Finite element analysis of deep drawing

“…Manabe et al 4 have proposed the interaction between the extension speed and the pressing force, having simulated the wrinkling and rupture of the metal material during the extension process, having analyzed the thickness distribution of the finished product, and having defined the range value of the wrinkle, indicating that the extension was related to the extension speed and the pressing force. Liu 5 No flywheel mechanism stores energy, and processing energy is provided by servo motor Figure 1.…”

“…Manabe et al 4 have studied the extension speed and the pressing force proposed by the research institute to simulate the wrinkling and rupture of the metal material during the extension process, analyze the thickness distribution of the finished product, and define the range value of the wrinkle, indicating the extension condition and the extension speed and the pressing force. The servo punch curve was discussed to improve the formability.…”

The effect of lubrication on die expansion during the deep drawing of axisymmetrical steel cups

“…Work in validating these models has to date been limited to indirect measurement of the film thickness as details were given by Mahdavian and Shao (1993), Mahdavian and He (1998). Even though in recent years numerous researchers (Shawki, 1968;Prakash et al, 2003;Kuvin, 2004;Manbe et al, 2005;Caglar et al, 2005) have investigated other aspects of deep drawing in particular by finite element simulation of the process, but the effect of die expansion or tooling deformation have been overlooked. 0924-0136/$ -see front matter © 2007 Elsevier B.V. All rights reserved.…”