FORMING DEVICE AND METHOD FOR OPERATING A FORMING DEVICE

Description

[0001] The invention relates to a forming device with a machine bed on which a first tool is arranged, and with a tool carrier which is mounted relatively movably on the machine bed and to which a second tool and a drive device for moving the tool carrier are assigned, wherein the second tool defines a variable-size working gap with the first tool, with a machine control for controlling the drive device and with a safety control for blocking the drive device, wherein the safety control is connected to at least one radiation source and to several radiation detectors arranged opposite the radiation source, wherein at least some of the beams emanating from the radiation source are aligned along a working edge of the first tool, and with a position measuring system assigned to the drive device,which is designed to provide position signals as a function of a position of the tool carrier, wherein the machine control system has a first position measuring system for cyclic processing of the position signals in a first, fast working cycle to first position values, and wherein the safety control system has a second position measuring system for cyclic processing of the position signals in a second, slow working cycle to second position values. Furthermore, the invention relates to a method for operating a forming device.

[0002] EP 2 940 369 A1 discloses a forming device with a machine bed and a tool carrier mounted thereon in a relatively movable manner, which is coupled to a drive device, a machine control system for controlling the drive device and a monitoring device which is designed to monitor movements of the tool carrier and to control a separating device upstream of the drive device, as well as with two position measuring systems, each designed to output position signals for determining the position of the tool carrier relative to the machine bed, wherein the first position measuring system is designed for a cyclical provision of first position signals in a first, fast working cycle and wherein the second position measuring system is designed for a cyclical provision of second position signals in a second, slow working cycle and wherein a deactivation of at least one radiation detector takes place,if a comparison results in a difference between the first and the second position signal being below a predefined value.

[0003] US 2002 / 0134922 A1 discloses a safety device for protecting an object entering the path of a moving tool of a press brake. For this purpose, a laser transmitter and laser receiver are provided for mounting in fixed relationship to a leading edge of the tool. A controller with a stopping device for stopping the forward movement of the tool in response to certain contingencies is also provided, which contingencies may include those involving an interruption or obstruction of the light beams, as well as those indicating a fault in the press or the safety device itself. The controller also includes means for laser control and processing, means for controlling the knife movement, means for processing the knife position, and means for detecting vibrations.

[0004] EP 3 444 044 A1 discloses a projector that projects laser light between a punch and a die, intended to impinge on an optical receiver connected to a safety controller that determines whether the optical receiver is in a state where it is receiving light or where the laser light is interrupted. The safety controller controls the lowering of the die and stops its movement if it detects that the optical receiver has entered the light-shielding state during a period in which a condition is met that a first distance between a tip of the punch and an upper end of a material is equal to or greater than a second distance between the tip of the punch and the optical receiver.The lowering of the tool continues even if it is determined that the optical receiver is in the light-blocking state during a period in which a condition that the first distance is smaller than the second distance is satisfied.

[0005] The object of the invention is to provide a forming device and a method for operating a forming device, in which an improved position-dependent deactivation of a radiation detector is enabled.

[0006] This object is achieved for a forming device of the type mentioned at the outset in that the safety controller is designed to carry out a comparison between a first status signal and a second status signal for deactivating a first radiation detector at a predetermined first deactivation position, wherein the first status signal is determined by comparing a first actual position value, obtained in particular from the machine controller by adding a first position correction value to the first position value, with a first deactivation position value, and wherein the second status signal is determined by comparing a second actual position value, obtained in particular from the safety controller by adding a second position correction value to the second position value, with the first deactivation position value, and wherein the safety controller is designed todeactivation when the first status signal matches the second status signal.

[0007] Preferably, the first status signal and the second status signal are a logical state, such as a logical high signal or a logical low signal, respectively. Preferably, it is provided that the first status signal is output as a logical high signal if there is identity or substantial agreement (within a predeterminable value interval) between the first actual position value and the first deactivation position value, and is otherwise output as a logical low signal. Furthermore, it is provided that the second status signal is output as a logical high signal if there is identity or substantial agreement (within a predeterminable value interval) between the second actual position value and the first deactivation position value, and is otherwise output as a logical low signal.In any case, the safety controller has the task of determining the second status signal and making the comparison between the first status signal and the second status signal.

[0008] The first status signal can be determined either in the machine control or in the safety control, whereby in the latter case the first position value or the first actual position value is provided by the machine control.

[0009] This approach is based on the consideration that the machine control system does not have any special precautions geared towards safety-related operation. Therefore, the first position value determined using the first position measuring system and the first actual position value are more likely to be inaccurate than the second position value and the second actual position value, since these are determined by the safety-related safety control system. Typically, the machine control system comprises a single processor with which the calculations required to control the forming device can be performed. The determination of the first position value and the first actual position value are part of this calculation, and thus the processor and its peripherals form the first position measuring system.Furthermore, it is provided, by way of example, that the second position value and the second actual position value are determined in the safety controller using at least two independently operating microprocessors, which together form the second position measuring system. The second actual position value is output by this second position measuring system only if there is a match between the second position values ​​and the second actual position values ​​determined by the two microprocessors.

[0010] This procedure enables more reliable deactivation of the first radiation detector at the desired deactivation position, since there must be agreement between the first actual position value, the second actual position value, and the deactivation position value. In the case of errors that can affect both the first actual position value and the second actual position value, comparing the first actual position value with the second actual position value and the first deactivation position value is more likely to rule out erroneous deactivation than is the case when considering a deviation interval between the first and second position signals.

[0011] Preferably, the first position correction value is a first constant value and the second position correction value is a second constant value, which are stored in the safety controller and which are adapted to the conditions of the respective forming device.

[0012] Advantageous further developments of the invention are the subject of the subclaims.

[0013] It is expedient if the safety controller is configured such that a deactivation of a second radiation detector at a predetermined second deactivation position is carried out, in particular exclusively, based on the second position value, wherein a distance of the first radiation detector from the second tool is greater than a distance of the second radiation detector from the second tool. It is assumed here that, upon reaching the first deactivation position, a reduction in the approach speed between the first tool and the second tool is carried out by appropriate control of the drive device and that the safety controller is capable of carrying out a safe and sufficiently precise determination of the position of the second tool relative to the first tool, despite the second, slow working cycle.Accordingly, the evaluation of the first position value calculated with the first, fast work cycle, which is calculated in the machine control and has a higher error probability, can be omitted.

[0014] It is preferably provided that the machine control is set up in such a way that the first position correction value is determined on the basis of a first, in particular maximum, approach speed for the approach of the second tool to the first tool and a first cycle time for the first work cycle, and that the safety control is set up in such a way that the second position correction value is determined on the basis of the first, in particular maximum, approach speed and a second cycle time for the second work cycle.

[0015] The first position correction value has a smaller value than the second position correction value and thus reflects that the machine control is operated with a fast working cycle, which results in a short first cycle time for the calculation of the first position value.

[0016] The first position correction value corresponds to the distance traveled by the second tool relative to the first tool within the first cycle time, assuming a uniform motion between the first tool and the second tool. Accordingly, the first actual position value obtained by adding the first position correction value and the first position value corresponds to the actual position of the second tool relative to the first tool.

[0017] The second position correction value corresponds to the distance traveled by the second tool relative to the first tool within the second cycle time, assuming a uniform movement between the first tool and the second tool. Accordingly, the second actual position value obtained by adding the second position correction value and the second position value also corresponds to the actual position of the second tool relative to the first tool.

[0018] In a further development of the invention, the safety controller is configured such that the deactivation of the first radiation detector only occurs if the second actual position value is present before the first actual position value. This ensures that the safety-relevant deactivation of the first radiation detector does not occur too early, at which point a user could still be endangered if the first radiation detector were already deactivated.

[0019] The invention also relates to a method for operating a forming device comprising the steps of: determining position signals from a position measuring system for calculating a time-variable distance between a first tool arranged on a machine bed and a second tool which is fixed to a tool carrier mounted on the machine bed so as to be relatively movable and which determines a variable-size working gap with the first tool, and processing the position signals in a first position measuring system of a machine control system, which is operated with a first, fast working cycle, to first position values ​​and processing the position signals in a second position measuring system of a safety control system, which is operated with a second, slow working cycle, to second position values, processing a first detector signal of a first radiation detector and processing a second detector signal of a second radiation detector,which are arranged at a first lateral end region of the second tool and which are illuminated by a radiation source arranged opposite at a second end region of the second tool, in the safety control system, wherein a distance of the first radiation detector to the second tool is greater than a distance of the second radiation detector to the second tool, enabling a power supply for a drive device coupled to the tool carrier by the machine control system and the safety control system when the gap width of the working gap is greater than a predetermined gap width, in order to reduce the gap width of the working gap at a first, in particular maximum, approach speed between the first tool and the second tool, performing a comparison between a first status signal and a second status signal,wherein the first status signal is determined by comparing a first actual position value obtained by the machine controller or by the safety controller by adding a first position correction value and the first position value with a first deactivation position value, and wherein the second status signal is obtained by comparing a second actual position value obtained by the safety controller by adding a second position correction value and the second position value with the first deactivation position value, and deactivating the first radiation detector if there is a match between the first status signal and the second status signal.

[0020] In a further development of the invention, it is provided that upon deactivation of the first radiation detector, the drive device is switched from the first approach speed to a second, in particular medium, approach speed.

[0021] In a further embodiment of the method, it is provided that the safety controller deactivates the second radiation detector at a second deactivation position if the second position value corresponds to the second deactivation position.

[0022] In a further development of the method, it is provided that upon deactivation of the second radiation detector, the drive device is switched from the second approach speed to a third, in particular low, approach speed.

[0023] In a further embodiment of the method, it is provided that the first position correction value is determined based on the first approach speed and a first cycle time for the first working cycle and that the second position correction value is determined based on the first approach speed and a second cycle time for the second working cycle.

[0024] Preferably, the method provides that the first deactivation position value has a first distance from a first deactivation position for deactivating the first radiation detector, wherein the first distance is dimensioned such that the comparison between the first actual position value and the second actual position value carried out by the safety controller within the second working cycle is completed before the tool carrier reaches the first deactivation position.

[0025] An advantageous embodiment of the invention is illustrated in the drawing. Figure 1 shows a schematic front view of a forming device, Figure 2 shows a schematic representation of the essential functional components of the forming device according to the Figure 1 , and Figure 3 shows a flow chart for determining a blanking position.

[0026] A according to the Figure 1The forming machine, exemplified as a die-bending machine 1, comprises a machine bed 2 to which two guide rods 3 are attached, which are designed for the linearly movable mounting of a tool carrier 4. The tool carrier 4 can be moved linearly in the vertical direction along the guide rods 3 in order to move a punch 5, which serves as a tool and is referred to as the first tool, relative to a die 6, referred to as the second tool. When the punch 5 moves in a closing movement direction 33, a working gap 20 between the punch 5 and the die 6 is reduced, so that a deformation of a workpiece (not shown) that can be inserted into the working gap 20 between the punch 5 and the die 6, for example a sheet metal panel, is made possible.

[0027] The die-bending machine 1 is equipped with a monitoring device 7, which is constructed, for example, from several components and is intended to minimize the risk of injury caused by the die-bending machine 1 and to ensure a rapid and trouble-free processing sequence for the workpieces to be machined. The monitoring device 7 comprises, for example, a light grid 21 attached to the tool carrier 4 with a transmitting device 8 and a receiving device 9. The transmitting device 8 provides several detection beams 14, which, purely for the sake of example, are aligned parallel to a longest edge 22 of the die 6 and can be received by radiation detectors 23, 24, 25 of the receiving device 9.

[0028] The radiation detectors 23, 24, 25 of the receiving device 9 each provide electrical signals to a safety controller 10 when detection beams 14 of the light grid impinge on the respective light-sensitive radiation detectors 23, 24, 25 (not shown in detail). Accordingly, the safety controller 10 can determine which of the detection beams 14 is interrupted, for example, by a user interfering in a hazardous area, and initiate an appropriate response depending on the size of the working gap 20.

[0029] The die-bending machine 1 further comprises a machine control 11, which is electrically coupled to a scanning device 27 of a position measuring system 12, to a foot switch 15, and to the safety control 10. The machine control 11 can be embodied, for example, as a computer numerical control (CNC). The machine control 11 enables a user to input information about the geometries of the punch 5, the die 6, and the workpiece (not shown), as well as about the desired deformation of the workpiece, and uses this information to determine the movement sequence for the punch 5 relative to the die 6. The foot switch 15 enables the operator to initiate the movement sequence.

[0030] In addition to the scanning device 27, the position measuring system 12 comprises a glass scale 26 attached to one of the guide rods 3, which serves as a measuring embodiment and can be scanned by the scanning device in a contactless manner, in particular optically, wherein the scanning device 27 is configured to provide an electrical position signal from which a position of the punch 5 relative to the die 6 can be determined.

[0031] To initiate a movement on the Fig.1illustrated tool carrier 4 and the punch 5 received thereon, the die bending machine 1 comprises a drive device 37 that can be controlled by the machine control 11. By way of example, the drive device 37 comprises an electric motor 50 that is coupled to a hydraulic pump 16 that can provide an oil flow to hydraulic cylinders (not shown) assigned to the guide rods 3. To provide the electrical energy required for this purpose, the electric motor 50 is electrically connected to the machine control 11. For safe operation of the drive device 37, a separating device 17 is looped into the electrical connection between the machine control 11 and the electric motor 50, which can be controlled by the safety control 10 and which likewise forms a component of the monitoring device 7.In a variant of the separating device not shown, this has shut-off valves for the oil flow to the hydraulic cylinders and is accordingly arranged between the oil pump and the hydraulic cylinders.

[0032] Adaptation of the position of the light grid 21 to punches 5 of different heights is made possible by the fact that the transmitting device 8 and the receiving device 9 are each mounted on the tool carrier 4 in a linearly movable manner by means of guide means 18. Preferably, the guide means 18 for the transmitting device 8 and the receiving device 9 are coupled to one another in such a way that synchronous adjustment of the two guide means 18 is ensured.

[0033] By way of example, it is provided that the position measuring system 12 and the machine control 11 are designed according to a first safety category of a safety standard, while the safety controller 10 is designed according to a second, higher safety category of the safety standard and thus meets increased safety requirements. By way of example, the safety controller 10 comprises at least two independently operating processors, which are designed to perform similar computing operations and each perform a mutual check in order to be able to reduce, for example, the probability of an incorrect position determination for the punch 5 relative to the die 6.

[0034] The machine control 11 is designed to process the position signal provided by the scanning device 27 with a clock frequency of, for example, 1 kHz, also referred to as the first working clock, so that a first position value output by the machine control 11 can be provided after a very short time period, which comprises one or only a few milliseconds.

[0035] In contrast, the safety controller 10 is significantly slower because, due to the requirements of the higher safety category, which are to be applied to the safety controller 10, a more extensive calculation and testing of the second position value calculated on the basis of the position signal is necessary, so that the second position value is output by the safety controller 10 at a low clock frequency, for example with a clock frequency of 100 Hertz.

[0036] The result of this is that a position signal provided by the scanning device 27 is provided by the machine control 11, for example, as a first position value after just one millisecond, but is only available as a second position value by the safety control 10 after 10 milliseconds, so that no direct comparison of the first position value with the second position value can be made.

[0037] In order to be able to make a meaningful comparison between the first position value and the second position value and in particular to be able to deactivate a radiation detector 23, 24, 25 depending on a position of the stamp 5, it is provided that the machine control 11 provides the most recent first position value to the safety control 10 and the safety control 10 carries out further processing of both the first position value and the second position value.

[0038] For this purpose, it is provided that the safety controller 10 adds the current first position value provided by the machine controller 11 to a first position correction value in order to obtain a first actual position value. It is further provided that the safety controller adds the respective current second position value to a second position correction value in order to obtain a second actual position value. A comparison can then be made in the safety controller 10 between the first actual position value, the second actual position value and a deactivation position value stored in the safety controller 10. By way of example, it can be provided that a deactivation of the first radiation detector 23 is carried out at a time which occurs immediately before an interruption of the associated detection beam 14 due to the approach of the tool carrier 4 equipped with the light grid 21 to the die 6.This prevents a safety-related shutdown of the drive device 37 by the safety controller 10 and the associated isolating device.

[0039] By way of example, it is provided that the first position correction value is calculated such that it corresponds to the distance traveled by the tool holder 4 at a first closing speed, in particular a maximum closing speed, during the time period required for the machine controller 11 to calculate the first position value. Furthermore, it is provided purely by way of example that the second position correction value is calculated such that it corresponds to the distance traveled by the tool holder at the first closing speed during the time period required for the safety controller 10 to calculate the second position value.

[0040] The first deactivation position value corresponds to a position of the tool carrier 4 with the punch 5 attached thereto relative to the die 6, which is a first distance away from the position of the tool carrier 4 at which the first radiation detector 23 must be blanked in order to prevent the detection beams 14 impinging on the first radiation detector 23 from being interrupted by the die 6 during the reduction of the working gap 20. The first distance corresponds to the distance traveled by the tool carrier 4 at the first closing speed during the time period required for the safety controller 10 to perform the comparison between the first actual position value, the second actual position value, and the first deactivation position value.

[0041] A schematic representation of the procedure for deactivating the first radiation detector 23 is shown in Figure 3Here, it is provided that the position signal of the position measuring system 12 is provided to both the safety controller 10 and the machine controller 11 via a signal line 51, which is connected to the scanning device 27.

[0042] In the machine controller 11, first position values ​​x(t) are calculated from the position signals s(t), whereby it is assumed purely by way of example that this calculation is carried out within a time period corresponding to the first working cycle of the machine controller 11. In the safety controller 10, second position values ​​y(t) are calculated, whereby it is assumed purely by way of example that this calculation is carried out within a time period corresponding to the second working cycle of the safety controller 10.The fact that the second operating cycle of the safety controller 10 is significantly longer than the first operating cycle of the machine controller 11 means that, for example, at a time when the second position value y(t10) calculated in the safety controller 11 based on the position signal s(t10) can be output, the first position value x(t12) calculated on the basis of the position signal s(t12) can already be output by the machine controller 11. In order to subsequently check the existence of the condition for blanking or deactivating the first radiation detector, which is formulated such that the positions calculated by the safety controller 10 and the machine controller 11 match the first deactivation position value, additional measures are required.

[0043] For this purpose, the first position value x(t) output by the machine controller 11 is transmitted to the safety controller 10 and, as part of a first arithmetic operation 52 in the safety controller 10, is added to a first position correction value k1. Subsequently, a comparison with the first deactivation position value z is performed as part of the first arithmetic operation 52. Alternatively, the first arithmetic operation 52 and the comparison can be performed in the machine controller 11. If the comparison is positive [t], a logical high level a=1, serving as the first status signal, is output from the first arithmetic operation 52 to a first buffer 55. If, however, this comparison is negative [f], an updated first position value x(t+1) is requested from the machine controller 11 and a logical low level a=0 is output to the first buffer 55.

[0044] Furthermore, the second position value y(t) determined by the safety controller 10 is added to a second position correction value k2 within the scope of a second arithmetic operation 53 in the safety controller 10, and then a comparison is made with the first deactivation position value z within the scope of the second arithmetic operation 53. If this comparison is positive [t], a logical high level b=1 serving as a second status signal is output from the second arithmetic operation 53 to a second buffer 56. If, however, this comparison is negative [f], an updated first position value y(t+1) is requested from the safety controller 10 and a logical low level b=0 is output to the second buffer 56.

[0045] Furthermore, a third arithmetic operation 54 is performed in the safety controller 10. This operation consists in comparing the logic level a (first status signal) stored in the first buffer 55 and the logic level b (second status signal) stored in the second buffer 56 with the high level 1. If the condition a=b=1 is met, the safety controller 10 provides a blanking signal 57. The blanking signal 57 can be used, for example, within the safety controller 10 to interrupt processing of sensor signals from the first radiation detector 23, so that a change in the signal level of the first radiation detector 23 does not trigger the isolating device 17.

[0046] The die bending machine 1 can be operated as follows: first, with the tool carrier 4 in a rest position in which it assumes a maximum distance from the machine bed 2 and the die 6 attached to it, a self-test of the light grid 21 is carried out. This checks whether the detector beams 14 trigger corresponding signals when they hit the radiation detectors 23, 24, 25. Furthermore, the transmitting device 8 and the receiving device 9 of the light grid 21 are positioned by means of the guide means 18 depending on the punch 5 mounted on the tool carrier 4. This takes into account the geometry of the punch 5 as well as the overtravel distance of the tool carrier 4, which can also be referred to as the braking distance and describes the distance traveled by the tool carrier 4 when an interruption of the light grid 21 is detected.This distance depends in particular on the second working cycle of the safety controller 10 as well as on the reaction time of the separating device 17 and the respective closing speed, i.e., the approach speed of the punch 5 and the die 6. Preferably, the first radiation detector 23 is arranged at a distance from the working edge 36 of the punch 5 such that this distance between the first radiation detector 23 and the working edge 36 corresponds at least to the overtravel distance.

[0047] Subsequently, after placing the workpiece on the die 6, the user can initiate machining by pressing the foot switch 15. For this purpose, a predeterminable movement sequence for the punch 5 is provided, which may include, for example, the following steps. In a first step, after pressing the foot switch 15, the tool carrier 4 is accelerated to a first closing speed, which is also referred to as "high-speed" or "rapid traverse." During this rapid movement, for example, all radiation detectors 23, 24, 25 are monitored. If, as the tool carrier 4 approaches the die 6, no interruption of at least one of the detection beams 14 is detected by the radiation detectors 23, 24, 25, the signals from the first radiation detector 23 are suppressed when a predeterminable distance between the punch 5 and the die 6 is reached.This blanking prevents undesired activation of the separating device 17, which would otherwise occur due to the interruption of the detection beams 14 impinging on the radiation detector 23.

[0048] To implement this blanking, both the safety controller 10 and the machine controller 11 determine position values ​​based on the position signals of the position measuring system 12. These position values ​​are then further processed in the safety controller 10 using position correction values ​​to produce actual position values, which in turn can be compared with the first deactivation position value in order to determine the first or second status signal. If the first status signal a and the second status signal b match, the first radiation detector 23 can then be deactivated. Furthermore, at the time the first radiation detector 23 is blanked, a switchover from the first approach speed or closing speed to a second approach speed or closing speed can also be performed in order to prevent the punch 5 from impacting the workpiece too quickly.

Claims

1. Forming device (1) with a machine bed (2), on which a first tool (6) is arranged, and with a tool carrier (4) which is accommodated on the machine bed (2) so as to be relatively movable and with which a second tool (5) and a drive device (37) for moving the tool carrier (4) are associated, wherein the second tool (5) determines a size-variable working gap (20) with the first tool (6), with a machine control (11) for controlling the drive device (37) and with a safety control (10) for blocking the drive device (37), the safety control (10) being connected to at least one radiation source (8) and to a plurality of radiation detectors (23, 24, 25) arranged opposite the radiation source (8), at least part of the radiation beams (14) emanating from the radiation source (8) being aligned along a working edge (36) of the first tool (6) as well as with a position measuring system (12) which is assigned to the drive device (37) and which is designed to provide position signals as a function of a position of the tool carrier (4), wherein the machine control (11) comprises a first path measuring system for cyclic processing of the position signals in a first fast working cycle to form first position values, fast operating cycle to form first position values, and the safety controller (10) having a second path-measuring system for cyclic processing of the position signals in a second, slow operating cycle to form second position values, characterized in that the safety controller (10) is configured for a deactivation of a first radiation detector (23) at a predetermined first deactivation position, to carry out a comparison between a first status signal (a) and a second status signal (b), the first status signal (a) being determined by comparison of a first position correction value, in particular from the machine control (11), by comparing a first actual position value, obtained in particular by the machine controller (11) by adding a first position correction value to the first position value, with a first deactivation position value, and the second status signal (b) being determined by comparing a second actual position value, obtained in particular by the safety controller (10) by adding a second position correction value to the second position value, with the first deactivation position value, and the safety controller (10) being designed to carry out the deactivation when the first status signal (a) corresponds to the second status signal (b).

2. Forming device (1) according to claim 1, characterized in that the safety controller (10) is set up in such a way that deactivation of a second radiation detector (24) is to be carried out at a predetermined second deactivation position, in particular exclusively, on the basis of the second position value, a distance of the first radiation detector (23) from the second tool (5) being greater than a distance of the second radiation detector (24) from the second tool (5).

3.

5. Forming device (1) according to claim 1 or 2, characterized in that the machine control (11) is set up in such a way that the first position correction value is determined on the basis of a first, in particular maximum, approach speed for the approach of the second tool (5) to the first tool (6) and a first cycle time for the first working cycle, and in that the safety control (10) is set up in such a way that the second position correction value is determined on the basis of the first, in particular maximum, approach speed and a second cycle time for the second working cycle.

4.

6. Forming device according to claim 1, 2 or 3, characterized in that the safety control (10) is set up in such a way that the deactivation of the first radiation detector takes place only if the second actual position value is present in time before the first actual position value.

5.

8. Method for operating a forming device (1), in particular designed according to one of the preceding claims, having the steps: Determining position signals of a position measuring system (12) for calculating a time-variable distance between a first tool (6), which is arranged on a machine bed (2), and a second tool (5), which is fixed to a tool carrier (4) accommodated on the machine bed (2) in a relatively movable manner and which determines a size-variable working gap (20) with the first tool (6), processing the position signals in a first displacement measuring system of a machine control (11), which is operated with a first, fast working cycle, to form first position values, and processing the position signals in a second displacement measuring system of a safety control (10) which is operated with a second, slow operating cycle, to second position values, processing a first detector signal of a first radiation detector (23) and processing a second detector signal of a second radiation detector (24), disposed at a first lateral end portion of the second tool (5) and which are illuminated by a radiation source (8) oppositely disposed at a second end portion of the second tool (5), in the safety controller (10), wherein a distance of the first radiation detector (23) from the second tool (5) is greater than a distance of the second radiation detector (24) from the second tool (5), enabling of a power supply for a drive device (37) coupled to the tool carrier (4) by the machine controller (11) and the safety controller (12) in the event of a gap width of the working gap (20) which is greater than a predetermined gap width, in order to reduce the gap width of the working gap (20) with a first, in particular maximum, approach speed between the first tool (6) and the second tool (5), carrying out a comparison between a first status signal (a) and a second status signal (b), wherein the first status signal (a) is obtained by comparing a first actual position value obtained by the machine controller (11) or by the safety controller (10) by adding a first position correction value and the first position value with a first deactivation position value, and wherein the second status signal (b) is obtained by comparing a second actual position value obtained by the safety controller (10) by adding a second position correction value and the second position value with the first deactivation position value, and deactivating the first radiation detector (23) when there is a match between the first status signal (a) and the second status signal (b).

6.

10. Method according to claim 5, characterized in that with the deactivation of the first radiation detector (23) a switching of the drive device (37) from the first approach speed to a second, in particular average, approach speed is performed.

7. Method according to claim 5 or 6, characterized in that a deactivation of the second radiation detector (24) is carried out by the safety controller (10) at a second deactivation position if the second position value coincides with the second deactivation position.

8. Method according to claim 7, characterized in that with the deactivation of the second radiation detector (24) a switching of the drive device (37) from the second approach speed to a third, in particular low, approach speed is performed.

9. Method according to claim 5, 6, 7 or 8, characterized in that the first position correction value is determined on the basis of the first approach speed and a first cycle time for the first operating cycle, and in that the second position correction value is determined on the basis of the first approach speed and a second cycle time for the second operating cycle.

10. Method according to any one of claims 5 to 9, characterized in that the first deactivation position value has a first distance to a first deactivation position for the deactivation of the first radiation detector (23), wherein the first distance is dimensioned such that the comparison between the first actual position value and the second actual position value performed by the safety controller (10) within the second working cycle is completed before the tool carrier (4) reaches the first deactivation position.