Effect of blank holder force with low frequency vibration technique in circular-cup deep-drawing using AZ31 magnesium alloy sheet

In the deep-drawing process, the application of low-frequency vibration to the blank material has recently been focused on with the aim of improving the friction performance between the die and the blank material. A servo-controlled press machine is suitable for applying low-frequency vibration to the blank during the deep-drawing process, because the punch speed and blank holder force (BHF) are easily controlled as process parameters by using the servo motors. In this study, a BHF with low-frequency vibration was proposed as a technique for improving deep-drawability, which is mainly affected by the friction performance and the lubricant condition. We found that the friction performance between the blank surface and the blank holder was decreased in the case of a BHF with low-frequency vibration since the lubricating oil rapidly flowed into the clearance during the forming process. Furthermore, for a BHF with low-frequency vibration, the punch force and the deformation resistance were lower than those in a deep-drawing test without low-frequency vibration.