System for Monitoring Standard Parts

Abstract

A system for measuring the misalignment of a tool (2) in a pressing device (1), the tool (2) comprising at least a first part (3) and a second part (4), the first and second parts being movable relative to each other in a guided manner by a guiding device, the guiding device comprising at least one guide pin (10) provided in the first part (3), the at least one guide pin being guided in a guide bush (12) provided in the second part (4), wherein the system comprises a measuring device (20) arranged to detect the misalignment of the tool (2). According to the invention, the measuring device (20) is mounted directly at the guiding device.

Description

Technical Field

[0001] The present invention relates to a system for monitoring standard parts, in particular a system for measuring misalignment of tools in a press device for stamping and / or molding, wherein deformation, deflection and / or strain of a guiding device are measured. Background Art

[0002] Press tools are used in hydraulic, pneumatic and / or mechanical presses to produce parts, in particular sheet metal parts in large quantities, by blanking, piercing, bending, forming, punching, etc. Processing equipment for stamping, pressing or molding includes stamping tools, pressing tools, injection molding tools or die-casting tools. Generally, the tools include a plurality of plates (also considered a plurality of tool halves), which are movable relative to each other and consist of at least a first part and a second part, in particular a punching die or a blanking die, or a mold. During the working stroke, the movement of the first part and the second part is guided from a closed position (in which the respective separating surfaces of the two parts are pressed against each other) to an open position and vice versa by a guiding device. The guiding device includes a plurality of guide pillars, which are installed, for example, in the first part and introduced into corresponding guiding elements, which are in particular guide bushes provided in the second part. The guide pillars and the guide bushes form a guiding device, which is used to precisely guide and align at least two parts of the tool so that they can be precisely centered in the closed position. Therefore, the parallelism of the surface pairs and the support surfaces of the tool and the die set (in particular of the first part and the second part) is monitored to verify whether the first part and the second part are congruent and / or consistently positioned relative to each other. In addition, the rectangularity of the guiding device can also be ensured.

[0003] As is well known, the guide pillar is formed as a cylinder protruding from the first part. The guide sleeve provided in the second part can be formed by a cage with rolling elements, where the rolling elements can be balls or rollers, especially balls or rollers inserted in rows. Importantly, the guiding device is configured such that there is no clearance for guiding the guide pillar in the corresponding guide sleeve of the second part for stamping tools or molding tools with high quality requirements for workpieces.

[0004] To further ensure that the first part and the second part of the tool are precisely aligned with each other during the closing and opening operations, additional centering devices can be provided. However, the forces acting on the parts of the tool during pressing will not only cause deformation of the tool itself but also deformation of the guiding device.

[0005] EP1980339A relates to a press-forming device and method that measure the strain of the tool generated by the pressure film force generated by a press during press-forming, the reaction force generated by the material to be processed, and the resulting deformation reaction that causes elastic deformation of the tool. It can be seen from this document that a strain measurement unit is provided in a component of the press to be controlled, especially the punch and / or die of the press, to determine the strain magnitude of the aforementioned components that occurs during press-forming. The strain measurement unit can be provided as a piezoelectric sensor or a strain gauge, or as an FBG sensor (Faber Bragg Grating sensor) using optical fibers, and can be configured to measure the strain generated by one of the punch and / or die of the pressure film press. However, for example, when the tool is installed in the pressing device, deviations in the parallelism of the surface pair and / or the squareness of the guiding device relative to the die may also occur, and these deviations cannot be detected by the disclosed method.

[0006] EP3042756A describes a method for detecting and determining the inclination of a cushion pad of a press machine. Information on a plurality of corresponding height positions in the vertical direction detected by height position detectors at a plurality of different horizontal positions can be used to calculate the inclination of the cushion pad of the die cushion device.

[0007] DE4415577A describes a device for compensating or adjusting deflection in a press to achieve evenness of a tool holder. The device includes a path sensor or a bending sensor, especially a path or bending sensor locally installed at the position of maximum elastic deformation.

[0008] In general, it is well known in the prior art that detection means are provided in the caulking tool and / or in the frame of the caulking device to detect deformations occurring during the operation of the caulking device. However, detection means associated with guiding means such as the guide columns and guide bushes of the caulking device are hardly known. When installing the tool in the caulking device and during operation, errors or misalignments of the tool may result in inaccurate dimensions of the caulked article, and may cause damage or destruction of the forming or caulking tool, or at least an increased wear of the forming or caulking tool, and ultimately result in higher costs due to the need to replace the tool. In particular, deviations in the parallelism of the surface pairs and / or support surfaces and deviations in the squareness of the guide columns cause serious problems with respect to the accuracy of the formed article. Summary of the Invention

[0009] Accordingly, an object of the present invention is to provide a system for measuring tool misalignment in a caulking device during set-up and operation. Hereinafter, the term caulking device also relates to a caulking machine, a molding machine or a similar device. In particular, the system is sufficiently robust to withstand an oily atmosphere and cleaning agents, and can be used to operate forming or caulking tools at high acceleration and speed, as well as high stroke frequencies. Another object of the present invention is to provide a system that can not only accurately determine the deformation of the guiding means, but also detect the direction of the deformation.

[0010] These problems are solved by a system for measuring the misalignment of a tool in a caulking device, wherein the tool comprises at least a first part and a second part, the first part and the second part being able to move relative to each other in a guided manner by means of guiding means, the guiding means comprising at least one guide column provided in the first part, the at least one guide column being guided in a guide bush provided in the second part, the system comprising measuring means arranged to detect the misalignment of the tool, the measuring means being mounted directly at the guiding means.

[0011] According to the present invention, these problems are solved by a system for measuring the misalignment of standard parts used in a pressing device. Hereinafter, the term "standard part" denotes guiding devices such as guide pillars and guide bushes, which are used to guide tools in a pressing device, such as stamping tools or injection molds. These guiding devices not only perform guiding within the tool, but also exert a considerable influence on the dynamic behavior of the tool, especially tools configured as dies and / or matrices. Problems such as die tilt, where the axis of the die of the pressing device is no longer aligned with the axis of the matrix, can have different causes. For example, multiple tools, especially multiple parts of a tool, are not installed in a stacked manner with respect to each other, resulting in stress and deflection of the guide pillars. In addition, problems can also occur during the operation of the tool, such as problems that may cause deviation of the stack due to backlash or due to thermal effects, as well as problems due to uneven punching pressure along the length of the stamping tool or due to the tilt of one of the parts of the tool. Since a die press or a mold press exhibits a certain amount of guiding clearance due to aging, the tool halves no longer stack with respect to each other, and thus the guide pillars may be bent during operation. The system according to the present invention is configured to measure and monitor misalignments such as deflection, deformation, and / or deviation, for example, misalignment with respect to squareness directly at the guiding device, especially at the guide pillars and / or guide bushes in the pressing device. In addition, the system is also adapted to measure the surface temperature of the guide pillars as well as the direction of deflection, deformation, and / or deviation. Therefore, the measuring device is mounted at the guiding device, especially at the guide pillar, where the measuring device can be mounted in a fixed manner or, in an alternative embodiment, is releasable.

[0012] Several types of measuring devices are known, which include various types of sensors embedded or attached to a structure in order to detect and monitor deformation, deflection, or misalignment (preferably at an early stage), so that timely intervention can be made to avoid further damage. Known devices for these purposes are strain gauge sensors, piezoelectric sensors, and fiber optic sensors.

[0013] The system for measuring the misalignment of a tool in a pressing device according to the present invention includes a measuring device to monitor deflection, deformation, and / or deviation, as well as stress and / or temperature, which is directly mounted at the guiding device, especially at the guide pillar. According to an embodiment of the present invention, a longitudinal hole is provided from the free end of at least one guide pillar, and the longitudinal hole is preferably configured as a blind hole or a through hole coaxial with the longitudinal axis of the guide pillar. The longitudinal hole is configured to accommodate the measuring device, where the diameter d1 of the longitudinal hole is smaller than the diameter of the guide pillar. In particular, the diameter d1 of the longitudinal hole is in the range of 0.1 mm to 10.0 mm.

[0014] A suitable measuring device is a strain gauge with a surface stress sensing element. Generally, a strain gauge includes a thin metal pattern or semiconductor, the resistance, capacitance, etc. of which will change significantly when deformed. Deformation is generally considered as the measurement (measurement, metric) of strain, and thus also the measurement of the force applied to the structure to which the strain gauge is attached. The strain gauge sensor is arranged on the structure to perform an accurate and reproducible measurement of stress changes, and is known for measuring, for example, acceleration, pressure, tension and force. Different types of strain gauges are known, such as semiconductor strain gauges, nanoparticle strain gauges and / or capacitive strain gauges, as well as fiber optic sensing for measuring strain along optical fibers.

[0015] According to an embodiment of the present invention, the measuring device is configured as a strain gauge sensor, wherein at least one strain gauge is attached to a pillar shaped substrate to form the sensor, and the pillar shaped substrate can be received in the longitudinal hole of at least one guide post. The pillar shaped substrate and at least one strain gauge can be made in one piece using appropriate techniques. However, they can be manufactured separately and then connected to each other by welding, bonding or other known techniques. In addition, the pillar shaped substrate can be configured as a flexible cylinder and can be positioned at any appropriate position in the longitudinal hole of at least one guide post. Advantageously, the pillar shaped substrate can be configured to have a lower stiffness than the guide post, in particular, the stiffness is approximately at least one order of magnitude lower than that of the guide post. Therefore, the deformation of the guide post is transmitted to the substrate without resistance or loss. Preferably, the pillar shaped substrate is configured as a cylinder that extends from the top to the bottom of the longitudinal hole, in particular from the free end of the guide post to the end of the blind hole, or its bearing in the first part and / or the second part of the tool. The strain gauge sensor is fixedly mounted in the longitudinal hole of the guide post by a holding device, in particular at the top or free end of the guide post and in particular at the opposite end of the bottom of the guide post. The holding device can be provided as a thread, a clamping device, an adhesive, etc.

[0016] The strain gauge can be designed as a printed, deposited or laser-structured strain gauge. In one embodiment of the strain gauge sensor, 3D printing technology for conductive materials is used to print the strain gauge sensor. By directly printing the sensor structure on the substrate material, high design freedom and flexibility can be achieved.

[0017] Suitable deposition methods include applying a deposition mask on the substrate surface of the columnar structure of the sensor, and depositing a strain gauge material on at least a portion of the substrate surface exposed by the holes in the deposition mask, the strain gauge material having a resistance that varies with stress. The deposition can be carried out by chemical vapor deposition and / or physical vapor deposition. The deposition method can use a laser-patterned mask, as well as a dielectric material and a vapor deposition layer of a sputtered conductive film to fabricate a highly sensitive strain gauge on a substrate surface with different compositions.

[0018] The strain gauge can also be fabricated by laser material removal of a homogenous conductive film, where in a first step, the conductive film is homogeneously deposited on the substrate surface, for example, by vacuum deposition. In a subsequent step, the conductive material is removed such that an insulating material is formed between the measurement structures.

[0019] To precisely detect the change in resistance, it is known to connect four strain gauges in a bridge arrangement and measure the differential voltage between the center terminals. Preferably, at least two strain gauge sensors are attached to opposite sides of the columnar substrate, and the columnar substrate is accommodated in a longitudinal hole in at least one guide post subjected to a bending force such that opposite pairs are in a compressive or tensile state, thereby providing the maximum differential voltage for a given strain. In some cases, it may be necessary to consider the effect of temperature on the resistance of the metal conductor, for example, as an error factor, or to provide a certain configuration of all the strain gauges and / or strain gauge sensors.

[0020] Using strain gauge sensors as measuring devices has some major advantages. For example, these sensors and their applications are state-of-the-art, so they can be set up in a simple way with no or only few dimensional limitations to consider. The fabrication of these sensors is not expensive, and they offer high flexibility in sensor design and the possibility of printing these sensing elements on almost any surface.

[0021] In another embodiment according to the present invention, a measuring device inserted into a longitudinal hole in at least one guide pin is configured as a capacitance sensor. The capacitance sensor includes a first cylinder having a first end face and a second cylinder having a second end face. The first cylinder and the second cylinder are inserted into the longitudinal hole and are respectively fixed to the ends of the guide pin by holding means such that the first end face and the second end face are oriented parallel to each other at a predetermined distance. Preferably, the first end face and the second end face are produced by cutting the cylinder diagonally into the first cylinder and the second cylinder, which increases the area of the end face and thus the capacitance of the capacitance sensor. The first cylinder and the second cylinder represent the plates of the capacitor, in particular two conductive elements such as metal or conductive polymer, which are separated from each other by a dielectric such as a liquid, a gas (e.g., air), or a solid by a very short distance. Due to the deformation of at least one guide pin equipped with a capacitance sensor caused by an external force, the distance between the two conductive elements, in particular the distance between the first end face serving as one capacitor plate and the second end face serving as the other capacitor plate, changes. Alternatively, additional forms of capacitor plates can be provided, in particular for narrow holes. For example, longitudinal capacitor plates can form a two fitting comb structure and its variants. Due to the deformation or positional deviation of the guiding means, the capacitor plates of the capacitance sensor will undergo translation and rotation, which will affect the distance between the capacitor plates. The deformation that produces the distance change can be detected by measuring the change in the resistance value of the capacitance, and can be evaluated according to the amplitude of the displacement and preferably also according to the direction of the displacement or deflection.

[0022] The change in the resistance value is determined by measuring the capacitor voltage-step response of the charging and discharging process with respect to a known rectangular signal of an original signal generated by an oscillator as a predetermined frequency or reference frequency. The change in the capacitance value is directly related to the distance between the capacitor plates of the capacitance sensor. According to this embodiment, two basic RC circuits are used to determine the charging and discharging behavior. The two basic RC circuits both include resistors having equal resistance values, but the capacitors they include have different capacitance values, in particular a reference capacitor and a capacitor subjected to deformation. Since the area of the capacitor plates and the resistance of the resistors they include remain constant, a change in the distance between the capacitor plates will result in a change in the detected signal. These can be measured precisely with respect to the original signal and the reference capacitor.

[0023] The advantage of using the difference between the so-called post-deformation frequency and the reference frequency is that it minimizes all possible error sources. As is well known, the oscillation frequency of an oscillator circuit is based on the impedance frequency, which includes, in addition to the resistance component between the electrodes, an inductance component and a capacitance component between the electrodes. Since the inductance component and the resistance component are constant, the oscillation frequency is affected only by the change in capacitance in the circuit. The difference between the post-deformation frequency and the reference frequency basically corresponds to the difference in electrical capacity only of the sensor unit before and after deformation, and is thus directly related to the distance between the plates of the capacitive sensor unit. Signal noise and external error sources can be minimized by using this difference as the measurement setup.

[0024] In another embodiment according to the present invention, the measuring device housed in the longitudinal hole of at least one guide post is configured as an optical fiber sensor. The optical fiber sensor is configured to measure strain along the optical fiber, which can be embedded in the longitudinal hole provided in at least one of the plurality of guide posts. Generally, optical sensor devices are based on detecting a modification or modulation in certain properties of light. Transmitted or reflected light can be modulated by changes in its amplitude, phase, frequency, and / or polarization state. Optical fiber sensors are not affected by electromagnetic interference, are chemically inert, are heat-resistant, and can be small and light, and exhibit excellent transmission ability, and can provide multiple measurement points along a single optical fiber, which can be multiplexed to provide distributed measurements with high spatial resolution.

[0025] Generally, an optical fiber sensor includes an integrated or separate transducer device having at least one measurement optical fiber, an optical connector, and a processing unit.

[0026] One design of an optical fiber sensor for measuring the deformation of a guide post is configured to have one fiber, which is called a measurement fiber, that is in mechanical contact with the columnar structure itself. The measurement fiber is attached at both of its ends and is preferably preloaded between its two ends. Alternatively, more than one measurement fiber can be provided. Due to the bending of the measuring device caused by the deformation of the columnar structure, one measurement fiber is elongated. The measurement fiber can be configured to provide multiple measurement points by implementing multiple optical reflections along the length of the measurement fiber.

[0027] Another embodiment of the measuring device includes another fiber, the so-called reference fiber, which is placed loosely within the same cylindrical structure and thus its length is not affected by deformations and / or bendings. The measuring fiber and the reference fiber can be implemented in one measuring device, in particular within the same cylindrical structure. Advantageously, in this embodiment, the length changes caused by temperature are equal for the measuring fiber and the reference fiber respectively, so that no further temperature compensation has to be considered.

[0028] Alternatively, the measuring fiber is implemented in the measuring device, while the reference fiber can be arranged independently, such that the spatial requirements of the measuring device are small. Light from a light source is guided to the sensor and back to the processing unit via a guiding element, where the guiding element is at least an optical fiber and an optical coupling device.

[0029] The processing unit of the measuring device can include an interferometer, such as a Fabry-Pérot interferometer, and can also include a converter unit for converting the optical signal from the measuring fiber into an electrical signal, and an electrical signal processor for further processing the received signal. According to one embodiment, the Fabry-Pérot interferometer can be configured to use one or several or continuously distributed wavelengths. This allows for an absolute measurement of the elongations of the measuring fiber, the value of which is greater than the wavelength of the light used.

[0030] Another design is based on Fiber Bragg Grating Technology for measuring strain and temperature, using an optical fiber with a periodic refractive index perturbation pattern inscribed in the core, which diffracts the optical signal in a mode guided at a specific wavelength into other modes. Other designs of fiber optic sensors have also been proposed to provide an interaction region between the light and the measurand.

[0031] Another type of fiber optic sensor is the low-coherence interferometer, which is based on splitting the power of a low-coherence source into the measuring fiber and the reference fiber of the interferometer via a fiber coupler. The light reflected by reflectors in the structure is recollected by the measuring fiber, the light from both the measuring fiber and the reference fiber is coupled back into the fiber coupler, and a part of the light is redirected to the detector. Due to the finite coherence length of the light source, optical interference is only observed when the optical path lengths of the light beams reflected by the structure reflector and the reference mirror are different and less than the coherence length.

[0032] According to an embodiment of the present invention, the measuring device is configured to modulate a sensor unit of electrical properties (e.g., resistance and / or capacitance), and is thus provided as passive. These sensors are powered by electrical energy, and the generated signals are transmitted and processed, in particular transmitted and processed by an amplifier and a processing unit. The connection of the sensor unit to the power supply and / or the processing unit can be provided by wire-bound transfer or by wireless transmission.

[0033] According to a preferred embodiment of the present invention, the measuring device of the system is adapted to determine the squareness of at least one guide post with respect to the deformation, deflection and / or deviation of the first part of the tool, in particular the magnitude of the deviation and the direction of the deviation. The deviation can be determined during the setting of the tool and during the operation of the pressing device.

[0034] Furthermore, the measuring device is adapted to be connected to a processing unit to transmit signals via wireless transmission.

[0035] In another embodiment, the temperature can be measured by known measuring devices and measuring methods of the state of the art, in particular using a platinum resistance thermometer. The detection of the temperature is independent of the measurement of the guide post deformation. Therefore, through an evaluation unit or a processing unit, a temperature correction can be directly applied to the signals from the strain gauge resistance, the optical structure, the wavelength and / or the capacitance.

[0036] According to the present invention, the deformation direction acting on the guide post can be calculated by the geometric alignment of the measuring device in the guide post, and the deformation magnitude can be evaluated based on the longitudinal elongation and / or compression of the guide post. In addition, the orientation of the measuring device relative to the tool can be mechanically defined and / or can be determined by a calibration step to be performed. By aligning the detected deformation direction with the coordinate system of the tool, the base of the guide post can be precisely aligned with its socket.

[0037] Embodiments of a system for measuring misalignment of a tool in a pressing device according to the present invention will be explained in more detail below with reference to the accompanying drawings: Description of the Drawings

[0038] Figure 1 A longitudinal section of a pressing device is shown, which includes a tool, in particular a first part and a second part, and the first part and the second part can move relative to each other in a guided manner through a guiding device;

[0039] Figure 2 A perspective view of a longitudinal section of a sensor according to a first embodiment of the present invention.

[0040] Figure 3Is a perspective view of a longitudinal section of a sensor according to a second embodiment of the present invention.

[0041] Figure 4a Is a schematic view of a guide pillar with a sensor according to a third embodiment of the present invention.

[0042] Figure 4b Is at the deflection position according to Figure 4a Schematic view of a guide pillar with a sensor of. Detailed implementation

[0043] Figure 1 Shown is the die-set structure of the pressing device 1, which includes the tool 2. Depending on the complexity of the tool 2, the tool 2 includes a plurality of plates that are put together and consist of at least a first part 3 or a first mold half and a second part 4 or a second half mold, in particular a blanking die or a stamping die, or a mold. In Figure 1 The die-set structure includes a female die represented by 8 and a die guide plate represented by 9. The first part 3 and the second part 4 of the tool 2 can be moved relative to each other from the closed position to the open position in a guided manner through a guiding device, and vice versa. Generally, when high guiding accuracy is required, guiding devices are used in tool or injection mold construction as well as in mechanical device and equipment structures.

[0044] In the tool 2, the first part 3 that can carry the guide pillar 10 can be separated from the second part 4, and the second part 4 is provided with corresponding guiding members, in particular a guide sleeve 12 for accommodating the guide pillar 10, and the guide pillar 10 is guided in the guide sleeve 12, for example, through a ball bearing in a cover part.

[0045] If the die-set structure is used for a molding operation, a mold can be attached to the separation surface of the first part 3 and / or the second part 4. In the closed position of the tool 2, the mold is filled with a material to be formed, such as a casting material pressed into the mold, especially in the horizontal direction. After opening the mold, a so-called perform can be removed from the mold.

[0046] In addition, the die-set structure can be used for blanking operations and / or stamping operations.

[0047] By setting the tool 2 in the pressing device 1, the parallelism of the surface pair and the support surface must be carefully maintained. Figure 1Figure 2 shows tool 2, which also includes a die 5 guided in a die guide plate 9, in particular a caulking tool or a punch. As shown in this figure, deviations in the congruency of plates 3 and 4, the guiding clearance of tool 2, or deviations in the angle of the support for the guiding device may result in an inclined female die axis 6. Further, if the guiding device, in particular the guide pillar 10, is deflected and / or deviated with respect to rectangularity, further deviations and misalignments in the congruency of the first part 3 and the second part 4 with respect to each other will occur.

[0048] According to the present invention, a measuring device for measuring the misalignment of a standard part such as guide pillar 10 is provided. Thus, a longitudinal hole 14 extending from one end (e.g., the free end) of guide pillar 10 and coaxial with the guide pillar axis 16 is provided, wherein the diameter of the longitudinal hole 14 is smaller than the diameter of guide pillar 10. As described later, a measuring device (not shown) is inserted into the longitudinal hole 14.

[0049] Figure 2 Figure 7 shows a perspective view of a longitudinal section of a measuring device 20 according to a first embodiment of the present invention. The measuring device 20 includes a cylindrical structure 22, on which a surface sensing element in the form of a strain gauge 24 is attached, thus forming a strain gauge sensor. The measuring device 20 is configured to be inserted into the longitudinal hole 14 of the guide pillar 10 and fixedly mounted to the end region of the guide pillar 10 by a holding element. Thus, an annular element 26 can be provided in the end region of the cylindrical structure 22, which abuts against the end face 11 of the guide pillar 10 when the cylindrical structure 22 is fully pushed into the longitudinal hole 14 and can be fixedly mounted in place by a press fit or the like.

[0050] At least one strain gauge 24 is provided at the circumference of the cylindrical structure 22. Preferably, two strain gauges 24 are attached in pairs to opposite sides of the cylindrical structure 22 such that both can detect compression and tension according to the deflection direction of the guide pillar 10.

[0051] Figure 3 Figure 14 shows a measuring device 20 according to a second embodiment of the present invention, wherein elements similar to those in the first embodiment are equivalently characterized. The measuring device 20 is configured as a capacitance sensor 30, which includes a first cylinder 32 and a second cylinder 34, wherein a first surface of the first cylinder 32 provides a first capacitor plate 36, a second surface of the second cylinder 34 provides a second capacitor plate 38, and the first capacitor plate 36 and the second capacitor plate 38 are separated by a distance d. If the guide pillar 10 (wherein the capacitance sensor 30 is embedded in the longitudinal hole 14 in any suitable manner) is deformed or deflected, the first capacitor plate 36 and / or the second capacitor plate 38 will undergo translation and / or rotation, which will affect the distance d and thus directly affect the determined capacitance value of the capacitance sensor 30.

[0052] Figure 4a and Figure 4b shows a measuring device 20 according to a third embodiment of the present invention. Figure 4a and Figure 4b schematically shows a guide post 10, in which an optical fiber sensor 40 is coaxially embedded in a longitudinal hole 14 with respect to the axis 16 of the guide post. The optical sensor 40 is configured as an optical fiber sensor (in particular an interferometric sensor), which includes a processing unit 42, and the processing unit includes an interferometer such as a Fabry - Perot interferometer (inter alia), a converter for converting an optical signal into an electrical signal, and a processor. For example, light from a low - coherence light source (not shown) is split into a measuring fiber 44 and a reference fiber 46 arranged inside the measuring device 20. The measuring fiber 44 is connected to the measuring device 20 such that the measuring fiber 44 is stretched when bent. Figure 4a shows the guide post 10 in a straight position. Figure 4b shows the guide post 10 where a deflection detectable by the optical fiber sensor 40 has occurred.

[0053] Although the present disclosure has been described with reference to specific devices, materials, and embodiments, those skilled in the art can easily determine the basic features of the present disclosure from the foregoing description, and at the same time, various changes and modifications can be made to adapt to various uses and features set forth in the following appended claims.

Claims

1. A system for measuring the misalignment of a tool (2) in a pressing device (1), the tool (2) comprising at least a first part (3) and a second part (4), the first part (3) and the second part (4) being able to move relative to each other in a guided manner by means of a guiding device, the guiding device comprising at least one guide pin (10) provided in the first part (3), the at least one guide pin being guided in a guide bush (12) provided in the second part (4), the system comprising a measuring device (20) arranged to detect the misalignment of the tool (2), characterized in that, The measuring device (20) is mounted directly at the guiding device, the measuring device (20) is mounted at the at least one guide pillar (10), or the measuring device (20) is mounted in a longitudinal hole (14) provided in the at least one guide pillar (10), so as to detect and monitor misalignment by means of the measuring device, enabling timely intervention to avoid further damage.

2. The system according to claim 1, wherein, The measuring device (20) is firmly fixed in the longitudinal hole (14) by a holding element (26).

3. The system according to any one of claims 1 to 2, wherein, The measuring device (20) is configured as a strain gauge sensor (24), which includes a cylindrical structure (22) and at least one strain gauge attached to the cylindrical structure.

4. The system according to claim 3, wherein, A pair of strain gauge sensors (24) are attached to opposite sides of the cylindrical structure (22).

5. The system according to any one of claims 1 to 2, wherein, The measuring device (20) is configured as a capacitance sensor (30), which includes a first cylinder (32) having a first capacitor plate (36) and a second cylinder (34) having a second capacitor plate (38), and the first capacitor plate (36) and the second capacitor plate (38) are separated from each other by a distance d.

6. The system according to any one of claims 1 to 2, wherein, The measuring device (20) is configured as an optical fiber sensor (40).

7. The system according to claim 6, wherein, The optical fiber sensor (40) is configured as an interferometric sensor.

8. The system according to claim 6, wherein The optical fiber sensor (40) is configured as a low-coherence interferometric sensor.

9. The system according to any one of claims 1 to 2, wherein The measuring device (20) is adapted to determine the deflection and / or deviation of the squareness of the at least one guide pillar (10) relative to the first part (3) of the tool (2).

10. The system according to claim 9, wherein, The measuring device (20) is adapted to determine the magnitude and the direction of the deviation of the squareness of the at least one guide pillar (10) relative to the first part (3) of the tool (2).

11. The system according to any one of claims 1 to 10, wherein, The measuring device (20) is configured to determine the deviation during the setting of the tool (2).

12. The system according to any one of claims 1 to 11, wherein, The measuring device (20) is adapted to be connected to a processing unit to transmit signals via wireless transmission.

13. The system according to any one of claims 1 to 12, wherein, The measuring device (20) is configured to determine the temperature of the at least one guide pillar (10) to which the measuring device (20) is attached.

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