Araco Kabushiki Kaisha

Naoki Yoshioka

Yuichi Yagami

Tsuyoshi Takahashi

Kenichi Kusunoki

Mikio Wada

Masanao Shiomi

By using a hydraulic forming device, a metal plate bodyis placed on a support sectionwith a hollow sectionformed on a lower diefilled with hydraulic fluid A. Subsequently, a blank holderis lowered to clamp the peripheral edge section of the placed metal plate bodywith the support section. Then, the upper dieis lowered relative to the lower dieto pressedly deform the central section of the metal plate bodyand to compress the hydraulic fluid A to increase the fluid pressure. A rib-like convex sectionis transferred onto the metal plate bodyby the increased fluid pressure of the hydraulic fluid A and a formed section. Further, the fluid pressure of the hydraulic fluid A is kept for a predetermined time. Then, the increased fluid pressure of the hydraulic fluid A is released.

Hydraulic forming process, hydraulic forming device and metal separator for a fuel cell formed by hydraulic forming process

In a forming press, a blank is pressed formed into a press-formed workpiece by means of an upper die and a lower die, while a peripheral edge portion of the blank is clamped by means of a die and a blank holder insert of the forming press. Subsequently, a central portion of the press-formed workpiece is partially held by means of the upper die and the lower die so as to draw a peripheral portion of the press-formed workpiece away from the central portion thereof, thereby removing strain from the press-formed workpiece.

Method for removing strain from press-formed workpiece, and forming press

A sheet metal formed thereon with a number of spaced projections, wherein the projections are formed by the steps of positioning the sheet metal between a female die formed with a number of spaced recesses at one surface thereof and a male die formed with a concavity to be coupled with the female die and a number of spaced projections located at the bottom of the concavity to correspond with the recesses of the female die and pressing the sheet metal under existence of hydraulic fluid between the sheet metal and the concavity of the male die.

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Okazaki, Japan

Naoki Yoshioka