A method for producing a complex sheet metal part includes clamping a border region of the metal sheet between a die ring of an upper tool part of a pressing tool and a downholder of a lower tool part of the pressing tool; moving the upper tool part further downwards thereby pulling the metal sheet over extended punch inserts of a punch of the lower tool part, thereby generating local material reserves of the metal sheet; moving the upper tool part further downwards while actively retracting the punch inserts, thereby releasing the local material reserves; and forming the metal sheet between the die and the punch using only the local material reserves.

The present invention discloses a forming device for a large thin-walled part with a curved surface, which includes a punch, a blank holder, a die, a lower die plate, a first annular sleeve and second annular sleeves. The first annular sleeve is connected with first driving oil cylinders. An inner diameter of the die is greater than an outer diameter of the punch. The first annular sleeve is arranged in a gap between the punch and the die. The second annular sleeve is arranged at the bottom of the punch. The first annular sleeve is arranged outside the second annular sleeve. The second annular sleeve is connected with second driving oil cylinders. The first driving oil cylinders and the second driving oil cylinders are connected with a hydraulic system.

The present invention discloses a forming device for a large thin-walled part with a curved surface, which includes a punch, a blank holder, a die, a lower die plate, a first annular sleeve and second annular sleeves. The first annular sleeve is connected with first driving oil cylinders. An inner diameter of the die is greater than an outer diameter of the punch. The first annular sleeve is arranged in a gap between the punch and the die. The second annular sleeve is arranged at the bottom of the punch. The first annular sleeve is arranged outside the second annular sleeve. The second annular sleeve is connected with second driving oil cylinders. The first driving oil cylinders and the second driving oil cylinders are connected with a hydraulic system.

A forming press for forming a sheet-like blank has a first thermally insulated frame part having a die with a negative engraving and a second thermally insulated frame part defining a chamber and having a punch movably disposed in the chamber. The sheet-like blank rests in a sealing manner on the second frame part and covers the punch so as to define a pressure chamber with the punch therein. A pressure generator provides a pressurized gas to the pressure chamber during a forming process.

A forming press for forming a sheet-like blank has a first thermally insulated frame part having a die with a negative engraving and a second thermally insulated frame part defining a chamber and having a punch movably disposed in the chamber. The sheet-like blank rests in a sealing manner on the second frame part and covers the punch so as to define a pressure chamber with the punch therein. A pressure generator provides a pressurized gas to the pressure chamber during a forming process.

A method includes: forming either one or both of convex and concave bead portions at surface portions corresponding to sites of a side wall portion on both sides of a convex curve site and to sites of a side wall portion on both sides of a concave curve site; and squashing the bead portions, wherein the bead portions formed on both sides of the convex curve site are tilted such that an end part of the bead portion positioned on the convex curve site side is farther from a baseline and the other end part is closer to the baseline; and the bead portions formed on both sides of the concave curve site are tilted such that an end part of the bead portion positioned on the concave curve site side is closer to the baseline and the other end part is farther from the baseline.

A method includes: forming either one or both of convex and concave bead portions at surface portions corresponding to sites of a side wall portion on both sides of a convex curve site and to sites of a side wall portion on both sides of a concave curve site; and squashing the bead portions, wherein the bead portions formed on both sides of the convex curve site are tilted such that an end part of the bead portion positioned on the convex curve site side is farther from a baseline and the other end part is closer to the baseline; and the bead portions formed on both sides of the concave curve site are tilted such that an end part of the bead portion positioned on the concave curve site side is closer to the baseline and the other end part is farther from the baseline.

An exemplary die assembly includes, among other things, a first die having a male bead, a second die having a female bead configured to receive the male bead to hold a workpiece between the first die and the second die, and a step in the male bead, the female bead, or both. An exemplary forming method includes, among other things, holding a workpiece between a male bead of a first die and a female bead of a second die, wherein the male bead, the female bead, or both have at least one step.

An exemplary die assembly includes, among other things, a first die having a male bead, a second die having a female bead configured to receive the male bead to hold a workpiece between the first die and the second die, and a step in the male bead, the female bead, or both. An exemplary forming method includes, among other things, holding a workpiece between a male bead of a first die and a female bead of a second die, wherein the male bead, the female bead, or both have at least one step.

A method of forming a surface in a panel includes positioning a panel blank between a stationary die and a moveable die of a die set, and moving the moveable die toward the stationary die to deform the panel blank therebetween. Positive stresses in the panel blank are maintained in the region of the panel blank that will form the surface by forming a bead along a length of the surface to be formed in the panel blank, as the moveable die moves toward the stationary die. The moveable die continues to move toward the stationary die, while maintaining positive stresses in the panel blank in the region of the panel blank that will form the surface, to further deform the panel blank into a formed shape that includes the surface.