US20090199614A1

US20090199614A1 - Forming tool and method for positioning the forming tool

Info

Publication number: US20090199614A1
Application number: US12/063,215
Authority: US
Inventors: York Widdel; Bernhard Spies; Heiko Thaler; Sebastian Rotter
Original assignee: Eckold GmbH and Co KG
Current assignee: Eckold GmbH and Co KG
Priority date: 2005-08-13
Filing date: 2006-08-07
Publication date: 2009-08-13
Also published as: DE102005038470A1; WO2007019822A1; DE102005038470B4; EP1912750A1

Abstract

The forming tool is provided for sheet-metal components and embodied in particular as a forming gripper. The forming tool can be positioned and handled in an automated manner by an industrial robot system. The forming tool has a component-probing system, which contains a probing element that is displaceable upon contact with the component. The displacement of the probing element can be ascertained by a measuring system. Furthermore, a suitable method for positioning the forming tool is provided.

Description

The invention relates to a forming tool for sheet-metal components, in particular a forming gripper, wherein the forming tool can be positioned and handled in an automated manner by means of an industrial robot system, according to the preamble of claim 1.
Furthermore, the invention relates to a method for positioning the forming tool according to the preamble of claim 11.
Forming tools of the type mentioned at the outset are known. For example, DE 299 18 486 U1 discloses a device for positioning finished sheet-metal pressed panels and a robot-guided manufacturing tool. The sheet-metal pressed panels are vehicle body parts. The exact actual position of the sheet-metal pressed panel inside the working space of the industrial robot in relation thereto is thereby determined. In the area of a support of the manufacturing tool a sensor is provided, which detects a contact by the support with the sheet-metal pressed panel and transmits corresponding signals to a control to stop the shifting of the support.
The object of the invention is to propose an alternative forming tool.
Furthermore, it is the object of the invention to disclose a suitable method for positioning the forming tool.
The object is attained with a forming tool with the features of claim 1. The forming tool according to the invention is characterized in that it has a component-probing system, which contains a probing element that is displaceable upon contact with the component, the displacement of which probing element can be ascertained by means of a measuring system. The forming tool is characterized by a relatively simple structural design and permits a reliable positioning relative to the sheet-metal component by means of an industrial robot system, the exact position of which sheet-metal component in the space does not have to be precisely known for forming. As soon as a contact with the component in the form of a displacement of the probing element is ascertained by means of the measuring system, the precise tool position can be determined and thus also the precise component position in the space. The probing operation is thus indirectly used in addition for determining the component position in the space. It is thus possible by means of the forming tool to carry out a precise forming process with a sheet-metal component, the position of which in the space was not initially sufficiently known. Both the positioning as well as the handling of the forming tool are thereby carried out in an automated manner by means of the industrial robot system. The forming tool can be in particular an embossing and/or stamping gripping device. The probing element is preferably displaceable against an elastic restoring force.
The probing element is preferably arranged in a die unit of the forming tool. It is possible through this to create a contact between the displaceable probing element and the sheet-metal component in the direct forming area of the forming tool. During the production of this contact, the forming tool is located in a precise probing position that can be determined by the industrial robot, from which position subsequently an accurately positioned forming starting position of the forming tool can be adopted relative to the component. This renders possible a reproducibly precise forming process on a respective component, the precise position of which in the space does not have to be exactly known for this purpose.
Advantageously, in the probing position the probing element projects on the front face outwards beyond the die and is rigidly connected to a reference element arranged in the die unit in a defined manner. Due to the functional and spatial separation of the probing element and the reference element, it is possible to carry out the actual measuring operation undisturbed by the probing operation. Since the probing element is rigidly connected to the reference element, a displacement of the probing element is transmitted precisely and directly to the reference element, so that the displacement of the probing element can be determined at the same time by means of the measuring system.
In the probing position, the probing element can project on the front face from the die by a defined probing length. The probing length is thus a safety distance of the die relative to the sheet-metal component after production of a contact of the probing element with the same component. The speed of the forming tool approaching the component can, if necessary, be greater up to the production and verification of a contact between the probing element and the component than during this contact until adoption of a defined forming starting position, i.e., during production of the contact between the die and the component with completely retracted probing element and forming not yet started. At this time the probing length is zero, since the probing element is fully retracted into the die against the elastic restoring force. With corresponding handling of the forming tool by means of the industrial robot system, the actual forming process of the sheet-metal component can then take place. The contact of the probing element is used for ascertaining the precise position of the component relative to the forming tool while at the same time ensuring a sufficiently large probing length, i.a., to avoid an undesirable collision between the die of the forming tool and the sheet-metal component.
The reference element and the measuring system are preferably arranged in a measuring area spaced apart from the forming area. This renders possible the use of a relatively robustly embodied probing element in the forming area and at the same time of a geometrically very precisely embodied sensitive measuring system in the spaced apart measuring area. The forming tool can thus be characterized by an adequate robustness in the forming area and at the same time by a measuring precision that can be reproduced free of disturbances.
The reference element preferably has a reference surface that is arranged at a defined measuring distance from the measuring system. The measuring system thereby preferably contains a distance sensor, which can be operatively connected to a control unit of the industrial robot system. A forming tool of this type is characterized by a structurally relatively simple design and is suitable for use in particular in an automated series production due to its reliable positioning and handling ability.
The measuring distance is advantageously greater than the probing length by at least a defined forming path. This makes it possible to measure a displacement of the probing element during the probing operation by means of the measuring system and immediately afterwards also the forming path during the forming operation on the sheet-metal component, since the probing element is displaced further against an elastic restoring force together with the die during the forming operation. This displacement can also be measured if necessary continuously by means of the measuring system within the measuring distance.
The forming tool can additionally be embodied as a stamping tool, the probing element having at the same time the function of a stamp, which after a stamping can be forcibly moved away from the component by means of a displacement system. This renders possible a correct opening of the forming tool after completion of the forming/stamping operation.
Furthermore, the object is attained through a method with the features of claim 11. The method according to the invention is characterized in that the forming tool is moved towards the component until the production of a contact between a probing element and the component, a displacement of a probing element from a defined probing position being measured by means of a measuring system to determine the exact position of the forming tool relative to the component. Before production of a contact with the component, the probing element thereby projects outwards on the front face beyond the die by a defined probing length. By means of the method it is possible to achieve the advantages mentioned above with respect to the forming tool.
The forming tool in addition can have a stamping function, and the probing element can at the same time have the function of a stamp. After stamping in the component has been completed, the stamp can thereby be moved away from the component forcibly by means of a displacement system. Several processing functions can thus be carried out on a component by means of the forming tool.
After forming on the component has been completed, the industrial robot system can move the forming tool away from the component and at the same time the forming stamp can carry out a movement relative to the die unit compensating for the movement of the forming tool, so that the forming stamp is continuously in contact with the component and the die unit is moved away from the component, relieving the forces acting on the component through it. Due to the relief defined with respect to the opening movement of the forming tool of those forces that act on the formed component through the closed forming tool, an undesirable recovery in the forming area of the component during opening of the forming tool can be avoided or at least restricted while guaranteeing a particularly high forming precision on the component.
Further advantages of the invention are shown by the specification.

The invention is explained in more detail based on a preferred exemplary embodiment with reference to a diagrammatic drawing.

They show:

FIG. 1 A diagrammatic side view, partially in longitudinal section, of a forming tool according to the invention with the probing element in contact with a component,

FIG. 2 The forming tool of FIG. 1 during the forming/embossing operation and

FIG. 3 The forming tool of FIG. 2 after the forming/embossing operation and in opened operating position.

FIG. 1 shows in diagrammatic form a forming tool 10, which is embodied as connectable to an industrial robot (not shown in the Fig.). The forming tool 10 can be a forming gripper and in particular an embossing gripper and/or a stamping gripper. For the automated positioning of the forming tool 10 by means of an industrial robot, the forming tool 10 is provided with a component-probing system 12, which contains a probing element 14. To this end the probing element 14 projects by a defined probing length B on the front face beyond the forming tool 10. By means of the component-probing system 12, it is possible to position the forming tool 10 in an automated manner relative to a sheet-metal component 16, wherein for this purpose the precise spatial position of the forming area of the component 16 does not need to be exactly known. The probing element 14 is arranged concentrically integrated in a die unit 20 such that it is displaceable (according to double arrow 42) to the right in the drawing plane (against an elastic restoring force of a compression spring 36). The die unit 20 furthermore contains a die 22, which concentrically encloses the probing element 14 and is held in a seating slot of a back rest 30 by means of compression springs 32. The tongs-shaped forming tool 10 furthermore contains a forming stamp 40, which with the die unit 20 forms an interstice in which after the rough positioning of the forming tool 10 by means of the industrial robot has been completed, the forming area of the sheet-metal component 16 lies. During the actual forming process the forming stamp 40 is moved against the die 22 to the right in the drawing plane.
The forming tool 10 is furthermore provided with a measuring system 18 that contains a distance sensor 28, which can be embodied an analog sensor. The probing element 14 thereby extends from the forming area of the forming tool 10 along the die 22 up to a measuring area in which a reference element 24 is arranged, which is rigidly connected to the probing element 14. The reference element 24 contains a flat reference surface 26, which lies at a defined measuring distance A relative to the distance sensor 28 at the probing element 14 lying in the probing position according to FIG. 1. In this probing position the probing element 14 projects on the front face outwards beyond the die 22, forming a defined probing length B relative to the front face of the die 22. This probing position results automatically as the normal position through the spring force of the compression spring 36 acting on the probing element 14 by means of a stud 34. The probing element 14 is thereby pressed by the acting spring force against a face of a displacement element 44 arranged in a defined displaceable manner in the die unit 20. Finally, FIG. 1 also shows a connection stamping cylinder 38.
After determining a displacement of the probing element 14—and thus also of the reference element 24—by means of the distance sensor 28 due to the beginning reduction of the measuring distance A, the corresponding data, namely the respectively exact moment of the start and of the end of the displacement of the probing element 14, are transmitted to a control unit of the industrial robot, by means of which the exact spatial gripper position at the start of the contact and the displacement path already covered by the probing element 14 (to the right in the drawing plane) can be determined. The exact spatial position of the forming area of the component 16 can thereby also be determined by means of the control unit of the industrial robot and the path yet to be covered by the die unit 20 and forming stamp 40 relative to the component 16 to adopt a correct forming position.
Subsequently, the industrial robot positions the forming tool 10 up to the production of a contact of the back rest 30 with the component 16, the position path of the forming tool 10 yet to be covered now being exactly known. Upon contact of the back rest 30 with the component 16, the probing element 14 is completely retracted into the die 22. In this defined forming position of the die unit 20, the forming stamp 40 is moved against the component 16 (to the right in the drawing plane) and, in cooperation with the fixed back rest 30 and the die 22 that can be displaced to the right against the elastic restoring force of the compression springs 32, brings about a correct forming in the component 16. The forming stamp 40 cooperating with the die 22 thus presses with its front face the deforming portion of the component 16 into a cavity limited circumferentially by a back rest 30, which cavity is released according to the starting axial displacement of the die 22 in the die unit 20. The back rest 30 is positionally stable during the actual forming process, i.e., arranged immovably. This forming is shown in FIG. 2.
To carry out the additional stamping operation in the component 16, the probing element 14, which at the same time has the function of a stamp, is moved by means of the connection stamping cylinder 38—with the interconnection of a power transmission system 48 connected to the stamp 14 by a stop 46—into a defined stamping position—according to FIG. 2 to the left in the direction of component 16. The stamp 14 thereby moves relative to the displacement element 44 fixed during this operation. The component 16 is now formed as well as provided with a stamping by means of the forming tool 10 according to FIG. 2.
To open the forming tool 10, the stamp 14 is moved to the right in the drawing according to double arrow 42, i.e., away from the component 16, by means of the displacement element 44 in cooperation with the connection stamping cylinder 38, while at the same time or subsequently the forming stamp 40 is moved according to the double arrow 50 to the left in the drawing, i.e., likewise away from the component 16. At the same time the back rest 30 fixed relative to the industrial robot is moved a little to the right by means of a movement of the industrial robot according to the double arrow 52 in the drawing, i.e., also away from the component 16. The die 22 is thus moved in its stop position relative to the back rest 30 due to the acting elastic restoring force of the compression springs 32. This resulting opening position of the forming tool 10 is shown in FIG. 3.
To position the forming tool 10 by means of an industrial robot, the same is moved towards the component 16 until the production of a contact between the probing element 14 projecting by the probing length B and the component 16. This specific moment during the positioning of the forming tool 10 is shown in FIG. 1. With a further relative movement of the die 22 with the concentric probing element 14, a displacement of the probing element 14 occurs against an elastic restoring force according to double arrow 42 in the drawing plane to the right. This leads to a corresponding displacement of the reference element 24 located in the measuring area, so that a reduction of the probing length B in the forming area causes a corresponding reduction of the measuring distance A in the measuring area. This change in the measuring distance A is determined precisely and simultaneously by the distance sensor 28, so that a controlled positioning of the forming tool 10 relative to the sheet-metal component 16 can occur such that the free front face of the back rest 30 can be brought in a controlled manner into contact with the sheet-metal component 16 to be formed. At this moment the probing element 14 is completely retracted into the die 22.
If the measuring distance A is larger than the probing length B at least by a defined forming path, the joint displacement of the probing element 14 together with the die 22 and thus the forming path resulting on the component 16 via the change of the measuring distance A due to the corresponding displacement of the reference element 24 can be directly ascertained by means of the distance sensor 28 even during the actual forming process. Thus the forming height (e.g., the embossing height) achieved on the component 16 in addition can also be detected by means of the distance sensor 28.
Thus after a robot-guided approach movement of the forming tool 10 (optionally at increased speed), a first contact between the probing element 14, which at the same time has the function of a stamp, and the component 16 is detected by means of the measuring system 18. The further traversing movement can then first be stopped or also only slowed down. The remaining residual traverse for positioning the forming tool 10 and for carrying out the forming operation is ascertained exactly by means of the control unit of the industrial robot. To place the back rest 30 against the component 16, an automated advance of the residual traverse occurs in particular at creep speed, i.e., at reduced speed, to increase the approaching and thus the positioning precision. A repeated measurement with correspondingly repeated position correction of the industrial robot can thereby optionally also take place. Due to the in principle mechanical approach probing of the component and thus detection of the component position in the range of action of the forming tool 10, a particularly high positioning reliability of the same can be achieved with components associated with positional tolerance (components with non-exact spatial position).
After component forming has been completed, the industrial robot moves the forming tool 10 away from the component 16. The forming stamp 40 at the same time performs a movement relative to the die unit 20 compensating for the movement of the forming tool 10, so that the forming stamp 40 is continuously in contact with the component 16, and the die unit 20, relieving the forces acting through it on the component 16, is moved away from the component 16. Through this an undesirable recovery in the forming area of the component 16 during opening of the forming tool 10 is avoided or at least restricted while guaranteeing a particularly high forming precision on the component 16. The forming tool 10 can subsequently easily be opened to completely release the component 16.

Claims

1-14. (canceled)

15. A forming tool for a sheet-metal component, which is positioned and handled in an automated manner by an industrial robot system, comprising:

a component-probing system including a probing element that is displaceable upon contact with the component; and

a measuring system configured to ascertain the displacement of the probing element.

16. The forming tool according to claim 15, wherein the probing element is displaceable against an elastic restoring force.

17. The forming tool according to claim 15, wherein the probing element is arranged in a die unit of the forming tool.

18. The forming tool according to claim 17, wherein, in a probing position, the probing element projects on a front face outwards beyond the die and is rigidly connected to a reference element arranged in the die unit in a defined manner.

19. The forming tool according to claim 18, wherein, in the probing position, the probing element projects on the front face from the die by a defined probing length (B).

20. The forming tool according to claim 18, wherein the reference element and the measuring system are arranged in a measuring area spaced apart from a forming area.

21. The forming tool according to claim 18, wherein the reference element has a reference surface that is arranged at a defined measuring distance (A) from the measuring system.

22. The forming tool according to claim 15, wherein the measuring system contains a distance sensor, which is operatively connected to a control unit of the industrial robot.

23. The forming tool according to claim 21, wherein the measuring distance (A) is greater than a probing length (B) at least by a defined forming path.

24. The forming tool according to claim 15, wherein the forming tool is embodied as a stamping tool and the probing element has at a same time a function of a stamp, which after a stamping can be forcibly moved away from the component by a displacement system.

25. A method for positioning a forming tool by an industrial robot relative to a component, the position of which is not exactly known at least in a forming area, comprising:

moving the forming tool towards a component until a production of a contact between a probing element and the component; and

measuring a displacement of the probing element from a defined probing position by a measuring system to determine an exact position of the forming tool relative to the component.

26. The method according to claim 25, wherein the forming tool includes a stamping function, and the probing element at a same time has a function of a stamp.

27. The method according to claim 26, wherein after stamping has been completed in the component, the probing element is forcibly moved away from the component by a displacement system.

28. The method according to claim 25, wherein after processing of the component has been completed by the forming tool, the industrial robot system moves the forming tool away from the component and at a same time a forming stamp carries out a movement relative to the forming tool thereby compensating for the movement of the forming tool, such that the forming stamp is continuously in contact with the component and a die unit is moved away from the component relieving forces acting on the component.

29. A forming tool, comprising:

a component-probing system having a probing element projecting by a defined probing length B on a front face beyond the forming tool;

a measuring system that contains a distance sensor which is configured to determine a displacement of the probing element; and

a reference element containing a reference surface which lies at a defined measuring distance A relative to the distance sensor at the probing element lying in a first probing position;

wherein the measuring system determines a displacement of the probing element by the distance sensor due to a beginning reduction of the defined measuring distance A.

30. The forming tool according to claim 29, wherein, in the probing position, the probing element projects on the front face outwards beyond the die, forming the defined probing length B relative to the front face of the die, and the probing position results automatically as a normal position through a spring force of a compression spring acting on the probing element by a stud.

31. The forming tool according to claim 29, wherein after determining a displacement of the probing element by the distance sensor due to a beginning reduction of the defined measuring distance A, the exact moment of start and of end of the displacement of the probing element are transmitted to a control unit of the industrial robot, by which an exact spatial gripper position at the start of contact and the displacement path covered by the probing element is determined.

32. The forming tool according to claim 29, wherein the probing element is arranged concentrically integrated in a die unit such that it is displaceable against an elastic restoring force of a compression spring.

33. The forming tool according to claim 29, wherein the forming tool is at least one of an embossing gripper and a stamping gripper.