WAVE ROLL DIE ASSEMBLY

A wave rolling assembly and a process for manufacturing a component for a vehicle using the wave rolling assembly is provided. The process includes conveying a metal coil through a first leveler to present a metal sheet, and conveying the metal sheet through a looping pit. The metal sheet travels from the looping pit to the wave rolling assembly for forming a plurality of waves along the side edges of the metal sheet. The wave rolling assembly stretches the metal sheet. The wave rolling assembly can include a die assembly or a roll forming apparatus. The metal sheet is then conveyed through a second leveler to flatten the metal sheet. The metal sheet is cut into blanks and formed into the finished component in a blanking press and die assembly. Less scrap is generated due to the reduced thickness along the edges and overall increased width of the blanks.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a wave rolling assembly for forming metal components, such as vehicle components, a system including the wave rolling assembly, and a method for forming the components using the wave rolling assembly.

2. Related Art

Components for vehicles, such as body panels, roofs, and hoods, are oftentimes formed by pressing, stamping, or otherwise shaping a metal blank in a die. The shaped blank is also cut or trimmed to a desired shape. The blank itself can be initially formed from a coil of metal, such as steel or aluminum. Typically, the coil passes through a leveler wherein it is flattened into a thin sheet. The sheet of metal then passes through a looping pit before being shaped in the die and cut to achieve the desired shape. During the cutting step, excess material (scrap) surrounding the finished component is removed. Manufacturers of the vehicle components try to limit the amount of scrap generated in order to reduce costs. One method used to reduce scrap during a trimming process includes vertically cutting waves into opposite ends of the metal blanks (pitch direction). However, additional methods for reducing scrap and thus reducing costs are desired.

SUMMARY

One aspect of the disclosure provides a system for manufacturing a metal component, for example a component for a vehicle. The system includes a wave forming assembly for forming a plurality of waves in a metal sheet. The wave forming assembly includes a plurality of wave roll inserts or rollers spaced from one another for applying pressure to the metal sheet and forming the waves in the metal sheet. The system further includes a leveler for flattening the waves formed by the wave forming assembly. The system also includes a press and die assembly for receiving the metal sheet after the leveler flattens the waves and forming the metal sheet.

Another aspect of the disclosure provides a wave rolling assembly. The wave rolling assembly includes a lower lock bead subplate and a pair of cassettes for receiving a metal sheet therebetween. The pair of cassettes are movable vertically for pressing and forming waves in the metal sheet. The pair of cassettes are also removable and replaceable. Each cassette includes a locking bead forming pad movable vertically and independent from the remainder of the cassette for pressing the metal sheet into the lower lock bead subplate and forming a first wave in the metal sheet. Each cassette also includes an upper wave roll insert adjacent the locking bead forming pad and a lower wave roll insert adjacent the lower lock bead subplate for forming second and third waves therebetween.

Another aspect of the disclosure provides a method of manufacturing a component. The method comprises the steps of: forming a plurality of waves in a metal sheet, flattening the waves formed in the metal sheet, and forming the metal sheet in a pressure and die assembly after flattening the waves.

DESCRIPTION OF EXAMPLE EMBODIMENTS

One aspect of the invention provides a wave rolling assembly10used in a process for forming metal components12, such as vehicle components. Example vehicle components include body panels, doors, roofs, and hoods. However, other types of vehicle components could be formed. The components12are typically formed from an aluminum-based or iron-based material, for example an aluminum alloy or steel blank.

An example of a production line including the wave rolling assembly10is shown inFIG.1. The production line begins with a coil stand14including a metal coil16wound around a spindle18. The metal coil16is formed of the aluminum-based or iron-based material, which is used to form the component12.

During the process of manufacturing the component12, the spindle18turns to continuously provide the coil16to a first leveler20. The first leveler20includes a plurality of rollers22,24which apply pressure to the coil16and progressively flatten the coil16and form the coil16into a metal sheet26. The first leveler20removes the curl from the coil16, but does not reduce the thickness of the coil16. More specifically, the first leveler20includes a top row of the rollers22and a bottom row of the rollers24, and the coil16travels between the top and bottom rows of rollers22,24. The sheet26exits the rollers22,24and travels continuously to a looping pit28. The looping pit28is an area of space capable of containing a portion of the sheet26.

In comparative processes used to form vehicle components12, the metal sheet26travels directly from the looping pit28to a press and die assembly30, where the metal sheet26is formed to the desired shape, depending on the intended vehicle application. However, according to embodiments of the present invention, the metal sheet26travels from the looping pit28to the wave rolling assembly10and a second leveler32, before the press and die assembly30. The wave rolling assembly10and the second leveler32pre-draw or stretch out the material of the metal sheet26in a width direction, which is traverse to the direction of travel of the metal sheet26. The pre-drawing and stretching ultimately reduces the amount of scrap produced in the production process, and thus reduces production costs.

More specifically, immediately after the looping pit28, the metal sheet26travels through the wave rolling assembly10which forms a plurality of waves34,36,38in the metal sheet26. According to an example embodiment, the wave rolling assembly10first forms a first wave34, referred to a lock step, along each outer edge of the metal sheet26. After the first wave34is formed, the wave rolling assembly10forms a second wave36and a third wave38along each outer edge of the metal sheet26, inward of the first wave34. The first wave34(lock step) holds the metal sheet26in place against manufacturing equipment during subsequent forming steps, for example when additional waves36,38are formed and leveled.FIGS.2and3illustrate an example of the first wave34(lock step), second wave36, and third wave38formed at each edge of the metal sheet26according to the example embodiment. According to this embodiment, the second and third waves36,38present a height of 10 mm. The waves34,36,38focus the amount and location of strain created in the metal sheet26, so that the desired amount and location of stretching and thinning of the metal sheet26can be achieved. In addition, less force is required to stretch and thin the metal sheet26when the waves34,36,38are formed in the metal sheet26, compared to a flat sheet.

Various different devices can be used as the wave rolling assembly10to form the waves34,36,38along the side edges of the metal sheet26. According to one embodiment, the wave rolling assembly10is a die assembly10a,for example the assembly10ashown inFIG.4,5, or6. The die assembly10aincludes a right and left cassette40,42which move vertically to press the metal sheet26into a lower lock bead subplate45and form the waves34,36,38. The right and left cassette40,42are removable and replaceable in order to accommodate metal sheets26of different widths. In the embodiment ofFIG.4, each cassette40,42includes a locking bead forming pad44which moves vertically, independent from the remainder of the cassette40or42, to press the metal sheet26into the lower lock bead subplate45and form the first wave32(lock step). The locking bead forming pad44typically applies a pressure to the metal sheet26ranging from 40 to 60 metric tons. According to this embodiment, each cassette40,42also includes upper wave roll insert46adjacent the locking head forming pad44and lower wave roll inserts46,48adjacent the locking bead forming pad44for forming the second and third waves36,38therebetween, after the locking bead forming pad44forms the first wave34(lock step). In the embodiment ofFIG.5, the locking bead forming pad44moves vertically, independent from the remainder of the cassette40or42, to press the metal sheet26into the lower wave roll insert48and form the first wave32(lock step). The upper and lower wave roll inserts46,48then form the second and third waves36,38therebetween. The upper and lower wave roll inserts46,48typically apply a pressure to the metal sheet ranging from 90 to 110 metric tons. The die assembly10ais typically used to stretch metal sheets26used to form smaller blanks, for example those having a pitch of less than 4000 mm.

According to another example embodiment, the wave rolling assembly10includes a roll forming apparatus10b.An example of the roll forming apparatus10bis shown inFIG.7. The roll forming apparatus10bincludes plurality of rollers50which form the first wave34(lock step) and additional waves36,38along the edges of the metal sheet26. The edges run parallel to the direction of travel of the metal sheet26. The location of the rollers50are typically provided in upper and lower rows. The location and size of the rollers can be adjusted depending on the size of the metal sheet26. The rollers50apply a pressure to the metal sheet26while the metal sheet26travels along the rollers50. The roll forming apparatus10bis typically used to stretch the metal sheets26used to form blanks having a pitch of greater than 4000 mm, such as blanks used to form hoods and roofs of vehicles.

After the wave rolling assembly10, the metal sheet26is conveyed to the second leveler32. The second leveler32can have the same design as the first leveler20, or a different design. The second leveler32applies pressure to the metal sheet26and flattens the waves3436,38out of the metal sheet26but does not further stretch or thin the material of the metal sheet26.

Typically, the width of the metal sheet26increases by at least 18%, such as 18% to 22%, for example 20%, between the start of the wave rolling assembly10and the exit of the second leveler32. The thickness of the edges of the metal sheet26is reduced by forming the waves3436,38in the metal sheet26, and the reduction in thickness varies along the waves3436,38. For example, the thickness may not change at the top of peaks and bottom of valleys of the waves3436,38. Typically, the thickness changes are parallel to the direction of the wave3436,38, and the material between the peaks and valleys is gradually thinned. The thinnest areas of the waves3436,38are typically at center points P between the peaks and valleys, and the thickness decreases gradually from the peaks or valleys to the center points P. Between the start of the wave rolling assembly10and the exit of the second leveler32, the thickness of the edges of the metal sheet26is typically reduced by at least 8% to 12% at the center points P. After the step of forming the waves, the edges of the metal sheet26are typically spaced from one another by a section of the metal sheet26that does not include the waves3436,38.

According to an example embodiment, the initial coil16has a width, at the start of the production process, of 1167 mm. The coil16is flattened in the first leveler20and has a width of 1167 mm upon exiting the first leveler20. The coil16then passes through the wave rolling assembly10where the width of the coil16increases to 1186 mm. The coil16then passes through the second leveler32, and the metal sheet26maintains the width of 1186 mm upon exiting the second leveler32.

The production process, which includes the wave rolling assembly10and the second leveler32, can be used to manufacture various different components12for vehicles.FIG.8is an example of a vehicle hood,FIG.9is an example of a roof panel,FIG.10is an example of a front door panel, andFIG.11is another example of a vehicle panel, each manufactured using the wave rolling assembly10and the second leveler32.