Detecting the geometry of a workpiece during an open-die forging process

Abstract

The invention relates to a method for detecting the geometry of a workpiece (2) during a forging process, in particular during an open-die forging process, said method having the steps of: conveying the workpiece (2) into a measuring region (31) of a measuring system (30) by means of a handling device (20); measuring at least one distance (d) between the workpiece (2) and an optical measuring system (34) of the measuring system (30) by means of at least one distance measuring system (32) and ascertaining at least one distance value therefrom; optically capturing the workpiece (2) by means of the optical measuring system (34) and determining all or part of the geometry of the workpiece (2) therefrom; and correcting the geometry of the workpiece (2) using the at least one distance value.

Description

[0001] Geometry detection of a workpiece during open-die forging

[0002] Technical area

[0003] The invention relates to a method for detecting the geometry of a workpiece during forging, in particular open-die forging, and to an arrangement comprising a forging device, preferably an open-die forging press, a handling device for conveying and aligning the workpiece and a measuring system for detecting the geometry of the workpiece.

[0004] Background of the invention

[0005] Forging is a non-cutting, forming process used primarily for steel, but also for some non-ferrous metals. The work required for forming is applied in the form of kinetic energy. If the forming movement is not mechanically limited by a fixed abutment or other means, it is called open-die forging.

[0006] Measuring systems for measuring the geometry of a workpiece in open-die forging are known, and they are usually based on laser measurement technology. Such systems are cost-intensive and require comparatively long measurement times, which limits their economic viability. Furthermore, for safety reasons, protective zones must be established and maintained.

[0007] When using a purely optical sensor, the problem is that the position and alignment of the workpiece relative to the measuring system is unknown or may be inaccurate, which prevents or at least complicates compensation for any deviations and measurement errors. i Description of the invention

[0008] An object of the present invention is to provide an improved method for detecting the geometry of a workpiece during forging, in particular open-die forging, as well as an improved arrangement with a forging device and a measuring system for detecting the geometry of the workpiece.

[0009] The object is achieved by a method having the features of claim 1 and an arrangement having the features of claim 9. Advantageous further developments follow from the subclaims, the following presentation of the invention and the description of preferred embodiments.

[0010] The method according to the invention serves to determine the geometry of a workpiece during forging, in particular open-die forging.

[0011] The workpiece is forged in a forging device, preferably designed as an open-die forging press. Metallic materials, particularly steel, nickel, titanium, zirconium, and aluminum, are suitable for the workpiece. Forging preferably takes place at temperatures above 800 °C. The desired geometries achieved through forging include, for example, round, rectangular, square, and square.

[0012] According to the method for geometry detection, the workpiece is transported by means of a handling device into a measuring area of ​​a measuring system. The measuring system, in particular its measuring area, is preferably located outside the forging device.

[0013] The measuring system is a combined measuring system comprising at least one distance measuring system and an optical measuring system, wherein the distance measuring system measures at least one distance between the workpiece and the optical measuring system. At least one distance value is determined from this. The optical measuring system (optically) records the workpiece, wherein the geometry of the workpiece is determined completely or at least partially from the recording. The at least one distance measuring system can have one or more distance sensors, preferably based on the radar and / or laser measuring principle. The optical measuring system has an optical sensor or a combination of several optical sensors, preferably implemented by a camera and / or a thermography system.

[0014] "Determining the geometry of the workpiece" means not only capturing an image (photo, film, etc.) of the workpiece using the optical measuring system, but also generating data about the geometric properties of the workpiece, including, for example, edge lengths, angles, curvature values, and the like. Furthermore, to fulfill this requirement, it is not necessary to determine the geometry of the workpiece in its entirety; it is sufficient to determine one or more geometric properties.

[0015] According to the invention, the thus determined geometry of the workpiece is corrected using the at least one distance value.

[0016] The determination of the geometry and its correction are carried out by means of a suitable electronic device, which may be part of the measuring system or may be provided independently and is generally referred to herein as the "control device".

[0017] The control device communicates with the various devices, assemblies, and the like, i.e., it is signal-connected to the components to be controlled, regulated, and / or read, thus in particular to the forging device, the handling device, and the measuring system. Communication between the control device and the components to be controlled, regulated, and / or read can be wired or wireless, digital or analog. The control device can receive and / or transmit signals (control signals, data, etc.) accordingly; both unidirectional and bidirectional signal transmission fall under the term "communication" in this context.The control system does not necessarily have to be implemented by a central computing device or electronic control system; it can also include decentralized and / or multi-level systems, control networks, cloud systems, and the like. The controller can also be an integral component of a higher-level system control system or communicate with such a system. The control system can also communicate with lower-level system controls, i.e., controllers assigned to the corresponding systems.

[0018] The combined measurement presented here for the geometry acquisition of the workpiece allows for a significant increase in measurement accuracy compared to purely optical systems. The acquisition of the workpiece geometry does not require cost-intensive, laser-based imaging measurement methods. Any deviations, such as those caused by workpiece misalignment or curvature, are compensated for using one or more distance measurement systems. This enables cost- and resource-efficient acquisition of workpiece measurements during forging, especially open-die forging.

[0019] In open-die forging, different diameters, unfavorable workpiece positioning, and especially in the case of a freely movable handling device that, for example, does not run on a fixed rail, can lead to different distances between the workpiece, in particular a possible workpiece center axis, and the optical measuring system. This, in turn, can result in an incorrect focus measurement plane that deviates from a target measurement plane. For this reason, the at least one distance value is preferably also used to determine a focus range of the optical measuring system and, if necessary, to adjust the focus of the optical measuring system accordingly.

[0020] Preferably, the orientation of the workpiece is determined from the at least one distance value and used to correct the geometry of the workpiece, whereby the measurement accuracy can be further increased.

[0021] Preferably, the complete or partial determination of the geometry of the workpiece is carried out using an image recognition algorithm, in particular an edge detection algorithm, in order to determine properties of the geometry of the workpiece in a simple and rapid manner.

[0022] Preferably, the complete or partial determination of the geometry of the workpiece comprises a conversion of pixels resulting from a sensor resolution of the optical measuring system into one or more length measurements via a conversion factor, whereby geometric properties of the workpiece, such as edge lengths, etc., can be determined in a simple and rapid manner.

[0023] During forging, particularly during open-die forging, it may happen that the workpiece is not held completely centrally by the handling device and / or has curvatures. By performing multiple distance measurements, particularly along a workpiece center axis, the distance between the workpiece and the optical measuring system can be determined and any measurement errors along the workpiece caused by workpiece misalignments and the like can be continuously compensated. For this reason, multiple distances between the workpiece and the optical measuring system are preferably determined during the distance measurement. Multiple distance measurements can be realized using multiple distance sensors or distance measuring systems. Alternatively or additionally, the workpiece and / or the distance measuring system can be designed to be movable or movable for this purpose.

[0024] Preferably, an incorrect alignment of the workpiece and / or a workpiece error, including unintentional curvatures, are determined from the plurality of determined distances and applied to correct the geometry of the workpiece.

[0025] Preferably, the determined and corrected geometry of the workpiece is incorporated into the process control of the forging device. Following the workpiece geometry acquisition by the measuring system, the determined and corrected geometry can be fed back into the control unit or another process control of the forging device in a further step, allowing it to be used, among other things, to check intermediate geometries and adjust the forging strategy.

[0026] The above-mentioned object is further achieved by an arrangement comprising a forging device, preferably an open-die forging press, for forging a workpiece, a handling device for conveying and aligning the workpiece, a measuring system for detecting the geometry of the workpiece, and a control device. The measuring system has a measuring range and, as a combined measuring system, at least one distance measuring system and one optical measuring system. The control device communicates with the forging device, the handling device, and the measuring system.

[0027] According to the invention, the control device is configured to convey the workpiece into the measuring range of the measuring system by means of the handling device; to measure at least one distance between the workpiece and the optical measuring system by means of the at least one distance measuring system and to determine at least one distance value therefrom; to pick up the workpiece by the optical measuring system and to determine the geometry of the workpiece completely or partially; and to correct the geometry of the workpiece by applying the at least one distance value.

[0028] The features, technical effects, advantages and embodiments described with regard to the method apply analogously to the arrangement.

[0029] Preferably, the at least one distance measuring system comprises one or more distance sensors, particularly preferably based on the radar and / or laser measuring principle. The optical measuring system preferably comprises an optical sensor or a combination of several optical sensors, in particular implemented by a camera and / or a thermography system. In this way, a structurally simple, reliable, and precise combined measuring system can be constructed for use in determining the geometry of the workpiece during forging, in particular open-die forging.

[0030] Preferably, the measuring system is arranged outside the forging device in order to be able to take an accurate measurement.

[0031] For the reasons stated above, the control device is preferably configured to use the at least one distance value to determine a focus range of the optical measuring system and / or to determine the orientation of the workpiece from the at least one distance value and to use it to correct the geometry of the workpiece.

[0032] For the reasons stated above, the measuring system and the control device are preferably configured to determine multiple distances between the workpiece and the optical measuring system during the distance measurement. The control device is preferably configured to determine an incorrect alignment of the workpiece and / or a workpiece error from the multiple determined distances and to apply this information to correct the geometry of the workpiece.

[0033] Preferably, the control device is configured to control and / or regulate the forging process of the forging device on the workpiece and to take into account the determined and corrected geometry of the workpiece in the process control of the forging device.

[0034] Further advantages and features of the present invention will become apparent from the following description of preferred embodiments. The features described therein can be implemented alone or in combination with one or more of the features set forth above, provided the features do not contradict each other. The following description of preferred embodiments is provided with reference to the accompanying drawings.

[0035] Short description of the characters

[0036] Preferred further embodiments of the invention are explained in more detail in the following description of the figures. In the figures:

[0037] Figure 1 shows schematically an arrangement with a forging device and a handling device;

[0038] Figure 2 shows a schematic diagram of a measuring system with combined distance and geometry measurement;

[0039] Figure 3 is an illustration of a possible deviation between an incorrect focus measurement plane and a target measurement plane; and Figure 4 is a schematic of a measurement system with measurement error compensation.

[0040] Detailed description of preferred embodiments

[0041] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements are provided with identical reference numerals in the figures, and a repeated description of these elements is partially omitted to avoid redundancy.

[0042] Figure 1 schematically shows an arrangement 1 with a forging device 10 for forging a workpiece 2 and a handling device 20.

[0043] The forging device 10 is preferably designed for open-die forging, preferably as an open-die forging press. In this case, a piston force is exerted on the workpiece 2, which is arranged outside the forging device 10 in Figure 1, by means of a piston-cylinder system and a forging tool, in order to deform it in a desired manner.

[0044] Metallic materials, particularly steel, nickel, titanium, zirconium, and aluminum, are considered for workpiece 2. Forging preferably takes place at temperatures above 800 °C. The geometries desired by forging include, for example, round, rectangular, square, and rectangular.

[0045] The handling device 20 is configured to move the workpiece 2, in particular to a desired position and into a desired orientation. For this purpose, the handling device 20 comprises a transport section 22, for example, designed as a vehicle, in particular an autonomous vehicle, and a manipulator section 24 configured to hold, rotate, pivot, and the like the workpiece 2. The manipulator section 24 preferably comprises a pair of tongs for gripping the workpiece 2.

[0046] The assembly 1 further comprises a control device 50, which communicates with the various devices, assemblies, and the like. The control device 50 is signal-connected to the components of the assembly 1 to be controlled or regulated and / or read out, thus in particular to the forging device 10, the handling device 20, and the measuring system 30 described below.

[0047] Communication between the control device 50 and the components to be controlled or regulated and / or read out can be wired or wireless, digital or analog. The control device 50 can receive and / or send signals (control signals, data, etc.) accordingly, whereby both signal transport in one direction and in both directions falls under the term "communication" in this context. The control device 50 does not necessarily have to be implemented by a central computing device or electronic control system, but rather decentralized and / or multi-level systems, control networks, cloud systems, and the like are included. The controller can also be an integral component of a higher-level system control system or communicate with such a system. The control device 50 can also communicate with lower-level system controls, i.e., controls assigned to the corresponding devices.

[0048] Figure 2 schematically shows a measuring system 30 for detecting the geometry of the workpiece 2 according to one exemplary embodiment. The measurement, which takes place in a measuring area 31, is realized by means of a combined measuring system 30 comprising a distance measuring system 32 and an optical measuring system 34. The distance measuring system 32 comprises one or more distance sensors, preferably based on the radar and / or laser measuring principle. The optical measuring system 34 comprises an optical sensor or a combination of several optical sensors, which are preferably implemented accordingly by a camera and / or a thermography system.

[0049] The distance measuring system 32 essentially determines the position of the workpiece 2 in space and / or its orientation through the manipulator section 24 of the handling device 20 relative to the optical measuring system 34. The optical measuring system 34, together with the control device 50, detects the component geometry of the workpiece 2 by using a suitable algorithm to generate the contour of the workpiece 2 and thus its geometric properties from the image data. The imaging measurement is corrected by measuring the distance d by the distance measuring system 32, thus enabling the most precise measurement of the component geometry possible.

[0050] An exemplary method for determining the geometry of the workpiece 2 during forging, in particular open-die forging, comprises the following steps:

[0051] (1) Moving the workpiece 2 into the measuring area 31 of the measuring system 30, preferably outside the forging device 10, by means of the handling device 20.

[0052] (2) Measuring the distance d between the workpiece 2 and the optical measuring system 34 by means of the distance measuring system 32. From this, the position and / or orientation of the workpiece 2 and the focus range of the optical measuring system 34 are determined with the help of the control device 50.

[0053] (3) Subsequently, an optical measurement of the component geometry of the workpiece 2 is performed using an imaging method of the optical measuring system 34, and the component geometry of the workpiece 2 is determined using a suitable image recognition algorithm. Suitable edge detection algorithms can be used for this purpose.

[0054] (4) Thereafter, any compensation or correction of the component geometry of the workpiece 2 takes place via the distance d and / or the orientation of the workpiece 2, which were measured in step (2).

[0055] The determination of the orientation of the workpiece 2 and the distance d of the workpiece to the optical measuring system 34 can be incorporated into the geometry acquisition process as follows:

[0056] In the simplest case, the optical measurement can be performed by converting pixels, which result from the sensor resolution of the optical measuring system 34, into linear dimensions using a conversion factor. For example, if the measuring area 31 is 5,000 mm wide and the optical measuring system 34 has a horizontal resolution of 2,048 pixels, 1 pixel corresponds to approximately 2.5 mm. This conversion factor determines the component geometry.

[0057] During open-die forging, different diameters, unfavorable positioning in the manipulator section 24, and especially in the case of a freely movable handling device 20 that, for example, does not travel on a fixed rail, can lead to different distances d between the workpiece 2, in particular any workpiece center axis 2a, and the optical measuring system 34. This, in turn, results in an incorrect focus measurement plane Ff, which deviates from a target measurement plane Fz, and thus leads to incorrect length measurements with respect to the workpiece geometry (see Figure 3).

[0058] The signal from the distance measuring system 32 is now used to determine the measuring distance d between the workpiece 2 and the optical measuring system 34, thus increasing the accuracy of the measuring system 30. During open-die forging, it may happen that the workpiece 2 is not completely centered in the tong-like manipulator section 24 of the handling device 20 and / or has curvatures. By measuring the distance multiple times along the workpiece center axis 2a, several distances d between the workpiece 2 and the optical measuring system 34 can be determined, and a measurement error along the workpiece 2 caused by workpiece misalignments and the like can be continuously compensated.

[0059] A multiple distance measurement can be realized by several distance sensors or distance measuring systems 32, as shown in Figure 4. Alternatively or additionally, the workpiece 2 and / or the distance measuring system 32 can be designed to be movable or movable for this purpose.

[0060] Following the geometry detection of the workpiece 2 by the measuring system 30, in a further step (5) the determined geometry can be fed back to the control device 50 or another process control of the forging device 10, whereby it can be used, among other things, to control intermediate geometries and to adapt the forging strategy.

[0061] The combined measuring system 30 presented herein allows for a significant increase in measurement accuracy when measuring the geometry of a workpiece 2 during forging, particularly open-die forging, compared to purely optical systems. The workpiece geometry can be measured without the need for cost-intensive, laser-based imaging measurement methods. Any compensation for deviations, for example, due to misalignments of the workpiece 2 or curvatures thereof, is achieved by using one or more distance measuring systems 32. In this way, cost- and resource-efficient measurement of the component during forging, particularly for open-die forging presses, is realized. Where applicable, all individual features presented in the exemplary embodiments can be combined and / or exchanged with one another without departing from the scope of the invention.

[0062] List of reference symbols

[0063] 1 Arrangement with forging device and handling device

[0064] 2 Workpiece

[0065] 2a Workpiece center axis

[0066] 10 Forging device

[0067] 20 Handling device

[0068] 22 Transport section

[0069] 24 Manipulator section

[0070] 30 measuring system

[0071] 31 measuring range

[0072] 32 Distance measuring system

[0073] 34 Optical measuring system

[0074] 50 Control device d Distance between workpiece and optical measuring system

[0075] Fz target measuring plane

[0076] Ff Incorrect focus measuring plane

Claims

Patent claims 1. A method for determining the geometry of a workpiece (2) during forging, in particular open-die forging, the method comprising: Transporting the workpiece (2) into a measuring area (31) of a measuring system (30) by means of a handling device (20); Measuring at least one distance (d) between the workpiece (2) and an optical measuring system (34) of the measuring system (30) by means of at least one distance measuring system (32) and determining therefrom at least one distance value; optically recording the workpiece (2) by the optical measuring system (34) and therefrom completely or partially determining the geometry of the workpiece (2); and Correcting the geometry of the workpiece (2) by applying the at least one distance value.

2. Method according to claim 1, characterized in that the at least one distance value is further used to determine a focus range of the optical measuring system (34).

3. Method according to claim 1 or 2, characterized in that the orientation of the workpiece (2) is determined from the at least one distance value and is used to correct the geometry of the workpiece (2).

4. Method according to one of the preceding claims, characterized in that the complete or partial determination of the geometry of the workpiece (2) using an image recognition algorithm, preferably an edge detection algorithm.

5. Method according to claim 4, characterized in that the complete or partial determination of the geometry of the workpiece (2) comprises a conversion of pixels resulting from a sensor resolution of the optical measuring system (34) into one or more length measurements via a conversion factor.

6. Method according to one of the preceding claims, characterized in that, within the scope of the distance measurement, several distances (d) between the workpiece (2) and the optical measuring system (34) are determined by means of at least one or more distance measuring systems (32).

7. Method according to claim 6, characterized in that from the plurality of determined distances (d) an incorrect alignment of the workpiece (2) and / or a workpiece error is determined and used to correct the geometry of the workpiece (2).

8. Method according to one of the preceding claims, characterized in that the determined and corrected geometry of the workpiece (2) is included in the process control of a forging device (10).

9. Arrangement (1) with a forging device (10), preferably an open-die forging press, for forging a workpiece (2), a handling device (20) for conveying and aligning the workpiece (2), a measuring system (30) for detecting the geometry of the workpiece (2) and a control device (50), wherein the measuring system (30) has a measuring area (31), at least one distance measuring system (32), and an optical measuring system (34), wherein the control device (50) is in communication with the forging device (10), the handling device (20), and the measuring system (30) and is configured to convey the workpiece (2) into the measuring area (31) of the measuring system (30) by means of the handling device (20); to measure at least one distance (d) between the workpiece (2) and the optical measuring system (34) by means of the at least one distance measuring system (32) and to determine at least one distance value therefrom; to pick up the workpiece (2) by the optical measuring system (34) and to determine the geometry of the workpiece (2) therefrom, completely or partially; and to correct the geometry of the workpiece (2) by applying the at least one distance value.

10. Arrangement (1) according to claim 9, characterized in that the at least one distance measuring system (32) has one or more distance sensors, preferably based on the radar and / or laser measuring principle, and / or the optical measuring system (34) has an optical sensor or a combination of several optical sensors, preferably realized by a camera and / or a thermography system.

11. Arrangement (1) according to claim 9 or 10, characterized in that the measuring system (30) is arranged outside the forging device (10).

12. Arrangement (1) according to one of claims 9 to 11, characterized in that the control device (50) is set up to use the at least one distance value to determine a focus range of the optical measuring system (34), and / or to determine the orientation of the workpiece (2) from the at least one distance value and to use it to correct the geometry of the workpiece (2).

13. Arrangement (1) according to one of claims 9 to 12, characterized in that the measuring system (30) and the control device (50) are set up to determine a plurality of distances (d) between the workpiece (2) and the optical measuring system (34) as part of the distance measurement.

14. Arrangement (1) according to claim 13, characterized in that the control device (50) is arranged to determine an incorrect alignment of the workpiece (2) and / or a workpiece error from the plurality of determined distances (d) and to use it for the correction of the geometry of the workpiece (2).

15. Arrangement (1) according to one of claims 9 to 14, characterized in that the control device (50) is designed to control and / or regulate the forging process of the forging device (10) on the workpiece (2) and to use the determined and corrected geometry of the workpiece (2) in the process control of the forging device (10).

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