Method for operating a pressing device, and pressing device

Abstract

A method for operating a pressing device, in particular an electrohydraulic or electromechanical pressing device for pressing a workpiece, comprising a drive unit for generating a pressing force, wherein the method comprises the following steps: detecting a pressure curve and / or a force curve of the pressing device; determining a complete pressing of the workpiece on the basis of the pressure curve and / or the force curve; and switching off the drive unit when a complete pressing is determined.

Description

[0001] October 9, 2025

[0002] Method for operating a press

[0003] The present invention relates to a method for operating a pressing device, in particular an electrohydraulic or electromechanical pressing device for pressing a workpiece. The present invention further relates to such a pressing device.

[0004] Common pressing tools consist of a housing containing a drive unit. The pressing tool also has a tool holder for a pressing tool. The drive unit moves a piston within a piston assembly, which interacts with the pressing tool to generate a pressing force. For this purpose, the drive unit includes an electric motor. The movement of the electric motor is transmitted to the piston either mechanically, in an electromechanical pressing tool, or hydraulically via a hydraulic pump to generate the desired pressing force.

[0005] The pressing tool typically has two pressing jaws that are moved from an open to a closed position by the movement of the drive unit. The workpiece to be pressed is either directly gripped by the pressing jaws or the pressing force of the pressing tool is transferred to a pressing ring or a pressing loop.

[0006] To achieve complete crimping, a specific pressing force is required to move the crimping tool into the closed position. This pressing force, however, depends on the workpiece and the crimping tool. For example, different workpiece materials may require different pressing forces. DE 10 106 360 CI proposes using a current limit for the motor, above which the motor is switched off. (October 9, 2025)

[0007] - 2 - However, only an absolute value of the motor current is considered, so this current limit may no longer apply when pressing a different workpiece. In WO 2012 / 110362, the opening of a check valve and the associated pressure drop in the electro-hydraulic drive unit are used, so that if the motor current drops due to the pressure drop, the motor is switched off. Here, the pressing force to be generated is determined by the pressure at which the check valve opens. This also has to be set manually and is then only applicable to a specific combination of workpiece and pressing tool. Thus, only the opening of the check valve is detected here.

[0008] Therefore, the user must input the required pressing force into the pressing tool to ensure a complete crimp with the correct force. An incorrectly set pressing force can lead to an incomplete crimp (if the force is set too low) or damage to the workpiece or the pressing tool (if the force is set too high). It is therefore essential that the user always sets the required pressing force correctly. In particular, there is a risk that an incomplete crimp will be difficult to detect externally if the pressing force is set too low. Especially when joining pipes, this can lead to leaks and significant damage.

[0009] The object of the present invention is to create a method and a pressing device with which a workpiece can be pressed reliably and safely.

[0010] The problem is solved by a method according to claim 1 and a pressing device according to claim 8.

[0011] The present invention provides a method for operating a pressing device, in particular an electrohydraulic or electromechanical one. October 9, 2025

[0012] - 3 -

[0013] A pressing device is provided for crimping a workpiece. The workpiece can be, in particular, a press fitting for connecting pipe ends. Specifically, the pressing device has a tool holder to which a crimping tool can be detachably or permanently attached. According to the invention, the pressing device has a drive unit for generating a crimping force. In particular, the drive unit has an electric motor that is powered by a power supply such as a battery connected to the pressing device. If the pressing device is an electro-hydraulic pressing device, the drive unit additionally has a hydraulic pump, wherein a crimping force is generated by the drive unit by means of the hydraulic pump and transmitted to the crimping tool, which is detachably or permanently attached to the pressing device, for crimping the workpiece.In this process, a piston is moved by the drive unit, and its movement is transferred to the pressing tool to generate the pressing force. The method according to the present invention comprises the following steps:

[0014] Detecting a pressure curve and / or a force curve of the pressing device;

[0015] Determining whether the workpiece is completely compressed based on the pressure curve and / or the force curve;

[0016] Switch off the drive unit when complete compression is detected.

[0017] Thus, the completeness of the crimping process is determined based on the measured pressure curve and / or the force curve of the crimping tool, and the drive unit is switched off upon completion of the crimping process. Therefore, according to the present method, no limit value for pressure or force is used to detect complete crimping, nor is any [missing information - likely a date or date].

[0018] - 4 - specific values ​​for the pressure curve or force, which may depend on the workpiece, the pressing tool, or the like. In particular, the completeness of the pressing is determined solely from the pressure curve and / or the force curve.

[0019] The pressure curve, as used here, refers to the pressure profile over time within the drive unit, particularly in an electro-hydraulic pressing tool. The drive unit may, for example, comprise a piston unit, in which case the pressure curve describes the pressure profile within the piston unit. However, the invention is not limited to a specific location for pressure measurement; therefore, pressure within a hydraulic pump, pressure in a supply line between the hydraulic pump and the piston unit, and / or pressure in a return line between the piston unit and a check valve can also be used. Similarly, the force profile refers to the pressure profile over time of the generated force, such as a pressing force, a piston force, or the like. Alternatively, the pressure profile can refer to the pressure over the pressing stroke, i.e., the distance traveled by the piston of the drive unit.Similarly, the force profile can refer to the force exerted along the pressing path. It has been shown that the pressure or force along the pressing path can exhibit characteristic features that allow conclusions to be drawn about the pressing process.

[0020] Due to the use of the pressure curve and / or the force curve, workpieces made of different materials can be used with the same drive unit. The user does not need to adjust the required pressing force, as the pressure curve and / or the force curve is used to determine whether the pressing has been completed. The inventors of the present invention recognized that when the pressing jaws of the pressing tool close, they come into contact after the plastic deformation of the workpiece is complete. No further plastic deformation of the workpiece occurs. (October 9, 2025)

[0021] - 5 - Elastic deformation of the pressing tool occurs. This elastic deformation exhibits different behavior in the pressure and force curves. However, elastic deformation of the pressing tool, at least over time, can lead to fatigue and subsequent damage, especially with numerous pressing operations where such elastic deformation occurs each time. This behavior is characteristic of a completed pressing operation, regardless of the workpiece material, the pressing tool used, or the type of workpiece. This characteristic behavior also affects the pressure and force curves, allowing conclusions to be drawn about the completion of the pressing operation based on these curves.

[0022] Preferably, the pressure profile is detected by a pressure sensor, particularly in an electro-hydraulic drive unit or an electro-hydraulic pressing device.

[0023] Preferably, the force profile is recorded using a force sensor, such as a strain gauge.

[0024] Preferably, the pressing path is detected via a position sensor, wherein in particular the position of the piston of the drive unit is detected by the position sensor.

[0025] Preferably, in addition to or instead of a direct measurement of the pressure or force profile by a pressure sensor or a force sensor, the pressure or force profile can be inferred, for example, by measuring a motor current, whereby the pressure and / or force profile can be inferred from the motor current. Here, too, no absolute value of the current is used, but rather the temporal profile of the current is taken into account, so that the pressure or force profile can be inferred from the time-dependent values.

[0026] - 6 -

[0027] The flow of the current can be used to infer the pressure curve or force curve.

[0028] Preferably, the pressure profile and / or the force profile over the entire pressing process is used to detect the complete pressing of the workpiece. Thus, all information provided by the pressure or force profile can be used to recognize complete pressing. In particular, it is detected from the beginning of the pressing process whether it is complete. Therefore, the entire pressure and / or force profile of the pressing process is used to predict whether the pressing was successful and complete.

[0029] Preferably, the drive unit comprises a motor connected to a hydraulic pump for supplying hydraulic fluid from a reservoir via a supply line to a piston unit. Furthermore, the drive unit includes an electronically controlled check valve in a return line connecting the piston unit to the reservoir. When the check valve is open, hydraulic fluid can flow back from the piston unit into the reservoir, allowing a piston of the piston unit to be pushed back to its starting position or the pressing tool to be moved into an open position. When the check valve is closed and hydraulic fluid is pumped from the reservoir into the piston unit by the hydraulic pump, a pressing force is generated, which is transmitted to the workpiece via the pressing tool. The check valve opens when a complete crimp is detected.Thus, upon detection of complete crimping, the motor or drive unit is switched off. Additionally, upon complete crimping, the non-return valve opens, allowing the crimping tool to be released from the workpiece. Specifically, the non-return valve opens simultaneously on October 9, 2025.

[0030] - 7 -

[0031] The engine is switched off, or the non-return valve is opened after the engine is switched off.

[0032] Preferably, the motor is not switched off due to the opening of the backflow valve, but due to the detected pressure curve and / or force curve.

[0033] Preferably, no limit value is used to switch off the drive unit and / or open the check valve. This differs in particular from the prior art, such as DE 10 106 360 CI, where a current limit value is used to switch off the drive unit. However, this limit value depends, for example, on the workpiece, the pressing tool, or the like, and would therefore have to be correctly set by the user depending on the application of the pressing device. Since the present invention specifically eliminates the use of a limit value, such a setting is no longer necessary. Instead, the pressure curve or force curve is used to detect complete crimping.

[0034] Preferably, the drive unit is switched off and / or the check valve is opened before a maximum force is reached. In particular, by considering the force and / or pressure profile of the pressing process, and especially the complete force and / or pressure profile, it is possible to terminate the pressing process as soon as the workpiece has been completely pressed. Specifically, the pressing process is terminated before elastic deformation of the pressing tool occurs, or only minimal elastic deformation occurs, thus protecting the pressing tool and preventing unnecessary, excessive premature fatigue. Conventional pressing tools are controlled by a fixed maximum force (or maximum pressure) that the drive unit must reach. For safety reasons, this maximum force is set in the prior art as follows: October 9, 2025

[0035] - 8 - a large value was chosen to ensure a safe and reliable crimping process once the maximum force is reached. The same applies to controlling the crimping process via a maximum pressure. However, this is detrimental to the service life of the drive unit and / or the crimping tool. Furthermore, such a high maximum force / pressure is not necessary for successful crimping.

[0036] Preferably, determining complete compression of the workpiece based on the pressure curve and / or the force curve includes:

[0037] Continuous transmission of the detected pressure and / or force to a trained detection module, whereby the trained detection module recognizes the complete compression based on the previous pressure profile and / or force profile.

[0038] Thus, using the trained detection module, a complete compression can be inferred from the pressure curve or the force curve.

[0039] Preferably, the detection module has a neural network for recognizing complete compression based on the pressure profile and / or the force profile.

[0040] Preferably, the neural network is a recurrent neural network (RNN) or a long short-term memory (LSTM) network for detecting complete grouting. These types of networks are particularly suitable for recognizing the characteristic progression or corresponding patterns of pressure and / or force curves that indicate the completion of grouting, and thus for detecting the completion of complete grouting.

[0041] Preferably, the training of the detection module and, in particular, the neural network comprises: providing a large number of predefined pressure profiles and / or predefined force profiles, wherein the predefined 9 October 2025

[0042] - 9 -

[0043] For pressure profiles and / or predefined force profiles, the time or compression path of complete compression is known. For training purposes, the time or compression path of complete compression determined by the detection module or neural network for a specific pressure profile or force profile is compared with the known time / compression path of complete compression for that same pressure profile or force profile. The weights of the neural network are then adjusted based on this comparison. Subsequently, the detection module or neural network is trained with another of the predefined pressure profiles until the time or compression path determined by the detection module or neural network is reached.The neural network determines the time / pressure path of complete compression for a specific pressure and / or force profile and confirms that this matches the known time / pressure path of complete compression, or that the difference is less than a predefined threshold. Thus, for training the detection module or neural network, a large number of pressure or force profiles are provided, for which the time or pressure path of complete compression is known and marked. The detection module's prediction of the time or pressure path of complete compression is then compared with the known time / pressure path of complete compression for the respective pressure or force profile. If the prediction of the detection module or neural network is sufficiently accurate, the detection module or neural network can be used for training purposes.The neural network is sufficiently trained and can therefore recognize complete crimping even for unknown pressure and / or force profiles. This applies in particular regardless of the workpiece material, type / style, and / or the crimping tool used.

[0044] Preferably, the training is conducted for a variety of different pressing tools, so that, in particular, a prediction can be made for all pressing tools considered in the training regarding the completeness of the pressing based on the pressure or force profile. October 9, 2025

[0045] - 10 -

[0046] Preferably, the training is carried out for a variety of different workpieces and, in particular, workpiece materials. This makes it possible to provide a single pressing device for different materials. In particular, the present invention makes it possible to provide a suitable control system, and it is no longer necessary to provide different pressing tools for different materials, which would prevent exceeding a maximum pressing force through the design and geometry of the respective pressing tool.

[0047] Preferably, the detection module is trained exactly once before the pressing tool is used. Subsequently, the trained detection module can be implemented in all pressing tools of the same type. Alternatively, the detection module of each pressing tool is trained independently, so that deviations, for example, in the force or pressure generation of the respective pressing tool, can also be taken into account. However, it has been shown that the detection of a complete pressing operation is independent of the absolute values ​​of the pressure or force curves, and that the curve itself is sufficient to recognize a complete pressing operation. Therefore, even minor fluctuations or offsets between different pressing tools still allow for a reliable prediction of a complete pressing operation.

[0048] Preferably, the pressing tool is automatically detected. This automated detection is achieved, for example, optically by providing a camera on the drive unit, so that the pressing tool can be identified by means of image recognition and / or recognition of suitable markings, such as a color marking, a barcode, a QR code, or the like, on the pressing tool. Alternatively, the automated detection of the pressing tool is carried out electronically, for example, when the pressing tool is connected to the drive unit.

[0049] - 11 - by means of electronic coding. Alternatively, the respective pressing tool is identified by the user and provided as user input to the drive unit. Based on the known pressing tool, an improved prediction can then be made based on the recorded pressure or force profile.

[0050] Preferably, there is no detection of the pressing tool and no user input of the pressing tool used, so that the detection module makes a suitable prediction of successful pressing regardless of the pressing tool used.

[0051] Preferably, the workpiece material is automatically detected or identified via user input, so that the known material can be taken into account by the detection module when predicting successful crimping. Automated material detection can be achieved, for example, through workpiece recognition, particularly optical workpiece recognition using a camera (by capturing an image or detecting a suitable marking such as a color mark, barcode, QR code, or the like), or by impedance measurement via the crimping tool or similar methods. It has been shown that the pressure or force profile differs for different materials, such as plastic, copper, brass, steel, or the like.

[0052] Preferably, there is no detection of the workpiece material and no user input of the material, so that the detection module makes a suitable prediction of successful crimping regardless of the material used in the workpiece.

[0053] Preferably, the type of workpiece is automatically recognized or identified by means of user input, so that the known type of 9 October 2025

[0054] - 12 - the detection module can be taken into account when predicting successful crimping. Automated identification of the workpiece type can be achieved, for example, through workpiece recognition, in particular optical workpiece recognition using a camera (by means of image capture or detection of a suitable marking such as a color marking, a barcode, a QR code, or the like). It has been shown that the pressure or force profile differs for different types of workpieces, such as sleeves, tees, or the like.

[0055] Preferably, there is no detection of the workpiece type and no user input of the workpiece type, so that the detection module makes a suitable prediction of successful crimping regardless of the workpiece used.

[0056] The present invention further relates to a pressing device, which is in particular designed as an electrohydraulic or electromechanical pressing device for pressing a workpiece. The pressing device comprises a drive unit and a control unit connected to the drive unit, the control unit being configured to carry out the method as described above. In particular, the control unit is integrated into the pressing device so that detection can be performed by the pressing device itself. Thus, the control unit is configured to infer complete pressing from the detected pressure and / or force profiles of the pressing device. In particular, the control unit comprises a detection unit as described above.

[0057] Furthermore, the present invention relates to a pressing device, which is designed in particular as an electrohydraulic or electromechanical pressing device for pressing a workpiece. The pressing device comprises a drive unit and a [missing information - likely a component or component] connected to the drive unit.

[0058] - 13 -

[0059] A communication unit is used, which is wirelessly connected to a control unit, for example via Bluetooth. The control unit is designed to carry out the procedure as described above. Therefore, the control unit is not directly integrated into the pressing device. In particular, the control unit can be integrated into a mobile user device such as a tablet, smartphone, or the like. Using the external control unit, it is possible to conclude that a complete crimp has been achieved based on the detected pressure and / or force profile. For this purpose, the pressure and / or force profile is transmitted from the pressing device to the control unit via the communication unit, and the control unit then performs a detection of the complete crimp.Upon detection of complete crimping, a corresponding control signal can then be transmitted from the user device to the communication unit to switch off the motor and preferably also to open a non-return valve. This has the advantage that, in particular, the implementation of the detection module, or the detection of complete crimping based on the pressure and / or force profile, can be carried out on an external device. This minimizes the computing power that would need to be integrated into the crimping tool. Instead, the existing computing power, for example in a smartphone or tablet, is used to detect complete crimping.

[0060] The invention will now be explained in more detail with reference to preferred embodiments and the accompanying figures.

[0061] The figures show:

[0062] Fig. 1 shows a schematic diagram of a pressing device according to the present invention, October 9, 2025

[0063] - 14 -

[0064] Fig. 2 shows a schematic flowchart of the method according to the present invention,

[0065] Fig. 3 shows a schematic force or pressure curve over time and

[0066] Fig. 4 shows a schematic force or pressure curve across the

[0067] Pressweg.

[0068] The pressing device 10 according to the present invention has a piston unit 22 in which a piston 24 is movable in the direction of arrow 26 to generate a pressing force. The movement of the piston 24 is transmitted to a pressing tool, which is detachably or permanently connected to the pressing device 10, and which then presses a workpiece, such as a press fitting. For this purpose, the pressing device 10 has a motor 12, which is connected to a hydraulic pump 14 via a motor shaft 13. Hydraulic fluid is pumped from a reservoir 20 to the piston unit 22 by means of the hydraulic pump 14 via a supply line 16, so that the piston 24 is moved in the direction of arrow 26 and a pressing force is generated. A pressure sensor 30 is arranged in a return line 28 to detect the pressure in the piston unit 22. Thus, a pressure profile over the entire pressing process can be detected via the pressure sensor 30. Such a pressure profile 36 is shown in the Fig.Figure 3 is shown as an example and illustrates the pressure over time t. Alternatively, the force could be used over time. It is also possible to use pressure and / or force over the pressing path as a pressure or force curve, respectively. This is shown in Figure 4 and described in detail below. At time t0, the pressing process is started. The electric motor 12 is started, and the hydraulic pump 14 delivers hydraulic fluid from the reservoir 20 to the piston unit 22. The piston 24 begins to move. At time t1, the pressing process starts. In particular, at time t1, the pressing tool engages with the workpiece, and a plastic deformation occurs.

[0069] - 15 -

[0070] Deformation of the workpiece begins. At time t2, a control unit 34 connected to the pressure sensor 30 detects that a complete compression has occurred based on the detected pressure profile. The inventors of the present invention recognized that during complete compression, the pressing jaws of the pressing tool meet. Plastic deformation of the workpiece no longer occurs. Instead, elastic deformation of the pressing tool takes place. This characteristically changes the pressure profile 36. This can be detected, in particular, by the control unit 34. If the control unit 34 detects a complete compression, the motor 12 is deactivated by the control unit 34. The embodiment shown in Fig. 1 is an electro-hydraulic pressing device.This device features a non-return valve 32, which is electronically controlled and also connected to the control unit 34. If the control unit 34 detects a complete crimp, not only can the electric motor 12 be stopped, but the non-return valve 32 is also opened. This leads to a pressure drop in the piston unit 22, which is also shown in Fig. 3. Simultaneously, hydraulic fluid can flow from the piston unit 22 back into the reservoir 20, and the piston 24 can be pushed back to its starting position opposite arrow 26, or the pressing jaws of the pressing tool can be forced apart in an open position.

[0071] Fig. 2 shows a schematic flow diagram of the method according to the present invention, which is implemented in particular in the control unit 34 of the pressing device 10. The method comprises the following steps:

[0072] In step SOI, a pressure curve and / or a force curve of the pressing device is detected.

[0073] In step S02, it is determined whether the workpiece is completely compressed based on the detected pressure profile and / or force profile.

[0074] In step S03, if complete crimping has been determined, the drive unit of the crimping tool is switched off. October 9, 2025

[0075] - 16 -

[0076] The control unit 34 includes, in particular, a trained detection module, which can infer complete compression from the pressure / force profile 36. The trained detection module can comprise a neural network, which may be configured, for example, as a recurrent neural network or as an LSTM network. To recognize complete compression from the pressure and / or force profile, the detection module must first be trained. Training the detection module, and in particular the neural network, comprises: providing a large number of predefined pressure and / or force profiles, where the time or compression path of complete compression is known for each of these predefined pressure and / or force profiles. For training, the pressure profile for a specific pressure or force profile is used.The time / pressure path of complete compression determined by the detection module or neural network is compared with the known time / pressure path of complete compression for this pressure or force profile. The weights of the neural network are then adjusted based on this comparison. Subsequently, the detection module or neural network is trained with another of the predefined pressure profiles until the time / pressure path of complete compression determined by the detection module or neural network for a specific pressure and / or force profile matches the known time / pressure path of complete compression, or the difference is less than a predefined threshold. Thus, a large number of pressure profiles are used for training the detection module or neural network.Force profiles are defined where the time / pressure path of complete grouting is known and marked. The detection module's prediction of the time / pressure path of complete grouting is thus compared with the known time / pressure path of complete grouting for the respective pressure or force profile. October 9, 2025.

[0077] - 17 -

[0078] Provided the prediction of the detection module or neural network is sufficiently accurate, the detection module or neural network is adequately trained and can therefore recognize complete crimping even for unknown pressure and / or force profiles. This applies regardless of the workpiece material, type, and / or pressing tool used. Alternatively, the workpiece material, pressing tool, and / or workpiece type can be passed to the detection module as additional parameters, enabling a more specific prediction. A detection module or neural network trained in this way can then be used in the pressing device to recognize complete crimping under a given pressure and / or force profile, even for unknown crimping operations, workpieces, and / or pressing tools.Manual adjustment of the required pressing force is therefore no longer necessary. The pressing device ends the pressing process each time the optimal pressing force is reached, as soon as the pressing is complete.

[0079] Although Fig. 1 shows an electro-hydraulic pressing tool, the same applies to a mechanical pressing device, where the movement of the electric motor 12 directly affects the movement of a piston. In particular, with electromechanical pressing devices, the force curve of the pressing force is directly determined, for example by a force sensor. The other aspects of the present invention can be transferred in the same way to an electromechanical pressing device.

[0080] The following refers to Figure 4. Figure 4 shows a force or pressure curve over a pressing stroke. The pressing stroke, for example, denotes the position of the piston 24 of a piston unit 22. Alternatively, the position of the pressing jaws can be used as the pressing stroke. October 9, 2025

[0081] - 18 -

[0082] Generally, the pressing path refers to the travel path of the drive unit and / or the pressing tool towards a closed position of the pressing device.

[0083] Figure 4 shows a first curve 40 for a workpiece made of a hard material, such as steel. With conventional pressing tools, the workpiece is compressed, followed by elastic deformation of the pressing tool, as represented by curve 44 in Figure 4. If, in a conventional control system, curve 44 exceeds a maximum force FMAX (or a maximum pressure), the drive unit is stopped and / or the check valve 32 is opened. This indicates that the pressing has been completed.

[0084] Fig. 4 shows a second curve 42 for a workpiece made of a softer material, such as plastic or copper. The forces required to compress the workpiece are lower than in the first curve 42. However, with conventional pressing tools, the compression of the workpiece is followed by a phase of elastic deformation of the pressing tool, shown by curve 46 in Fig. 4. The compression only ends when the maximum force FMAX is reached.

[0085] According to the present invention, the completion of the crimping process is determined based on the respective curves 40 and 42. At the respective points 48 and 50 in the force (or pressure) curve, the detection module registers that the crimping of the workpiece is complete, and the crimping process is terminated accordingly. The crimping stroke no longer increases. Furthermore, no additional forces are generated that the crimping tool must absorb. The load on the crimping tool decreases significantly, as only those forces necessary for the crimping process act upon it. October 9, 2025

[0086] - 19 -

[0087] Thus, the present invention provides a method and a pressing device in which the detection of a complete crimp no longer depends on a predefined limit set by the user. In particular, the drive is not switched off or the check valve is not opened based on a preset limit; instead, the point at which the drive unit switches off is determined solely based on the pressure and / or force curve. Therefore, the pressing device can be used to crimp different workpieces and different pressing tools, especially without requiring any additional adjustments by the user. This significantly simplifies operation and simultaneously avoids errors caused by incorrect settings of the required pressing force.

Claims

October 9, 2025 - 20 - Patent claims 1. Method for operating a pressing device, in particular an electrohydraulic or electromechanical pressing device for pressing a workpiece, with a drive unit for generating a pressing force, wherein the method comprises the steps: - Detecting a pressure curve and / or a force curve of the pressing device; - Determining complete compression of the workpiece based on the pressure curve and / or the force curve; - Switch off the drive unit when complete compression is detected.

2. Method according to claim 1, wherein the drive unit comprises a motor, the motor being connected to a pump for conveying hydraulic fluid from a reservoir via a supply line to a piston unit, an electronically controlled return valve in a return line connecting the piston unit and the reservoir, wherein when the valve is open the hydraulic fluid can flow back from the piston unit into the reservoir, wherein when a complete compression is detected the return valve is opened.

3. Method according to claim 1 or 2, wherein no limit value is used to switch off the drive and / or open the backflow valve. October 9, 2025 - 21 - 4. Method according to any one of claims 1 to 3, wherein determining complete compression of the workpiece comprises the following: Continuous transmission of the detected pressure and / or force to a trained detection module, whereby the trained detection module recognizes the complete compression based on the previous pressure profile and / or force profile.

5. Method according to claim 4, wherein the detection module comprises a neural network for detecting complete compression.

6. Method according to claim 5, wherein the neural network is a recurrent neural network or an LSTM network for detecting complete compression.

7. A method according to any one of claims 4 to 6, wherein the training of the detection module and in particular the neural network comprises: providing a plurality of predetermined pressure profiles and / or predetermined force profiles, wherein for the predetermined pressure profiles and / or predetermined force profiles the time and / or pressing path of complete compression is known, wherein for the training the time and / or pressing path of complete compression determined by the neural network is compared with the known time or pressing path of complete compression and the weights of the neural network are adjusted until the determined time or pressing path of complete compression for a specific pressure profile and / or force profile matches the known time or pressing path of complete compression or the difference is less than a predetermined limit value. October 9, 2025 - 22 - 8. Pressing device, in particular an electrohydraulic or electromechanical pressing device for pressing a workpiece, comprising a drive unit and a control unit, wherein the control unit is configured to carry out the method according to one of claims 1 to 7.

9. Pressing device, in particular an electrohydraulic or electromechanical pressing device for pressing a workpiece, comprising a drive unit and a communication unit, wherein the communication unit is connected to a control unit, wherein the control unit is configured to carry out the method according to one of claims 1 to 7.

10. Pressing device according to claim 9, wherein the control unit is integrated into a mobile user terminal device.

11. Pressing device according to one of claims 8 to 10, wherein the control unit comprises the detection unit according to one of claims 4 to 7.

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