Device and method for hot forming, in particular forging, of a workpiece

Abstract

Method for hot forming, in particular forging, of a workpiece (8), in which a) the workpiece (8) is formed in a forming process during a working stroke (H) in a working space (A) of two tools (4, 6) of a forming machine (1) moving towards each other, and b) the workpiece (8) is held in a forming position (U) located in the working space (A) by means of a handling device (7) during the forming process, wherein c) the handling device (7) pre-positions the workpiece (8) in the working space (A) in a predetermined pre-position (V) spaced apart from the tools (4, 6) before the forming process, and wherein d) the workpiece (8) pre-positioned in the pre-position (V) is suspended in the work space (A) for a predetermined minimum time interval, which depends on the respective forming process, within a working stroke, so that the contact time of the workpiece (8) with the tools (4, 6) is minimized, and is moved by the handling device (7) to the forming position (U) in a movement synchronous with a tool (4) moved in the working stroke (H) along a tool movement axis (W) to the forming position (U).

Description

[0001] The invention relates to a device and a method for hot forming, in particular forging, of a workpiece.

[0002] For the industrial forging of workpieces, impact forming machines are particularly well-known. Impact forming machines comprise a work area or workspace in which two tools are movable relative to each other. Generally, the tool movement is achieved by a linear motion of at least one tool along a tool movement axis.

[0003] Before a forming process, the workpiece is placed on a tool according to a forming position within the tool's working area. Subsequently, during the tool's working stroke, the workpiece is formed by the impact force or forming energy when the tool strikes the workpiece.

[0004] The required forming force and forming temperature depend on the specific material, as well as on the requirements for dimensional accuracy and surface quality.

[0005] Malleable materials are essentially all malleable metals and metal alloys, including both ferrous materials such as steels and non-ferrous metals such as magnesium, aluminum, titanium, copper, nickel, and alloys thereof. The temperatures occurring during forging can range from 550°C to 750°C (so-called semi-hot forming) and higher, for example, above 900°C (so-called hot forming).

[0006] The forming temperature is usually set in a temperature range in which the formability or flowability of the material required for forming is present, in which recovery and recrystallization processes take place in the material, and in which undesirable phase transformations can also be avoided.

[0007] From DE 10 2004 015 675 B4, it is known to use handling devices, in particular industrial robots, for the automated handling of workpieces during forging. As described in DE 10 2004 015 675 B4, such handling devices can include a gripper device or gripper system and a transport device or manipulator coupled to the gripper device for spatial movement of the gripper device. The gripper device is configured for grasping and transferring the workpieces, for inserting them into the forming tool, and correspondingly for removing or transporting the workpieces after the forming process. A corresponding handling device and an associated forming machine are also known from WO 2005 / 023455 A1.

[0008] Due to the forging and forming forces occurring during forging, as well as the comparatively high dynamics of the forming process itself, it is necessary under certain circumstances to hold the workpiece during the forming process.

[0009] DE 10 2004 015 675 B4 discloses in this context a handling device for a forging machine with which a workpiece can be held during a forming process. In this device, the gripper for grasping the workpiece and the transport device or manipulator for the gripper or the workpiece are rigidly coupled in an operating position. During the forming process, the rigid coupling is released, whereby the gripper and the transport device or manipulator are only elastically decoupled via a damping element after the rigid coupling is released. In the rigidly coupled state, the damping element acts as a fixed bearing. The damping element dampens the shocks and vibrations occurring during the forming process, so that these cannot be transmitted from the gripper system to the manipulator.

[0010] German patent DE 20 2020 100 030 U1 describes a robotic gripper arm for forming processes, e.g., for hammer forging, in which the workpiece is held by the robotic gripper arm during forming. The robotic gripper arm comprises a gripper mounted on a base for handling a workpiece to be formed by forming tools and for placing the workpiece onto the tool. DE 20 2020 100 030 U1 exclusively addresses the problem that a workpiece can expand laterally during forming, which, according to DE 20 2020 100 030 U1, causes an undesirable deformation of the gripper. To solve this problem, DE 20 2020 100 030 U1 proposes to decouple the gripper translationally during forming in the direction of expansion of the workpiece, i.e. laterally, so that the robot gripper arm moves laterally in accordance with the lateral expansion of the workpiece.

[0011] It is an object of the invention to provide a new method and a new apparatus for hot forming, in particular forging, of a workpiece. Furthermore, a method and an apparatus for hot forming are to be provided with which improved forming results can be achieved.

[0012] This problem is solved by the features of the independent claims. Embodiments of the invention result from the features of the dependent claims and from the following description.

[0013] According to one of the insights underlying the invention, in the above-described, known forging machines for hot forming, particularly for bulk forming, the workpiece held in the forming position remains in contact with the forming tool for a comparatively long time. This can cause the workpiece to cool down, especially locally, or even to cool completely, which can have an adverse effect on the forming result and workpiece quality. An improvement in the forming result by reducing the cooling before the actual forming process can be achieved, in particular, through the device-related and process-related configurations described herein according to the invention.

[0014] According to one embodiment, a method for hot forming a workpiece is provided. The hot forming is preferably bulk forming, and more preferably forging. The apparatus used to carry out the method can, for example, include a forming machine, in particular a percussion forming machine, a hammer (e.g., hydraulic), a screw press, and the like. Hot forming is also understood to include semi-hot forming, particularly within the temperature ranges mentioned above.

[0015] The forming machine can have a stationary tool and a moving tool, e.g., hydraulically or mechanically, which, in order to form the workpiece, is moved from a starting position along a tool movement axis towards the stationary tool in a working stroke. The workpiece is formed in the area of, or upon reaching, the forming point. After forming, the tool is moved back to its starting position in a return stroke.

[0016] However, the underlying invention is not limited to forming machines with a stationary and a moving or movable tool, but can also be applied in the same way to forming machines with two tools, e.g. moving towards the forming point.

[0017] The process involves the workpiece being formed in a forming operation during a working stroke within the workspace of two converging tools of a forming machine. The workpiece is held in a forming position within the workspace by means of a handling device during the forming process.

[0018] The handling device may also be designed to move the workpiece towards and away from the work area and / or to reposition or relocate the workpiece within the work area, for example, if the workpiece is formed in several successive forming operations.

[0019] The method provides that the handling device, which is particularly capable of automated operation, pre-positions the workpiece in the working area in a predetermined pre-position (or intermediate position, or waiting position) at a distance from the tools before the forming process, i.e., before forming by the tools. The pre-position can be understood as a waiting position located within the working stroke, in which the handling device positions the workpiece. In the pre-position or waiting position, the workpiece is arranged at a distance from the tools, in particular such that heat transfer, especially heat conduction through mechanical contact, from the workpiece to the tool(s) is reduced, preferably avoided, or made negligible.In particular, the pre-position can be chosen such that thermal contact between the workpiece and the tool(s) is avoided, thus essentially preventing heat transfer from the workpiece to the tools.

[0020] Regarding the tool(s), the pre-positioning of the workpiece in the pre-position represents a suspended position within the workspace, where the workpiece is held, for example, only by the handling device. The method provides for the workpiece to be suspended in the workspace for a certain period of time. This period can, for example, be within the duration of the working stroke. The workpiece can be suspended in the pre-position while the tools move relative to each other.

[0021] If one of the tools is stationary and the other is moving during the working stroke, the preliminary position can be selected such that the side of the workpiece facing the stationary tool maintains a predetermined distance from the stationary tool. This distance can be chosen, for example, taking into account the temperature of the workpiece, to reduce, or preferably substantially prevent, heat transfer from the workpiece to the tool. More generally, the preliminary position can be defined or selected such that the side of the workpiece facing each tool maintains a predetermined minimum distance from the tool in the preliminary position, at least for a given time interval or time window during the working stroke.The time window is preferably selected and the handling unit is preferably operated such that the time interval or time window in which the workpiece has no contact with the tool(s) is maximized. The minimum distance can be selected depending on the workpiece, the shape of the workpiece and / or the tools, and / or the workpiece temperature.

[0022] The pre-position can be maintained for a predetermined minimum time interval in the process, whereby the minimum time interval may depend on the respective forming machine, the respective forming process, the movement of the tool(s), the type of workpiece material, the workpiece shape, the tool shape, the tool engraving, the workpiece temperature, etc.

[0023] One aspect of the proposed procedure provides that: The workpiece, pre-positioned in the pre-position, is suspended in the workspace for a predetermined minimum time interval, which depends on the respective forming process, within a working stroke, so that the contact time of the workpiece with the tools is minimized, and is moved to the forming position by the handling device in a movement synchronous with a tool moving along a tool movement axis to the forming position in the working stroke.

[0024] In this process, the workpiece is held in the pre-position, for example, suspended, at a distance from the tools. This distance is preferably chosen such that heat transfer from the workpiece to the tool(s) through thermal contact is essentially avoided. To move the workpiece into the forming position, the handling device can perform a transfer or movement process in which the workpiece is (automatically) moved from the pre-position to the forming position. If one of the tools is stationary, the handling device can be operated so that the workpiece in the forming position is positioned on or almost on the stationary tool. The transfer or movement process can be triggered depending on the position of the moving tool, for example, depending on the distance between the moving tool and the workpiece in the pre-position.A corresponding trigger can be selected or specified in such a way that the handling device has sufficient time to properly position the workpiece before the moving tool hits the, for example, the stationary tool.

[0025] The proposed method minimizes the contact time between the workpiece and the tools within a working stroke, e.g., in the period before the actual forming process. This allows for the cooling of the workpiece before forming and a reduction in heat input into the tools, particularly due to the lack of direct thermal contact between the workpiece and the tool(s). Specifically, cooling due to thermal contact can be reduced to a minimum.

[0026] In one embodiment, the preliminary position can be selected such that the workpiece, in the preliminary position, or at least upon reaching the preliminary position, maintains a predetermined distance, for example, a predetermined minimum distance, from the forming position and / or from a stationary tool, such as a support position on the stationary tool, in the direction of the tool's axis of movement. The preliminary position can be selected such that the predetermined distance and / or the preliminary position itself is maintained or assumed for a certain duration, e.g., a predetermined minimum duration. This minimum duration is preferably longer, and in particular significantly longer, than the switching times, stopping times, and / or braking times of the respective handling devices used.

[0027] For example, the pre-position can be chosen such that the duration in which the workpiece can be held suspended, in particular suspended at rest, in the pre-position is maximized for the duration of the working stroke, while simultaneously maintaining a preferred distance at which workpiece cooling or cooling relevant for the forming process is avoided by heat input or heat dissipation into the tool.

[0028] The proposed procedure is therefore suitable for reducing the contact time of the workpiece with the tools before the forming process in order to counteract, for example, local cooling of the workpiece.

[0029] According to one design, the synchronous movement is executed and / or triggered as soon as the tool, moving towards the forming position, reaches a reference position during its working stroke. The reference position can be selected depending on the specific forming process. For example, the reference position can be chosen such that the handling device has sufficient time from the trigger until the moving tool makes contact, in order to properly position the workpiece in the forming position, e.g., on a tool, and possibly to perform further operations. Such further operations can be performed, for example, to convert the handling device into a configuration that allows at least parts or sections of the handling device to be held elastically, and in particular with elastic damping, away from the workpiece, at least for the duration of the forming process.to decouple the workpiece from vibrations or impacts propagating through it during forming. Such elastic decoupling may be necessary if parts or sections of the handling device are sensitive to shocks and impacts, etc., that occur during forming, because the proposed method involves holding or fixing the workpiece by the handling device during forming.

[0030] As already indicated, the synchronous movement can be carried out or set up in such a way that the workpiece reaches the forming position, for example a forming position on a stationary tool, and, if necessary, the handling unit is elastically decoupled before the moving tool applies pressure to the workpiece for forming.

[0031] Synchronous movement can be understood, in particular, as a movement that occurs concurrently with or in conjunction with the movement of the moving tool, whereby the workpiece, guided or moved by the handling device, precedes the moving tool towards the forming position, and the workpiece reaches the forming position before the moving tool. The precedence of the workpiece can be adjusted, and is preferably adjusted, so that the handling device has sufficient time in the area of ​​the forming position to position and / or align the workpiece and, after positioning and / or alignment, if necessary, sufficient time to adjust the elastic decoupling.

[0032] According to one embodiment, the alignment of the workpiece in the pre-position or waiting position can, with the exception of a displacement or movement parallel to the tool movement axis, i.e., parallel to the movement of the moving tool, essentially correspond to the alignment provided for the forming position.

[0033] Depending on the specific configuration, the handling device can comprise a gripper system and a manipulator designed for the spatial movement of the gripper system. The manipulator can be a robot arm or similar device. The gripper system can, for example, include at least one gripper unit with one, two, or more gripping elements or gripper fingers for grasping and holding the workpiece and, optionally, one or more gripper drives. The gripper unit can be attached to the manipulator, for example, via an arm or leg.

[0034] A gripper is defined as any element that enables the grasping and holding of a workpiece, for example, in the manner of a clamp, clip, or gripper, etc. The manipulator, in the broadest sense, forms a transport or movement unit for the gripper system, with which the gripper system can be moved spatially and, if necessary, aligned, for example, according to several translational degrees of freedom and one or more rotational degrees of freedom.

[0035] The gripper system can be connected to the manipulator via an intermediate damping element, in particular a mechanically damping, elastic element (or: elasto-mechanical damping element), more precisely via one, two, or more such damping elements, and can be at least partially elastically decoupled from the manipulator by the (at least one) damping element and / or be elastically decoupled. The damping element can, for example, be an elasto-mechanical damping element or absorber element for damping or absorbing vibration, shock, impact, and / or impact energy, comprising, for example, a damper / absorber material made of plastic. The damping element effects an elasto-mechanical damping decoupling, also referred to herein as "elastic decoupling."

[0036] In general, the damping element can be designed and mounted to elasto-mechanically decouple the gripper system from the manipulator, so that vibrations, shocks, and the like propagating from the gripper system towards the manipulator during the forming process can be at least partially damped and / or at least partially absorbed. Advantageously, the damping element is designed, configured, and mounted in such a way that the manipulator, which is generally less mechanically robust, can nevertheless withstand the loads that occur during the operation of the combination of forming machine and handling device during the forming process and that act on the damping element via the gripper system.

[0037] The gripper system can be coupled to the manipulator in such a way that the manipulator is elastically decoupled from the gripper system via the damping element, at least for the duration of the forming process or forming step. The damping element can comprise one or more materials, making it flexible and / or compliant and / or damping, restoring, or elasto-mechanically absorbing.

[0038] An elasto-mechanically decoupled gripper system is known by way of example from DE 10 2004 105 675 B4. Such a gripper system can be used, for example, in the process sequence proposed above.

[0039] According to one design, the handling device is operated or can be operated in such a way that the gripper system, with the workpiece pre-positioned, is at least partially elastically decoupled from the manipulator via the damping element, i.e., elasto-mechanically decoupled.

[0040] The damping element can, for example, comprise a block, strip, or cylinder made of elastic, flexible, and / or compliant, damping, and / or resilient material, containing, for example, one or more plastics such as elastomers. In addition to the elastic material, other materials or elements can be incorporated, for example, to achieve suitable elasto-mechanical properties. An elastic element usable within the scope of the invention is described, for example, in DE 10 2004 015 675 B4. The damping element can, for example, comprise a block of elastic material arranged between two metal discs or plates, wherein the elastic material can, for example, absorb pressure and / or shear forces. In particular, the damping element can comprise a rubber buffer or be designed as such.

[0041] According to one embodiment, the handling device is operated, or can be operated, in such a way that the gripper system, at least in the workpiece's initial position, is supported, or is supported, by at least one preload element with a variably adjustable or a fixed preload force against or on the manipulator. The preload element can be, for example, a spring element (e.g., with a fixed preload force), a pneumatic element, and / or a hydraulic element (each, for example, with a variably adjustable preload force). The preload element can be configured such that the generated or generable preload force, e.g., acting on the gripper system, is sufficient to hold the gripper system with the workpiece in a positionally stable manner relative to the manipulator, enabling the manipulator to position and handle the gripper system with the workpiece stably and safely.For example, the preload force can be selected so that it can absorb the (weight) forces and moments caused by the gripper system and workpiece, so that the gripper system with the gripped workpiece can be moved and positioned stably and reliably by the manipulator despite the fastening via the damping element.

[0042] The pretensioning element can be attached, for example, to an arm (or leg, boom, or extension) of the manipulator on one side and to an arm (or leg, boom, or extension) of the gripper system on the other, for example, on the opposing sides of the respective arms, and can pretension them against each other. The arm of the gripper system can be fixedly mounted or clamped to the arm of the manipulator via the damping element, whereby the mounting or clamping point of the pretensioning element on the arm of the manipulator can be positioned at a distance from the free end of the arm. End mounting at the free end of the arm is also possible.

[0043] Accordingly, the bearing or clamping point on the arm of the gripper system can be arranged or mounted at a distance from the end attached to the manipulator.

[0044] In one embodiment, the workpiece is placed onto a tool by the synchronous movement of the manipulator and thus the gripper system with the workpiece, reaching the forming position, for example, at the end of the synchronous movement. The position of the workpiece on the tool corresponds to the forming position of the workpiece defined by the tool. When the workpiece is in contact with the tool, i.e., when or as soon as the workpiece rests on the tool, the handling device can be operated or adjusted in such a way that the manipulator is at least partially elastically decoupled from the gripper system. This means that the handling device can be operated in such a way that elastic decoupling is ensured at least during the forming process and the associated forces it generates. This applies both before and after the forming process, e.g.,Following a waiting or cooling period after the forming process to allow for any deformation effects on the manipulator, the manipulator and the gripper system can be rigidly coupled. Thus, it can be provided that elastic decoupling exists only and at least within the time frame of the forming process. Outside of this time frame, the manipulator and the gripper system can be rigidly coupled. A rigid coupling outside of the forming process is advantageous with regard to precise workpiece movement.

[0045] In one configuration, the handling device can be operated such that the gripper system and the manipulator are mechanically rigidly coupled before the workpiece is positioned in the pre-position, before it is positioned in the forming position, and / or after the forming process has been completed. The rigid coupling can, for example, be released after positioning in the forming position and before forming, and then re-established after the forming process.

[0046] According to one embodiment, adjusting or setting the rigid coupling and / or releasing the rigid coupling between the gripper system and the manipulator can be achieved by essentially complementary movements of the manipulator relative to the gripper system and / or by essentially complementary movements of a coupling element. The gripper system can be essentially stationary, e.g., unmoved, during the adjustment and / or release of the rigid coupling. The movement of the manipulator relative to the gripper system can include rotation, tilting, pivoting, and / or angling. The coupling element can, for example, comprise an adjustable coupling rod and / or a (e.g., adjustable) locking element. Such coupling elements can be connected to an adjusting element that can move the coupling element between a rigidly coupled and a decoupled position.Accordingly, the complementary movements can be arranged such that a first movement sequence positions the manipulator relative to the gripper system in such a way that it is elastically decoupled from the gripper system, while a second, complementary movement sequence positions the manipulator relative to the gripper system in such a way that it is rigidly coupled to the gripper system.

[0047] In the proposed process flow, for example, it is possible that the workpiece is placed on the tool, and that the manipulator, with the workpiece in place, is angled or tilted relative to the gripper system using the tool as a counter-support, thus eliminating a rigid coupling between the manipulator and the gripper system.

[0048] A handling device with manipulator and gripper system, in which the manipulator can be optionally elastically decoupled and rigidly coupled to the gripper system, is known, for example, from DE 10 2004 015 675 B4, wherein the handling device known therefrom can be used, for example, for the process described herein.

[0049] According to a device configuration, a device for hot forming, in particular forging, of a workpiece is provided, especially by impact forming. The device is, for example, configured so that it can be used or operated in or during a process described herein.

[0050] Within the scope of the invention, a device is further provided comprising a forming machine, a handling device, and at least one control unit, which are configured and equipped to execute a method with all features according to one of the methods and method embodiments described herein according to the invention. For example, the control unit can comprise a computing unit, e.g., a control or regulating unit, or a computer unit, for controlling or regulating the handling device and / or the forming machine, which includes a memory with computer-readable electronic commands which, when executed by the computing unit, effect a method in the device as described herein according to the invention.

[0051] An apparatus according to the invention can comprise at least one forming machine, for example, at least one impact forming machine. The forming machine can comprise at least two tools that can be moved relative to each other and are configured to perform a forming operation during a working stroke within a working area of ​​the tools. The working area of ​​the tools is defined by their range of motion. The forming machine can, for example, have a stationary and a movable tool, wherein the movable tool is moved towards the stationary tool in a working stroke to perform a forming operation, for example, in a vertical movement, and performs a return stroke after the forming operation. Such operation corresponds to a generally known forming machine, for example, for hot forming and / or bulk forming.

[0052] The device comprises at least one handling device for handling, i.e., for automated handling, workpieces. The handling device, in turn, may comprise at least one manipulator for the spatial movement of at least one gripper system coupled to the manipulator. The gripper system is configured to grip and / or hold the workpiece even during the forming process.

[0053] Within the scope of this invention, a handling device shall in particular be understood to be an automated system for handling workpieces, such as an industrial robot, with which a workpiece can be brought into the working area of ​​the forming machine and positioned, and with which the workpiece can be held during the forming process.

[0054] The device comprises at least one control unit for controlling and / or regulating the movements of at least the handling device, e.g. the manipulator and the gripper system, wherein the control unit is configured to control or regulate the handling device in such a way that the workpiece is pre-positioned in the working space in a predetermined pre-position (or: waiting position) spaced away from the tools before the forming process.

[0055] The control unit is designed to control or regulate the handling device, in particular the manipulator and the gripper system, and, if applicable, the movements of the tool(s), such that the handling device transfers the workpiece from the pre-position to the forming position in a movement synchronous with a tool moving towards the forming position during its working stroke, as soon as the tool moving towards the forming position reaches a reference position, in particular a predetermined or predefinable one, during its working stroke, with the workpiece being held by the handling device during the forming process. The synchronous movement can include a movement parallel to the moving tool, the movement advantageously being executed such that the workpiece precedes the tool. This operating mode corresponds to the process sequence described above, and reference is also made to the corresponding explanations above, which apply accordingly to the device.

[0056] According to one embodiment of the device, the handling device can comprise one, i.e., at least one, manipulator and one, i.e., at least one, gripper system connected to the manipulator. The gripper system is connected to the manipulator via an intermediate damping element. In the non-rigidly coupled configuration already described above, the damping element enables elastic decoupling of the gripper system from the manipulator. In particular, the damping element has elasto-mechanical properties that dampen or absorb mechanical energy propagating in and through the gripper system during the forming process in the form of oscillations, shocks, vibrations, etc., so that these effects do not propagate, or do not propagate substantially, into the manipulator. The damping element is thus designed to at least partially, preferably to a large extent, dampen or absorb the effects of the forming process transmitted and propagating through the gripper system.to absorb.

[0057] The control unit can be configured to control or regulate the manipulator and / or a coupling element in such a way that the gripper system and the manipulator are elastically decoupled via the damping element during operation according to the proposed process sequence at or immediately after reaching the forming position for the workpiece, but before the forming process begins. This device configuration corresponds to one or more of the process configurations described above, and reference is made in full to the above explanations.

[0058] According to a device-specific embodiment, the device further comprises a pre-tensioning element, in particular a spring, pneumatic or hydraulic element, with which the gripper system is supported or can be supported on or against the manipulator with a variably adjustable or a fixed pre-tensioning force.

[0059] In one embodiment, the control unit can also be configured to control or regulate the preload force in the case of a variably adjustable preload force, for example in such a way that the preload force supports the gripper system with the gripped workpiece resting on the manipulator, at least in the pre-position.

[0060] Exemplary embodiments of the invention are described below with reference to the attached figures. These show: Fig. 1 schematically a first embodiment of a device for hot forming in a first operating stage; Fig. 2 the device of Fig. 1 in a second operational stage; Fig. 3 schematically a second embodiment of a device for hot forming in a first operating stage; and Fig. 4 the device of Fig. 3 in a further operational stage.

[0061] In the figures, identical, functionally equivalent, or functionally analogous elements and components are designated with the same reference symbols.

[0062] Fig. Figure 1 schematically shows, at least partially, a device for hot forming. The device comprises a forming machine 1 and a handling unit 2. The forming machine 1 can be a forming machine, in particular a percussive one, such as a forging hammer, especially a drop forging hammer.

[0063] The forming machine 1 comprises, for example, an upper tool 4 (upper die) coupled to a ram 3 and a lower tool 6 (lower die) coupled to, for example, a scraper 5. The operating method for positioning a workpiece, described below in connection with a scraper hammer, can also be applied to a counter-hammer and other forming machines.

[0064] In the example shown, the lower tool 6 is stationary, and the upper tool 4 can be moved up and down by a stroke movement H and a return stroke movement R. During the stroke movement H and the return stroke movement R, the upper tool 4 moves along a tool movement axis W. To execute a forming cycle, in particular a forging cycle, the ram 3 with the upper tool 4 moves from an upper reversal point in the stroke movement H towards the lower tool 6. The forming process takes place in the region of the lower reversal point, where the upper and lower tools interact. From the lower reversal point, the ram 3 with the upper tool 4 moves back up in the return stroke movement R and can perform another forming cycle upon reaching the upper reversal point.

[0065] The device further comprises a handling device 7, which is configured and designed to pick up a workpiece 8 from a feeder (not shown) and position it in the working area A of the forming machine 1, hold it during a forming process, and place it on a tray (not shown) after the forming process. The handling device 7, comprising, for example, an industrial robot, is thus responsible for or configured to perform the (automatic) handling of the workpiece 8.

[0066] The handling device 7 comprises a manipulator 9, for example a robot arm, with a rotary drive 10, from which a manipulator arm 11 extends. The rotary drive 10 enables the manipulator arm 11 to rotate about an axis of rotation which, in the view of the figures, runs parallel to the longitudinal extent of the manipulator arm 11.

[0067] The manipulator arm 11 has a coupling element 12 at its free end. In the present example, the coupling element 12 extends approximately perpendicular to the manipulator arm and has a bearing surface 20 at its free end, which in the illustrated embodiment is located at the top. Fig. 2 and Fig. 3) on. In the in Fig. In the operating state shown in Figure 1, a leg 13 of a gripper system 14 rests on the support surface 20, such that the leg 13 is supported on the manipulator arm 11. The coupling between the coupling element 12 and the leg 13 can comprise a loose resting position (in the sense of the application, a rigid coupling). In embodiments, the coupling can comprise a coupling element or a coupling mechanism with which the leg 13 can be actively mechanically coupled to the manipulator arm 11. For this purpose, the coupling element 12 can, for example, comprise an actively releaseable and lockable locking mechanism. If a coupling element is present, the leg 13 can be coupled to the manipulator arm 11, for example, during the movements for feeding and removing workpieces 8, so that the leg 13 is rigidly coupled to the manipulator arm 11. During the forming orDuring a forming cycle, the rigid coupling, if present, is released, so that the manipulator arm 11 is elastically decoupled from the leg 13 via the damper element 15 and, due to the elasticity of the damper element 15, can tilt to a certain extent relative to the leg 13. The tilting between the leg 13 and the manipulator arm 11 for releasing or establishing the rigid coupling is described in more detail below.

[0068] The coupling element 12 is in the Fig. 1 shown operating stage is coupled with the leg 13 (or: arm) of the gripper system 14, and rests on the support surface 20, is therefore rigidly coupled with the leg 13.

[0069] At the end pointing away from the manipulator 9, the gripper system 14 has gripping elements 16 (or: a gripper unit) attached to the leg 13 (not shown in detail), which are designed and intended to grip and hold the workpiece 8, wherein the gripping elements 16 are designed, e.g. with regard to height and arrangement of the holding or gripping elements 16, so that they can hold the workpiece 8 even during a forming process.

[0070] The leg 13 is coupled to the manipulator arm 11 at the end pointing towards the manipulator 9 via the damping element 15. For example, the damping element 15 can be attached to the manipulator arm 11 on one side and to the leg 13 on the other, e.g. by a mechanically fixed or detachable connection.

[0071] Between the attachment points on the manipulator arm 11 and the leg 13, the damping element 15 has a section made of elastic material which fulfills two functionalities.

[0072] On the one hand, the damping element 15, due to its elasticity, allows the leg 13 to tilt relative to the manipulator arm 11. This tiltability makes it possible to adjust the leg 13 and the manipulator arm 11 in a first operating state ( Fig. 1) to mechanically and rigidly couple the manipulator arm 11 to the leg 13 in a second operating state ( Fig. 2, Fig. 3) to decouple elastically, wherein the leg 13 and the manipulator arm 11 are connected to each other via the damping element 15 in the second operating state and are simultaneously coupled via the elastic material acting as a damper and / or absorber.

[0073] On the other hand, in the second operating state, the damping element 15 or the elastic material dampens or absorbs mechanical energy which, with the rigid coupling released, is transferred from the workpiece 8 to the leg 13 during deformation. This damping or absorption reduces, and preferably substantially prevents, the propagation of the mechanical energy transferred from the workpiece 8 to the leg 13 during deformation into the manipulator arm 11 and into mechanically connected components. In this way, sensitive components of the manipulator 9 can be protected.

[0074] The damping element 15 can, for example, be designed as a type of rubber bearing and may comprise, for instance, two opposing metal plates or discs with a block of rubber or, more generally, of an elastic material arranged between them. The metal plates or discs are rigidly connected to the block, and may have attached or integrated fastening elements for screw fastening. By means of the fastening elements, which may be provided on opposite sides of the damping element, such a damping element can, for example, be operatively fastened to the leg 13 on one side and to the manipulator arm 11 on the other, so that the intermediate block elasto-mechanically decouples the leg 13 and the manipulator arm 11.

[0075] The coupling element 12 and the damping element 15 are attached to the manipulator arm 11 at opposite ends. In the embodiments shown, the coupling element 12 is located at the free end of the manipulator arm 11, and the damping element 15 is located at the end facing the rotary drive 10, at a predetermined distance from the rotary drive 10 in the example shown. On leg 13, the damping element 15 is attached to the end facing away from the gripping elements 16.

[0076] The coupling element 12 and the damping element 15 are attached and arranged such that the gripper system 14, in particular the leg 13, is in a first operating position according to Fig. 1 is rigidly coupled to the manipulator 9, in particular the manipulator arm 11, and that the gripper system 14, in particular the leg 13, is in a second operating position according to Fig. 2 (and e.g. the operating positions according to Fig. 3 to Fig. 4) is elastically decoupled from the manipulator 9, in particular the manipulator arm 11. These operating positions will be discussed in more detail below.

[0077] In the elastically decoupled operating position of the Fig. In Figure 2, the gripper system 14, specifically the leg 13, is connected to the manipulator arm 11 only via the damping element 15. In this operating position, the damping element 15 acts as a damper or absorber for forces acting on the leg 13 that arise during the forming process, thus elastically decoupling the leg 13 from the manipulator arm 11. Without the damping element 15, these forces would be transmitted almost entirely via the leg 13 of the gripper system 14, which holds the workpiece 8 during the forming process, to the manipulator arm 11 and the manipulator 9 as a whole. This would, or could, lead to damage when using conventional manipulators, such as industrial robots. In the rigidly coupled operating position, the damping element 15 essentially acts like a fixed bearing, with the leg 13 of the gripper system 14 being rigidly fixed via the coupling element 12.

[0078] During a forming process with the device according to Fig. 1. The manipulator 9 with gripper system 14 positions the workpiece 8 in the working area A of the forming machine 1 in a pre-position V or a waiting position. This positioning can take place, for example, while the ram 3 is performing the return stroke R, the ram 3 is in the area of ​​the upper reversal point and / or in an initial phase of the stroke movement H (working stroke).

[0079] In the preliminary position V, the workpiece 8 has a predetermined distance D to the lower tool 6, as well as a distance to the upper tool 4. The distance D is chosen such that no significant heat transfer can occur from the workpiece 8 to the lower tool 6. Furthermore, the distance D is chosen so that the workpiece 8 is positioned sufficiently close to the lower tool 6 so that, on the one hand, the workpiece 8 remains in the preliminary position V, i.e., suspended above the lower tool 6, for as long as possible during the stroke movement H, and on the other hand, the workpiece 8 can be moved by the manipulator 9 into the forming position U in a comparatively short time. Fig. 2) can be transferred to the lower tool 6. The distance D between the top of the lower tool 6 and the bottom of the workpiece 8 can, for example, be in the range between 1 mm and 10 mm, in particular between 1 mm and 5 mm.

[0080] Positioning the workpiece 8 in the pre-position V, for example such that the workpiece 8 is held suspended, or in particular suspended and stationary, above the lower tool 6 for as long as possible, has the advantage that the contact time of the warm workpiece 8 with the lower tool 6, i.e., the thermal contact, can be significantly reduced, thereby reducing the cooling of the workpiece 8 in the period before the forming process. This, in turn, has a beneficial effect on the forming result.

[0081] To perform a forming operation, the workpiece 8 is moved into the forming position U on the lower tool 6 by a corresponding movement of the manipulator 9. The transfer to the forming position U can be triggered or initiated, for example, as soon as the ram 3 or the upper tool 4 reaches a reference position P, which may be predetermined. Fig. 1) achieved.

[0082] If the bear reaches 3 or the upper tool reaches 4 (as in Fig. 1) Once the reference position P, which can be determined or recorded, for example by a (not shown) displacement measuring system, is established, the handling device 7 is instructed, for example by a (not shown) control unit such as a computer unit, to move the workpiece 8 into the forming position. Fig. Figure 2 shows the operating stage in which the workpiece 8 is positioned in the forming position U on the lower tool 6, i.e. after the handling device 7 has transferred the workpiece 8 from the pre-position V to the forming position U.

[0083] The transfer of the workpiece 8 from the preliminary position V to the forming position U takes place synchronously with the movement of the upper tool 4 or bear 3 in the direction of the lower tool 6, whereby the handling device 7 is controlled in such a way that the workpiece 8 precedes the upper tool 4, and the workpiece 8 reaches the forming position U before the upper tool 4 hits the workpiece 8.

[0084] The advance, in particular the movement guidance of the handling device 7, and the reference position P are selected or set so that the handling device 7 has sufficient time after reaching the forming position U to release the rigid coupling between the manipulator arm 11 and the leg 13 caused by the coupling element 12.

[0085] As can be seen from a synthesis of the Fig. 1 and Fig. 2 results in the handling device 7 moving the workpiece 8 first parallel to the lifting movement H of the bear 3 downwards into the forming position U on the lower tool 6. This movement is in Fig. 1 indicated by arrow 17. Immediately following this, i.e., after placing the workpiece 8 in the forming position U, the manipulator 9 performs a rotary, tilting, or rotational movement, indicated by the curved arrow 18. Fig. 2, wherein the leg 13 and the manipulator arm 11 tilt relative to each other with respect to an imaginary axis of rotation in the region of a tilting point or tilting axis K in the region of the damping element 15, in particular the elastic material. Through this or in connection with this rotational, tilting or rotating movement, in which the workpiece 8 remains unchanged in its position on the lower tool 6, the rigid coupling between the leg 13 and the manipulator arm 11 caused by the coupling element 12 is released, so that the manipulator arm 11 is elastically decoupled from the leg 13 of the gripper system 14 via the damping element 15.

[0086] After the rigid coupling is released, the bear 3, through its continuous movement parallel to the stroke movement H in the direction of the lower tool 6, reaches the forming point U, and the workpiece 8 is formed accordingly.

[0087] After the forming process, the ram 3 with the upper tool 4 moves in the return stroke R to the upper reversal point of the ram 3. The handling device 7, in particular the manipulator arm 11, performs a movement opposite to the aforementioned rotary, tilting, or rotational movement after the forming process, causing the coupling element 12 to again rest against, engage with, and / or couple to the leg 13. The leg 13 is thereby rigidly coupled to the manipulator arm 11 again. In this rigidly coupled operating position, the handling device 7 can perform further movements with the workpiece 8, e.g., repositioning for further forming operations, or the handling device can transfer the formed workpiece 8 to a storage unit. The handling device 7 can then transfer another workpiece 8 to the work area A, with subsequent forming according to the steps described above.

[0088] The described operating mode with positioning in the pre-position and decoupling of the gripper system 14, or of the leg 13, from the manipulator arm 11 in the forming position U can be carried out accordingly for each forming process.

[0089] The in Fig. 3 to Fig. The embodiment shown in section 4 is essentially based on the same forming machine, so reference is made to the above explanations regarding the forming machine itself.

[0090] Just like with Fig. 1 and Fig. 2 will be used in the design according to Fig. 3 to 4 the workpiece 8 in the preliminary position V, in particular initially suspended, in particular suspended at rest, above the lower tool 6 and simultaneously spaced apart from the upper tool 4 ( Fig. 3) positioned.

[0091] In the example of the Fig. The handling unit 2, as shown in sections 3 to 4, also comprises a handling device 7, a manipulator 9, a rotary drive 10, a manipulator arm 11, and a gripper system 14. The gripper system 14 is coupled to the manipulator arm 11 via a leg 13 and a damping element 15. The damping element 15 provides elastic decoupling between the manipulator arm 11 and the gripper system 14, or leg 13, unless a rigid coupling exists between the leg 13 and the coupling element 12. A change between the rigidly coupled and the elastically decoupled positions can be achieved, analogous to the first embodiment, by a tilting, pivoting, or rotational movement.

[0092] The Fig. Figure 3 shows a situation in which the workpiece 8 is suspended above the upper tool 6 in the pre-position V (waiting position) and still spaced away from the upper tool 4. Fig. Figure 4 shows that the workpiece 8 is formed by the upper tool 4.

[0093] In the design of the Fig. 3 and Fig. 4 The handling device 7 has a preload element 19 which is formed in the longitudinal extension of the manipulator arm 11 between the damper element 15 and the end of the manipulator arm 11 facing away from the damper element 15, corresponding to the end at which the coupling element 12 is located in the embodiment shown. In this variant, the coupling element 12 can be omitted.

[0094] The preload force of the preload element 19 is set such that it can absorb the weight of gripper system 14 with leg 13 and tool 8, and hold the leg 13 with the workpiece 8 held by the gripper system 14 at a distance from the manipulator arm 11, in particular in a floating position.

[0095] In the exemplary embodiment, the preload element 19 is designed as a pneumatic or hydraulic element that is arranged between and connected to the manipulator arm 11 and the leg 13. Such preload elements 19 allow for variable adjustment of the preload force, and thus, for example, an adaptation of the preload force to the weight of the gripper system 14 and the workpiece 8, or to the torque generated by them with respect to the tilting axis K. If the handling unit 2 of the second embodiment provides for a rigid coupling, the manipulator arm 11 can include a coupling element 12. A variably adjustable preload element 19 can be provided, which is operated or can be operated such that, for example, by reducing the preload force, the leg 13 can be rigidly coupled to the coupling element 12 in a first operating state when the workpiece 8 is gripped, and that, for example,By increasing the preload force, the leg 13, when the workpiece 8 is gripped, is no longer rigidly coupled to the coupling element 12 in a second operating state, and the leg 13 is elastically decoupled from the manipulator arm 11 via the damper element 15. In the rigidly coupled state, the leg 13 can rest on the support surface 20, and in the decoupled state, the leg 13 can be lifted from the support surface 20.

[0096] Furthermore, a suitably configured hydraulic or pneumatic preloading element 19 can generate a damping effect supporting the damping element 15.

[0097] The preloading element 19 is designed to generate a variable preload force that acts between the point of application on the manipulator arm 11 and the point of application on the leg 13. This supports the leg 13, and with it the entire gripper system 14, against the manipulator arm 11, so that the gripper system 14 with workpiece 8 can be stably positioned by the effect of the preload force, for example in the pre-position V suspended above the lower tool 6.

[0098] The above explanations show that the invention described herein reduces the cooling of the workpiece during hot forming prior to the forming process by shortening the contact time between the workpiece and the tools. In particular, this allows for improved forming results. Furthermore, a shorter contact time between the workpiece and the tool(s) reduces the heat input into the tools. Reference symbol list 1 forming machine 2 handling units 3 Bear 4 Upper tool 5 abutments 6 lower tools 7 Handling device 8 workpiece 9 Manipulator 10 Rotary drive 11 Manipulator arm 12 coupling element 13 thighs 14 Gripper system 15 damper element 16 gripping elements 17 Arrow, parallel movement 18 Arrow, rotational movement 19 Preload element 20 contact area A workspace D distance H lifting movement K tilting axle P Reference position R recoil movement U forming position V Preposition W tool movement axis

Claims

[1] Method for hot forming, in particular for forging, a workpiece (8), in which a) the workpiece (8) is formed in a forming process during a working stroke (H) in a working space (A) of two tools (4, 6) of a forming machine (1) which are moved towards one another, and b) the workpiece (8) is held in a forming position (U) located in the working space (A) by means of a handling device (7) during the forming process, wherein c) the handling device (7) pre-positions the workpiece (8) in the working space (A) before the forming process in a predetermined pre-position (V) spaced from the tools (4, 6), and wherein d) the workpiece (8) pre-positioned in the pre-position (V) is positioned in a floating manner in the working space (A) for a predetermined minimum time interval, which is dependent on the respective forming process, within a working stroke, so that a contact time of the workpiece (8) with the tools (4, 6) is minimized, and is moved by the handling device (7) to the forming position (U) in a movement synchronous to a tool (4) moved in the working stroke (H) along a tool movement axis (W) to the forming position (U). [2] Method according to claim 1, wherein the workpiece (8) in the pre-position (V), but at least when reaching the pre-position (V), in the direction of a tool movement axis (W) along which the moving tool (4) moves, has a predetermined distance (D) from the forming position (U) and / or a predetermined distance (D) from a stationary tool (6). [3] Method according to one of claims 1 or 2, wherein the synchronous movement in step d) is carried out and / or triggered as soon as the tool (4) moved towards the forming position (U) reaches a reference position (P) in the working stroke (H), wherein the synchronous movement is preferably carried out in such a way that the workpiece (8) reaches the forming position (U) before the tool (4) acts on the workpiece (8) for forming. [4] Method according to one of claims 1 to 3, wherein an orientation of the workpiece (8) in the pre-position (V) corresponds to an orientation provided for the forming position (U) except for a displacement or movement parallel to the tool movement axis (W). [5] Method according to one of claims 1 to 4, wherein the handling device (7) comprises a gripper system (14) and a manipulator (9) designed for the spatial movement of the gripper system (14), wherein the gripper system (14) is connected to the manipulator (9) via an intermediate damper element (15). [6] Method according to claim 5, wherein the handling device (7) is operated or operable in such a way that - the gripper system (14) is or will be elastically decoupled from the manipulator (9) via the damper element (15) when the workpiece (8) is pre-positioned; and / or - the gripper system (14) is or is supported on or against the manipulator (9) at least in the pre-position of the workpiece (8) by a pre-tensioning element (19), in particular a spring, pneumatic or hydraulic element, with a variably adjustable or a fixed pre-tensioning force. [7] Method according to claim 5, wherein the workpiece (8) is placed on a tool (6) by the synchronous movement to the forming position (U), and wherein, with the workpiece (8) in place, the handling device (7) is operated in such a way that the manipulator (9) is or is at least partially elastically decoupled from the gripper system (14) immediately before and during the forming process via the damper element (15). [8] Method according to one of claims 5 to 7, wherein the handling device (7) is operated such that the gripper system (14) and the manipulator (9) are or are substantially rigidly coupled by a rigid coupling before the positioning of the workpiece (8) in the pre-position (V) and / or after the forming process has taken place. [9] Method according to claim 8, wherein adjusting the rigid coupling and / or releasing the rigid coupling between the gripper system (14) and the manipulator (9) is carried out by essentially complementary movements of the manipulator (9) relative to the gripper system (14) and / or by essentially complementary movements of a coupling element (12), wherein the gripper system (14) is or remains essentially stationary during the adjusting and / or releasing of the rigid coupling, and wherein the movement of the manipulator (9) relative to the gripper system (14) preferably comprises pivoting and / or angling. [10] Device for hot forming, in particular forging, a workpiece (8), in particular for use in one of the methods according to one of claims 1 to 9, comprising a) a forming machine (1), in particular a percussive forming machine, having at least two tools (4, 6) which can be moved relative to one another for carrying out a forming process during a working stroke (H) in a working space (A) of the tools (4, 6); b) a handling device (7) for handling workpieces (8), which is designed to grip and / or hold the workpiece (8) even during the forming process; c) at least one control unit for controlling and / or regulating the movements of the tools (4, 6) and the handling device (7), wherein the control unit is designed to control or regulate at least the handling device (7) in such a way that d) the workpiece (8) is pre-positioned in the working space (A) in a predetermined pre-position (V) spaced from the tools (4, 6) prior to the forming process, and e) the handling device (7) transfers the workpiece (8) from the pre-position (V) to the forming position (U) in a movement synchronous with a tool (4) moved in the working stroke (A) to the forming position (U), as soon as the tool (4) moved towards the forming position (U) reaches a reference position (P) in the working stroke (A), wherein the workpiece (8) is held by the handling device (7) during the forming process (U), wherein the handling device (7) positions the workpiece (8) pre-positioned in the pre-position (V) in a floating manner in the working space (A) for a predetermined minimum time interval, which depends on the respective forming process, within a working stroke, so that a contact time of the workpiece (8) with the tools (4, 6) is minimized. [11] Device according to claim 10, wherein the handling device (7) comprises a manipulator (9) and a gripper system (14) connected to the manipulator (9), wherein the gripper system (14) is connected to the manipulator (9) via an intermediate damper element (15), wherein the control unit is preferably designed to control or regulate the manipulator (9) and / or a coupling element (12) in such a way that the gripper system (14) and the manipulator (9) are elastically decoupled via the damper element (15) during operation according to e) upon or immediately after reaching the forming position (U) for the workpiece (8), but before the forming process. [12] Device according to claim 11, further comprising a pre-tensioning element (19), in particular a spring, pneumatic or hydraulic element, with which the gripper system (14) is or can be supported on or against the manipulator (9) with a variably adjustable or a fixed pre-tensioning force, wherein the control unit is preferably further configured to control or regulate the pre-tensioning force in the case of a variably adjustable pre-tensioning force, such that the pre-tensioning force supports the gripper system (14) with the workpiece (8) at rest on the manipulator (9), in particular with a pre-tensioning force, at least in the pre-position (V). [13] Device according to one of claims 10 to 12, wherein the forming machine (1), the handling device (7) and the at least one control unit are arranged to carry out a method according to one of claims 1 to 9.

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