Press Processing Equipment

Abstract

To provide a press machining device capable of improving a calculation accuracy of abrasion loss of a punch.SOLUTION: A press machining device performs punching to a workpiece. A press machining device includes: a punch moving in a press direction and having a press surface facing the workpiece and a side surface connected to the press surface; a die on which a hollow part into which the punch is inserted is formed, and on which the workpiece is placed; a sensor unit detecting a load applied on the punch; and a control part controlling the punch, the die, and the sensor unit. The control part generates a first load waveform showing a relation between the load and the time after punching on the basis of temporal variation in the load detected by the sensor unit. The control part calculates an abrasion loss of the side surface of the punch on the basis of a part corresponding to a period when the punch is raised from the bottom dead point of the first load waveform.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a press working device. [Background technology]

[0002] 2. Description of the Related Art In press working for punching a plate-shaped workpiece, a device for measuring the processing resistance when punching the workpiece is known.

[0003] The punching characteristic measuring device described in Patent Document 1 measures the punching force during punching by converting the change over time in deformation of the frame during punching into an electrical signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 62-40938 Summary of the Invention [Problem to be solved by the invention]

[0005] The punching characteristic measuring device described in Patent Document 1 has room for improvement in terms of improving the accuracy of calculating the amount of wear of the tool.

[0006] The present disclosure provides a press working device that can improve the accuracy of calculating the amount of wear of a punch. [Means for solving the problem]

[0007] A press working apparatus according to one aspect of the present disclosure includes: A press processing device that performs punching on a workpiece, A punch that moves in a pressing direction and has a pressing surface facing the workpiece and a side surface connected to the pressing surface; a die having a hollow portion into which the punch is inserted and on which the workpiece is placed; a sensor unit for detecting a load applied to the punch; a control unit that controls the punch, the die, and the sensor unit; Equipped with The control unit generating a first load waveform indicating a relationship between the load and time after punching based on a change over time of the load detected by the sensor unit; The amount of wear on the side surface of the punch is calculated based on a portion of the first load waveform that corresponds to a period during which the punch is rising from the bottom dead center. [Effects of the Invention]

[0008] According to the stamping device of the present disclosure, the accuracy of calculating the amount of wear of the punch can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating a press working device according to a first embodiment of the present disclosure. [Figure 2] Schematic diagram showing the punch of the press processing device in Figure 1 at the bottom dead center [Figure 3] FIG. 2 is a top view showing the sensor unit of the press working device of FIG. [Figure 4] A flowchart illustrating a process for determining whether or not a punch needs to be polished in a press working device. [Figure 5A] Schematic diagram showing the process of punching a workpiece using a press processing device [Figure 5B] Schematic diagram showing the process of punching a workpiece using a press processing device [Figure 5C] Schematic diagram showing the process of punching a workpiece using a press processing device [Figure 5D] Schematic diagram showing the process of punching a workpiece using a press processing device [Figure 5E] Schematic diagram showing the process of punching a workpiece using a press processing device [Figure 5F] Schematic diagram showing the process of punching a workpiece using a press processing device [Figure 5G] Schematic diagram showing the process of punching a workpiece using a press processing device [Figure 6] Graph showing a load waveform generated based on the load detected by a sensor during punching and the position of the punch from the bottom dead center. [Figure 7] A graph illustrating the effect of the progression of punch wear on the load waveform in Figure 6. [Figure 8] Graph showing an example of the relationship between the impulse of the punch and the first wear amount of the press surface of the punch [Figure 9] Graph showing an example of the relationship between the maximum load of the stable waveform portion in the second period and the second wear amount of the side surface of the punch 1 [Figure 10] Graph showing an example of the relationship between the maximum load in the third period and the third wear amount of the side surface of the punch 1 DETAILED DESCRIPTION OF THE INVENTION

[0010] (Background to the invention) Press working, which involves punching a plate-shaped workpiece, is a technique that generally involves pressing the workpiece loaded on a die with a stripper and forcing part of the workpiece into the die with a punch to punch out a desired shape. Press working by punching is generally used in a wide range of fields, including home appliances, precision machinery, and automobile parts.

[0011] In press processing using punching, there is known a punching characteristic measuring device, such as that described in Patent Document 1, which measures the punching force during punching by converting the change over time in frame deformation during punching into an electrical signal.

[0012] The punching characteristic measuring device described in Patent Document 1 converts frame deformation during punching into an electrical signal to measure the punching force during punching. The punching force is the resistance force when a die is used to punch a laminate. As the die becomes worn, the punching force increases, so it has been studied to use the punching force to calculate the die wear state and determine whether the tool needs to be re-ground.

[0013] However, the punching characteristic measuring device described in Patent Document 1 detects deformation of the frame at a position away from the processing position of the die, which has the problem that it is not possible to calculate the wear state of the die with high accuracy.

[0014] The present inventor(s) have studied a press working device that can accurately calculate the amount of wear of a punch, and have arrived at the following invention. The following describes examples of aspects of the present disclosure.

[0015] <Aspect 1> A press processing device that performs punching on a workpiece, A punch that moves in a pressing direction and has a pressing surface facing the workpiece and a side surface connected to the pressing surface; a die having a hollow portion into which the punch is inserted and on which the workpiece is placed; a sensor unit for detecting a load applied to the punch; a control unit that controls the punch, the die, and the sensor unit; Equipped with The control unit generating a first load waveform indicating a relationship between the load and time after punching based on a change over time of the load detected by the sensor unit; calculating a wear amount of the side surface of the punch based on a portion of the first load waveform corresponding to a period during which the punch is rising from the bottom dead center; Press processing equipment.

[0016] According to the stamping device of this aspect, the amount of wear on the side surface of the punch can be calculated more accurately than in the past.

[0017] <Aspect 2> the control unit generates the first load waveform after the punching process based on the compressive load applied to the punch detected by the sensor unit. The press processing apparatus according to aspect 1.

[0018] According to the stamping device of this aspect, the amount of wear on the side surface of the punch can be calculated with higher accuracy.

[0019] <Aspect 3> the control unit calculates the amount of wear on the side surface of the punch based on a waveform of the first load waveform in a time interval from a time when the load is first detected to a time when the load reaches zero. The press processing device according to aspect 1 or aspect 2.

[0020] According to the stamping device of this aspect, the amount of wear on the side surface of the punch can be calculated with higher accuracy.

[0021] <Aspect 4> The control unit calculates the amount of wear on the side surface of the punch based on a first load waveform in a time interval from when the punch starts to rise to when the punch passes through the hole in the workpiece. The press working device according to any one of aspects 1 to 3.

[0022] According to the stamping device of this aspect, the amount of wear on the side surface of the punch can be calculated with higher accuracy.

[0023] <Aspect 5> a gap sensor for detecting the position of the punch; The control unit detects, based on the detection result of the gap sensor, that the punch is at the bottom dead center and that the punch has passed through the hole in the workpiece. The press processing apparatus according to aspect 4.

[0024] According to the stamping device of this aspect, the amount of wear on the side surface of the punch can be calculated with higher accuracy.

[0025] <Aspect 6> a wear amount of the side surface of the punch is a third wear amount; The control unit further generating a second load waveform indicating a relationship between the load and time from the start to the end of the punching process based on the change over time of the load detected by the sensor unit; Calculating a first wear amount of the press surface of the punch based on the second load waveform during a first period from a start time of the punching process to a time when the load reaches a maximum value and then reaches zero; A second wear amount of the side surface of the punch is calculated based on a portion of the second load waveform corresponding to a second period from the end of the first period to the end of the punching process. The press working device according to any one of aspects 1 to 5.

[0026] According to the press working device of this aspect, the amount of wear on the press surface and side surface of the punch can be calculated with higher accuracy.

[0027] <Aspect 7> the control unit calculates an impulse applied to the punch during the first period based on the second load waveform, and calculates the first wear amount based on the calculated impulse. A press processing apparatus according to aspect 6.

[0028] According to the press working device of this aspect, the amount of wear on the press surface of the punch can be calculated with higher accuracy.

[0029] <Aspect 8> the second load waveform has, in the second period, a vibration waveform portion in which the load changes over time, and a stable waveform portion in which the load changes over time smaller than the vibration waveform portion, The control unit calculates the second wear amount based on the maximum load in the stable waveform portion. A press processing apparatus according to aspect 6 or aspect 7.

[0030] According to the stamping device of this aspect, the amount of wear on the side surface of the punch can be calculated with higher accuracy.

[0031] <Aspect 9> 9. The press processing apparatus according to any one of aspects 6 to 8, wherein the control unit determines that it is necessary to polish the press surface of the punch when the first wear amount is greater than a predetermined first threshold value.

[0032] According to the press working device of this aspect, it is possible to accurately determine whether or not polishing of the press surface of the punch is necessary.

[0033] <Aspect 10> A press processing apparatus as described in aspect 9, wherein the control unit determines that it is necessary to grind the side surface of the punch when the second wear amount and / or the third wear amount is greater than a predetermined second threshold value.

[0034] According to the stamping device of this aspect, it is possible to accurately determine whether or not polishing of the side surface of the punch is necessary.

[0035] <Aspect 11> The first threshold is greater than the second threshold. A press processing apparatus according to aspect 10.

[0036] According to the stamping device of this aspect, it is possible to accurately determine whether or not the punch needs to be polished.

[0037] <Aspect 12> the sensor unit includes a plurality of sensors that detect the load; 12. The press working apparatus according to any one of aspects 1 to 11.

[0038] According to the stamping device of this aspect, the load acting on the punch can be detected in detail, and it is possible to more accurately determine whether or not the punch needs to be polished.

[0039] <Aspect 13> Further, a gap sensor is provided to detect the position of the punch. 13. The press working apparatus according to any one of aspects 1 to 12.

[0040] The stamping apparatus according to this aspect can determine whether the relative position of the punch with respect to the die is appropriate and can start measuring the load on the punch at an appropriate timing, thereby making it possible to more accurately determine whether or not the punch needs to be polished.

[0041] Hereinafter, an embodiment will be described with reference to the drawings.

[0042] (Embodiment 1) [Overall configuration] Fig. 1 is a schematic diagram showing a stamping apparatus 100 according to a first embodiment of the present disclosure. Fig. 2 is a schematic diagram showing a state in which a punch 1 of the stamping apparatus 100 of Fig. 1 is at bottom dead center. Fig. 3 is a top view showing a sensor unit 6 of the stamping apparatus 100 of Fig. 1. Note that some components are not shown in Figs. 2 and 3. The stamping apparatus 100 according to this embodiment will be described with reference to Figs. 1 to 3.

[0043] The XYZ coordinate system shown in each drawing is for facilitating understanding of the embodiment and is not intended to limit the embodiment. In each drawing, the X direction is the width direction of the press working apparatus 100, the Y direction is the depth direction of the press working apparatus 100, and the Z direction is the height direction of the press working apparatus 100.

[0044] The press working apparatus 100 is an apparatus that performs punching on a plate-shaped workpiece 5, and is, for example, a servo screw press apparatus that can be controlled with high precision. In this embodiment, the press working apparatus 100 includes a press apparatus main body 9 and a control unit 18. The press apparatus main body 9 includes a punch 1, a die 2, and a sensor unit 6.

[0045] The press body 9 and the control unit 18 may be housed in a single housing. For example, the control unit 18 may be housed in the housing of the press body 9. In this case, it can be said that the press working apparatus 100 has the punch 1, the die 2, the sensor unit 6, and the control unit 18.

[0046] Alternatively, the press device main body 9 and the control unit 18 may not be housed in a single housing, but may be provided separately in separate locations. In this disclosure, an embodiment in which the press device main body 9 and the control unit 18 are provided separately in this manner is also referred to as a "press processing device 100." Such an embodiment may also be referred to as a "press processing system."

[0047] As shown in Fig. 1, a press body 9 of a press processing device 100 has an upper die including a punch 1 attached to a slide 7, and a lower die including a die 2 attached to a bolster 8. Based on commands from a control unit 18, the press body 9 rotates a ball screw 12 connected to a servo motor 11 to drive the slide 7 up and down in the pressing direction (Z direction) along a shaft 10 at a predetermined speed. This operation of the press body 9 allows the workpiece 5 to be punched.

[0048] The punch 1 is a tool that moves in the press direction (Z direction) to punch out the workpiece 5. As shown in FIG. 2, the punch 1 has a press surface 1a that faces the workpiece 5 and a side surface 1b that connects to the press surface 1a. The punch 1 is attached to a slide 7 together with a stripper plate 3 that presses the workpiece 5 against the die 2 during punching. As the slide 7 moves, the punch 1 is pressed against the workpiece 5 to perform the punching process. In this embodiment, as shown in FIG. 3, the punch 1 has a circular press surface 1a. This allows the workpiece 5 to be punched out in a circular shape.

[0049] In this embodiment, the cutting edge of the punch 1 is formed in a cylindrical shape with a circular press surface 1a having a diameter of 4.5 mm, and punches a circular hole in the workpiece 5. The punch 1 is made of, for example, a superhard material. An example of a superhard material is a general term for a metal (alloy) in which at least one carbide of W (tungsten), Cr (chromium), Mo (molybdenum), Ti (titanium), Zr (zirconium), Hf (hafnium), V (vanadium), Nb (niobium), or Ta (tantalum) is bonded with an Fe-group metal (e.g., Fe, Co, or Ni). As the superhard material, for example, an alloy equivalent to VM-40 of the Cemented Carbide Tool Association Standard (CIS) can be used.

[0050] As shown in FIG. 2, a workpiece 5 is placed on the die 2 during punching. The die 2 has a hollow portion 2a into which the punch 1 is inserted. The hollow portion 2a is a through-hole that passes through the die 2 in the Z direction. The die 2 is attached to a bolster 8 together with a die plate 4 that holds the die 2. Like the punch 1, the die 2 is made of, for example, a superhard material.

[0051] The workpiece 5 is a plate-shaped material to be processed by the press processing device 100. A plurality of workpieces 5 or a coil-shaped workpiece 5 is transported in the X direction or Y direction by a transport unit (not shown) in accordance with the pressing operation of the press device main body 9, and is sequentially subjected to punching.

[0052] In this embodiment, the workpiece 5 is made of SUS301-EH material, which is a type of steel classified as austenitic stainless steel. SUS301-EH material is a material used, for example, for mainsprings or springs in automobile parts. In this embodiment, the workpiece 5 has a thickness of 0.031 mm, a hardness of 529 HV, and a tensile strength of 1,679 N / mm 2 is.

[0053] The sensor unit 6 is a load sensor that detects the load applied to the punch 1. In this embodiment, the sensor unit 6 detects the load applied to the punch 1 in the press direction (Z direction). More specifically, the sensor unit 6 detects the load applied to the punch 1 in the press direction (Z direction) when punching the workpiece 5. Specifically, it detects a positive reaction force P1 (see FIG. 2) in the press direction (Z direction) of the punch 1 when punching the workpiece 5. The sensor unit 6 also detects a load applied in the press direction (Z direction) when the punch 1 is withdrawn from the bottom dead center after punching the workpiece 5. Specifically, it detects a negative reaction force P2 (see FIG. 2) in the press direction (Z direction) of the punch 1 when the punch is withdrawn from the bottom dead center.

[0054] In this embodiment, in order to detect the load acting on the punch 1 with the sensor unit 6, the punch 1, sensor unit 6, and free shank 20 above the sensor unit 6 are integrated with a fastening bolt (not shown) or the like. Therefore, as described above, it is possible to detect the positive reaction force P1 (see FIG. 2) in the press direction (Z direction) of the punch 1 when punching the workpiece 5, and also to detect the load acting in the press direction (Z direction) when the punch 1 is withdrawn from the bottom dead center after punching the workpiece 5.

[0055] As shown in FIG. 3, in this embodiment, the sensor unit 6 includes four sensors 6a to 6d. Each of the sensors 6a to 6d can detect the load applied to that position in the press direction (Z direction). In this embodiment, the sensors 6a and 6b are arranged symmetrically in the Y direction, and the sensors 6c and 6d are arranged symmetrically in the X direction. In this embodiment, the sensors 6a to 6d are arranged concentrically. Whether or not a certain portion of the punch 1 is worn affects the load applied to that portion, so arranging the sensors 6a to 6d in this manner makes it easier to determine which portion of the punch 1 is worn.

[0056] The control unit 18 controls the punch 1, the die 2, and the sensor unit 6. In this embodiment, the control unit 18 has a press controller 14, a sensor controller 15, a calculation unit 16, and a determination unit 17. The control unit 18 is configured with digital circuits such as a microcomputer, a CPU, an MPU, a GPU, a DSP, an FPGA, and an ASIC.

[0057] The press controller 14 drives the servo motor 11 to rotate the ball screw 12, thereby driving the slide 7 up and down in the press direction (Z direction) at a predetermined speed.

[0058] The sensor controller 15 is electrically connected to the sensor unit 6 of the punch 1 and a gap sensor 13 (described later), and outputs the detection values ​​of the sensor unit 6 and the gap sensor 13 to the calculation unit 16.

[0059] The calculation unit 16 generates a load waveform that indicates the relationship between the load applied to the punch 1 and time based on the load detected by the sensor unit 6, and calculates the amount of wear of the punch 1 based on the load waveform. When punching is repeated, the punch 1 gradually wears out. The calculation unit 16 calculates the amount of wear of the press surface 1a and side surface 1b of the punch 1. Details of the generation of the load waveform and the calculation of the amount of wear will be described later.

[0060] The determination unit 17 determines whether or not the punch 1 needs to be polished based on the amount of wear on the press surface 1a and the side surface 1b calculated by the calculation unit 16. As the amount of wear on the punch 1 increases, the accuracy of the punching dimensions of the workpiece 5 gradually deteriorates. For this reason, it is advisable to polish the punch 1 when the amount of wear exceeds a predetermined threshold. When the determination unit 17 determines that the punch 1 needs to be polished, it outputs a signal to the press controller 14 to interrupt the punching process. Upon receiving the notification, the press controller 14 stops the servo motor 11 and interrupts the punching process.

[0061] In this embodiment, the stamping apparatus 100 is equipped with a gap sensor 13 that detects the position of the punch 1. More specifically, as shown in FIG. 2, the gap sensor 13 can detect that the punch 1 is in the lowest possible position, i.e., at the bottom dead center. The gap sensor 13 can also detect how much the punch 1 has risen from the bottom dead center. The gap sensor 13 can be configured, for example, by a displacement sensor that measures a minute distance between the punch 1 and an object to be measured in a non-contact manner.

[0062] The gap sensor 13 is attached at an arbitrary position on the lower die of the press working device 100, which includes, for example, the die 2, the die plate 4, and the bolster 8. The gap sensor 13 detects contact with the upper die, which includes, for example, the punch 1, the stripper plate 3, and the slide 7, thereby detecting that the punch 1 is at the bottom dead center and the position (height) of the punch 1 from the bottom dead center.

[0063] Furthermore, the gap sensor 13 can determine the start timing for detecting the load on the punch 1. Specifically, the start timing can be determined based on the gap of the gap sensor 13 and the position of the punch 1 from the bottom dead center so that detection of the load on the punch 1 can be started at the same timing for each punching shot. In this way, the gap sensor 13 can be used as a trigger for detecting the load on the punch 1. Furthermore, for example, by arranging the gap sensors 13 at each of the four corners of the lower die, it can be detected whether the upper die and the lower die are arranged parallel to each other. Note that the gap sensor 13 is not an essential component, and the stamping apparatus 100 does not necessarily have to include the gap sensor 13.

[0064] [Determining whether punch polishing is necessary] 4 is a flowchart illustrating a process for determining whether or not grinding of the punch 1 is necessary in the press working apparatus 100. The determination of whether or not grinding of the punch 1 is necessary will be described with reference to FIG.

[0065] In the press working device 100, when punching is started, the sensor unit 6 detects the load applied to the press direction (Z direction) of the punch 1 (step S1). In this embodiment, the load is detected by each of the sensors 6a to 6d.

[0066] The load detected by the sensor unit 6 is output to the calculation unit 16 via the sensor controller 15 of the control unit 18. The calculation unit 16 generates a load waveform that indicates the relationship between the load applied to the punch 1 and time (step S2).

[0067] 5A to 5G are schematic diagrams showing the process of punching a workpiece 5 using a stamping apparatus 100. FIG. 6 is a graph showing the load (left vertical axis) detected by sensors 6a to 6d during punching and the position of punch 1 from the bottom dead center (right vertical axis). FIG. 6 shows a superimposed load waveform generated based on the load detected by each of sensors 6a to 6d. The load waveforms will be explained with reference to FIGS. 5A to 5G and 6. Note that all waveforms in FIG. 6 and the dashed waveform in FIG. 7, which will be described later, show load waveforms when punch 1 is not worn at all or is almost not worn at all.

[0068] When punching begins, punch 1 descends in the Z direction from the top dead center and comes into contact with workpiece 5 (Fig. 5A). Top dead center refers to the highest position that punch 1 can be at. Time C1 in the graph in Fig. 6 indicates the point in time when punch 1 comes into contact with workpiece 5 and the load on punch 1 or the load on sensor unit 6 causes the positive reaction force P1 (see Fig. 2) in the press direction (Z direction) to become greater than 0.

[0069] When punch 1 comes into contact with workpiece 5, punch 1 begins to punch out workpiece 5, as shown in FIG. 5B. As a result, a load begins to be applied to punch 1 from time C1, and the load on punch 1 increases rapidly, reaching a maximum value P0 at time m1. Height H shown in FIG. 6 represents the position (height) of punch 1 relative to bottom dead center at time C1. When punch 1 is at a position H from bottom dead center at time C1, punch 1 in FIG. 5A comes into contact with the top surface of workpiece 5, and a positive reaction force P1 shown in FIG. 2 begins to be applied to punch 1.

[0070] After time C1, when the workpiece 5 is cut by the punch 1 as shown in FIG. 5C, the load on the punch 1 drops to 0, and the cutting is complete. The point in time when the load on the punch 1 reaches 0 is time C2 (cutting complete) in FIG. 6. The cutting complete time C2 represents the point in time when the load on the punch 1 drops to 0 within a predetermined period after the load on the punch 1 reaches its maximum value P0. The load on the punch 1 drops to 0 because the punch 1 punches through the workpiece 5 and there is no longer any resistance to the punch 1.

[0071] When the load on punch 1 becomes zero at time C2, the load on sensor unit 6, i.e., the positive reaction force P1 in the press direction (Z direction) (see Figure 2), disappears. For a moment, the load on punch 1 or the load on sensor unit 6 changes to a negative reaction force P2 in the press direction (Z direction) (see Figure 2). As shown in Figure 6, a negative load is applied immediately after time C2, then returns to a positive load due to a reaction force. After that, the load on punch 1 gradually converges to zero. The period from time C2 until the load converges corresponds to the vibration waveform portion shown in Figure 6. As the cut workpiece 5 is pushed between punch 1 and die 2 (see Figure 5D), a positive reaction force P1 in the press direction (Z direction) (see Figure 2) may be applied to punch 1 or sensor unit 6. After that, the load on punch 1 is applied for a while, and then punch 1 reaches bottom dead center (position 0) (see Figure 5E). At time C3 in Figure 6, the load on punch 1 becomes zero.

[0072] During the period between time C3 and time C4 in FIG. 6, punch 1 is stopped at bottom dead center (position 0) (the state shown in FIG. 5E). Then, as punch 1 ascends in the Z direction from time C4 (bottom dead center) in FIG. 6 toward top dead center (see FIGS. 5E to 5F), a negative reaction force P2 (see FIG. 2) in the press direction (Z direction) may be applied to punch 1 or sensor unit 6 due to the pulling out of punch 1. In other words, a compressive load is applied to punch 1. After that, the punch 1 is subjected to a load for a while until it is completely pulled out of workpiece 5 (see FIG. 5G). This corresponds to the point at which the load on punch 1 becomes zero, i.e., the state shown in FIG. 6 at time C5. From the graph in FIG. 6, it can be seen that the position of punch 1 from bottom dead center at time C5 is H.

[0073] When the amount of wear on the punch 1 is small, for example, when the punch 1 is new or has just been polished, the load waveforms detected by the sensors 6a to 6d will have approximately the same shape as shown in Fig. 6. Due to subtle differences in the clearance between the punch 1 and the die 2, the load waveforms detected by the sensors 6a to 6d may be slightly different as shown in Fig. 6.

[0074] 4, after step S2, the calculation unit 16 calculates the amount of wear of the punch 1 (step S3). The amount of wear of the punch 1 is calculated based on the respective load waveforms shown in FIG.

[0075] During the period from the start of punching (time C1) to time C2 when the load reaches 0 after reaching its maximum value P0 (first period T0 in FIG. 6), that is, the period from when the punch 1 comes into contact with the workpiece 5 until the workpiece 5 is cut, the load is mainly applied to the press surface 1a of the punch 1. The amount of wear on the press surface 1a of the punch 1 is calculated based on the load waveform during the first period T0.

[0076] During the period (second period Ts0) from time C2 to the end of the punching process (time C3), i.e., the period from when the workpiece 5 is cut until the load on the punch 1 becomes zero, the load is mainly applied to the side surface 1b of the punch 1. During the second period Ts0, the cut workpiece 5 is pulled between the punch 1 and the die 2, causing a load to be applied to the side surface 1b of the punch 1. As shown in FIG. 6, during the second period Ts0, the load waveform has a vibration waveform portion in which the load changes over time, and a stable waveform portion Ps0 following the vibration waveform portion in which the load changes over time and is smaller than that of the vibration waveform portion. The wear amount of the side surface 1b of the punch 1 is calculated based on the load waveform during the second period Ts0. Note that the change in load is smaller in the stable waveform portion than in the vibration waveform portion means that the change in load per given time is smaller in the stable waveform portion than in the vibration waveform portion.

[0077] The sensors 6a to 6d are fixed to the punch 1 by the free shank 20. A gap is formed between the flange receiving portion of the free shank 20 and the flange receiving portion of the free shank holder 22. When punching of the workpiece 5 is completed, the load applied to the sensors 6a to 6d, specifically, the positive reaction force P1 in the pressing direction (Z direction) of the punch 1, becomes zero. Because there is a gap between the flange receiving portion of the free shank 20 and the flange receiving portion of the free shank holder 22, the flange receiving portion of the free shank 20 comes into contact with and separates from the flange receiving portion of the free shank holder 22 in reaction to punching the workpiece 5. The upper surface of the free shank 20 also comes into contact with and separates from the backing plate 21. The load detected at this time appears in the vibration waveform portion of Figure 6. After the reaction from punching the workpiece 5 subsides, the punch 1 reaches the bottom dead center while the workpiece 5 and the side surface 1b of the punch 1 are in contact. The load detected at this time appears in the stable waveform portion.

[0078] During the period (third period Tsb0) from time C4 (bottom dead center position 0) to when the punch 1 is pulled out of the workpiece 5 (time C5), that is, the period until the load on the punch 1 by the workpiece 5 becomes 0, the load is mainly applied to the side surface 1b of the punch 1. This is due to the punch 1 being pulled out of the workpiece 5.

[0079] Furthermore, during the third period Tsb0, when the punch 1 rises from the bottom dead center toward the top dead center, i.e., until the punch 1 is released from the workpiece 5, the flange receiving portion of the free shank 20 comes into contact with and separates from the flange receiving portion of the free shank holder 22. During this contact, a negative reaction force P2 in the pressing direction (Z direction) of the punch 1 is applied to the sensors 6a to 6d. This load appears in the graph of FIG. 6 as resistance to the punch 1 from the workpiece 5. Therefore, as shown in FIG. 6, during the third period Tsb0, the load waveform has multiple decreasing waveform portions. The amount of wear on the side surface 1b of the punch 1 is calculated based on the load waveform during the third period Tsb0.

[0080] In this embodiment, the load waveform in the third period is sometimes referred to as the “first load waveform,” and the load waveform showing the relationship between the load and time from the start to the end of punching is sometimes referred to as the “second load waveform.” The second load waveform includes the load waveform in the first period and the load waveform in the second period.

[0081] The load on the punch 1 increases as the wear of the punch 1 progresses due to repeated punching. FIG. 7 is a graph illustrating the effect of the progress of wear of the punch 1 on the load waveform. The solid line in FIG. 7 indicates the load detected by the sensor 6a when a worn punch 1 is used. FIG. 7 shows only the load detected by the sensor 6a. The dashed line in FIG. 7 indicates the load detected by the sensor 6a when a non-worn punch 1 is used. The load waveform shown by the dashed line in FIG. 7 is the same as the load waveform detected by the sensor 6a shown in FIG. 6. In reality, the load is detected by the sensor unit 6 including sensors 6a to 6d, but for convenience, only the load detected by the sensor 6a is shown.

[0082] As shown in Figure 7, as wear of punch 1 progresses, the maximum load applied to punch 1 increases from maximum value P0 to maximum value P1. Furthermore, as wear of punch 1 progresses, the time at which the load reaches 0 shifts from time C2 to time C6. Therefore, the first period T1 of the load waveform when wear of punch 1 progresses becomes longer than the first period T0 of the load waveform when punch 1 is not worn.

[0083] Furthermore, the second period Ts1 of the load waveform when the punch 1 is worn changes to the second period Ts0 of the load waveform when the punch 1 is not worn. That is, as the wear of the side surface 1b of the punch 1 progresses, the length of the second period becomes shorter. Furthermore, as the wear of the punch 1 progresses, the maximum load of the punch 1 in the stable waveform portion increases from Ps0 to Ps1.

[0084] 7, as the wear of the punch 1 progresses, the maximum value of the load applied to the punch 1 during the period from time C4 to time C5 (third period Tsb0) increases from Psb0 to Psb1. On the other hand, the length of the third period Tsb0 may not change.

[0085] Here, calculation of the wear amount of the punch 1 based on the load waveform will be described. The wear amount of the punch 1 includes a first wear amount of the press surface 1a of the punch 1 and a wear amount of the side surface 1b of the punch 1. In this embodiment, the first wear amount of the press surface 1a and the wear amount of the side surface 1b are calculated separately. The wear amount of the side surface 1b includes a second wear amount calculated based on the load waveform in the second periods Ts0 and Ts1, and a third wear amount calculated based on the load waveform in the third period Tsb0.

[0086] The first wear amount can be calculated based on the impulse of the punch 1 during the first periods T0 and T1. The impulse of the punch 1 is the product of the load applied to the punch 1 and time, and is expressed as the area of ​​the load waveform during the first periods T0 and T1.

[0087] When a workpiece 5 made of SUS301-EH material and having a thickness of 0.03 mm is punched at an instantaneous punching speed of 3 mm / s without press oil, the relationship shown in formula (1) holds between the impulse D of the punch 1 and the first wear amount a of the press surface 1 a of the punch 1. D=4×10 -5 ×a 3 -0.0005×a 2 +0.003×a+3.6 (1)

[0088] Fig. 8 is a graph showing an example of the relationship between the impulse D and the first wear amount a of the punch 1. For example, when the impulse of the punch 1 is 4 Nms, the first wear amount a can be calculated to be 23 µm from formula (1) and Fig. 8.

[0089] The second wear amount of the side surface 1b of the punch 1 can be calculated based on the maximum loads Ps0 and Ps1 of the stable waveform portion in the second periods Ts0 and Ts1.

[0090] When a workpiece 5 made of SUS301-EH material with a thickness of 0.03 mm is punched at an instantaneous punching speed of 3 mm / s without press oil, the relationship shown in formula (2) holds between the maximum load Ps of punch 1 during the second periods Ts0 and Ts1 and the second wear amount b. Ps=6.667×b 3 -2×10 -12 ×b 2 +8.3333×b+5 (2)

[0091] 9 is a graph showing an example of the relationship between the maximum load Ps of the stable waveform portion and the second wear amount b during the second periods Ts0 and Ts1. For example, when the maximum load Ps is 29 N, the second wear amount b can be calculated to be 1.25 μm using equation (2) and FIG.

[0092] The third wear amount of the side surface 1b of the punch 1 can be calculated and estimated based on the maximum loads Psb0 and Psb1 of the load of the punch 1 in the third period Tsb0.

[0093] When a workpiece 5 made of SUS301-EH material with a thickness of 0.03 mm is punched at an instantaneous punching speed of 3 mm / s without press oil, the relationship shown in equation (3) holds between the maximum load Psb of the punch 1 in the third period Tsb0 and the third wear amount c of the side surface 1b of the punch 1. Psb=20×c 3 +25×c+15 (3)

[0094] Fig. 10 is a graph showing an example of the relationship between the maximum load Psb of the load on the punch 1 during the third period Tbs0 and the third wear amount c of the side surface 1b of the punch 1. From equation (3) and Fig. 10, for example, when the maximum load Psb is 87 N, it can be calculated that the third wear amount c of the side surface 1b of the punch 1 is 1.25 µm.

[0095] As described above, the calculation unit 16 calculates the first wear amount a of the press surface 1a based on the impulse of the punch 1 during the first period T1 of the load waveform, calculates the second wear amount b of the side surface 1b based on the maximum load Ps1 of the stable waveform portion during the second period Ts1 of the load waveform, and calculates the third wear amount c of the side surface 1b based on the maximum load Psb1 of the punch 1 during the third period Tsb0 of the load waveform. In this embodiment, the stamping apparatus 100 has sensors 6a to 6d, and generates the four load waveforms shown in FIG. 6. Therefore, the first wear amount a, the second wear amount b, and the third wear amount c are calculated for each of the four load waveforms.

[0096] For example, in multi-layer punching, in which multiple workpieces 5 are stacked and punched simultaneously, the workpieces 5 tend to be cut by fracture rather than shear, which increases the load on the press surface 1a of the punch 1. For this reason, as multi-layer punching is repeated, the impulse in the first period T1 of the load waveform increases significantly. In such multi-layer punching, the first wear amount a can be calculated more accurately based on the change in the impulse in the first period T1 of the load waveform.

[0097] Similarly, in multilayer punching, the load on the side surface 1b of the punch 1 is also large. For this reason, as punching is repeated, the maximum load Ps1 in the stable waveform portion in the second period Ts1 of the load waveform increases significantly, and the maximum load Psb1 of the punch 1 in the third period Tsb0 of the load waveform increases significantly. Therefore, in multilayer punching, the second wear amount b or the third wear amount c can be calculated more accurately from changes in the maximum load Ps1 in the stable waveform portion in the second period Ts1 of the load waveform or the maximum load Psb1 of the punch 1 in the third period Tsb0 of the load waveform.

[0098] 4, after step S3 of calculating the wear amount of the punch 1, the determination unit 17 determines whether or not the wear amount of the punch 1 exceeds a threshold value (steps S41 and S42). The determination unit 17 determines whether or not grinding of the punch 1 is necessary based on whether or not each of the first wear amount a of the press surface 1a and the second wear amount b and third wear amount c of the side surface 1b exceeds a threshold value (see step S5).

[0099] Specifically, the determination unit 17 determines that grinding of the punch 1 is necessary (step S5) if the first wear amount a is greater than a predetermined first threshold (Yes in step S41) or if the second wear amount b and / or the third wear amount c are greater than a predetermined second threshold (Yes in step S42). In step S41, if at least one of the first wear amounts a for each of the four load waveforms is greater than the first threshold, the determination unit 17 determines that the first wear amount a is greater than the predetermined first threshold. In addition, in step S42, if at least one of the second wear amounts b or the third wear amounts c for each of the four load waveforms is greater than the second threshold, the determination unit 17 determines that the respective thresholds have been exceeded (Yes in step S42).

[0100] When a 5 μm burr was generated on a punched product, the wear amount was measured and found to be 23 μm for the first press surface 1 a and 1.25 μm for the second and third wear amounts for the side surface 1 b. Therefore, assuming a burr size tolerance of 5 μm, the maximum allowable first wear amount a can be set to 23 μm, and the maximum allowable second wear amount b can be set to 1.25 μm. Therefore, as an example, the first threshold value can be set to 23 μm and the second threshold value can be set to 1.25 μm. The first and second threshold values ​​are not limited to these values ​​and may be determined based on the allowable burr size. The first and second threshold values ​​may also be determined based on processing conditions such as the materials of the workpiece 5, punch 1, and die 2, the punching speed, and the presence or absence of press oil.

[0101] In punching, the press surface 1a of the punch 1 generally wears faster than the side surface 1b. This is because a greater load is applied to the press surface 1a than to the side surface 1b during punching. As shown in the load waveform in FIG. 6, the maximum load P0 in the first period T0 is greater than the maximum load Ps0 in the stable waveform portion of the second period Ts0 and the maximum load Psb0 in the third period Tsb0, which indicates that the load applied to the press surface 1a is greater than the load applied to the side surface 1b. For this reason, for example, the first threshold value may be set to a value greater than the second threshold value.

[0102] When the determination unit 17 determines that the punch 1 should be ground (Yes in step S5), the press controller 14 stops driving the press processing device 100, the punching process is interrupted, and the process of determining whether or not grinding of the punch 1 is necessary in Fig. 4 ends. When the determination unit 17 determines that none of the first wear amount, the second wear amount, and the third wear amount exceeds their respective threshold values ​​(No in step S42), the process returns to step S1 and the punching process continues.

[0103] In step S41 or step S42, if any one of the first wear amounts a calculated from the load waveforms by the sensors 6a to 6d exceeds a first threshold, it is determined that grinding of the punch 1 is necessary, and the punching process is interrupted. Similarly, if any one of the second wear amounts b or third wear amounts c calculated from the load waveforms by the sensors 6a to 6d exceeds a second threshold, it is determined that grinding of the punch 1 is necessary, and the punching process is interrupted.

[0104] [effect] The above-described embodiment provides a press working apparatus capable of accurately calculating the amount of wear of the punch 1. In the press working apparatus 100, the sensor unit 6 detects the load applied to the punch 1. A load waveform is generated based on the detected load. The load waveform has a first period (T0, T1) during which the load is applied primarily to the press surface 1a of the punch 1, a second period (Ts0, Ts1) during which the load is applied primarily to the side surface 1b of the punch 1, and a third period (Tsb0) during which the load is applied primarily to the side surface 1b of the punch 1. The amount of wear of the punch 1 is calculated based on the maximum value of the load in the load waveform and the change in the time it takes to reach the maximum value. More specifically, the first amount of wear (a) of the press surface 1a of the punch 1 is calculated based on the waveform for the first period (T0, T1). The second amount of wear (b) of the side surface 1b of the punch 1 is calculated based on the waveform for the second period (Ts0, Ts1). The third amount of wear (c) of the side surface 1b of the punch 1 is calculated based on the waveform for the third period (Tsb0). In this way, the amount of wear on each of the press surface 1a and the side surface 1b can be calculated from the load waveform, so the amount of wear on the punch 1 can be calculated with high accuracy.

[0105] Furthermore, since the necessity of grinding the punch is determined based on the first wear amount a and the second wear amount b or the third wear amount c of the punch 1, the accuracy of determining the necessity of grinding can be improved.

[0106] In the above embodiment, the workpiece 5 is made of SUS301-EH material, but the material is not limited to this. The workpiece 5 can be made of various metal materials.

[0107] In the above embodiment, an example in which four sensors 6a to 6d are arranged on punch 1 has been described, but the present invention is not limited to this. The number of sensors constituting sensor unit 6 may be one or more.

[0108] In the above-described embodiment, the punch 1 has a circular pressing surface 1a, but the present invention is not limited to this. The shape of the pressing surface 1a is not limited to a circle, and may be any shape such as a polygon or an ellipse.

[0109] Furthermore, in the above-described embodiment, an example has been described in which it is determined that the punch 1 should be ground when the first wear amount a of the press surface 1a is greater than the first threshold value, but the present invention is not limited to this. As shown in the graph of Fig. 8, based on the relationship between the impulse D of the punch 1 and the first wear amount a of the press surface 1a, it may be determined that the punch 1 should be ground when the impulse D of the punch 1 is greater than a predetermined threshold value.

[0110] In the above-described embodiment, an example has been described in which it is determined that the punch 1 should be ground when the second wear amount b of the side surface 1b is greater than the second threshold value, but the present invention is not limited to this. As shown in the graph of Fig. 9, it may also be determined that the punch 1 should be ground when the maximum load in the stable waveform portion of the second period is greater than a predetermined threshold value.

[0111] Furthermore, in the above-described embodiment, an example has been described in which it is determined that the punch 1 should be ground when the third wear amount c of the side surface 1b is greater than the second threshold value, but the present invention is not limited to this. As shown in the graph of Fig. 10, it may also be determined that the punch 1 should be ground when the maximum load of the punch 1 in the third period is greater than a predetermined threshold value. [Industrial Applicability]

[0112] The press working device of the present disclosure is useful as a device for punching any workpiece used in home appliances, medical equipment, etc. [Explanation of symbols]

[0113] 1 punch 1a Press surface 1b side 2 Die 2a Hollow part 3 Stripper plate 4 Die Plate 5 Work 6 Sensor Unit 6a~6d Sensors 7 slides 8 Bolster 9 Press unit body 10 shaft 11 Servo motor 13 Gap sensor 14 Press Controller 15 Sensor Controller 16 Arithmetic section 17 Judgment section 18 Control Unit 20 Free Shank 21 Back King Plate 22 Free shank holder 100 Press processing equipment

Claims

1. A press processing device that performs punching on a workpiece, A punch that moves in a pressing direction and has a pressing surface facing the workpiece and a side surface connected to the pressing surface; a die having a hollow portion into which the punch is inserted and on which the workpiece is placed; a sensor unit for detecting a load applied to the punch; a control unit that controls the punch, the die, and the sensor unit; Equipped with The control unit generating a first load waveform indicating a relationship between the load and time after punching based on a change over time of the load detected by the sensor unit; calculating a wear amount of the side surface of the punch based on a portion of the first load waveform corresponding to a period during which the punch is rising from the bottom dead center; Press processing equipment.

2. the control unit generates the first load waveform after the punching process based on the compressive load applied to the punch detected by the sensor unit. The press working device according to claim 1 .

3. the control unit calculates the amount of wear on the side surface of the punch based on a waveform of the first load waveform in a time interval from a time when the load is first detected to a time when the load reaches zero. The press working device according to claim 1 .

4. The control unit calculates the amount of wear on the side surface of the punch based on a first load waveform in a time interval from when the punch starts to rise to when the punch passes through the hole in the workpiece. The press working device according to claim 1 .

5. a gap sensor for detecting the position of the punch; The control unit detects, based on the detection result of the gap sensor, that the punch is at the bottom dead center and that the punch has passed through the hole in the workpiece. The press working device according to claim 4.

6. a wear amount of the side surface of the punch is a third wear amount; The control unit further generating a second load waveform indicating a relationship between the load and time from the start to the end of the punching process based on the change over time of the load detected by the sensor unit; calculating a first wear amount of the press surface of the punch based on the second load waveform during a first period from a start time of the punching process to a time when the load reaches a maximum value and then reaches zero; calculating a second wear amount of the side surface of the punch based on a portion of the second load waveform corresponding to a second period from the end of the first period to the end of the punching process; The press working device according to claim 1 .

7. the control unit calculates an impulse applied to the punch during the first period based on the second load waveform, and calculates the first wear amount based on the calculated impulse. The press working device according to claim 6.

8. the second load waveform has, in the second period, a vibration waveform portion in which the load changes over time, and a stable waveform portion in which the load changes over time smaller than the vibration waveform portion, The control unit calculates the second wear amount based on the maximum load in the stable waveform portion. The press working device according to claim 6.

9. The stamping device according to claim 6 , wherein the control unit determines that it is necessary to grind the pressing surface of the punch when the first wear amount is greater than a predetermined first threshold value.

10. 10. The press processing device according to claim 9, wherein the control unit determines that it is necessary to grind the side surface of the punch when the second wear amount and / or the third wear amount is greater than a predetermined second threshold value.

11. The first threshold is greater than the second threshold. The press working device according to claim 10.

12. the sensor unit includes a plurality of sensors that detect the load; The press working device according to claim 1 .

13. Further, a gap sensor is provided to detect the position of the punch. The press working device according to claim 1 .

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