Press machine and abnormality detection method for press machine

Abstract

The invention provides a press machine and the like capable of detecting die abnormality. The press machine includes: a detection unit that detects a load value when a material to be processed is press-processed; a storage unit that stores the load value detected by the detection unit in association with identification information of a mold attached to the press when the load value is detected; a calculation unit that calculates the position of the center of load acting on the press on the basis of the stored load value, calculates the calculated position of the center of load as the amount of eccentricity from the center of the press, obtains an eccentric load, and generates distribution data of the eccentric load for each mold; a determination unit that determines an abnormality on the basis of an eccentric load determined from the load value detected by the detection unit and distribution data of an eccentric load corresponding to a mold attached to the press at the time of load value detection; and a notification unit that notifies an abnormality on the basis of a determination result by the determination unit.

Description

Technical Field

[0001] The invention relates to a press and a method for detecting abnormality of the press. Background Art

[0002] In the past, a known method is to detect the stamping load during stamping processing, calculate the eccentricity based on the detected stamping load, and judge it as a stamping abnormality when the detected stamping load exceeds the allowable stamping load based on the calculated eccentricity (the range of the allowable eccentricity load line diagram determined by the manufacturer for each stamping) (see patent document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-209887 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The above-mentioned conventional methods are used to protect the function of the press. On the other hand, in addition to stamping protection, the user of the press needs to manage the state of the mold and the precision of the formed product. In the event of mold abnormalities and poor product precision, early detection and early response are required. Mold abnormalities or poor product precision mainly occur within the range of the allowable eccentric load line diagram, so it is difficult to capture mold abnormalities or poor product precision in the conventional methods.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide a press machine capable of detecting abnormality of a mold and a method for detecting abnormality of the press machine.

[0009] Solutions to technical problems

[0010] (1) The press machine according to the present invention is characterized in that it includes: a detection unit, which detects a load value when a workpiece is stamped; a storage unit, which stores the load value detected by the detection unit in correspondence with identification information of a mold installed on the press machine when the load value is detected; a calculation unit, which calculates the position of the load center acting on the press machine based on the stored load value, calculates the position of the load center as an eccentricity from the center of the press machine, calculates the eccentric load, and generates distribution data of the eccentric load of each mold; a judgment unit, which judges an abnormality based on the eccentric load calculated based on the load value detected by the detection unit and the distribution data of the eccentric load corresponding to the mold installed on the press machine when the load value is detected; and a notification unit, which notifies the abnormality based on the judgment result of the judgment unit.

[0011] Furthermore, the present invention relates to an abnormality detection method for a press, which is characterized in that it includes: a detection step, which detects the load value when a workpiece is stamped; a storage step, which stores the load value detected by the detection step in correspondence with the identification information of the mold installed on the press when the load value is detected; a calculation step, which calculates the position of the load center acting on the press according to the stored load value, calculates the position of the load center as the eccentricity from the center of the press, calculates the eccentric load, and generates distribution data of the eccentric load of each mold; a judgment step, which judges the abnormality based on the eccentric load calculated according to the load value detected by the detection step and the distribution data of the eccentric load corresponding to the mold installed on the press when the load value is detected; and a notification step, which notifies the abnormality based on the judgment result of the judgment step.

[0012] According to the present invention, the load value detected by the detection unit is stored in correspondence with the identification information of the mold installed on the press during detection, the position of the load center acting on the press is calculated based on the stored load value, the calculated position of the load center is calculated as the eccentricity from the center of the press, the eccentric load is calculated, and the distribution data of the eccentric load of each mold is generated in advance. The abnormality is judged based on the eccentric load calculated based on the load value detected by the detection unit and the distribution data of the eccentric load corresponding to the mold installed on the press during the load value detection, thereby detecting the abnormality of the mold. Here, the so-called load center means the center of gravity of the load. Furthermore, the center of the press means the center position of the slider on the plane orthogonal to the direction of movement of the slider (up and down direction).

[0013] (2) In the press machine according to the present invention, the calculation unit may use data of a plurality of eccentric loads arbitrarily selected by a user from a data group of eccentric loads corresponding to the same die as distribution data of the eccentric loads corresponding to the die.

[0014] The abnormality detection method for a press machine according to the present invention may be such that, in the calculation step, data of a plurality of eccentric loads arbitrarily selected by a user from a data group of eccentric loads corresponding to the same die may be used as distribution data of the eccentric loads corresponding to the die.

[0015] (3) The press machine according to the present invention may further include a display control unit that causes the display unit to display an image in which a data group of eccentric loads corresponding to the same die is plotted.

[0016] The abnormality detection method for a press machine according to the present invention may further include a display control step of causing a display unit to display an image in which a data group of eccentric loads corresponding to the same die is plotted.

[0017] (4) In the press machine according to the present invention, the display control unit may display, on the display unit, waveform data of a load value corresponding to data arbitrarily selected by a user from among the data group displayed on the display unit.

[0018] The abnormality detection method for a press machine according to the present invention may be such that, in the display control step, waveform data of a load value corresponding to data arbitrarily selected by a user from among the data group displayed on the display unit is displayed on the display unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram showing an example of the structure of a press machine according to the present embodiment.

[0020] Figure 2 It is a diagram showing an example of a load sensor.

[0021] Figure 3 Detailed description of the invention is a flowchart showing the flow of processing for generating distribution data of an eccentric load.

[0022] Figure 4 is a diagram showing an example of stored load values.

[0023] Figure 5 This is a diagram showing an example of display of a data group of eccentric loads corresponding to the same die.

[0024] Figure 6 This is a diagram showing an example of display of a data group of eccentric loads corresponding to the same die.

[0025] Figure 7 This is a diagram showing an example of display of a data group of eccentric loads corresponding to the same die.

[0026] Figure 8 This is a diagram showing an example of display of a data group of eccentric loads corresponding to the same die.

[0027] Fig. 9 This is a diagram showing an example of display of a data group of eccentric loads corresponding to the same die.

[0028] Fig.10 This is a diagram showing an example of display of a data group of eccentric loads corresponding to the same die and waveform data of load values.

[0029] Fig.11 Detailed description of the process of detecting an abnormality.

[0030] Fig.12 It is a diagram for explaining the abnormality detection method according to the present embodiment.

[0031] Fig.13 This is a diagram showing an example of a change in distribution of an eccentric load. DETAILED DESCRIPTION

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0033] Figure 1 1 is a diagram showing an example of the structure of a press (servo press) involved in the present embodiment. The press 1 converts the rotation of the servo motor 10 into the up and down reciprocating motion (reciprocating linear motion, lifting motion) of the slider 17 by an eccentric mechanism that converts the rotational motion into the linear motion, and performs stamping processing on the workpiece by using the up and down reciprocating motion of the slider 17. The press 1 has a servo motor 10, an encoder 11, a drive shaft 12, a drive gear 13, a main gear 14, a crankshaft 15, a connecting rod 16, a slider 17, a pad 18, a control device 100, a user interface 110 (operating unit), and a display 120 (display unit). The press is not limited to a servo press, and can be, for example, a mechanical press using a flywheel, or a direct-acting press using a ball screw. In this case, the encoder can be set at the shaft end of the crankshaft 15 or the shaft end of the ball screw.

[0034] The drive shaft 12 is connected to the rotating shaft of the servo motor 10, and the drive gear 13 is connected to the drive shaft 12. The main gear 14 meshes with the drive gear 13, the crankshaft 15 is connected to the main gear 14, and the connecting rod 16 is connected to the crankshaft 15. The rotating shafts such as the drive shaft 12 and the crankshaft 15 are supported by appropriately arranged bearings (not shown). An eccentric mechanism is formed by the crankshaft 15 and the connecting rod 16. Through this eccentric mechanism, the slider 17 connected to the connecting rod 16 can be raised and lowered relative to the pad 18 on the stationary side. Here, the press machine 1 is a two-point driven press machine in which the crankshaft 15 and the slider 17 are connected by two connecting rods 16 that also function as a suspension. An upper mold 20 is mounted on the slider 17, and a lower mold 21 is mounted on the pad 18.

[0035] The press machine 1 includes a right load sensor 30 and a left load sensor 31 for detecting the load value when the workpiece is pressed in each pressing cycle. Figure 2 As shown, the right load sensor 30 is a strain gauge mounted on the right column 40 (right side frame) of the press machine 1, and the left load sensor 31 is a strain gauge mounted on the left column 41 (left side frame) of the press machine 1. In addition, a pressure sensor provided in a hydraulic chamber formed in the slide 17 may be used as the right load sensor 30 and the left load sensor 31. The output data (voltage signals of the strain gauge or the pressure sensor) of the right load sensor 30 and the left load sensor 31 are input to the control device 100.

[0036] The control device 100 includes a stamping control unit 101, a detection unit 102, a storage unit 103, a calculation unit 104, a judgment unit 105, a notification unit 106, and a display control unit 107. In addition, the control device 100 can also be divided into an independent device for controlling a press composed of a stamping control unit 101, a display control unit 107, a user interface 110, and a display 120, and an independent device for detecting a load composed of a detection unit 102, a storage unit 103, a calculation unit 104, a judgment unit 105, a notification unit 106, a display control unit 107, a user interface 110, and a display 120. In this case, the output data of the right load sensor 30 and the left load sensor 31 are directly input into the device for detecting the load. Furthermore, as needed, the operation information of the press such as the information of the crank angle is input from the device for controlling the press into the device for detecting the load.

[0037] The detection unit 102 receives the data output from the right load sensor 30 and the data output from the left load sensor 31 in each stamping cycle, converts the received data according to the calibration data stored in the storage unit 103, and detects the load values ​​(right load value and left load value) during the stamping process. The calibration data shows the relationship between the voltage signal and the load value, and is measured in advance using a load cell or the like and stored in the storage unit 103.

[0038] The storage unit 103 stores the load value detected by the detection unit 102 in association with identification information (die number) of dies (upper die 20 and lower die 21 ) attached to the slide 17 and the pad 18 of the press machine 1 when the load value is detected.

[0039] The calculation unit 104 calculates the position of the load center acting on the press 1 based on the stored load value, calculates the calculated position of the load center as the eccentricity from the center of the press 1 to obtain the eccentric load (a group of the total load value and the eccentricity), and generates the distribution data of the eccentric load of each mold. The generated distribution data of the eccentric load of each mold is stored in the storage unit 103. Here, the calculation unit 104 can also use the data of multiple eccentric loads arbitrarily selected by the user in the data group of eccentric loads corresponding to the same mold as the distribution data of the eccentric load corresponding to the mold (for example, normal distribution data).

[0040] The determination unit 105 determines abnormality based on the eccentric load obtained by the calculation unit 104 from the load value detected by the detection unit 102 and distribution data of the eccentric load corresponding to the die mounted on the slide 17 and the pad 18 of the press machine 1 when the load value is detected.

[0041] The notification unit 106 notifies of an abnormality based on the determination result of the determination unit 105. For example, when the determination unit 105 determines that there is an abnormality, the notification unit 106 outputs information indicating that fact to the display 120.

[0042] The display control unit 107 causes the display 120 to display an image in which the data group of eccentric loads corresponding to the same mold is plotted in a graph. Furthermore, the display control unit 107 may display on the display 120 waveform data of load values ​​corresponding to data arbitrarily selected by the user from the data group displayed on the display 120.

[0043] The user interface 110 is a well-known input unit (for example, a mouse, a trackball, a keyboard, etc.) that can operate the display 120. In addition, the user interface 110 may be provided integrally with the display 120. In this case, the input means is displayed on the display 120.

[0044] The display 120 is a liquid crystal display (LCD (Liquid Crystal Display)). Other well-known display devices (such as organic EL (Electro Luminescence (Electroluminescence)) etc.) can be used as the display 120. In addition, a touch panel type display can also be used as the display 120. As a touch panel, a touch panel of a well-known type such as a resistive film type, an electrostatic capacitance type, a surface type electrostatic capacitance type, and a projection type electrostatic capacitance type can be used. If it is a touch panel type, input operation can be performed by directly touching the display 120 with a finger or a pen.

[0045] Figure 3 Detailed description of the invention is a flowchart showing the flow of processing for generating distribution data of eccentric load.

[0046] The processing of steps S10 to S13 is a processing for storing load values. The load values ​​are stored when the mold is installed on the press machine 1 for trial operation (mold testing). First, the detection unit 102 receives the data output from the right load sensor 30 and the data output from the left load sensor 31, converts the received data based on the calibration data stored in the storage unit 103, and detects as a load value (step S10). Next, the control device 100 determines whether one cycle of the press machine has been completed based on the current crank angle information (step S11). If one cycle has not been completed ("N" in step S11), it transfers to step S10 to continue the detection of the load value. If one cycle has been completed ("Y" in step S11), the storage unit 103 adds a time stamp to the detected load value of one cycle (waveform data of the right load and waveform data of the left load), and stores it in correspondence with the mold number of the mold installed on the slide 17 and the pad 18 of the press machine 1 during the detection (step S12). Figure 4 An example of stored load values ​​is shown. Figure 4As shown, the load waveform WR of one cycle detected based on the data from the right load sensor 30 and the load waveform WL of one cycle detected based on the data from the left load sensor 31 are stored as load values ​​corresponding to the die number. Next, the control device 100 determines whether to end the storage of the load value (step S13). If the storage continues ("N" in step S13), it transfers to step S10, and thereafter, the load value is stored for each stamping cycle.

[0047] The processing of steps S14 to S20 is the processing of generating the distribution data of the eccentric load. First, the control device 100 selects the mold number based on the user's operation on the user interface 110 (step S14). Next, the calculation unit 104 extracts the load value corresponding to the selected mold number from the stored load value data (step S15), calculates the position of the load center acting on the press 1 according to each extracted load value, calculates the calculated position of the load center as the eccentricity from the center of the press 1 to obtain the eccentric load, and generates a data group of the eccentric load corresponding to the selected mold number (step S16). The eccentricity (eccentric position) can be based on a waveform that synthesizes the waveforms of the left and right load values ​​(load waveform WR, load waveform WL) showing the left and right load values ​​at the peak and the distance between the right load sensor 30 and the left load sensor 31 ( Figure 2 The distance dc shown is calculated based on the balance of the moments. The eccentricity refers to the value when the waveform synthesizing the left and right load waveforms shows a peak value. When the right load is larger than the left load, it is a positive value, and when the left load is larger than the right load, it is a negative value. The greater the difference between the left and right loads, the larger the absolute value. The so-called eccentric load refers to a set of data consisting of the peak value (total load value) of the waveform synthesizing the left and right load waveforms and the eccentricity calculated based on the left and right load values. In addition, when a pressure sensor provided in a hydraulic chamber formed in the slider 17 is used as the right load sensor 30 and the left load sensor 31, the eccentricity is based on the left and right load values ​​when the waveform synthesizing the left and right load values ​​shows a peak value and the distance between the two connecting rods 16 (point interval, Figure 2 The distance dp shown is used to calculate.

[0048] Next, the display control unit 107 causes the display 120 to display an image on which the generated eccentric load data group is plotted (step S17 ). Figure 5 An example of a graph in which a data set of eccentric loads is plotted is shown. Figure 5 The image shown is an image of a data set of eccentric loads corresponding to the same mold (selected mold number) plotted in a graph (scatter plot) with the horizontal axis (X axis) representing the eccentric position (unit: mm) and the vertical axis (Y axis) representing the total load value (unit: kN). The black dot in the figure represents one data point of the eccentric load.

[0049] Next, the user selects a range (normal range) showing a normal distribution from the data group of the eccentric load displayed on the display 120 (step S18). The calculation unit 104 stores the data in the selected range as the normal distribution data of the eccentric load corresponding to the mold number selected in step S14 in the storage unit 103 (step S19).

[0050] In step S18, since the eccentric load data group may contain eccentric load data based on the load value detected during the material passing through the mold and eccentric load data based on the load value detected during the empty punching, which cannot be called normal data, Figure 6 As shown, the user specifies the range R of the normal distribution in the data group of the eccentric load on the display 120. The range R can be specified by using the user interface 110 to specify the display 120 and by directly touching the display 120 with a finger or a pen. However, if the user actually specifies the range R, it is difficult to determine which data is specified as the range R from a plurality of data groups. Therefore, the following describes a method of providing the user with the material for the determination.

[0051] (Part 1) Figure 7 As shown, the data group of the eccentric load can also be displayed according to the general practice (symbol) according to the operation information of the press machine 1. For example, it is also possible to display the data group obtained during stable operation with white dots when the operation selection switch (micro speed, inching, cut-off, stable, continuous) is in the state of selecting "continuous (continuous operation)" during the stamping operation. On the other hand, it is also possible to display the data group obtained during the process of the material passing through the die and during unstable operation such as empty punching with black dots when the operation selection switch is in the state of selecting "micro speed", "inching (inching operation)" or "stable (one up and down stroke that can ensure safety (safe and stable process))". The operation information of the press machine 1 corresponding to the data of each load value is pre-correlated and stored in the storage unit 103 by the number of pieces (pieces) of the press machine 1 (the value of the production counter of the press machine 1), so that it can also correspond to the data of each eccentric load. In addition, a button for displaying or non-displaying the data group can also be set on the screen according to the state of the operation selection switch.

[0052] (Part 2) Figure 8As shown, the data groups of eccentric loads can also be displayed according to the general practice based on the accuracy information of the formed product. For example, when the product accuracy is judged to be "good", the obtained data group can be displayed as white dots, and when the product accuracy is judged to be "bad", the obtained data group can be displayed as black dots. The judgment of the quality of product accuracy is not limited to "good" and "bad", and can be further subdivided and displayed according to the general practice according to the respective circumstances. The information of product accuracy corresponding to the data of each load value is pre-correlated with the number of pieces of press 1 (the value of the production counter of press 1) and stored in the storage unit 103, so that it can also correspond to the data of each eccentric load. The judgment of the quality of product accuracy can be automatically input into the storage unit 103 in real time from the inspection device (not shown) during the stamping operation, or the result of the sampling inspection can be manually input into the storage unit 103. The input result of the quality judgment is stored in the storage unit 103.

[0053] (Part 3) Fig. 9 As shown, the data set of the eccentric load can also be displayed as a routine in arbitrary elapsed time units based on the information of the timestamp. For example, the data set can also be displayed as a routine in elapsed time units every 30 minutes from the start of operation. When producing with a new mold, the load value data sometimes changes during the process of changing from the initial wear after the start of operation (the state in which the slight bumps on the parts are removed) to the subsequent stable wear. Even in such a case, if it is displayed as a routine in elapsed time units, it is easy to identify the time-dependent changes in the eccentric load and to select the data of the eccentric load after the change to stable wear.

[0054] (Part 4) Fig.10 As shown, the waveform data of the load value corresponding to the data arbitrarily selected by the user in the data group of the eccentric load displayed on the display 120 can also be displayed on the display 120. Fig.10 In the example shown, the waveform data (load waveform WR, load waveform WL) of the load value corresponding to the eccentric load EL indicated by the white dot in the figure arbitrarily selected by the user in the eccentric load data group is displayed above the image of the eccentric load data group. At this time, the date and time when the data was detected can also be displayed together with the waveform data of the load value. In this way, the user can determine which data is included in the range R of the normal distribution based on the waveform of each data of the eccentric load.

[0055] By adopting the above method, it is possible to provide the user with judgment materials when specifying the range R, and the user can also easily judge which data can be specified as the range R of the normal distribution later.

[0056] Next, the control device 100 determines whether to continue the process (generate normal distribution data of the eccentric load corresponding to another mold number) (step S20), and if the process is to be continued (Y in step S20), the process proceeds to step S14.

[0057] Fig.11 1 is a flowchart showing the process flow of detecting an abnormality. Detection of an abnormality is performed during normal press operation.

[0058] First, the detection unit 102 receives the data output from the right load sensor 30 and the data output from the left load sensor 31, converts the received data based on the correction data stored in the storage unit 103, and detects it as a load value (step S30). Next, the control device 100 determines whether one cycle of stamping has ended based on the information of the current crank angle (step S31). If one cycle has not ended (N in step S31), it transfers to step S30 to continue the detection of the load value. If one cycle has ended (Y in step S31), the calculation unit 104 calculates the eccentricity based on the load value of one cycle detected (the waveform data of the right load and the waveform data of the left load), and obtains the eccentric load (a group of the total load value and the eccentricity) (step S32).

[0059] Next, the judgment unit 105 obtains the distance (deviation) between the eccentric load obtained in step S32 and the average value and the standard deviation σ of the normal distribution data of the eccentric load corresponding to the mold number of the mold mounted on the slide 17 and the pad 18 of the press machine 1 when the load value is detected in step S30 (step S33), and determines whether the distance is within a prescribed distance (step S34). When the eccentric load obtained in step S32 is more than a prescribed distance (for example, 3σ to 6σ) away from the average value of the normal distribution data (N in step S34), the notification unit 106 notifies an abnormality (step S35).

[0060] Next, the control device 100 determines whether to continue the abnormality detection process (step S36). When the process is continued (Y in step S36), the process moves to step S30, and thereafter detects abnormalities based on the eccentric load obtained in each pressing cycle.

[0061] According to the present embodiment, the load value detected by the detection unit 102 is stored in advance in correspondence with the mold number of the mold installed on the slide 17 and the pad 18 of the press machine 1 when the load value is detected, and the eccentric load is calculated based on the stored load value, and the normal distribution data of the eccentric load of each mold is generated. Based on the eccentric load calculated based on the load value detected by the detection unit 102 during the stamping operation and the normal distribution data of the eccentric load corresponding to the mold installed on the slide 17 and the pad 18 of the press machine 1 when the load value is detected, an abnormality is judged, thereby detecting an abnormality of the mold. For example, Fig.12 As shown, when the eccentric load EL based on the load value detected during stamping operation is more than a specified distance away from the average value of the normal distribution ND of the eccentric load during normal operation due to mold abnormality or poor product precision, the abnormality can be detected even if the eccentric load EL is within the range of the allowable eccentric load line diagram AD. On the other hand, in the existing method, as long as the eccentric load EL is within the range of the allowable eccentric load line diagram AD, the abnormality cannot be detected. Furthermore, by adopting the present embodiment, by using the data within the range arbitrarily specified by the user in the data group of eccentric loads corresponding to the same mold as the normal distribution data of the eccentric load corresponding to the mold, the data of the eccentric load based on the load value detected during the process of the material passing through the mold and during empty punching can be excluded, and appropriate normal distribution data of the eccentric load can be produced.

[0062] Furthermore, in this embodiment, the change of the mold can be inferred based on the change in the distribution of the eccentric load corresponding to the same mold. For example, the distribution of the normal eccentric load of the mold just after maintenance is Figure 6 The distribution within the range R shown in the figure is the distribution of the eccentric load corresponding to the same mold after tens of thousands of impacts. Fig.13 In the case of the distribution shown, since the distribution of the eccentric load tends to move to the upper left, it is inferred that the punch and the die on the upstream side of the die are being worn or some abnormality is occurring. In this way, changes and abnormalities in the die can be quickly detected based on changes in the distribution of the eccentric load corresponding to the same die, and die maintenance can be performed at the optimal time.

[0063] In the above example, the case where the distribution data of the eccentric load is regarded as the normal distribution data, and the distance (deviation) from the average value of the normal distribution data to the object is calculated to judge the abnormality, but the method of judging the abnormality is not limited to this. For example, the MT (Mahalanobis-Taguchi) method can also be used to regard the distribution data of the eccentric load (data of multiple eccentric loads selected by the user in the data group of eccentric loads corresponding to the same mold) as the unit space, and the Mahalanobis distance from the center of the unit space to the object is calculated to judge the abnormality.

[0064] In addition, Patent Document 1 discloses a method for producing an allowable load diagram (equivalent to Fig.12 There is no calculation method for the AD), but this is a method that has always been well known among those skilled in the art. The allowable eccentric load diagram produced by this calculation method is only limited by the point capacity, and does not take into account the influence of the inclination of the slider, etc. Therefore, even when the press is used with a load within the allowable value of the eccentric load, there are concerns about the occurrence of adverse conditions such as deterioration of product accuracy, sintering of the slider guide, breakage of the mold, and further damage to the frame or points of the press due to the inclination of the slider. In order to avoid the occurrence of such adverse conditions, each press manufacturer produces a synthetic allowable load diagram based on the limitation of the point capacity, taking into account the safety factor and the limitation of the inclination of the slider, and provides it to the user.

[0065] Furthermore, although the embodiments of the present invention have been described in detail as above, it will be easily understood by those skilled in the art that various modifications can be made without substantially departing from the novel features and effects of the present invention.

[0066] Description of Reference Numerals

[0067] 1. Press, 10. Servo motor, 11. Encoder, 12. Drive shaft, 13. Drive gear, 14. Main gear, 15. Crankshaft, 16. Connecting rod, 17. Slider, 18. Pad, 20. Upper die, 21. Lower die, 30. Right load sensor, 31. Left load sensor, 40. Right column (right frame), 41. Left column (left frame), 100. Control device, 101. Stamping control unit, 102. Detection unit, 103. Storage unit, 104. Calculation unit, 105. Judgment unit, 106. Notification unit, 107. Display control unit, 110. User interface, 120. Display.

Claims

1. A press machine, characterized in that: include: A detection unit that detects a load value when a workpiece is punched; a storage unit that stores the load value detected by the detection unit in correspondence with identification information of a die mounted on the press when the load value is detected; a calculation unit that calculates the position of the load center acting on the press according to the stored load value, calculates the position of the load center as an eccentricity from the center of the press, obtains the eccentric load, and generates distribution data of the eccentric load for each mold; a determination unit that determines abnormality based on the eccentric load obtained from the load value detected by the detection unit and distribution data of the eccentric load corresponding to the die mounted on the press when the load value is detected; as well as A notification unit notifies an abnormality based on the determination result of the determination unit.

2. The press according to claim 1, characterized in that: The calculation unit uses data of a plurality of eccentric loads arbitrarily selected by a user from among a data group of eccentric loads corresponding to the same mold as distribution data of the eccentric loads corresponding to the mold.

3. The press according to claim 2, characterized in that: The device further includes a display control unit that causes the display unit to display an image in which a data group of eccentric loads corresponding to the same mold is plotted.

4. The press according to claim 3, characterized in that: The display control unit displays, on the display unit, waveform data of a load value corresponding to data arbitrarily selected by a user from among the data group displayed on the display unit.

5. A method for detecting abnormality of a press machine, characterized in that: include: A detection step, which detects the load value when the material being processed is subjected to stamping; a storing step of storing the load value detected in the detecting step in correspondence with identification information of a die mounted on the press when the load value is detected; a calculation step, which calculates the position of the load center acting on the press according to the stored load value, calculates the position of the load center as the eccentricity from the center of the press, calculates the eccentric load, and generates distribution data of the eccentric load of each mold; a judging step of judging abnormality based on the eccentric load obtained according to the load value detected in the detecting step and distribution data of the eccentric load corresponding to the die installed on the press when the load value is detected; as well as A notification step of notifying an abnormality based on the determination result of the determination step.

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