The authors have been developing a pipe bender which fabricates pipes of three-dimensional complex shapes from straight pipes based on the penetration bending method. This bender is composed of a movable die supported by a drive mechanism, a fixed die and a pipe feeder. A 3-RPSR parallel mechanism was employed as the movable-die drive mechanism, and its kinematic design was figured out under th...

Bending operations are frequently used to produce sheet metal components. Spring-back is an issue in sheet metal forming processes and some times is a principle problem for producing precise components. This is more important if some kind of cuttings exists on the bending surfaces. Experiments show that punched holes on bending surfaces affect the value of the spring-back. In this paper the spr...

Thin-walled tube bending is still to be considered a new and advanced technique. The process has been adopted into several industries such as aero and automotive. This process may produce a wrinkling, bulking and tearing phenomenon if the process parameters are inappropriate, especially for tubes with large diameter and thin wall thickness. Push bending process is one of the methods used for be...

The objective of this study is to evaluate the existing test methods of die strength, including widelyaccepted three-point and four-point bending tests, and a newly-proposed point-load test by testing silicon die specimens with different surface conditions. It has been reported that there are three factors to influence die strength: the surface conditions of the die (including grinding-mark dir...

The V-die bending force is an important parameter in respect of press machine capacity selection, but it has not been the focus previous research. Furthermore, while various modified formulas proposed research were calculated using theory, they are insufficient for predicting actual force. Based on mechanism, a new formula this study, which generated only allowance zone also legs next to zone. ...

The sheet metal bending process plays an important role in production and springback is unintended consequence of this operation. If the die performed without knowing amount springback, it difficult to produce parts within acceptable tolerance values. behavior part be bent also affects size die. In particular, case a 90° U bend die, manufacturing cost with compensation method high. Therefore, e...