FE Analysis on Deformation Mechanism of Strain-Rate-Sensitive Materials in Cylindrical Deep-Drawing with Combination Punch Speed and Blank Holder Control

Abstract

In the sheet stamping of strain-rate-sensitive materials, the forming limit is governed by punch speed (SPD) as well as blank holding force (BHF). In previous research, a combination control algorithm for simultaneously varying SPD and BHF was proposed to achieve high-speed deep-drawing. In this study, finite element (FE) simulation is conducted for circular-cup deep-drawing with combination SPD/BHF control in order to reveal the deformation mechanism of the improvement of deep-drawability. The numerical results demonstrate that even though the blank material has a low strain-rate dependence at room temperature, the drawability and production rate can be improved by properly varying SPD/BHF. It is found, from the simulation results, that a relatively low SPD with a low BHF in the early forming stage causes less thickness reduction at the punch shoulder. In the middle-to-last stage, therefore, the remaining blank can be successfully drawn into the die cavity with SPD and BHF higher than the critical constant SPD and BHF.

Advanced In-Process Control System for Sheet Stamping and Tube Hydroforming Processes

“…By using this sophisticated complex control system, the validity of intelligent processing scheme was investigated for cold forming of small m value materials as well as warm/hot forming process of higher m value materials. From the experimental [19] and FE simulation [18] works for a steel sheet SPCE at room temperature, it was confirmed that the complex variable BHF/SPD fuzzy control approach can achieve successful process to avoid fracture even over 50 mm/min and over BHF=6 kN of allowable constant punch speed and BHF conditions, repectively, as shown in Fig. 21.…”

“…Therefore, if appropreate variable forming path could be found out in the small successful space, the variable BHF/SPD control sheet stamping process can be provided in the real production process. This is an advantage of variable BHF/SPD control approach and expresses its forming principle [18]. Fig.…”

“…18 [14]. In addtion, a virtual fuzzy BHF control sheet stamping system constructed in the FEM simulation model was developed and it can assist the process and control system designs of new sheet stamping system [16], [17], [18]. By using this virtual system, pre-evaluation of the newly developed system will be conducted, thereby it can contribute to shortening the development design period.…”

CO-JP-4 Simultaneous Optimization of Variable Blank Holder Force Trajectory and Tools Motion in Deep Drawing via Sequential Approximate Optimization

“…There are ft:w papers focusing on such controlling technique. in Refs, (16,17), in order to eliminate wrinkling during deep drawing, the BHF and the punch speed are controlled separately. The closed-loop type algorithm for wrinkling eSimination called the alternating blank holder contro1 method has been developed.…”

Simultaneous Optimization of Variable Blank Holder Force Trajectory and Tools Motion in Deep Drawing via Sequential Approximate Optimization

“…In Refs. (16,17), in order to eliminate wrinkling during deep drawing, the BHF and the punch speed are controlled separately. The closed-loop type algorithm for wrinkling elimination called the alternating blank holder control method has been developed.…”