Loading and Unloading Units and Methods for Sheet Metal Processing

Abstract

A loading and unloading unit for sheet metal providing a first tool holder is provided. Therewith, sheet metal processing tools may be passed from a first tool magazine that is attached to a fixed unit of the loading and unloading unit to a second tool holder integrated in a sheet metal processing machine or to a tool fixture of the sheet metal processing machine, and, thus, the number of tools automatically exchangeable in the sheet metal processing machine can be increased to create a more efficient and space-saving manufacturing process.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority under 35 U.S.C. §120 to, PCT Application No. PCT/EP2009/009253, filed on Dec. 23, 2009, which claimed priority to European Patent Application No. EP 08022326.6, filed on Dec. 22, 2008. The contents of both of these priority applications are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The invention relates to loading and unloading units and methods for sheet metal processing.

BACKGROUND

Many punching machines include an integrated magazine for storing punching tools used for executing certain machining steps during production of sheet metal parts. During production of sheet metal parts, which typically includes many different machining steps (e.g. punching different shapes, nibbling, thread forming), a large number of different tools are necessary. The storing capacity of tool magazines that are integrated in punching machines is often insufficient to support the many tools used to execute different machining steps.

There are different possibilities for providing a larger number of tools than that which may be accommodated in conventional tool magazines that are integrated in punching machines.

In some cases, tools can be exchanged manually (e.g., by an operator) in the tool magazine during breaks in machining processes. However, such manual methods can cause interruptions in the machining process and schedule, and also require manual effort. Therefore, such methods are generally inefficient.

Another alternative is to include a separate tool magazine in which punching tools are stored so that the punching tools can be automatically exchanged in the tool magazine that is integrated in the punching machine and picked up from the tool holders to be used for machining. However, such an alternative requires additional components of the punching machine and such components correlate to additional costs and enlarged space requirements of the punching machine. Moreover, due to the substantially high number of different machining steps that a given punching machine can be expected to execute during use, the possible number of tools to be stored is often insufficient to ensure an adequate economic production even when a separate standard tool magazine is used.

Also, in other types of sheet metal processing machines, namely bending machines, an automatic exchange of the tools is possible. The bending tools are also stored in a tool magazine in the bending machine and they are automatically moved to a position to be used in a bending station. However, due to the large dimensions of the bending tools, the cost associated with the bending tools in or at the machine can be more expensive than that of punching tools.

Further types of sheet metal processing machines in which an automatic tool exchange can be used include combination machines that combine multiple processing capabilities. Examples of such combination machines include punching/bending machines and punching/laser machines.

SUMMARY

In some aspects of the invention, a handling system is provided which automatically exchanges tools within a sheet metal processing machine without creating considerable additional space requirements or requiring substantially larger capital expenditures to be used.

In some aspects of the invention, a handling system is provided that allows a sheet metal processing device to use the same assemblies for accomplishing different tasks (e.g., to use a sheet metal workpiece loading and unloading unit as a tool handling system).

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1a shows a side view of a loading and unloading unit for a sheet metal workpiece with a tool magazine for punching and forming tools;

FIG. 1b shows an enlarged plan view of a rotatable holder with two tool holders;

FIG. 1c is a schematic side view of a sheet metal picking unit with a tool holder gripping a bending tool positioned in a tool holder;

FIG. 2 is a perspective view of a punching machine;

FIG. 3 is a perspective view of a bending machine;

FIGS. 4a through 4c illustrate tool exchange procedure for a bending machine.

DETAILED DESCRIPTION

FIG. 1a is a side view of a loading and unloading unit 1 of a sheet metal processing machine. The loading and unloading unit 1 includes a fixed unit 2. The fixed unit 2 includes a frame with two vertical stands 3 and a horizontal linear unit 4. At a movable portion of the horizontal linear unit 4, a vertical linear unit 5 is provided which is movable in a vertical direction. At its lower end, the vertical linear unit 5 includes a sheet metal picking unit 6. The sheet metal picking unit 6 includes devices (e.g., gripping fingers, vacuum nozzles, and/or magnets) for picking up sheet metal plates.

A drive 7 (e.g., an electric motor or actuator) is included in the vertical linear unit 5 for moving the vertical linear unit 5 with the sheet metal picking unit 6 in a first horizontal direction along the horizontal linear unit 5 (X-direction) and for moving in a second horizontal direction (Y-direction). A drive 8 is also included for moving the sheet metal picking unit 6 in a vertical direction.

Alternatively, one single drive can be included to provide all motion capabilities of the drive 7 and the drive 8.

A rotatable holder 9 is provided on the upper side of the sheet metal picking unit 6. The rotatable holder 9 includes two first tool holders 10 for holding tools 11 used for sheet metal processing (e.g., punching tools). The holder 9 is attached to the sheet metal picking unit 6 so that it is rotatable about a vertical axis 12. As shown in FIG. 1b, when viewed in the direction of the axis 12 (e.g., from the top or the bottom), the tool holders 10 are positioned 90° from each other. However, in some embodiments, the tool holders 10 are positioned at different angles (e.g., 180°) from each other.

In some embodiments, the rotatable holder 9 includes only one tool holder 10. In other embodiments, multiple tool holders 10 are positioned side by side in the X-direction along the sheet metal picking unit 6. In some embodiments, more than two tool holders 10 are included and are arranged around the axis 12 in a revolver-like manner. In some embodiments, in addition to a rotating around the axis 12, the rotatable holder 9 translates in the Y-direction and/or the first tool holders 10 translate radially relative to the rotatable holder 9. Also, in some embodiments, tool holders 10 provided side by side at the tool picking unit 6 can translate in the Y-direction.

Opening and closing movements of the first tool holders 10 to grip tools 11 are typically driven and controlled pneumatically. The rotary movement of the rotatable holder 9 is also typically driven and controlled pneumatically, by a pneumatic rotary drive. Alternatively, in some embodiments, the movements of the tool holders 10 and the rotatable holder 9 are driven and controlled by an electrical drive (e.g. a stepping motor). Such an arrangement can be beneficial when more than two first tool holders 10 are positioned at the rotatable holder 9.

In some embodiments, an interface is provided so that the additional weight due to moving the tool holders 10 which are held on the sheet metal picking unit 6 is not always transported during use. This interface can be the joint between the sheet metal picking unit 6 and one of the tool holders 10 or the rotatable holder 9 on which the tool holders 10 are arranged. In some embodiments, multiple interfaces are provided. The interfaces can also be movable in the Y-direction, or movement can be performed by a tool holder fixed to the interface or by the rotatable holder.

The rotatable holder 9 or the tool holder 10 is fixed at the interface by a magnetic force, a form-fit attachment, or other appropriate techniques.

A first tool magazine 13 for punching tools is provided between the two vertical stands 3. Multiple (e.g., six in the illustrated embodiment) second tool holders 14 for punching tools are included in the tool magazine 13, which are horizontally arranged side by side in the X-direction. As shown in FIG. 1a, punching tools 11 are held in the second tool holders 14.

In order to provide multiple second tool holders 14, in some embodiments, the tool magazine 13 includes the second tool holders 14 arranged along several horizontal planes. Alternatively, in some embodiments, the second tool holders 14 are arranged along one horizontal plane and positioned consecutively in the Y-direction. Also, in some embodiments, the second tool holders 14 are arranged side by side in X-direction and Y-direction.

When used with bending machines, second tool holders 14 suitable for receiving and supporting bending tools are provided, which are also arranged between the two vertical stands 3. In some embodiments, the first tool magazine 13 for punching tools or the first tool magazine 13 for the bending tools is not integrated in the fixed unit 2. In such embodiments, the first tool magazine 13 is a separate component of the machine and is arranged in or near the field of motion of the sheet metal picking unit 6.

In some embodiments, the first tool magazine 13 is positioned on the sheet picking unit 6.

As shown in FIG. 1a, a second tool magazine 15 is also included, which will be explained in greater detail below with regards to FIG. 2.

FIG. 1c shows a schematic side view of a sheet metal picking unit 6 with a fourth tool holder (e.g., a vacuum nozzle) 39 arranged on the lower side of the sheet metal picking unit 6. The first tool magazine 13 with the second tool holders 14 and bending tools 11 positioned in the tool holders 14 are also shown in FIG. 1c. In some embodiments, multiple fourth tool holders 39 are included on the sheet metal picking unit 6. The fourth tool holders 39, while described as vacuum nozzles, can alternatively or additionally be gripping fingers and/or magnets. During use, these multiple fourth tool holders 39 can be used for picking up sheet-metal plates as well as for picking up tools designed in a suitable manner. When using vacuum nozzles or magnets as tool holders, it has been found favorable to use tools having at least one larger flat portion to allow for proper engagement with the tool holder. Including larger flat portions on tools can be especially beneficial when bending tools 11 are used.

FIG. 2 shows a sheet metal processing machine in the form of a punching machine 21 that is used with or includes the loading and unloading unit 1. The punching machine 21 includes a C-frame 22 that consists of a torsionally stiff, steel-welded construction. At a rear region of the C-frame 22, a hydraulic power unit 23 is positioned, by which a ram 25 is hydraulically driven by a ram drive.

At the lower inside region of the C-frame 22, a lower tool fixture 24 is positioned for receiving and holding a lower part of a punching tool 11. The lower part of the tool is rotatable up to 360° using a rotary drive and can be locked and fixed at any desired angular position.

At the upper inside region of the C-frame 22, a ram 25 is provided. The ram 25 includes an upper tool fixture to receive and hold an upper part of a punching tool 11 in a form-fit and backlash-free manner. The ram 25 is also rotatable up to 360° and can be locked in any desired angular position. To provide rotation to the ram 25, a second rotary drive is provided.

The rotary drives as well as the driving devices 7, 8 of the loading and unloading unit 1 are controlled by a machine controller, which is provided in a separate control cabinet. The machine controller also controls a ram controller as well as all of the linear drives for moving a sheet metal plate 26 and actuators for special functions (e.g., to move the part flap 27 up and down). The machine controller includes a keyboard to enable a user to input information and a monitor that can output data to be viewed by the user. The control functions of the drives and actuators are controlled by microprocessors, and machining programs and operation parameters are stored electronically in a storage device of the machine controller.

At the lower inside region of the C-frame 22, a table 28 is arranged that includes a cross rail 29 with a linear magazine (i.e., the second tool magazine 25). Clamping claws 30 for retaining the sheet-metal plate 26 are arranged along the cross rail 29. The clamping claws 30 can be arranged at, or relocated to, suitable locations along the cross rail 29 so that the sheet metal plate 26 is safely retained but is not gripped at positions where machining shall be conducted. Multiple (e.g., three in the illustrated embodiment) third tool holders 31 for receiving multiple (e.g., two in the illustrated embodiment) punching tools 11 are included along the linear magazine 15. In front of the lower tool fixture 24, the part flap 27 is arranged centrally for transferring outward smaller sheet metal parts.

During punching operations, the table 28 travels along a programmed range of positions in the Y-direction together with the cross rail 29 on which the clamping claws 30 are arranged to hold the sheet metal plate 26. The cross rail 29, along with the clamping claws 30 and sheet metal plate 26, travels along a programmed range of positions in X-direction, whereby the sheet metal plate 26 slides over the table 28. Then, with the sheet metal plate 26 in a desired position, a punching stroke is performed by the ram 25. Subsequently, the sheet metal plate 26 is moved to the next punching position and a subsequent punching stroke can be performed.

During use, the punching tools 11 are automatically exchanged based on the punching operation to be executed, such exchange being controlled by the machine controller. For exchanging the tools 11 from the second tool magazine 15, the cross rail 29 is driven by a linear drive along the X-direction so that the position of the tool 11 to be exchanged in the X-direction corresponds to the position of the lower tool fixture 24 in the X-direction. Then, the cross rail 29 travels together with the table 28 in the Y-direction so that a central axis of the punching tool 11 is aligned with a central axis of the lower tool fixture 24 and the ram 25, so that the punching tool 11 can be held in the lower tool fixture 24 and in the ram 25. If a tool is positioned in the ram 25 and in the lower tool fixture 24, this tool is dispensed to a free space in the linear magazine 15 before the next tool is brought to the ram 25 and the lower tool holder 24.

For exchanging a tool 11 from the first tool magazine 13 with a tool in the upper tool fixture 25 and the lower tool fixture 24, first, the necessary punching tool 11 is taken from the first tool magazine 13. The sheet metal picking unit 6 travels in the X-direction such that the axis 12 of the rotatable holder 9 is aligned with a central axis 17 of the desired punching tool 11. Subsequently, the sheet metal picking unit 6 travels in the Y-direction so far backwards that the first tool holder 10 may grip the punching tool 11 (i.e., an orifice 16 (referring to FIG. 1a) of the first tool holder 10 can grip the punching tool 11 in a form-fit manner). Then, a closing movement of the first tool holder 10 is performed and the punching tool 11 is removed from the second tool holder 14 of the first tool magazine 13 of the sheet-metal picking unit 6 and moved in the opposite Y-direction by a forward movement. Then, the sheet-metal picking unit 6 travels in X-direction until the central axis 17 of the punching tool is aligned with the central axis of the upper tool fixture 25 and lower tool fixture 24 and, subsequently, the sheet-metal picking unit 6 analogously travels in the Y-direction. Thereafter, the punching tool 11 is received and retained by the tool fixtures 24, 25 in a conventional manner. When used in this manner, it is necessary that a free space is available in front of the lower tool fixture 24 because the movement for exchanging tools is typically horizontal. For creating the free space in front of the lower tool fixture 24, the part flap 27 is moved downward vertically. However, to hinge the part flap 27 to move only downward is insufficient because in this case, the hinge axis of the part flap 27 remains unchanged in the region of collision with the tools to be exchanged in the tool fixtures 24, 25.

As an alternative to moving the sheet metal picking unit 6 in the Y-direction, in some embodiments, only the first tool holder 10 or the rotary holder 9 travels in Y-direction.

The first tool holder 10 is typically moved in the Y-direction, however, the movement of the first tool holder 10 is selected such that it moves in relation to the second tool holder 14 so that the punching tool 11 can be taken out of the second tool holder 14 or the punching tool 11 can be delivered to the second tool holder 14.

In addition to the respective described methods for changing punching tools 11 of the first tool magazine 13 and the second tool magazine 15 in and out of the tool fixtures 24, 25, other methods for exchanging the punching tools 11 are possible.

In some embodiments, the punching tool 11 to be exchanged in the second tool magazine 15 is removed from the first tool magazine 13 by one of the first tool holders 10 and then passed to a third tool holder 31 in the second tool magazine 15 in the same manner that a punching tool 11 is placed in the upper tool fixture 25 and the lower tool fixture 24. When a punching tool 11 is already present in the third tool holder 31 in which the punching tool 11 is to be placed from the first tool holder 10, the rotatable holder 9 is rotated approximately 90° or the sheet metal picking unit 6 is moved in the X-direction such that another of the first tool holders 10 is positioned to remove the punching tool 11 present in this third tool holder 31. Subsequently, the rotatable holder 9 is rotated in the opposite direction, here approximately 90°, or the sheet metal picking unit 6 is moved in the opposite X-direction in order to pass the punching tool 11 to be exchanged to this third tool holder 31. The punching tool 11 that was removed from the second tool magazine 15 can then be either moved to the first tool magazine 13 or it can be inserted in the upper tool fixture 25 and the lower tool fixture 24.

Using similar techniques, the punching tools 11 may be removed from the second tool magazine 15 and moved directly to the first tool magazine 13.

In some embodiments, in which two or more of the first tool holders 10 are arranged side by side on the sheet metal picking unit 6, multiple punching tools 11 can be removed from the first tool magazine 13 and moved to the second tool magazine 15 (or removed from the second tool magazine 15 and moved to the first tool magazine 13) at the same time.

Further, depending on the number of the first tool holders 10 arranged side by side on the sheet metal picking unit 6 or the number of the tool holders included on the rotatable holder 9, several punching tools 11 may be used and positioned in other first tool holders 10.

The method for exchanging the punching tools from the first tool magazine 13 may be executed along with the loading the punching machine 21 with a sheet metal plate (i.e., the punching machine can load a sheet metal plate and the desired punching tools at the same time). In this manner, first, the desired punching tools 11 are taken from the first tool magazine 13, then, the sheet metal plate 26 is removed from a magazine in the region of the fixed unit 2 by gripping devices or vacuum nozzles and the obtained punching tools 11 are moved to the punching machine along with the sheet metal plate 26. Then, the punching tools 11 are placed in either the second tool magazine 15 or the upper tool fixture 25 and lower tool fixture 24. The sheet metal plate 26 is placed on the table 28 and moved to a position to be retained by the clamping claws 30. The unloading of manufactured sheet metal parts may also be executed along with the exchange of punching tools 11 in the first tool magazine 13.

FIG. 3 shows a bending machine 33 having a basic structure that is similar to that of the punching machine 21 shown in FIG. 2 and described above. The bending machine 33 includes an upper tool fixture 34 with a drive 36 and a lower tool fixture 35 as well as a controller. Some machine components (e.g. the tool fixtures 34, 35 and the driving device 36) are optimized for the bending process using bending tools. As shown in FIG. 3, sheet metal 26 is furnished with cut outs 37 which are bent upward using the bending machine to form upwardly bent sheet metal portions 38.

The exchanging of additional sheet metal processing tools 11 (e.g., bending tools) from the first tool magazine 13 to the bending machine or out of the bending machine to the first tool magazine 13 may also occur directly in the second tool magazine of the bending machine or directly in the tool fixtures 34, 35.

In FIGS. 4a to 4c, the upper tool fixture 34 and the lower tool fixture 35 for bending tools 11 and the sheet metal picking unit 6 with the fourth tool holder 39 (from FIG. 1b) are respectively shown. The bending tools 11 respectively include a lower part (e.g., a1, b1) and an upper part (e.g., a2, b2).

A method of exchanging the bending tools out of, and into, the tool fixtures 34, 35 is described below.

As shown in FIG. 4a, a bending tool with a lower part a1 and an upper part a2 is accommodated in the tool fixtures 34, 35. To begin removing the bending tool, the sheet metal picking unit 6 travels toward the tool holders 34, 35 so that the fourth tool holder 39 is located above the lower part al, the fourth holder 39 attaches to the lower part of the tool a1 (shown in view I), the lower part a1 is loosened or released from the lower tool fixture 35, and the fourth holder 39 removes the lower part of the tool a1 out of the lower tool fixture 35 (shown in view II).

With the lower part of the tool a1 removed from the lower tool fixture 35, a lower part b1 is inserted in the lower tool fixture 35 using the fourth holder 39 (shown in view III). Once the lower part b1 is inserted in the lower tool fixture 35, the lower part b1 is fixed or fastened in place in the lower tool fixture 35.

As shown in FIG. 4b, the upper tool fixture 34 having the upper part of the tool a2 is moved downward to contact the lower part b1, which is positioned in the lower tool fixture 35. Once in contact with the lower part b1, the upper part of the tool a2 is loosened or released from the upper tool fixture 34 so that when the upper tool fixture 34 moves upward and away from the lower tool fixture 35, the upper part of the tool a2 remains positioned on the lower part of the tool b1 (shown in view IV).

Then, the sheet metal picking unit 6 travels so that the fourth tool holder 39 is located above the upper part of the tool a2, which is positioned on the lower part of the tool a1 picks up the upper part of the tool a2 (shown in view V).

With the upper part of the tool a2 removed from of the machine (shown in view VI), the upper part of the tool b2 can be moved toward the tool fixture 35 and placed on top of the lower part of the tool b1 by the sheet metal picking unit 6 and the fourth tool holder 39 (shown in view VII of FIG. 4c).

To complete the exchange of the bending tool, the upper tool fixture 34 travels downwards and picks up the upper part of the tool b2 (shown in view VIII). Once the upper tool fixture 34 receives the upper part of the tool b2, the upper tool fixture 34 retains the upper part of the tool b2 and moves back upward (shown in view IX).

In some cases, the removal of tools from the first tool magazine or the placement of tools into the first tool magazine can be executed in parallel to the production of sheet metal parts. Therefore, while sheet metal is machined in the sheet metal processing machine, a tool can be removed from the first tool magazine or placed in the first tool magazine by the loading and unloading unit 1 for sheet metal workpieces without considerable disturbance of the machining procedure (e.g., punching or bending of the sheet metal).

A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. A loading and unloading unit for a sheet metal processing machine, the loading and unloading unit comprising:

a fixed unit; and

a sheet metal picking unit comprising: at least one device configured to pick up sheet metal; at least one driving device for moving the sheet metal picking unit in at least one horizontal axis; and at least one first tool holder for holding a sheet metal processing tool.

2. The loading and unloading unit according to claim 1, wherein the fixed unit comprises a first tool magazine with at least one second tool holder.

3. The loading and unloading unit according to claim 1, wherein the sheet metal picking unit comprises at least two first tool holders.

4. The loading and unloading unit according to claim 1, wherein the at least one first tool holder can move in relation to the sheet metal picking unit.

5. The loading and unloading unit according to claim 4, wherein the loading and unloading unit comprises a plurality of first tool holders that are fixedly positioned in relation to each other.

6. The loading and unloading unit according to claim 4, wherein the loading and unloading unit comprises a plurality of first tool holders that can rotate relative to the sheet metal picking unit.

7. The loading and unloading unit according to claim 1, wherein the sheet metal processing tool is a punching tool.

8. The loading and unloading unit according to claim 1, wherein the sheet metal processing tool is a bending tool.

9. A sheet metal processing machine comprising:

a loading and unloading unit comprising: a fixed unit; and a sheet metal picking unit comprising: at least one device configured to pick up sheet metal; at least one driving device for moving the sheet metal picking unit in at least one horizontal axis; and at least one first tool holder for holding a sheet metal processing tool; and

a controller configured to control the at least one driving device to move the sheet metal picking unit.

10. The sheet metal processing machine according to claim 9, wherein the processing machine is a punching machine that comprises an upper tool fixture and a lower tool fixture.

11. The sheet metal processing machine according to claim 9, wherein the processing machine is a bending machine that comprises an upper tool fixture and a lower tool fixture.

12. The sheet metal processing machine according to claim 9, wherein the controller is adapted to output signals to the at least one driving device such that at least one sheet metal processing tool is passed from a first tool magazine attached to the fixed unit to a second tool magazine of the sheet metal processing machine or to a tool fixture of the sheet metal processing machine.

13. The sheet metal processing machine according to claim 9, wherein the controller is adapted to output signals to at the least one driving device such that the sheet metal processing tool can be taken from the second tool magazine of the sheet metal processing machine or from a tool fixture of the sheet metal processing machine.

14. A sheet metal processing tool exchange method, the method comprising:

using a loading and unloading unit of a sheet metal processing machine as a tool holder of the sheet metal processing machine to move a sheet metal processing tool from a first tool magazine that is attached to a fixed unit of the loading and unloading unit to a second tool magazine of the sheet metal processing machine.

15. The method according to claim 14, further comprising using the loading and unloading unit of the sheet metal processing machine as a tool holder of the sheet metal processing machine to move the sheet metal processing tool from the second tool magazine of the sheet metal processing machine to the first tool magazine attached to the fixed unit.

16. The method according to claim 14, wherein moving the sheet metal processing tool occurs while a sheet metal plate is loaded into the sheet metal processing machine or while a manufactured sheet metal part is unloaded from the sheet metal processing machine.

17. The method according to claim 14, wherein the sheet metal processing tool is moved from the first tool magazine while a sheet metal plate is machined in the sheet metal processing machine.

18. The method according to claim 14, wherein the sheet metal processing tool is moved to the first tool magazine while a sheet metal plate is machined in the sheet metal processing machine.

19. A sheet metal processing tool exchange method, the method comprising:

using a loading and unloading unit of a sheet metal processing machine as a tool holder of the sheet metal processing machine to move a sheet metal processing tool from a first tool magazine that is attached to a fixed unit of the loading and unloading unit to a tool fixture of the sheet metal processing machine; and

removing the sheet metal processing tool from the tool fixture of the sheet metal processing machine.

20. The method according to claim 19, further comprising using a sheet metal picking unit of the loading and unloading unit to replace a sheet metal processing tool comprising a lower part and an upper part, the lower part of the sheet metal processing tool being disposed in a lower part of the tool fixture and the upper part of the sheet metal processing tool being disposed in a upper part of the tool fixture,

wherein the upper part of the tool fixture moves relative to the lower part of the tool fixture to release the upper part of the sheet metal processing tool and place the upper part of the sheet metal processing tool on the lower part of the sheet metal processing tool so that it can be picked up by the sheet metal picking unit in a subsequent step.

21. The method according to claim 19, further comprising using a sheet metal picking unit of the loading and unloading unit to replace a sheet metal processing tool comprising a lower part and an upper part, the lower part of the sheet metal processing tool being disposed in a lower part of the tool fixture and the upper part of the sheet metal processing tool being configured to be received in an upper part of the tool fixture,

wherein the upper part of the sheet metal processing tool is placed on the lower part of the sheet metal processing tool that is disposed in the lower part of the tool fixture using the sheet metal picking unit, the upper part of the sheet metal processing tool being retained by the upper tool holder in a subsequent step.