Patent Application
20050120766
1. Field of the Invention
The present invention relates to an apparatus and a method for forming an article and performing a secondary operation on the article in-situ, and more particularly to an apparatus for superplastic forming an article and performing a cutting, flanging, and/or restrike operation on the article while the article is in the apparatus.
2. Background Art
Forming methodologies, such as superplastic forming, are used to make various metal parts. In superplastic forming, a sheet of metal having superplastic characteristics is formed into a desired shape using a die. More specifically, the die and metal sheet are heated to a temperature at which the metal sheet exhibits superplastic characteristics, then gas pressure is applied to stretch a portion of the sheet into a die cavity.
Secondary operations, such as trimming, were previously performed on the part after it was removed from the die. Performing secondary operations apart from the die increases facilities and tooling costs, labor costs, floor space requirements, and overall process cycle time. In addition, the use of separate secondary operations reduces part quality due to warpage that occurs if the part is removed from the die before it is sufficiently cooled, mishandling, and misalignment if parts are improperly refixtured to perform a secondary operation.
Before applicant's invention, there was a need for an apparatus and a method for forming an article and performing secondary operations in-situ to reduce costs and improve quality. Problems associated with the prior art as noted above and other problems are addressed by applicant's invention as summarized below.
According to one aspect of the present invention, an apparatus for superplastic forming an article and performing a secondary operation on the article in-situ is provided. The apparatus includes a die having a cavity having a forming surface of a predetermined shape. A closure seals against the die. A source of pressurized gas is supplied to force a sheet located between the cavity and the closure into contact with the cavity and form a portion of the sheet into the forming surface. A tool is movably connected to the apparatus and is configured to perform a secondary operation on the sheet. The tool is advanced to perform the secondary operation while the sheet is held in compression between the cavity and closure and in contact with the forming surface.
The tool may be disposed adjacent to the perimeter of the die or closure. The apparatus may include an aperture adapted to receive the tool. The aperture may be disposed in the die, the closure, and/or outside the cavity.
According to another aspect of the invention, an apparatus for shaping an article made from a metal sheet and performing a secondary operation on the article in-situ is provided. The apparatus includes first and second die members and a source of pressurized gas. The first die member includes a cavity defining a predetermined shape and an aperture. A tool is disposed in the aperture and is slidably engageable with the article. The second die member includes an inlet for providing pressurized gas to force the metal sheet against the cavity to shape the article. The tool is advanced to perform a secondary operation on the article after the article is shaped and before the article is removed from the cavity.
The secondary operation may be a cutting operation performed with a cutting tool, a flanging operation performed with a flanging tool, and/or restrike operation performed with a restrike tool. The second die member may include an indentation for receiving the tool when the tool is advanced.
According to another aspect of the invention, a method for making an article with a superplastic forming apparatus is provided. A metal sheet is secured between the die and the closure. A portion of the metal sheet is superplastic formed into a predetermined shape corresponding to a cavity in the die. A tool is advanced to engage the article and perform a secondary operation on the article when the article is secured between the die and the closure. The tool is retracted and the die and the closure are moved apart to allow the article to be removed from the die.
The step of advancing the tool to engage the article may occur while a portion of the sheet is being superplastic formed. The step of advancing the tool to engage the article may include providing a pressurized gas to force the metal sheet against the tool and keeping the tool advanced until the metal sheet retains a shape imparted by the tool. The step of retracting the tool may occur after the die and closure are moved apart.
Referring to
The forming apparatus 10 includes a die lid or closure 12 and a die 14. In the embodiment shown in
The closure 12 and/or die 14 may be moveable with respect to each other. Movement may be accomplished using any suitable mechanism, such as hydraulic, pneumatic, or mechanical devices.
In
The die 14 includes a second cavity 22 having a predetermined shape. The die 14 may include multiple cavities for forming more than one part. The die 14 may also include a heated platen 24 for heating the die 14 and a cooling plate 26 for cooling the die 14. The heated platen 24 and cooling plate 26 may also support the die 14.
In the embodiment shown in FIGS. 1 and
The tool 30 may have any suitable configuration for the secondary operation being performed. The secondary operations may include cutting, flanging, and/or restriking. The term “cutting” refers to any operation that severs a portion of the part, such as a trimming or piercing operation.
Referring to
A metal sheet 40 is used to form one or more parts. The metal sheet 40 may be made from any suitable material that exhibits superplastic properties, such as aluminum, magnesium, steel, or titanium.
The metal sheet 40 is positioned between the closure 12 and the die 14 to form a part. A seal is created between the closure 12, the die 14, and the metal sheet 40 when the forming apparatus 10 is closed. Pressurized gas is provided via inlet 16 to the cavity 18 to create a pressure differential between cavities 18 and 22, respectively, to facilitate forming of the part. Optionally, a sealing bead and a corresponding groove may be disposed on the closure 12 and the die 14 to promote sealing.
Referring to
A method for performing a cutting operation will now be described in more detail. In
In
In
Subsequently, the movable member 32 and the tool 30 may be retracted. The closure 12 and die 14 may be moved apart to permit removal of the part. The metal sheet 40 may be removed from the forming apparatus 10 in any suitable manner, such as by gas ejection, mechanical ejection, or manual removal.
Referring to
The forming apparatus 110 includes a closure 112 and a die 114. The closure 112 includes an indentation that provides clearance for a cutting tool 130 when the cutting tool 130 is advanced. Since the tool 130 is located outside the die 114, the die 114 does not include an aperture.
In
In
In
Referring to
In
In
In
Referring to
In
In
In
The embodiments previously discussed may be combined in any combination. For example, a forming apparatus may be created that includes any suitable number of cutting, flanging, and/or restriking operations. Moreover, the secondary operations and their respective tools may be located in either the closure or the die and in any suitable combinations.
While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.
