JP2020001052A - Press molding abnormality detection method - Google Patents

Abstract

To provide a press molding abnormality detection method that controls a molding operation in response to an abnormality caused by a fractured piece generated from a workpiece in a mold during operation of a press molding device to minimizes an influence on the mold.SOLUTION: The press molding device comprises the workpiece placement part formed on one of the first mold part or the second mold part, a plurality of load detection parts installed around the placement part to detect a load between the first mold part and the second mold part. and the control unit that acquires the load value detected by the load detection part, wherein the control unit determines the press molding to be abnormal, when the load value detected by at least one of the plurality of load detection parts is out of the predetermined range, during the first mold unit and the second mold unit are pressed by the fractured fragments generated from the workpiece remaining in the peripheral part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for detecting an abnormality in press molding, and more particularly to a method for detecting abnormality in molding caused by broken pieces of a work material generated during molding.

  In a press forming apparatus, a workpiece (work) is press-formed by mutual pressing of a mold (upper mold) and a mold (lower mold). At the time of press working of a workpiece, the workpiece is processed by a predetermined pressing load between dies in terms of processing accuracy (see Patent Document 1 and the like).

  Among the press moldings, the deep drawing press molding is formed by inflow molding in which a material is caused to flow and molded. Friction heat is generated at the time of molding, and when continuous processing is performed, the die portion and the ring portion in contact with the material inflow portion expand. For this reason, the upper and lower gaps become narrower than the thickness of the sheet metal, causing inflow failure, cracking the sheet metal at the time of molding, and causing a part of the sheet metal to break.

  If the broken pieces generated from the workpiece remain in the mold and a new sheet metal of the workpiece is carried into the mold and molding is performed, the molding itself will not stop at the molding failure. May cause damage. In order to avoid such mold damage, there has been proposed an abnormality determination method that enables measurement of the distance between the molds (see Patent Document 2 and the like). According to the method of Patent Document 2, the presence or absence of broken fragments can be confirmed before the workpiece is carried in. However, it is not sufficient to detect an abnormality in the mold during operation.

  Therefore, there is a need for a mechanism and a method for minimizing the influence on the mold in response to an abnormality in the mold during operation of the press molding apparatus.

JP 2009-12006 A JP 2010-42442 A

  The present invention has been made in view of the above points, and controls the molding operation in response to an abnormality caused by a broken piece generated from a workpiece in a mold during operation of a press molding apparatus, and performs press molding. Provided is a press molding abnormality detection method for minimizing the influence of the apparatus on a mold.

  That is, in the first embodiment of the present invention, the workpiece is placed between the first mold part and the second mold part, and press-formed by pressing the first mold part and the second mold part. A press forming abnormality detection method in a press working device, wherein the press working device comprises: a placing portion for a workpiece formed on at least one of the first mold portion and the second mold portion; A plurality of load detectors installed around the first mold part for detecting a load between the first mold part and the second mold part; and the plurality of load detectors being connected to the plurality of load detectors to detect the load. And a control unit for acquiring a load value, wherein the control unit is configured such that when a fractured piece generated from a work material remains in the surrounding portion, the first mold portion and the second mold portion are pressed. Whether the load value detected by at least one of the plurality of load detection units is within the predetermined range According to the press molding abnormality detection method characterized by determining the press-molding in the case of deviating abnormal.

  In a second mode, the control section controls a pressing operation of the first mold section or the second mold section, and when it is determined that press molding is abnormal, the control section controls the first mold section or the second mold section. The present invention relates to the press forming abnormality detecting method according to the first embodiment, in which the pressing operation of the second mold portion is stopped.

  A third form relates to the press forming abnormality detecting method according to the first or second form, wherein the press forming is draw press forming.

  In a fourth mode, the load detection section is housed in a distance block, and the distance block is installed in at least one of the first mold section or the second mold section. The present invention relates to the press molding abnormality detection method described above.

  According to the press molding abnormality detection method of the present invention, during operation of the press molding apparatus, the molding operation is controlled in response to an abnormality caused by a broken piece generated from the workpiece in the mold, and the metal of the press molding apparatus is controlled. The influence on the mold can be minimized.

It is an overall sectional view of a press working device. It is a principal part sectional view at the time of normal molding. It is principal part sectional drawing at the time of abnormal molding. 5 is a flowchart illustrating a process of a control unit. It is a fragmentary perspective view showing other forms of a load detection part.

  The press forming abnormality detecting method of the present invention will be described using the press working apparatus 1 of FIG. The press working apparatus 1 is provided with a first mold part 11 (referred to as a die or the like) and second mold parts 12, 13 (12: a punch, 13: a ring or the like). The press processing apparatus 1 of the embodiment will be described as a processing apparatus for drawing press forming. Therefore, the second mold portion of the device is formed by a combination of a punch 12 for drawing and a ring 13 around the punch.

  The workpiece 10 (work) such as a metal plate material is placed on a placing portion 40 which is a predetermined position of the ring 13 of the second mold portion, and is subjected to drawing press forming by receiving pressure from the punch 12. The peripheral portion of the workpiece 10 is in contact with the mounting portion 40 of the ring 13 of the second mold portion. Therefore, the peripheral portion of the workpiece 10 is fixed by pressing the mounting portion 40 of the ring 13 and the contact portion 50 of the first mold portion 11 (see FIG. 2).

  The punch 12 of the second mold part is fixed on the bolster 16. The cushion pad 15 is installed below the bolster 16. A die cushion mechanism is provided below the cushion pad 15 (not shown). As the die cushion mechanism, an air type (air die cushion), a servo type (servo die cushion), or the like is used. The ring 13 disposed around the punch 12 is disposed above the bolster 16 and is pushed up by the cushion pad 15 and the cushion pin 14. For this reason, the load applied to the ring 13 during the drawing press forming is appropriately adjusted and pushed down by the first mold portion 11.

  A slide 17 (ram) is arranged above the first mold part 11 (die). Then, a slide drive unit 18 is installed above the slide 17. A motor, a gear, a cam, a crank, and the like are installed inside the slide driving unit 18 (the inside is not shown). Then, the crank is moved by the rotation of the motor, and the slide 17 is moved up and down. It should be noted that the drawings show the main parts of the press working apparatus necessary for the description of the present invention, and naturally include mechanisms and configurations other than those shown.

  According to the press working apparatus 1 of the illustrated embodiment, the peripheral portion 51 of the ring 13 of the second mold portion and the peripheral portion 41 of the first mold portion 11 are close to each other with the workpiece 10 interposed therebetween (see FIG. 2). Therefore, the peripheral portion 51 of the ring 13 and the peripheral portion 41 of the first mold portion 11 are in contact with each other with the workpiece 10 interposed therebetween. At this time, the pressing load between the dies (between the ring 13 and the first mold part 11) is detected by the plurality of load detection units 20.

  The position where the load detecting unit 20 is installed is a mold part surface area other than the place used for the drawing press forming of the workpiece 10. In the illustrated example, the load detection unit 20 is disposed on a peripheral portion 51 of the ring 13 (second mold portion). Although not shown, the load detection unit 20 can also be installed on the peripheral part 41 of the first mold part 11. The number and positions of the load detectors 20 are appropriately determined according to the size and shape of the mold (the first and second mold portions) and the size and shape of the workpiece 10. As described in FIG. 2 and subsequent figures, the load detecting unit 20 is installed for the purpose of detecting an abnormality at the time of repeating press forming at an early stage and minimizing damage to equipment such as a mold.

  The press working apparatus 1 includes a control unit 30, and the plurality of load detection units 20 are connected to the control unit 30 by signal lines 31. The slide drive unit 18 is controlled by the control unit 30. Therefore, the operation of moving up and down (forward / backward) of the first mold portion 11 and the ring 13 is controlled.

  The load detecting unit 20 is a known sensor that converts a pressing load between dies into an electric signal, such as a load cell, a piezoelectric sensor, and a strain gauge. In the embodiment of FIG. 1, each load detection unit 20 is in a form of a wired connection with the control unit 30 by a signal line 31. Alternatively, a wireless connection mode in which a signal is transmitted from the load detection unit 20 itself may be used.

  First, a normal draw press forming will be described with reference to FIG. The illustration shows only main members such as a mold. In FIG. 2A, the workpiece 10 made of a steel plate is placed on the placing portion 50 of the ring 13 of the second mold portion. Then, the edge portion 10 e of the workpiece 10 is fixed at a predetermined position by the pressing of the mounting portion 50 of the ring 13 and the contact portion 40 of the first mold portion 11 as the first mold portion 11 descends.

  Next, as shown in FIG. 2B, the first mold portion 11 further descends, and the ring 13 also descends in conjunction with the control of the die cushion mechanism. At this time, since the position of the punch 12 does not change, the central portion 10c of the workpiece 10 is pushed up from below by the punch 12. Therefore, the central portion 10c of the workpiece 10 is extended along the drawing die surface 11a of the first die portion 11 with the lowering of the first die portion 11 (pushing up by the punch 12), and the desired drawing press forming is performed. It is processed into a shape.

  Finally, as shown in FIG. 2C, the drawing press forming of the workpiece 10 is completed, and a molded product 10P (finished product) is completed. The first mold part 11 rises and is separated from the punch 12 and the ring 13), and the workpiece 10 (the molded product 10P) is taken out.

  Since the press forming of the embodiment is the draw press forming, the amount of deformation applied at the time of forming into a workpiece is partially increased. For this reason, frictional heat is generated by repetition of ordinary drawing press forming, and in rare cases, there is a possibility that the workpiece is broken due to a change in pressing between the dies during drawing press forming. In this case, if the molding operation is continued while the broken pieces separated from the work material remain in the mold, raw material waste due to poor molding of the work material, damage to the mold, etc., are serious in terms of production efficiency. This will cause trouble.

  Therefore, if a broken fragment can be detected beforehand, it is possible to deal with problems such as damage to a mold and reduction in work efficiency. In FIG. 3A, a broken piece 10x is generated from the workpiece 10 at the time of the previous drawing press forming, and the broken piece 10x remains on the mounting portion 40 of the ring 13 of the second mold portion. is there. Then, a new workpiece 10 is supplied with the broken pieces 10x remaining, and further, the first mold portion 11 descends and the broken pieces 10x remaining on the mounting portion 40 of the ring 13 of the second mold portion. The workpiece 10 is being pressed together.

  As can be seen from FIG. 3A, a difference occurs between the peripheral portion 41 of the first mold portion 11 and the peripheral portion 51 of the ring 13 of the second mold portion depending on the presence or absence of the broken piece 10x. For this reason, the load values detected by the plurality of load detection units 20 vary. The detection signal of each load detector 20 is transmitted to the controller 30 (see FIG. 1). That is, when the first mold portion 11 and the ring 13 of the second mold portion are pressed, the load value detected by at least one load detection unit 20 of the plurality of load detection units 20 is out of the predetermined range. Therefore, in the case of the state shown in FIG. 3A, the press forming (drawing press forming) in the press working apparatus 1 is determined to be abnormal through the control unit 30.

  When the control unit 30 of the press working apparatus 1 determines that the press forming is abnormal, as in the embodiment shown in FIGS. 3B and 3C, the control unit 30 controls the pressing operation of the first mold unit 11, The control unit 30 stops the pressing operation between the first mold units 11. In particular, in the press working apparatus 1 of the embodiment, the first mold portion 11 is reversed from descending to ascending when the pressing operation is stopped. For this reason, the press forming (drawing press forming) of the workpiece 10 with the broken pieces 10x remaining is stopped, and it is possible to avoid damage to the mold.

  Then, as shown in FIG. 3 (c), the broken pieces 10x are removed from the inside of the mold (the mounting portion 40 of the ring 13 in the drawing), returned to the normal state of FIG. 2 again, and newly processed. Press forming (draw press forming) of the material 10 is performed.

  More specifically, when the load value detected by the load detection unit 20 during normal press molding is, for example, “100 kN” and a range of “± 5 kN” is set before and after, the load value is detected by the load detection unit 20. The applied load value is in the range of 95 to 105 kN. Therefore, if all of the plurality of load detection units fall within the range, it is determined that normal press molding is performed, and molding is continued.

  On the other hand, when one of the plurality of load detectors 20 detects a load out of the above-mentioned range (100 ± 5 kN) such as 90 kN or 110 kN, for example, a broken piece The possibility of abnormalities caused by residuals is high. Therefore, the control unit 30 continuously tracks the load value detected by the load detection unit, so that the molding is temporarily stopped at the time of an abnormality, the mold is opened, and the abnormal state can be quickly removed. . At the same time, when an abnormality in the load value is detected, an appropriate warning such as sounding a warning such as a buzzer or lighting a warning lamp may be executed through the control unit 30.

  Here, the outline of the control of the molding in the control unit 30 will be described using the flowchart of FIG. After the workpiece 10 of the steel plate is supplied to and placed on the placing portion 40 of the ring 13 of the second mold portion, the first mold portion 11 is lowered with respect to the ring 13 by driving of the slide driving portion 18. Thus, the pressing of the workpiece 10 is performed (S101). At the time of pressing, the control unit 30 checks whether the load values detected by all of the plurality of load detection units 20 are within the normal range (S102).

  The case where the total load value is within the normal range (Yes in S102) is a state in which a broken piece or the like as shown in FIG. In this case, since it is in a normal state, the first mold portion 11 is continuously lowered, and the press forming (draw press forming) is continued as it is through the contact between the workpiece 10 and the punch 12 (S103). Then, after the predetermined molding is completed, the first mold part 11 is raised and the mold is opened (S104). Thereafter, the workpiece 10 (10P) that has been formed is removed from the mold.

  On the other hand, if the detected load value of any one of the plurality of load detection units 20 is out of the normal range, it is determined to be abnormal (No in S102). Specifically, as shown in FIG. 3 (a) and the like, the broken pieces 10x generated by the immediately preceding molding remain in the mold. In this case, if molding is continued by lowering the first mold part 11, there is a possibility that the mold may be damaged. Therefore, the pressing is stopped (S105). Then, the first mold part 11 is inverted from the descent and lifted to open the mold (S104). At this time, the broken pieces are removed from the mold, and after confirming that the mold surface is normal, the workpiece 10 is again supplied and placed on the placement section 40 of the ring 13 of the second mold section. The steps after the pressing in S101 are repeated.

  When the load detection unit 20 is installed in the mold, a distance block can be interposed. A hole for installing the distance block is formed in the mold in advance. The distance at the time of pressing between the dies is finely adjusted through the distance block. The load detector 20 is housed in the distance block 60. Then, the distance block 60 containing the load detection unit 20 is installed on at least one of the first mold unit 11 and the second mold unit.

  FIG. 5 shows another embodiment when the load detection unit 20 is installed on the mold. Referring to FIG. 5, a step portion 52 is provided in a peripheral portion 51 of the ring 13 of the second mold portion, and a distance block 60 is installed in the step portion 52. An accommodation hole 62 is formed in the distance block 60, and the load detection unit 20 is accommodated in the accommodation hole 62. Although the size of the load detecting portion is appropriate, it is cylindrical with a height of 30 to 50 mm and a diameter of 50 to 80 mm. By using the distance block for installation of the load detection unit, a process of separately forming a hole for installation of the load detection unit in the mold is omitted, which is simple. In particular, unnecessary processing of the mold is not preferable from the viewpoint of strength reduction.

  The press molding abnormality detection method of the present invention controls the molding operation and minimizes the influence on the mold during operation of the press molding apparatus in response to an abnormality caused by a broken piece generated from the workpiece in the mold. Can be stopped. Thus, it is possible to contribute to improvement of work efficiency.

DESCRIPTION OF SYMBOLS 1 Press processing apparatus 10 Work material 10e Edge part of work material 10P Molded product 10x Broken piece 11 1st type | mold part (die)
11a drawing die surface 12 punch (second die part)
13 ring (2nd mold part)
14 Cushion pin 15 Cushion pad 16 Bolster 17 Slide 18 Slide drive unit 20 Load detection unit 30 Control unit 31 Signal line 40 Contact unit 41 Peripheral unit 50 Placement unit 51 Peripheral unit 52 Step unit 60 Distance block 62 Housing hole

Claims (4)

A press forming abnormality detecting method in a press working apparatus for placing a workpiece between a first mold part and a second mold part and performing press forming by pressing the first mold part and the second mold part. hand,
The press working device,
A mounting portion for a workpiece formed on at least one of the first mold portion or the second mold portion,
A plurality of load detection units installed around the placement unit for detecting a load between the first mold unit and the second mold unit;
A control unit connected to the plurality of load detection units and acquiring a load value detected by the plurality of load detection units,
The control unit includes:
By the broken fragments generated from the work material remaining in the surrounding portion,
Pressing when the load value detected by at least one of the plurality of load detection units is out of the predetermined range when the first mold unit and the second mold unit are pressed is determined to be abnormal. Press molding abnormality detection method characterized by the above-mentioned.   The control section controls the pressing operation of the first mold section or the second mold section, and when it is determined that the press molding is abnormal, the control section presses the first mold section or the second mold section. The press forming abnormality detecting method according to claim 1, wherein the operation is stopped.   The press forming abnormality detecting method according to claim 1 or 2, wherein the press forming is drawing press forming.   The press forming abnormality according to any one of claims 1 to 3, wherein the load detection unit is accommodated in a distance block, and the distance block is provided on at least one of the first mold part and the second mold part. Detection method.

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