JP2017209698A - Press device and backing plate used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backing plate having a structure capable of finely and dynamically observing a pressure applied to a piercing punch and to provide a press device capable of quickly detecting abnormality of the piercing punch from a pressure change detected on such a backing plate.SOLUTION: Control means according to the present invention is composed of: storage means which stores a pressure change detected by a sensor 16 provided on a holding cylinder part 15 formed on a backing plate 13 in order to detect a pressure applied to a piercing punch 10 as a pressure waveform, with time; comparison means which compares the pressure waveform stored by the storage means at every stroke of an upper die holder 3; and stopping means which judges that the piercing punch 10 is abnormal when the pressure waveform compared by the comparison means is different from a preceding pressure waveform and stops the driving means.SELECTED DRAWING: None

Description

  The present invention relates to a press device that performs press processing by applying pressure to a workpiece, and relates to a press device that can detect an abnormality based on a change in pressure generated by a piercing punch. It relates to the backing plate used.

  A punch press molding method and apparatus disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 10-202400) is a mold maker in which a molding die composed of a punch and a die is attached to a punch press, and trial punching molding is performed. During machining, the molding height of the ram that can be moved up and down by the hydraulic cylinder is gradually increased to obtain the desired molding height of the molding die, the pressure of the hydraulic cylinder at this time is also obtained, and the molding height is The pressure of the hydraulic cylinder is represented by a pressure parameter that represents the forming tonnage at the time of forming, and when the workpiece is actually formed, the falling end parameter and the pressure parameter are punched. The pressure or the lower end position of the hydraulic cylinder can be stored in advance in the storage device by simply inputting it into the storage device of the press in advance, without performing a test hit for a new molding die. It is characterized in that the ram has to be increased when it reaches to one of the two parameters being 憶.

  The punch press machining method and apparatus disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 11-300428) are used in an apparatus for punching a workpiece by hitting a punch with a ram that can be moved up and down by a hydraulic cylinder. Depending on the type of mold, for example, when a normal punch is used, it switches to the first hydraulic pressure detection device arranged at the closest position of the hydraulic cylinder, and when a cluster punch is used, it is separated from the first hydraulic pressure detection device. The operation of the punch press is stopped when an overload of the hydraulic cylinder is determined by the first or second hydraulic pressure detection device.

  The press device disclosed in Patent Document 3 (Japanese Patent Application Laid-Open No. 2009-297744) includes a pressure sensor that detects a pressure generated between a die and a product part of a workpiece, and is driven by a control device. The raising / lowering means for raising and lowering the punch raises the punch when the applied pressure detected by the pressure sensor is equal to or higher than a preset threshold based on the surface roughness of the shearing surface that can be formed on the workpiece by the vitality. It is characterized by being lowered again later.

  A punch break detection device and apparatus for multiple punches disclosed in Patent Document 4 (Japanese Patent Laid-Open No. 7-32065) detects punch breaks during high-speed punching with a mold having multiple punches, and immediately stops the press. Therefore, a large number of punches are grouped into groups of about 100, and each group is fixed to the upper die with a fixing member, the load is detected with a sensor on the backup plate, and a charge-up and comparison measurement unit is provided for each sensor. The load peak value detected by the sensor and the change in waveform are compared and measured, and a press stop signal is transmitted from the comparison measurement unit in the case of an abnormality.

JP-A-10-202400 Japanese Patent Laid-Open No. 11-300428 JP 2009-297744 A Japanese Patent Laid-Open No. 7-32065

  As a conventional method for detecting breakage of a piercing punch, in the case of a progressive type or transfer press type, the presence or absence of a hole is detected by a contact type or non-contact type sensor, for example, at the next stage after drilling. When a hole is not detected, it is determined that the piercing punch in the previous process is broken or a material shift has occurred, and a technology for transmitting a signal to stop the press is established. The detection component set has been widely marketed and applied to production sites. This technology uses the characteristics of a progressive die that places holes at the same pitch in the same mold, and detects them at the next stage. Therefore, in the case of a die other than the progressive die, there is a problem that an abnormality in the piercing process cannot be detected.

  As disclosed in Patent Document 4 described above, the stress state generated in the piercing punch in press working is observed using a load cell, and the breakage of the piercing punch is determined by the change in the maximum pressure of the plurality of piercing punches. It has been impossible to detect abnormalities of individual piercing punch edges that have been judged and stopped at the level where the press is stopped, and which has an impact on product quality, which is a major market need.

  Since the appearance of a piercing punch is usually difficult to observe due to the presence of a stripper, the damage status of a piercing punch can only be determined by looking at the occurrence status of burrs, etc. that occur in the product. Had the problem of being after product processing. The problem with this judgment after product processing is that if a burr or hole shape defect exceeding the specified value is observed, especially if it is produced using an automatic transfer device, the entire lot is defective. Therefore, a large loss occurs, such as deburring by additional handwork, or disposal if the degree of abnormality is excessive. Furthermore, when the production is continued without knowing that the piercing punch is broken during automatic production, the press machine is stopped abnormally only after the die is broken by the broken piece, which may cause a great damage.

  As described above, piercing punches used for drilling in press dies are subject to cutting edge wear and chipping depending on the strength, plate thickness, hardness and working conditions of the workpiece. When burrs are generated or severe, broken pierce punch fragments damage the mold, which often impedes press part production.

  The abnormalities that occur in these piercing punches are difficult to observe directly during production, so burrs that occur in the product are discovered after a certain amount of production processing, or are detected after the mold is damaged, etc. Since the damage tends to spread easily, it is important to minimize damage and how to manage the piercing punch condition before the damage occurs. It is one of.

  In addition, from the viewpoint of mold cost, the widely used piercing punch is made of a relatively inexpensive grade, rather than using an expensive tool material or a highly durable surface treatment. There is a tendency to produce while paying attention to the damage of the piercing, which is a factor that increases the importance of damage management of the piercing punch.

  Furthermore, as described in Patent Documents 1 to 4 described above, the pressure (load) applied to the piercing punch is detected, and when the pressure is equal to or higher than a predetermined value, it is determined that there is an abnormality and the press machine is stopped. As already known, the devices described in Patent Documents 1 to 4 have a structure that delicately detects a change in pressure (load or load) applied to a piercing punch, and uses a pressure waveform during normal piercing as a reference. As such, it is impossible to detect various piercing punch anomalies.

  For this reason, the present invention quickly detects an abnormality of the piercing punch from the backing plate having a structure capable of delicately and dynamically observing the pressure applied to the piercing punch and the pressure change detected in the backing plate. The press apparatus which can be provided is provided.

  Therefore, the backing plate according to the present invention is attached to the lower mold holder to which the mold is mounted, the upper mold holder to which the piercing punch is mounted and reciprocates with respect to the lower mold holder, the upper holder, Used in a press apparatus having an upper pad for fixing a product to a lower mold holder, a drive means mounted on the upper holder and reciprocating the upper mold holder, and a control means for controlling the drive means; It constitutes a part of a holding mechanism for fixing the piercing punch to the upper mold holder, and is disposed between the piercing punch and the upper mold holder, and corresponds to the piercing punch of the backing plate A holding cylindrical portion having a diameter equivalent to the shaft diameter of the piercing punch is formed in the portion to be detected, and the pressure applied to the piercing punch is detected in the holding cylindrical portion. In which the pressure detection sensor are provided. In addition, this term is applied also to the reverse structure type which arrange | positions a piercing punch in a lower mold | type.

  As a result, a holding cylindrical portion that receives the pressure of the piercing punch is formed on the backing plate, and a pressure detection sensor, for example, a strain detection sensor is provided on the holding cylindrical portion, so that the pressure of the piercing punch can be detected delicately. It is possible to do.

  Furthermore, the press device according to the present invention includes a lower mold holder to which a mold is mounted, an upper mold holder to which a piercing punch is mounted and reciprocates with respect to the lower mold holder, and the upper holder. In the press apparatus, comprising: an upper pad for fixing a product to the lower mold holder; a driving means mounted on the upper holder for reciprocating the upper mold holder; and a control means for controlling the driving means. A holding mechanism for holding the punch on the upper die holder includes a backing plate disposed between the piercing punch and the upper die holder, and a punch retainer for fixing the piercing punch to the backing plate. The piercing punch is held on the backing plate by a cylindrical portion formed on the backing plate, the circle The unit includes a pressure detection sensor for detecting the pressure applied to the piercing punch, and the control means stores the pressure change detected by the sensor over time as a pressure waveform. And comparison means for comparing the pressure waveform stored in the storage means for each stroke of the upper holder, and when the pressure waveform compared by the comparison means is different from the previous pressure waveform, And determining means for stopping the driving means.

  As a result, the pressure applied to the piercing punch when the product is punched between the molds is detected by the sensor for each stroke of the upper mold holder and stored in the storage means as a pressure waveform. When the pressure waveform is compared with the previous pressure waveform and they are different, it can be determined that the piercing punch is abnormal. In this case, although the previous pressure waveform is used as a reference, an average value of the first several pressure waveforms may be set as a reference waveform, or a pressure waveform measured in advance may be used as a reference.

  The cylindrical portion preferably has a diameter equivalent to the shaft diameter of the pierce punch. Thus, it is possible to reliably receive the pressure applied to the piercing punch by the cylindrical portion while securing the strength of itself. Further, the pressure detection sensor is preferably a strain detection sensor that measures strain.

  Further, in the present invention, the control means uses the pressure increase point of the piercing punch as a piercing start point, and when the latest piercing start point is not detected at the previous piercing start point by comparison of the comparison means. Preferably, it is determined that the piercing punch is broken or dropped, and the driving means is stopped by the stopping means. Thereby, it is possible to determine whether the piercing punch is broken or dropped, and to stop the driving of the press device, and it is possible to prevent the mold from being damaged or the product from being defective.

  Furthermore, the present invention provides the control means in which the pressure increase point of the piercing punch is set as a piercing start point, and the latest piercing start point is earlier than the previous piercing start point by comparing detection information. In some cases, it is desirable that it is determined that the two pieces of the pierced hole scrap and the next product are overlapped due to the lifted dregs, and the driving unit is stopped by the stopping unit. Accordingly, it is possible to determine that the scraping of the piercing hole due to the punching up and the next product overlaps, and the driving unit can be stopped by the stopping unit. Damage can be prevented.

  Further, the present invention provides the control means in which the point at which the pressure of the piercing punch is maximized is set as the maximum pressure point, the pressure is set as the breaking start pressure, and the pressure from the point at which the pressure of the piercing punch is maximized is minimized. The point at which the pressure has dropped to the pressure is taken as the break end point and that pressure is taken as the break end pressure, the latest break start pressure is higher than the previous break start pressure, and the latest break start point is higher than the previous break start point. When it is delayed and / or when the latest breaking end pressure is greater than the previous breaking end pressure, it is determined that scrap has occurred and scrap has accumulated in the mold, and the stopping means It is desirable to stop the driving means. As a result, it is determined that scrap has occurred and scrap has accumulated in the mold, and the drive means can be stopped by the stop means, thereby preventing damage to mold components. It is something that can be done.

  Further, according to the present invention, in the control means, the point at which the pressure of the piercing punch drops from the maximum to the lowest pressure is set as a break end point, and the latest pressure of the piercing punch is changed from the highest to the lowest pressure. If the changing pressure change rate is greater than the previous pressure change rate and / or if the pressure change after the latest break end point is greater than the previous pressure change, an abnormality has occurred in the cutting edge of the piercing punch It is desirable to determine and stop the driving means by the stopping means. Thus, it is determined that an abnormality has occurred in the cutting edge of the piercing punch, and the driving means can be stopped by the stopping means, so that discharge of defective products due to abnormal cutting edge can be prevented.

  According to the present invention, the abnormality can be observed for each single piercing punch, so that it is possible to stop the press machine by detecting a clear pressure fluctuation such as conventional piercing punch breakage or double punching. It is also possible to individually detect pressure fluctuations at the edge of the piercing punch, such as clogging, scraping, and chipping, and it is possible to take measures before the damage spreads. It is possible to prevent the occurrence of loss expenses.

  In addition, if the monitoring data is used to determine when to replace the piercing punch, a pre-maintenance system can be constructed, and an innovative improvement in the mold management method can be expected.

  Furthermore, not only damage abnormality of the piercing punch itself, but also the abnormal stress that occurs in the piercing punch as a result can be detected individually, so the contents of accidental mold abnormalities such as die height setting mistakes, piercing punch setting mistakes, clogging, etc. It is possible to determine the location from the type of pressure waveform, prevent a mold breakage accident, and take an appropriate response promptly.

  Finally, the shape of the backing plate that receives the piercing punch is made to conform to the shape of the conventional backing plate, so that it can be easily applied to a wide range of needs in the press working market.

It is a schematic block diagram of the press apparatus which concerns on this invention. It is a schematic block diagram of the punch part of the press apparatus which concerns on this invention. It is a disassembled perspective view of the punch part of the press apparatus which concerns on this invention. It is sectional drawing of the punch part of the press apparatus which concerns on this invention. It is a perspective view which shows an example of the backing plate which comprises the punch part of the press apparatus which concerns on this invention. It is a perspective view which shows another example of the backing plate which comprises the punch part of the press apparatus which concerns on this invention. It is the flowchart figure which showed an example of the control performed in the control apparatus of the press apparatus which concerns on this invention. It is the figure which showed the pressure basic waveform which showed the fluctuation | variation of the pressure concerning a piercing punch detected for every press operation | work of the press apparatus which concerns on this invention. It is the figure which showed the pressure waveform which showed the fluctuation | variation of the pressure concerning a piercing punch when two sheets are extracted. It is the figure which showed the pressure waveform which showed the fluctuation | variation of the pressure concerning a piercing punch in the case of clogging. It is the figure which showed the pressure waveform which showed the fluctuation | variation of the pressure concerning a piercing punch when the edge of a piercing punch is abnormal.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, for example, the press device 1 according to the present invention includes a lower mold holder 2 on which products to be punched are continuously placed, and an upper part that reciprocates relative to the lower mold holder 2. A mold holder 3, an upper mold pad 4 that moves up and down together with the upper mold holder 3, and holds and fixes a product between the mold holder 3 and the lower mold holder 2 during punching; the upper mold holder 2 and the upper mold pad 4; Is provided with a driving device 5 for moving the product up and down, and a punch portion 6 provided for drilling at a predetermined position of the product.

  2 to 4, for example, the punch portion 6 is fixed to the lower mold holder 2 (button die) 9 and the upper mold holder 3, and the punch (button) A die piercing punch 10 that is inserted into the die 9 to make a hole in the product, and further includes a holding mechanism 11 for fixing the piercing punch 10 to the upper mold holder 3. The holding mechanism 11 includes a backing plate 13 for fixing the piercing punch 10 to the upper mold holder 3 and a piercing retainer 12 for fixing the piercing punch 10 to the backing plate 13. The plate 13 and the piercing retainer 12 are fixed to the upper mold holder 3 by bolts 14. Further, the backing plate 13 is formed with a holding cylindrical portion 15 for receiving the piercing punch 10. The holding cylindrical portion 15 is formed to have a diameter equivalent to the shaft diameter of the piercing punch 10, and is formed so that the pressure applied to the piercing punch 10 is reliably applied to the holding cylindrical portion 15. Furthermore, as this embodiment, a strain gauge 16 is provided on the side surface of the holding cylindrical portion 15 as pressure detecting means.

  The lower die holder 2 is provided with a scrap chute 7 for removing punched debris below the punch portion 6. A spring mechanism 8 is disposed between the upper mold holder 3 and the upper mold pad 4 so that the upper mold holder 3 and the upper mold pad 4 are lowered with respect to the lower mold holder 2, A product to be processed by the die pad 4 is fixed between the lower die holder 2 and the upper die holder 3 is further lowered so that a piercing punch 10 fixed to the upper die holder 3 penetrates the product. Then, the product is inserted into the mold 8 and the product waste is discharged to the scrap chute 7 side.

  Further, the press device 1 is provided with a control unit 20 for controlling the operation of the press device 1. The control unit 20 analyzes and analyzes the digital signal from the A line connected to the press-side interlock and the PLC with an external device such as an analyzer via an amplifier, an A / D converter, and a PLC (Programmable Logic Controller). Have a B line.

  For example, as shown in FIG. 5, the backing plate 13A according to the second embodiment of the present invention is provided with a backing plate 15A having a load cell on the backing plate having a shape conforming to the conventional backing plate. Further, a through hole 15B having substantially the same diameter as the backing cell 15A is provided. Reference numeral 15C denotes a mounting groove for mounting wiring from a load cell for detecting pressure.

  The backing plate 13B according to the third embodiment of the present invention is provided with the backing plate 15A ′ with the load cell according to the second embodiment corresponding to each piercing punch on the backing plate for the collective retainer having an arbitrary shape. 13B is provided with a through hole 15B ′ having substantially the same diameter as the backing cell 15A ′. Reference numeral 15C 'denotes a mounting groove for mounting wiring from a load cell for detecting pressure.

  The fourth embodiment of the present invention is characterized in that the press device 1 is controlled based on the pressure waveforms detected in the backing plates 13, 13A, 13B.

  In the fourth embodiment, the control unit 20 according to the present invention includes a detection unit 21 that receives a signal from the strain gauge 16 for detecting the pressure applied to the piercing punch 10 and detects a change in pressure. A storage unit 22 for storing the pressure waveform detected by the detection unit 21; a comparison unit 23 for comparing the previous pressure waveform stored in the storage unit 22 with the latest pressure waveform detected by the detection unit 21; The comparison unit 23 determines at least a comparison result of the pressure waveform, and is configured at least by the control unit 24 that controls the driving device 5.

  The abnormality determination control of the piercing punch 10 according to the present invention that is executed in the control unit 24 is, for example, shown in the flowchart of FIG. In this flowchart, starting from step 100, initial setting (n = 1) is executed in step 101, and press work is started in step 102.

  In step 103, the pressure P (n) in one stroke of the piercing hunch 10 is detected over time in the detection unit 21, and the pressure P (n) detected in the detection unit 21 is detected in the storage unit 22 in step 104. Remembered. In step 105, the pressure waveform W (n) for the nth stroke is set from the pressure P (n) and time stored in the storage unit 22.

  In step 106, the pressure waveforms are compared. Specifically, the previous pressure waveform W (n−1) and the latest pressure waveform W (n) are compared, and if there is no abnormality in the determination in step 107, the process proceeds to step 108, and the number of times ( 1 is added to n), and the same control is repeated.

  When the pressure waveform W (n) is normal, the pressure waveform W (n) shows a basic waveform as shown in FIG. 8, for example. The pressure P (n) increases from the piercing start point ts to the maximum pressure Ptb. The point in time is determined as the maximum pressure point tbs, and the point in time at which the pressure suddenly drops and reaches the minimum pressure is determined as the fracture end point tbe.

  In the comparison of the pressure waveforms in step 106, if no pressure increase occurs even at the piercing processing start point ts, it can be determined that the piercing punch 10 has been broken or dropped. Then, the press device 1 is stopped. Thus, when the piercing punch 10 is broken or dropped, the press device 1 can be automatically stopped.

Further, when the pressure waveform W (n) is a pressure waveform as shown in FIG. 9, for example,
Specifically, the latest piercing start point ts (n) is earlier than the previous piercing start point ts (n-1) (ts (n-1)> ts (n)), or the latest When the maximum pressure Ptb (n) of the slag becomes considerably larger than the previous maximum pressure Ptb (n-1), it is determined that two sheets have been removed (the state in which the scrap of the pierced hole and the next product overlapped due to unloading) Is done. Further, in the case of this defect, since the latest increase in the pressure P (n) becomes abnormally high, there is a possibility that the piercing punch 10 may be damaged. Therefore, the latest piercing processing start point ts (n) is the start of the previous piercing processing. If it is earlier than the point ts (n−1) by a predetermined range or more, it is necessary to immediately determine an abnormality as two sheets are removed and proceed to Step 109 to automatically stop the press device 1 automatically. .

  Further, when the pressure waveform W (n) is a pressure waveform as shown in FIG. 10, for example, the pressure rise from the previous break start point tbs (n−1) becomes two steps, and the latest maximum The pressure Ptb (n) is higher than the previous maximum pressure Ptb (n-1), and the pressure P (n) at the break end point tbe (n) is higher than the previous break end point tbe (n-1). Is higher, it can be determined that a clogging of the waste (a problem has occurred in the discharge of the scrap and the scrap has accumulated in the mold 9) has occurred, and the process proceeds to step 109 to automatically press the apparatus. 1 needs to be automatically stopped. Thereby, damage to the mold 9 can be prevented.

  Furthermore, when the pressure waveform W (n) is a pressure waveform as shown in FIG. 11, for example, the pressure drop from the latest break start point tbs (n) is the previous break start point tbs (n− The pressure Pba (n) after the latest breaking end point tbe (n) is abruptly compared to the pressure drop from 1), and the pressure Pba (n−1) after the previous breaking end point tbe (n−1) If it is larger than 1), it can be determined that the cutting edge abnormality of the piercing punch 10, for example, chipping (chip) of the cutting edge, galling of the cutting edge, or wear damage has progressed. It is necessary to automatically stop the press apparatus 1.

  In piercing punches at the mass production site of press processing, rather than punch breakage and clogging, there is a quality problem that leads to burrs and deformation of the product as a result of galling of the cutting edge blade surface as the number of mass production shots increases, wear damage. Due to such an abnormality of the piercing punch edge, a pressure waveform generated in the piercing punch slightly changes as the degree of abnormality progresses. By monitoring this, it is possible to determine when to replace the piercing punch or prevent mass production of defective products.

DESCRIPTION OF SYMBOLS 1 Press apparatus 2 Lower mold holder 3 Upper mold holder 4 Upper mold pad 5 Drive apparatus 6 Press part 7 Scrap chute 8 Spring apparatus 9 Mold 10 Pierce punch 11 Holding mechanism 12 Punch retainer 13, 13A, 13A 'Backing plate 14 Bolt 15 , 15A, 15A 'Holding cylinder 15B, 15B' Backing cell 15C, 15C 'Mounting groove 16 Strain gauge 20 Control unit 21 Detection unit 22 Storage unit 23 Comparison unit 24 Control unit

Claims (7)

A lower mold holder to which a mold is mounted, an upper mold holder to which a piercing punch is mounted and reciprocating with respect to the lower mold holder, and an upper holder are mounted, and the product is fixed to the lower mold holder. Used in a press apparatus having an upper pad, a drive means mounted on the upper holder and reciprocating the upper mold holder, and a control means for controlling the drive means, and fixing the piercing punch to the upper mold holder In a backing plate that constitutes a part of a holding mechanism for performing, and is disposed between the pierce punch and the upper mold holder,
A holding cylindrical portion having a diameter equivalent to the shaft diameter of the piercing punch is formed in a portion corresponding to the piercing punch of the backing plate,
The backing plate according to claim 1, wherein a pressure detection sensor for detecting a pressure applied to the piercing punch is provided on the holding cylindrical portion. A lower mold holder to which a mold is mounted, an upper mold holder to which a piercing punch is mounted and reciprocating with respect to the lower mold holder, and an upper holder are mounted, and the product is fixed to the lower mold holder. In a press apparatus having an upper pad, a drive means mounted on the upper holder and reciprocating the upper mold holder, and a control means for controlling the drive means,
2. The backing plate according to claim 1, wherein a holding mechanism for holding the piercing punch in the upper die holder is disposed between the piercing punch and the upper die holder, and the piercing punch is fixed to the backing plate. And a punch retainer for, and
The control means includes a storage means for storing the pressure change detected by the sensor over time as a pressure waveform, a comparison means for comparing the pressure waveform stored in the storage means for each stroke of the upper mold holder, A press apparatus comprising: a stopping unit that determines that the piercing punch is abnormal and stops the driving unit when the pressure waveform compared by the comparing unit is different from the previous pressure waveform.   The press apparatus according to claim 2, wherein the pressure detection sensor is a strain detection sensor that measures strain.   In the control means, when the pressure increase point of the piercing punch is set as the piercing start point, and the latest piercing start point is not detected at the previous piercing start point by comparison of the comparison means, the piercing punch breaks or The press apparatus according to claim 2 or 3, wherein the pressing device is determined to fall off and the driving unit is stopped by the stopping unit.   In the control means, when the pressure increase point of the piercing punch is set as the piercing start point, and the latest piercing start point is earlier than the previous piercing start point by comparison of the comparison means, 5. The driving unit is stopped by the stop unit by determining that the scrap of the pierced hole and the next product overlapped with each other, and stopping the drive unit. 6. Press equipment.   In the control means, the point at which the pressure of the piercing punch is maximized is set as the breaking start point, the pressure is set as the breaking start pressure, and the point at which the pressure of the piercing punch is reduced from the maximum point to the minimum pressure And the pressure as the rupture end pressure, the latest rupture start pressure is higher than the previous rupture start pressure, and the latest rupture start point is later than the previous rupture start point, and / Alternatively, when the latest breaking end pressure is greater than the previous breaking end pressure, it is determined that a problem has occurred in scrap discharge and scrap has accumulated in the mold, and the driving unit is stopped by the stopping unit. The press apparatus according to any one of claims 2 to 5.   In the control means, the point at which the pressure of the piercing punch drops from the maximum to the lowest pressure is set as the break end point, and the pressure change rate at which the latest piercing punch pressure changes from the maximum to the lowest pressure is If the pressure change rate is greater than the previous pressure change and / or if the pressure change after the latest break end point is greater than the previous pressure change, it is determined that an abnormality has occurred in the cutting edge of the piercing punch, and the stopping means The press device according to any one of claims 2 to 6, wherein the driving means is stopped by.

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