Process Monitor for Open Forging

Abstract

The present invention relates to a method for monitoring and adjusting a free forging process, the method comprising: a) calculating the geometric shape development of a workpiece during free forging using an empirical model; b) calculating the workpiece temperature across the cross-section of the forged workpiece in parallel with step a), i.e., simultaneously or at least partially temporally overlapping; c) preferably, calculating the shape change distribution over the length of the workpiece using the geometric shape development calculated in step a); and d) adjusting the shape change distribution manually or automatically in a predetermined region based on the shape change distribution calculated in step c). Furthermore, the present invention relates to a free forging press configured and provided to carry out this method.

Description

Technical Field

[0001] 1. Field of the Invention The present invention relates to a method for monitoring and adjusting a free forging press, and a free forging press connected to an open-loop control and a closed-loop control unit and configured and provided to implement this method.

[0002] 2. Description of the Related Art Free forging is a deformation processing technique belonging to forging, which aims to improve the mechanical properties of a workpiece and manufacture a blank portion. In the case of free forging, the workpiece is deformed under pressure using tools that move relative to each other, where the tools may be smooth or may partially have the shape of the workpiece itself. The workpiece shape is generated by precise guiding of the workpiece and control of the deformation force acting on the workpiece by the tools. In this case, usually, a number of working strokes of the tools are required until the workpiece takes its desired shape.

[0003] In this case, the workpiece is usually detected by a forging manipulator and gradually deformed over the entire length to be deformed between the foot line at the starting end of the area to be deformed and the hood line at the ending end of the area to be deformed. Therefore, the length of the workpiece can be obtained from the distance between the hood line and the foot line.

[0004] Free forging is carried out as a hot deformation processing process within a predetermined temperature window for the workpiece. This workpiece temperature depends on the material, and moreover, it is usually set according to the desired deformation of the workpiece up to the final geometry and the pass schedule, and the deformation energy introduced into the workpiece is also considered.

[0005] From U.S. Patent Application Publication No. 2005 / 0247092, a method and apparatus for optimizing a forging process are known. Similarly, International Publication No. 2005 / 113172 discloses a method and apparatus for optimizing a forging process. However, these devices and methods known from the prior art require extremely costly measurement techniques to optimize the forging process and do not enable online temperature calculation and adjustment of the free forging process. The solutions known from the prior art further do not take into account round blocks, stepped shafts, partially forged regions, and conical casting blocks when calculating shape changes or shape change distributions inside the workpiece. Therefore, the solutions known from the prior art are costly and do not provide desirable results for adjusting various modes of the free forging process.

[0006] 3. Problem to be Solved by the Invention Accordingly, an object of the present invention is to provide a method and a free forging press that can provide a comprehensive solution for process monitoring in a free forging press without relying on costly measurement technology systems. In the present invention, the above object is solved by a method including the features described in claim 1 and a free forging press including the features described in claim 13. Advantageous configurations of the present invention are particularly described in the dependent claims.

[0007] 4. Summary of the Invention According to the present invention, there is provided a method for monitoring and adjusting a free forging press, the method including: step (a) of calculating a geometric shape development of a workpiece during free forging using an empirical model; step (b) of calculating a workpiece temperature across a cross-section of the forged workpiece in parallel with step (a), that is, simultaneously or at least partially overlapping in time; step (c) of preferably calculating a shape change distribution over the length of the workpiece using the geometric shape development calculated in step (a); and step (d) of automatically or manually adjusting the shape change distribution to a predetermined region based on the shape change distribution calculated in step (c).

[0008] This provides a comprehensive solution for process monitoring during free forging. Costly measurement technology systems can be fully, preferably completely avoided. During free forging, the elongation of the workpiece along the longitudinal axis of the workpiece is intended to increase by a value ΔL in length during each stroke, while the width increases by ΔΒ based on the free side of the workpiece. In this case, the ratio of the length change to the width change, the so-called elongation, depends strongly on the material, temperature, and tool. Therefore, the prediction or pre-calculation of the geometry is only possible conditionally. Existing measurement technology solutions for creating geometry development are extremely complex and costly due to severe ambient conditions and can therefore only be used in minor forging.

[0009] The solution of the present invention to overcome this problem assumes that the workpiece is moved to a defined initial position, where preferably a footprint for the forging process is set. Subsequently, the workpiece is forged and is then gradually moved through the press to a predetermined final position, preferably defined as the hood line. On the manipulator side, the hood line of the starting end of the workpiece extending to the above-mentioned footprint is defined. Thereby, the length of the workpiece is obtained from the difference between the hood line and the footprint.

[0010] Then, during forging, the geometry development is calculated via the pass schedule and the relationship with the spread, known to those skilled in the art.

[0011] At a predetermined point in time, for example after each second pass, the measurement of the distance between the footprint and the hood line can be repeated, thereby detecting the actual geometry development and, if necessary, correcting errors in the geometry calculation that may occur. Therefore, there is a possibility of detecting the material-dependent elongation characteristics and spread characteristics with respect to the model for geometry calculation.

[0012] Furthermore, preferably, the press stroke, the press force and / or the manipulator position are detected by a suitable sensor device and used by the press and possibly also by the manipulator to identify the spread and length changes of the workpiece. This is usually done during operation by one or two manipulators, and when using two forging manipulators, preferably the transfer of the workpiece from the first manipulator to the second manipulator is also taken into account.

[0013] Preferably, when all the above-mentioned parameters are stored in a database in parallel with the process, this gives rise to the possibility of obtaining a self-learning and continuously improving model for geometric shape measurement and geometric shape calculation in open-die forging.

[0014] Temperature is a decisive target quantity during open-die forging. This is because temperature substantially affects the material properties, especially the microstructure of the workpiece. During forging, the temperature can only be measured at the surface, and the temperature inside cannot be measured. Therefore, the method according to the invention assumes calculating the workpiece temperature across the cross-section of the forged workpiece, and this calculation of the workpiece temperature is carried out simultaneously with or at least partially overlapping in time and thus in parallel with the step of calculating the geometric shape development of the workpiece during open-die forging using an empirical model.

[0015] Suitably, the calculation of the temperature distribution is carried out by one or more measurement systems, such as pyrometers or thermography systems, that measure the surface temperature at one or more points on the workpiece surface. Then, the calculation of the temperature distribution inside the workpiece is carried out using a temperature model known to those skilled in the art. Preferably, the calculated temperature distribution is shown to the press operator, which advantageously assists in the monitoring and adjustment of open-die forging. In particular, this enables the operator to interrupt the process at any time or to make changes as desired on the operator side.

[0016] The calculation of the geometric shape development of the workpiece during open-die forging is preferably the basis for a further important step of the method according to the invention, namely for the step of calculating the distribution of shape changes over the length of the workpiece. Subsequently, the geometric shape quantities obtained when calculating the geometric shape development are used as input quantities for the shape change model, whereby the distribution of shape changes and thus the core compression during open-die forging can be calculated in parallel with the process. For this purpose, current shape change models are described, for example, in the disclosure Dominik Recker “Entwicklung von schnellen Prozessmodellen und Optimierungsmoeglichkeiten fuer das Freiformschmieden“ Jahr 2014, Shacker-Verlag, Aachen. The calculation of the distribution of shape changes over the length of the workpiece is extremely important for open-die forging. This is because the process characteristics during open-die forging result in a non-uniform distribution of shape changes in the workpiece.

[0017] According to the invention, preferably, the shape change model, in particular the shape change model by Recker described above, is extended to further geometric shapes of the workpiece to be forged, in particular with respect to partially forged blocks, conical blocks, polygonal blocks and round blocks. For this purpose, when using the shape change model in a manner known per se to the person skilled in the art, it is necessary to take into account the distribution of shape changes depending on the special geometric shape of the workpiece to be manufactured.

[0018] Finally, according to the invention, the distribution of shape changes in a predetermined region is adjusted based on the pre-calculated distribution of shape changes. Thus, the invention provides an overall system for process adjustment in open-die forging in which process quantities and quality quantities, geometric shapes, shape changes and temperatures are utilized using process data and adjustment algorithms.

[0019] Particularly preferably, in this context, a predetermined temperature window for the open-die forging process is controlled, and preferably, if there is a deviation from a predetermined acceptable temperature window for the workpiece, a warning is output to the press operator. Particularly preferably, this method preferably automatically proposes, and in some cases independently or at least after permission by the press operator, a proposal for continuing the open-die forging process in order to achieve an ideal shape change distribution.

[0020] Particularly preferably, the method according to the invention does not use any other measurement data in addition to the measurement of the workpiece temperature and, optionally, the measurement of the measurement signals of the open-die forging press and / or at least one workpiece manipulator. This limits the use of the measurement sensor device and the associated complexity to a minimum, while still enabling complete process monitoring of open-die forging.

[0021] Particularly preferably, in order to enable the quickest possible post-adjustment of the open-die forging process, steps (a)-(c), and thus the calculation of the geometric shape development, the parallel calculation of the workpiece temperature across the cross-section, and the calculation of the shape change distribution across the length of the workpiece, are calculated together online during the open-die forging process.

[0022] Particularly preferably, the calculation of the geometric shape development includes the calculation of the elongation and spreading characteristics of the workpiece, preferably depending on the material. This advantageously supports the monitoring and adjustment of the open-die forging process itself.

[0023] In another preferred embodiment of the method according to the invention, an empirical model is used such that the parameters determined during the calculation of the geometric shape development of the workpiece are used as input quantities for the shape change model, and the shape change model determines the shape change distribution. Preferably, in the case of a non-uniform shape change distribution, the core compression is also determined across the cross-section and / or the length of the workpiece. This provides a method that enables, particularly in the case of a workpiece geometry deviating from a round geometry, especially in the case of a stepped shaft, the best possible information regarding the characteristics of the free forging process and the workpiece to be processed.

[0024] In this context, preferably, an open-loop control and a closed-loop control unit are provided, and the open-loop control and the closed-loop control unit are connected to a database in which all the detected measurement data and the calculated parameters are stored. This achieves a method by which the adjustment algorithm can be set so that, preferably in a self-learning manner, the best possible forging results are achieved even when manufacturing complex workpiece geometries and special workpiece articles.

[0025] Here, particularly preferably, the open-loop control and the closed-loop control unit indicate to the operator the calculated quantities of the geometry distribution and / or the shape change distribution and / or the temperature change distribution, and preferably further output a warning in the case of a deviation from a predefined region, and / or output a proposal for adjusting the free forging process, for the purpose of complying with a predefined region and / or for achieving an ideal shape change distribution. This provides a method by which the best results of free forging, an optimized pass schedule, and an optimal workpiece article can be manufactured.

[0026] According to another aspect of the invention, there is provided a free forging press machine that is connected to the open-loop control and the closed-loop control unit, is configured to carry out the method of the invention according to the first aspect described above, and is provided.

[0027] Therefore, all advantages and technical effects related to the method according to the present invention can also be achieved by using the open-die forging press according to the present invention.

[0028] 5. Description of the Drawings Hereinafter, the present invention will be described in more detail with reference to two drawings. In these drawings, preferred embodiments of the present invention are described in more detail, but these are not suitable for limiting the protection scope of the present invention defined in the claims.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

[0030] 6. Detailed Description of the Drawings FIG. 1 shows an open-die forging press 1 with two forging tools 2, 3 movably arranged relative to each other. The upper forging tool 3 is movably arranged inside the open-die forging press 1 relative to the lower forging tool 2, and the workpiece 4 is held by a forging manipulator 5 and brought close to the forging tools 2, 3 at the start of the open-die forging process. At this point, a footline 7 that determines the starting end of the workpiece 4 or at least the length of the workpiece 4 to be forged is determined.

[0031] Figure 2 shows the same open-die forging press 1 as shown in Figure 1, and the workpiece 4 is fully deformed between the forging tools 2, 3 at the end of the open-die forging process. At this point, a hood line 8 that determines the end portion of the workpiece 4 to be deformed is determined. Then, from the difference between the foot line 7 and the hood line 8 shown in Figure 1, the length ΔL of the workpiece 4 during the open-die forging process can be specified. A person skilled in the art can also determine the material-dependent spread ΔΒ from this, based on the invariance of mass and volume. During the forging process, the geometric shape development can be calculated through the path schedule executed during the deformation of the workpiece 4 and the known relationships regarding the spread. A person skilled in the art is well aware that this type of material-dependent relationship is, for example, from Tomlinson, A; Stringer, J.D.: “Spread and elongation in flat tool forging“ (Journal of the Iron and Steel Institute 193, 1959, pp. 157 - 162). This can avoid errors that would otherwise occur continuously due to unknown workpiece characteristics.

Explanation of reference numerals

[0032] 1 Open-die forging press 2 Forging tool 3 Forging tool 4 Workpiece 5 Forging manipulator 7 Foot line 8 Hood line

Claims

1. A method for monitoring and adjusting a free forging process, comprising: The method includes: a) calculating a geometric shape development of a workpiece during free forging using an empirical model; b) calculating a workpiece temperature across a cross-section of the forged workpiece in parallel with step a), i.e., simultaneously or at least partially overlapping in time; c) preferably, calculating a shape change distribution along the length of the workpiece using the geometric shape development calculated in step a); d) adjusting the shape change distribution manually or automatically in a predetermined region based on the shape change distribution calculated in step c). A method as described above.

2. The method according to claim 1, wherein in step a), a footprint line and a hood line for the free forging process are defined and the geometric shape development is optionally corrected.

3. The method according to claim 1 or 2, wherein in step b), the measurement of the workpiece temperature is preferably performed using a pyrometer or a thermography system, and the free forging process is adjusted, optionally, for the purpose of complying with a predetermined workpiece temperature range.

4. The method according to claim 3, wherein the measured temperature is used as a comparison quantity in a calculation model, and the calculation model calculates the temperature distribution across the entire cross-section of the workpiece, preferably also along the length of the workpiece.

5. The method according to claim 3 or 4, wherein monitoring and preferably adjusting compliance with a predetermined workpiece temperature range depending on the material is performed.

6. The method according to any one of claims 3 to 5, wherein no other measurement data is used, in addition to the measurement of the workpiece temperature and optionally the measurement signals of a free forging press and / or at least one workpiece manipulator, preferably also in addition to the measurement of the press stroke, press force and manipulator position.

7. The method according to any one of claims 1 to 6, wherein steps a) to c) are calculated online together during the free forging process.

8. The method according to any one of claims 1 to 7, wherein the workpiece is a round block, a stepped shaft and / or a conical casting block and / or may have a partially forged region.

9. The method according to any one of claims 1 to 8, wherein the calculation of the geometric shape development preferably includes the calculation of the elongation characteristics and spreading characteristics of the workpiece, depending on the material.

10. The quantity for the geometric shape development calculated in step a) is used as an input quantity for a shape change model, and the shape change distribution is determined by the shape change model. Preferably, in the case of a non-uniform shape change distribution, core compression is determined over the cross-section and / or length of the workpiece. The method according to any one of claims 1 to 9.

11. An open-loop control and a closed-loop control unit are provided, and the open-loop control and the closed-loop control unit are connected to a database in which all detected measurement data and calculated parameters are stored. The method according to any one of claims 1 to 10.

12. The open-loop control and the closed-loop control unit show the calculated quantities of the geometric shape distribution and / or the shape change distribution and / or the temperature distribution to the operator. Preferably, further, in the case of a deviation from the target state due to a region with an overly low shape change, a warning is output and / or a proposal for adjusting the open-die forging process is output for the purpose of complying with a predetermined region and / or for achieving an ideal shape change distribution. The method according to claim 11.

13. An open-die forging press, which is connected to an open-loop control and a closed-loop control unit and is configured and provided to carry out the method according to any one of claims 1 to 12. An open-die forging press.

14. The open-loop control and the closed-loop control unit of the open-die forging press according to claim 13 are connected to a database capable of storing all measurement data detected by a sensor device and parameters calculated by a shape change model.

15. The open-loop control and closed-loop control unit is connected to a display unit, and using the display unit, the calculated quantities of the geometric shape distribution and / or shape change distribution and / or temperature distribution can be shown to the operator, and preferably further, a warning can be output in case of deviation from a predetermined region, and / or a proposal for adjusting the free forging process can be output for the purpose of complying with the predetermined region and / or for achieving an ideal, preferably uniform shape change distribution, the free forging press according to claim 13 or 14.

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