Press working apparatus

Abstract

A press working apparatus of the present disclosure is a press working apparatus that performs press working on a workpiece, including a punch including a press surface and a side surface connected to the press surface, a die on which the workpiece is placed, the die including a hollow portion in which the punch is to be inserted, a position sensor that detects a position of the punch, a vibration sensor that detects a vibration of the die, and a controller that controls the punch, the die, the position sensor, and the vibration sensor, wherein the controller generates a vibration waveform indicating a relationship between the vibration detected by the vibration sensor and a time after the punch reaches a bottom dead center, and calculates a first wear amount of the side surface of the punch based on the vibration waveform.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a press working apparatus.BACKGROUND ART

[0002] In press working for punching a plate-shaped workpiece, there has been known a device for measuring working resistance generated when the workpiece is punched.

[0003] In a punching characteristic measurement apparatus described in PTL 1, a temporal change in deformation of a frame at the time of punching is converted into an electric signal to measure a punching force.CITATION LISTPatent Literature

[0004] PTL 1: Unexamined Japanese Patent Publication No. S62-40938SUMMARY OF THE INVENTION

[0005] A press working apparatus according to one aspect of the present disclosure is a press working apparatus that performs press working on a workpiece, the press working apparatus including: a punch including a press surface and a side surface connected to the press surface; a die on which the workpiece is placed, the die including a hollow portion in which the punch is to be inserted; a position sensor that detects a position of the punch; a vibration sensor that detects a vibration of the die; and a controller that controls the punch, the die, the position sensor, and the vibration sensor, wherein the controller: generates a vibration waveform indicating a relationship between the vibration detected by the vibration sensor and a time after the punch reaches a bottom dead center; and calculates a first wear amount of the side surface of the punch based on the vibration waveform.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a schematic diagram illustrating a press working apparatus according to a first exemplary embodiment of the present disclosure.

[0007] FIG. 2 is a schematic diagram illustrating a bottom dead center state of a punch of the press working apparatus in FIG. 1.

[0008] FIG. 3 is a top view illustrating a vibration sensor of the press working apparatus in FIG. 1.

[0009] FIG. 4 is a flowchart for describing processing of calculating the wear amount of a side surface of the punch in the press working apparatus.

[0010] FIG. 5A is a schematic diagram illustrating a step of punching a workpiece with a press working apparatus.

[0011] FIG. 5B is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0012] FIG. 5C is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0013] FIG. 5D is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0014] FIG. 5E is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0015] FIG. 5F is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0016] FIG. 5G is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0017] FIG. 6 is a graph illustrating a relationship between a load (left vertical axis) detected by four vibration sensors, a position (right vertical axis) from a bottom dead center of punch 1, and time in punching.

[0018] FIG. 7A is a graph illustrating a vibration waveform generated when wear of the punch of FIG. 6 has not progressed.

[0019] FIG. 7B is a graph illustrating a vibration waveform generated when wear of the punch of FIG. 6 has progressed.

[0020] FIG. 8 is a graph illustrating an example of a relationship between maximum value Asb of vibration of a die and a first wear amount of a side surface of the punch in period Tsb0.

[0021] FIG. 9 is a schematic diagram illustrating a press working apparatus according to a second exemplary embodiment.

[0022] FIG. 10 is a schematic diagram illustrating a state where a punch of the press working apparatus in FIG. 9 is at a bottom dead center.

[0023] FIG. 11 is a top view illustrating a load sensor of the press working apparatus in

[0024] FIG. 9.

[0025] FIG. 12 is a flowchart for describing processing of calculating the wear amount of a side surface of the punch in the press working apparatus in FIG. 9.

[0026] FIG. 13 is a graph in which load waveforms generated based on loads detected by four load sensors and vibration waveforms generated based on vibrations detected by the four vibration sensors illustrated in FIG. 6 are arranged.

[0027] FIG. 14 is a graph in which a load waveform and a vibration waveform generated when the wear of the punch has not progressed are superimposed on a load waveform and a vibration waveform generated when the wear of the punch has progressed in FIG. 13.

[0028] FIG. 15 is a graph illustrating an example of a relationship between maximum value Ps of the load applied to the punch and a second wear amount of the side surface of the punch in period Ts0.

[0029] FIG. 16 is a graph illustrating an example of a relationship between maximum value Psb of the load of the punch and a third wear amount of the side surface of the punch in period Tsb0.DESCRIPTION OF EMBODIMENTBackground to Present Disclosure

[0030] Press working of performing punching on a plate-shaped workpiece is generally a technique capable of obtaining a predetermined shape by pressing a workpiece loaded on a die with a stripper, pushing a part of the workpiece into the die with a punch, and performing punching. Press working by punching is generally used in a wide variety of fields such as home appliances, precision machines, and automobile parts.

[0031] In press working by punching, as in a punching characteristic measurement apparatus described in PTL 1, there is known a punching characteristic measurement apparatus that measures a punching force at the time of punching by converting a temporal change in frame deformation at the time of punching into an electric signal.

[0032] In the punching characteristic measurement apparatus described in PTL 1, frame deformation at the time of punching is converted into an electric signal, and a punching force at the time of punching is measured. The punching force is a resistance force when a laminate is punched with a mold. Since the punching force increases as the mold wears, it has been studied to use the punching force to calculate the wear state of the mold and determine the necessity of re-polishing the tool.

[0033] However, in the punching characteristic measurement apparatus described in PTL 1, the deformation of the frame at a position more distant than the working position of the mold is detected, there is a problem that the wear state of the mold cannot be calculated with high accuracy. The punching characteristic measurement apparatus described in PTL 1 still has room for improvement in terms of improvement in calculation accuracy of the wear amount of the tool.

[0034] The inventor(s) of the present invention have studied a press working apparatus capable of accurately calculating the wear amount of the punch, and have reached the following disclosure. The present disclosure provides a press working apparatus capable of improving calculation accuracy of a wear amount of a punch.First Exemplary Embodiment[Overall Configuration]

[0035] FIG. 1 is a schematic diagram illustrating press working apparatus 100 according to a first exemplary embodiment of the present disclosure. FIG. 2 is a schematic view illustrating a bottom dead center state of punch 1 of press working apparatus 100 of FIG. 1. FIG. 3 is a top view illustrating vibration sensor 19 of press working apparatus 100 of FIG. 1. In FIGS. 2 to 3, some components are not illustrated. With reference to FIGS. 1 to 3, press working apparatus 100 according to the present exemplary embodiment will be described.

[0036] The X-Y-Z coordinate system illustrated in each drawing is provided to facilitate the understanding of the exemplary embodiments, and is not intended to limit the scope of the exemplary embodiments in any way. In each drawing, an X direction is a width direction of press working apparatus 100, a Y direction is a depth direction of press working apparatus 100, and a Z direction is a height direction of press working apparatus 100.

[0037] Press working apparatus 100 is an apparatus that performs punching on plate-shaped workpiece 5, and the apparatus is, for example, a servo screw press machine that can be controlled with high accuracy. In the present exemplary embodiment, press working apparatus 100 includes press apparatus body 9 and controller 18. Press apparatus body 9 includes punch 1, die 2, position sensor 13, and vibration sensor 19.

[0038] Press apparatus body 9 and controller 18 may be accommodated in one housing. Alternatively, controller 18 may be a control circuit such as a CPU mounted on an apparatus different from press apparatus body 9, for example, an electronic device or the like. Even when controller 18 is mounted on an apparatus different from press apparatus body 9, press apparatus body 9 and controller 18 are collectively referred to as “press working apparatus”. Alternatively, when controller 18 is mounted on an apparatus different from press apparatus body 9, press apparatus body 9 and controller 18 may be collectively referred to as “press working system”.

[0039] Press working apparatus 100 includes punch 1, die 2, position sensor 13, vibration sensor 19, and controller 18.

[0040] As illustrated in FIG. 1, press apparatus body 9 of press working apparatus 100 has an upper die including punch 1 attached to slide 7 and a lower die including die 2 attached to bolster 8. Press apparatus body 9 rotates ball screw 12 connected to servomotor 11 based on a command from controller 18 to vertically drive slide 7 in a pressing direction (Z direction) at a predetermined speed along shaft 10. Workpiece 5 can be punched through such an operation of press apparatus body 9.<Punch>

[0041] Punch 1 is a tool for punching workpiece 5 by moving in the pressing direction (Z direction). As illustrated in FIG. 2, punch 1 has press surface 1a facing workpiece 5 and side surface 1b connected to press surface 1a. Punch 1 is attached to slide 7 together with stripper plate 3 that presses workpiece 5 against die 2 at the time of punching. With the movement of slide 7, punch 1 is pressed against workpiece 5, and punching is performed. In the present exemplary embodiment, punch 1 has circular press surface 1a. Thus, workpiece 5 can be punched into a circular shape.

[0042] In the present exemplary embodiment, punch 1 is formed in a columnar shape having circular press surface 1a with a diameter of 4.5 mm, and a round hole is punched into workpiece 5. Punch 1 is made of, for example, a cemented carbide material. Examples of the cemented carbide material include an artificial metal (alloy) in which nine carbides of tungsten (W), chromium (Cr), molybdenum (Mo), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), and tantalum (Ta) are bonded with an Fe-group metal (Fe, Co, or Ni). As the cemented carbide material, for example, an alloy corresponding to VM-40 of the cemented carbide tool standard (CIS) can be adopted.<Die>

[0043] As illustrated in FIG. 2, workpiece 5 is placed on die 2 at the time of punching. Hollow portion 2a into which punch 1 is inserted is formed in die 2. Hollow portion 2a is a through hole penetrating die 2 in the Z direction. Die 2 is attached to bolster 8 together with die plate 4 for holding die 2. Similarly to punch 1, die 2 is made of, for example, a cemented carbide material. As illustrated in FIG. 3, vibration sensor 19 that detects vibration of die 2 is disposed in die 2.<Position Sensor>

[0044] Position sensor 13 is a sensor that detects the position of punch 1. More specifically, position sensor 13 can detect that punch 1 illustrated in FIG. 2 is in the lowest possible position, that is, in a bottom dead center state. Further, position sensor 13 can detect how much punch 1 has risen from the bottom dead center state. In the present exemplary embodiment, the degree of rise from the bottom dead center state is detected as the position of punch 1. Position sensor 13 can be made up of, for example, a variation sensor that measures a minute distance interval from a measurement object in a non-contact manner.

[0045] Position sensor 13 can be mounted in any position of the lower die of press working apparatus 100 including die 2, die plate 4, and bolster 8, for example. Position sensor 13 detects contact between position sensor 13 and the upper mold including punch 1, stripper plate 3, and slide 7 to detect that punch 1 is in the bottom dead center state, and detects the position of punch 1 by measuring the distance between the upper mold and position sensor 13.

[0046] Based on the position of punch 1 detected by position sensor 13, the start timing of the detection of the vibration of die 2 with vibration sensor 19 can be determined. Specifically, the detection start timing can be determined based on the gap of position sensor 13 and the position from the bottom dead center of punch 1 so that the vibration of die 2 can be detected at the same timing at the shot time of the punching. Thus, position sensor 13 can be used as a trigger for vibration detection of die 2 with vibration sensor 19. Further, for example, by disposing position sensor 13 at each of the four corners of the lower mold, whether the upper mold and the lower mold are disposed in parallel can also be detected.<Vibration Sensor>

[0047] Vibration sensor 19 is a sensor that detects vibration of die 2. Vibration sensor 19 detects the vibration transmitted from workpiece 5 to die 2 when workpiece 5 is punched. As illustrated in FIG. 3, in the present exemplary embodiment, vibration sensor 19 includes four vibration sensors 19a to 19d. In the present exemplary embodiment, four vibration sensors 19a to 19d are disposed at equal intervals around hollow portion 2a of die 2. Specifically, vibration sensor 19a and vibration sensor 19b are disposed symmetrically in the X direction, vibration sensor 19c and vibration sensor 19d are disposed symmetrically in the Y direction, and four vibration sensors 19a to 19d are disposed concentrically. By disposing four vibration sensors 19a to 19d like this, which portion of punch 1 is worn is more easily grasped.<Controller>

[0048] Controller 18 controls punch 1, die 2, position sensor 13, and vibration sensor 19. In the present exemplary embodiment, controller 18 includes press controller 14, sensor controller 15, calculation unit 16, and determination unit 17. Controller 18 includes a digital circuit such as a microcomputer, a CPU, an MPU, a GPU, a DSP, an FPGA, or an ASIC, for example.

[0049] Press controller 14 drives servomotor 11 to rotate ball screw 12, thereby vertically driving slide 7 in the pressing direction (Z direction) at a predetermined speed.

[0050] Sensor controller 15 is electrically connected to position sensor 13 and vibration sensor 19 and outputs detection values of sensors 13 and 19 to calculation unit 16.

[0051] Calculation unit 16 generates a vibration waveform indicating the relationship between the vibration of die 2 and the time after punch 1 reaches the bottom dead center based on the vibration detected by vibration sensor 19, and calculates a first wear amount of side surface 1b of punch 1 based on the vibration waveform. When the punching is repeated, punch 1 gradually wears. In the present exemplary embodiment, calculation unit 16 calculates the wear amount of side surface 1b of punch 1. The generation of the vibration waveform and the calculation of the wear amount will be described later in detail.

[0052] Determination unit 17 determines whether polishing of punch 1 is necessary based on the first wear amount of side surface 1b calculated by calculation unit 16. When the wear amount of punch 1 has increased, the accuracy of the punching dimension of workpiece 5 gradually deteriorates. Thus, it is preferable to polish punch 1 at a timing when the wear amount has exceeded a predetermined threshold value. When determination unit 17 determines to polish punch 1, determination unit 17 outputs a signal to press controller 14 to interrupt the punching. After receiving the signal, press controller 14 stops servomotor 11 and interrupts the punching. Determination unit 17 is not an essential component, and controller 18 does not have to determine whether polishing of punch 1 is necessary.<Workpiece>

[0053] Workpiece 5 is a plate-shaped material to be worked by press working apparatus 100. A plurality of workpieces 5 are conveyed in the X direction or the Y direction by a conveyance unit (not illustrated) in accordance with the pressing operation of press apparatus body 9, and the workpieces 5 are sequentially subjected to punching.

[0054] In the present exemplary embodiment, workpiece 5 is made of SUS301-EH material which is a steel type classified as austenitic stainless steel. The SUS301-EH material is, for example, a material used as a mainspring or a spring of an automobile component. In the present exemplary embodiment, the thickness of workpiece 5 is 0.03 mm, the hardness is 529 HV, and the tensile strength is 1,679 N / mm2.[Calculation of Wear Amount]

[0055] FIG. 4 is a flowchart for describing processing of calculating the wear amount of side surface 1b of punch 1 in press working apparatus 100. The calculation of the wear amount of side surface 1b of punch 1 will be described with reference to FIG. 4.

[0056] When press working apparatus 100 starts punching, vibration sensor 19 detects vibration of die 2 in step S1. In the present exemplary embodiment, punching is started in press working apparatus 100, and detection of vibration of die 2 is started by vibration sensor 19 when position sensor 13 has detected that punch 1 has reached the bottom dead center. In the present exemplary embodiment, the vibration of die 2 is detected by each of four vibration sensors 19a to 19d.

[0057] In step S2, calculation unit 16 generates a vibration waveform indicating a relationship between vibration of die 2 and time. The vibration of die 2 detected in step S1 is output to calculation unit 16 by sensor controller 15 of controller 18, and a vibration waveform is generated by calculation unit 16.

[0058] FIGS. 5A to 5G are schematic diagrams illustrating steps of punching workpiece 5 with press working apparatus 100. FIG. 6 is a graph illustrating a relationship between a load (left vertical axis) detected by four vibration sensors 19a to 19d, a position (right vertical axis) from a bottom dead center of punch 1, and time in punching. FIG. 6 is a graph in which four vibration waveforms generated based on the vibration of die 2 detected by each of four vibration sensors 19a to 19d are superimposed. FIG. 6 illustrates the vibration waveform formed when side surface 1b of punch 1 has not worn much yet.

[0059] When the punching has started, punch 1 lowers in the Z direction from the top dead center state, and punch 1 comes into contact with workpiece 5 as illustrated in FIG. 5A. The top dead center state refers to a state in which punch 1 is at the highest possible position. In FIG. 6, time C1 indicates the time when punch 1 starts to come into contact with workpiece 5.

[0060] When punch 1 comes into contact with workpiece 5, punching to workpiece 5 is started by punch 1 as illustrated in FIG. 5B. Thereafter, as illustrated in FIG. 5C, a part of workpiece 5 is cut off by punch 1, and the cutting of workpiece 5 is completed. In the graph of FIG. 6, time C2 indicates the time when the cutting of workpiece 5 is completed by punch 1. At the time of punching workpiece 5 with punch 1, positive reaction force P1 in the −Z direction illustrated in FIG. 2 is applied to punch 1.

[0061] When the cutting of workpiece 5 is completed, as illustrated in FIG. 5D, punch 1 pushes a portion cut from workpiece 5 into the hollow portion of die 2. At this time, the load applied to punch 1 changes from positive reaction force P1 to negative reaction force P2 in the direction (+Z direction) opposite to the direction of positive reaction force P1 illustrated in FIG. 2. After the cutting of workpiece 5 is completed, positive reaction force P1 and negative reaction force P2 are alternately applied to punch 1, and thus punch 1 vibrates. The vibration of punch 1 is transmitted to die 2 via workpiece 5. Region R1 in FIG. 6 illustrates the detected vibration of die 2 after the cutting of workpiece 5 is completed.

[0062] Thereafter, as illustrated in FIG. 5E, punch 1 reaches the bottom dead center. In FIG. 6, the time when punch 1 has reached the bottom dead center is time C3. As illustrated in region R2 in FIG. 6, vibration may be detected before punch 1 reaches the bottom dead center. This vibration is generated because of transmission of vibration from workpiece 5 to die 2 when workpiece 5 cut from the tip of punch 1 is separated and falls.

[0063] When punch 1 reaches the bottom dead center at time C3, punch 1 stops at the bottom dead center until time C4. At time C4, punch 1 starts to rise from the bottom dead center. When punch 1 rises from the bottom dead center, punch 1 and workpiece 5 may interfere with each other as illustrated in FIG. 5F, and vibration is transmitted from punch 1 to die 2 via workpiece 5. This vibration continues until punch 1 rises and comes out of the hollow portion of die 2 completely, as illustrated in FIG. 5F. The vibration of die 2 generated when punch 1 rises from the bottom dead center is illustrated in region R3 in FIG. 6. As illustrated in FIG. 5G, when punch 1 completely comes out of hollow portion 2a of die 2, the vibration of die 2 is not detected.

[0064] When the wear amount of punch 1 is small, for example, when punch 1 has just been polished, the vibration waveforms of respective vibration sensors 19a to 19d have substantially the same shape as illustrated in FIG. 6. The vibration waveforms of vibration sensors 19a to 19d may be slightly different because of a slight difference in clearance between punch 1 and die 2.

[0065] In FIG. 6, for the sake of explanation, the vibration waveform from when punch 1 starts to lower from the top dead center to when punch 1 reaches the bottom dead center and then returns to the top dead center again is illustrated. However, as described later, in the present exemplary embodiment, it is sufficient that at least the vibration waveform after punch 1 reaches the bottom dead center is generated.

[0066] The description returns to FIG. 4. After calculation unit 16 generates the vibration waveform in step S2, calculation unit 16 calculates the wear amount of side surface 1b of punch 1 in step S3. The wear amount of side surface 1b of punch 1 is calculated based on each vibration waveform illustrated in FIG. 6.

[0067] When punch 1 rises, as illustrates in FIG. 5F, side surface 1b of punch 1 and workpiece 5 interfere with each other. Thus, the vibration of punch 1 is transmitted to die 2 via workpiece 5. As side surface 1b of punch 1 wears because of repeating punching, the vibration of die 2 increases.

[0068] As the wear of side surface 1b of punch 1 progresses, the vibration waveform of die 2 generated when punch 1 is pulled out from hollow portion 2a of die 2 changes after punch 1 reaches the bottom dead center. Thus, in the present exemplary embodiment, the first wear amount of side surface 1b of punch 1 is calculated from time C4 to time C5, that is, using a vibration waveform indicating a change in vibration in a predetermined period from when punch 1 starts to rise from the bottom dead center. The predetermined period from when the punch 1 starts to rise from the bottom dead center can be a period from when punch 1 starts to rise from the bottom dead center at time C4 to when punch 1 completely comes out of hollow portion 2a of die 2 at time C5. Alternatively, the predetermined period may be a time from time C4 until punch 1 reaches the top dead center.

[0069] FIG. 7A is a graph illustrating a vibration waveform generated when wear of punch 1 of FIG. 6 has not progressed. FIG. 7B is a graph illustrating a vibration waveform generated when wear of punch 1 of FIG. 6 has progressed.

[0070] As illustrated in FIG. 7A, the maximum value of the vibration of die 2 in period Tsb0 is maximum value Asb0. As illustrated in FIG. 7B, when the wear of side surface 1b of punch 1 has progressed, the maximum value of the vibration of die 2 in period Tsb0 becomes maximum value Asb1. As illustrated in FIGS. 6 to 7B, vibration sensor 19 detects vibration larger than 0 and vibration smaller than 0 depending on the direction of vibration. Thus, maximum value Asb of vibration may be the maximum value of the absolute value of vibration in period Tsb0.

[0071] When the wear of side surface 1b has progressed, maximum value Asb1 of the vibration of die 2 in period Tsb0 becomes larger than maximum value Asb0 of the vibration of die 2 when the wear of side surface 1b has not progressed. In this manner, the maximum value of the vibration of die 2 in period Tsb0 changes depending on the state of progress of the wear of side surface 1b. Thus, calculation unit 16 can calculate first wear amount d of side surface 1b of punch 1 based on the maximum value of the vibration of die 2 in period Tsb0.

[0072] For example, when workpiece 5 is a stainless-steel plate made of SUS301-EH material having a thickness of 0.03 mm, punching is performed under the conditions of an instantaneous speed of punch 1 at the time of punching of 3 mm / s and with no press oil. Under the conditions, the relationship of Formula (1) shown below is established between maximum value Asb of the vibration of die 2 in period Tsb0 and first wear amount d of side surface 1b of punch 1.Asb=20×d3+50×d2+20×d+50(1)

[0073] FIG. 8 is a graph illustrating an example of the relationship between maximum value Asb of vibration of die 2 and first wear amount d of side surface 1b of punch 1 in period Tsb0. According to Formula (1) and FIG. 8, for example, when maximum value Asb of the vibration of die 2 in period Tsb0 is 180 m / s2, first wear amount d of side surface 1b of punch 1 is calculated to be 1.20 μm.

[0074] As described above, calculation unit 16 calculates first wear amount d of side surface 1b of punch 1 based on maximum value Asb of the vibration of die 2 in period Tsb0 in the vibration waveform. In the present exemplary embodiment, press working apparatus 100 includes four vibration sensors 19a to 19d, and four vibration waveforms illustrated in FIG. 6 are generated. Thus, first wear amount d is calculated for each of the four vibration waveforms. Calculation unit 16 can calculate the wear position of punch 1 by calculating first wear amount d for each of the four vibration waveforms. For example, first wear amount d with respect to the vibration waveform generated by the detection value of vibration sensor 19a indicates the wear amount of the portion of side surface 1b of punch 1 facing vibration sensor 19a when punch 1 reaches the bottom dead center. In the present exemplary embodiment, four vibration sensors 19a to 19d are disposed. Thus, it is possible to specify a portion where wear has progressed or a portion where wear has not progressed in side surface 1b of punch 1 to some extent.

[0075] For example, in multilayer punching in which a plurality of workpieces 5 are stacked in multiple layers and simultaneously punched, the load on the side surface of punch 1 increases. Thus, when side surface 1b of punch 1 has worn with repeating punching, maximum value Asb of the vibration of die 2 in period Tsb0 significantly increases. Therefore, by using maximum value Asb of the vibration of die 2 in period Tsb0, first wear amount d of side surface 1b of punch 1 can be accurately calculated.

[0076] The description returns to FIG. 4. After first wear amount d of side surface 1b of punch 1 is calculated, determination unit 17 determines in step S4 whether polishing of punch 1 is necessary.

[0077] When first wear amount d of side surface 1b of punch 1 has exceeded a first threshold value, determination unit 17 determines that polishing of punch 1 is necessary. In the present exemplary embodiment, when at least one of first wear amounts d calculated by the four vibration waveforms is larger than the first threshold value, determination unit 17 determines to polish punch 1.

[0078] For example, when a burr of 5 μm was generated in the punched product, first wear amount d of side surface 1b of punch 1 was 1.20 μm. Assuming that the allowable range of the size of the burr is 5 μm, the maximum value of allowable first wear amount d of side surface 1b can be defined as 1.20 μm. Thus, the first threshold value can be set to 1.20 μm. The magnitude of the first threshold value may be set based on the magnitude of the allowable burr. Alternatively, the magnitude of the first threshold value may be set based on working conditions such as materials of workpiece 5, punch 1, and die 2, a punching speed, and presence or absence of press oil.

[0079] When determination unit 17 has determined in step S4 that polishing of punch 1 is necessary, the driving of press working apparatus 100 is stopped by press controller 14, the punching is interrupted, and the processing ends.

[0080] When determination unit 17 has determined in step S4 that polishing of punch 1 is not necessary, the punching continues, and the processing returns to step S1.Effects

[0081] According to the exemplary embodiment described above, it is possible to provide press working apparatus 100 capable of accurately calculating the wear amount of side surface 1b of punch 1. In press working apparatus 100, the vibration of die 2 is detected by vibration sensor 19. A vibration waveform is generated based on the detected vibration. The vibration waveform is a waveform indicating the relationship between the vibration detected by vibration sensor 19 and the time after punch 1 reaches the bottom dead center. First wear amount d of side surface 1b of punch 1 is calculated based on the vibration waveform. When punch 1 rises toward the top dead center after reaching the bottom dead center, a load is applied to side surface 1b of punch 1. Thus, by using the vibration waveform generated after punch 1 reaches the bottom dead center, first wear amount d of side surface 1b of punch 1 can be accurately calculated.

[0082] In the exemplary embodiment described above, an example in which press working apparatus 100 includes four vibration sensors 19a to 19d has been described, but the present disclosure is not limited to this configuration. The number of vibration sensors 19 may be one or two or more.

[0083] In the exemplary embodiment described above, an example has been described in which controller 18 includes determination unit 17, and determination unit 17 determines whether polishing of punch 1 is necessary based on first wear amount d calculated by calculation unit 16. However, the present disclosure is not limited to this configuration. Controller 18 does not have to include determination unit 17 as long as calculation unit 16 can calculate first wear amount d of side surface 1b of punch 1 based on the vibration waveform with vibration sensor 19 in press working apparatus 100.

[0084] In the exemplary embodiment described above, an example in which the material of workpiece 5 is the SUS301-EH material has been described, but the present disclosure is not limited to this configuration. Workpiece 5 can be made of various metal materials. The thickness of workpiece 5 is not limited to 0.03 mm but may be any thickness.

[0085] In the exemplary embodiment described above, an example in which punch 1 has circular press surface 1a has been described, but the present disclosure is not limited to this configuration. The shape of press surface 1a is not limited to a circular shape, but may be any shape such as a polygonal shape or an elliptical shape.Second Exemplary Embodiment

[0086] With reference to FIGS. 9 to 11, a second exemplary embodiment will be described. The second exemplary embodiment includes components identical or equivalent to those in the first exemplary embodiment, the components being denoted by the same reference marks as those in the first exemplary embodiment. The description already given for the first exemplary embodiment is omitted for the second exemplary embodiment.

[0087] FIG. 9 is a schematic diagram illustrating press working apparatus 100A according to the second exemplary embodiment. FIG. 10 is a schematic diagram illustrating a state in which punch 1 of press working apparatus 100A of FIG. 9 is at the bottom dead center. FIG. 11 is a top view illustrating load sensor 6 of press working apparatus of FIG. 9. The second exemplary embodiment is different from the first exemplary embodiment in that press working apparatus 100A includes load sensor 6 that detects a load applied to punch 1. In addition, the second exemplary embodiment is different from the first exemplary embodiment in that the wear amount of side surface 1b of punch 1 is calculated based on the load waveform indicating the relationship between the load detected by the load sensor and time.

[0088] As illustrated in FIGS. 9 and 10, press working apparatus 100A includes load sensor 6. Load sensor 6 is a sensor that detects a load applied to punch 1. In the present exemplary embodiment, load sensor 6 detects a load applied in the pressing direction (Z direction) of punch 1 when workpiece 5 is punched with punch 1. As illustrated in FIG. 10, the load applied in the pressing direction of punch 1 includes positive reaction force P1 in the −Z direction and negative reaction force P2 in the +Z direction. Positive reaction force P1 is a load applied to punch 1 mainly when punch 1 punches workpiece 5 (FIGS. 5A to 5C). Negative reaction force P2 is a load applied to punch 1 mainly when punch 1 rises from the bottom dead center (FIGS. 5D to 5F).

[0089] In the present exemplary embodiment, to detect the load applied to punch 1 with load sensor 6, punch 1, load sensor 6, and free shank 20 on the upper side of load sensor 6 are fixed by a fastening bolt (not illustrated) or the like. Thus, load sensor 6 can detect both positive reaction force P1 in the −Z direction when workpiece 5 is punched out and negative reaction force P2 in the +Z direction when punch 1 rises from the bottom dead center.

[0090] As illustrated in FIG. 11, in the present exemplary embodiment, load sensor 6 includes four load sensors 6a to 6d. In the present exemplary embodiment, load sensor 6a and load sensor 6b are disposed symmetrically in the Y direction, and load sensor 6c and load sensor 6d are disposed symmetrically in the X direction. In the present exemplary embodiment, four load sensors 6a to 6d are disposed concentrically at equal intervals. The disposition of four sensors 6a to 6d like this makes it easier to grasp which part of punch 1 is worn.

[0091] As illustrated in FIG. 9, in the present embodiment, sensor controller 15 of controller 18 is electrically connected to load sensor 6, position sensor 13, and vibration sensor 19, and the sensor controller 15 outputs detection values of respective sensors 6, 13, and 19 to calculation unit 16 of controller 18.

[0092] In addition to the vibration waveform described in the first exemplary embodiment, calculation unit 16 generates a load waveform indicating the relationship between the load detected by load sensor 6 and the time from the start of working based on the load of punch 1 detected by load sensor 6. Calculation unit 16 calculates first wear amount d of the side surface of punch 1 based on the vibration waveform. Calculation unit 16 calculates second wear amount b of side surface 1b of punch 1 based on the load waveform in the time from when the working on workpiece 5 is completed to when punch 1 reaches the bottom dead center in the generated load waveform. Further, calculation unit 16 calculates third wear amount c of side surface 1b of punch 1 based on the load waveform in a predetermined period from when punch 1 starts to rise from the bottom dead center in the generated load waveform.

[0093] Determination unit 17 determines whether polishing of punch 1 is necessary based on at least one of first wear amount d, second wear amount b, and third wear amount c of side surface 1b calculated by calculation unit 16. For example, when at least one of second wear amount b and third wear amount c has exceeded the second threshold value, determination unit 17 may determine that polishing of punch 1 is necessary. Alternatively, determination unit 17 may determine that polishing of punch 1 is necessary when the largest value among first wear amount d, second wear amount b, and third wear amount c has exceeded a predetermined threshold value.[Calculation of Wear Amount]

[0094] FIG. 12 is a flowchart for describing processing of calculating the wear amount of side surface 1b of punch 1 in press working apparatus 100A of FIG. 9. The calculation of the wear amount of side surface 1b of punch 1 in the present exemplary embodiment will be described with reference to FIG. 12. Step S11, step S13, and step S15 in FIG. 12 are the same processing as step S1, step S2, and step S3 in FIG. 4, respectively, and thus description thereof is omitted.

[0095] In step S12, load sensor 6 detects a load applied to punch 1. In the present exemplary embodiment, each of four load sensors 6a to 6d detects a load. The load detected by load sensor 6 is output to calculation unit 16 via sensor controller 15 of controller 18. In step S14, calculation unit 16 generates a load waveform indicating the relationship between the load applied to punch 1 and time.

[0096] FIG. 13 is a graph in which load waveforms generated based on the loads detected by four load sensors 6a to 6d and vibration waveforms generated based on the vibrations detected by four vibration sensors 19a to 19d illustrated in FIG. 6 are arranged. In FIG. 13, the load waveform and the vibration waveform are arranged with the horizontal axis aligned. FIG. 13 illustrates a load waveform and a vibration waveform at the time when side surface 1b of punch 1 has not worn much yet.

[0097] As illustrated in FIG. 5A, when the punching has started, punch 1 works in the +Z direction from the top dead center, and punch 1 comes into contact with workpiece 5. In the graph of FIG. 13, the position from the bottom dead center of punch 1 comes at height H at time C1. When punch 1 is positioned at height H from the bottom dead center, that is, at time C1, punch 1 is in contact with the upper surface of workpiece 5 as illustrated in FIG. 5A. When punch 1 comes into contact with workpiece 5, positive reaction force P1 starts to be applied to punch 1. Thus, time C1 in the graph of FIG. 13 is a time point when punch 1 comes into contact with workpiece 5 and positive reaction force P1 applied to punch 1 has become larger than 0. In the load waveform of FIG. 13, positive reaction force P1 is indicated by a value larger than 0, and negative reaction force P2 to be described later is indicated by a value smaller than 0.

[0098] When punch 1 comes into contact with workpiece 5, punching of workpiece 5 is started by punch 1 as illustrated in FIG. 5B. Thus, a load starts to be applied to punch 1 from time C1, and the load on punch 1 rapidly increases. The load applied to punch 1 reaches maximum value P0 at time m1.

[0099] As illustrated in FIG. 5C, when workpiece 5 is cut by punch 1, the load on punch 1 decreases to 0, and the working on workpiece 5 is completed. In FIG. 13, the time point when the working on the workpiece is completed is time C2. Time C2 represents a time point when the load related to punch 1 has decreased to 0 after the load of punch 1 reaches maximum value P0. The reason for the decrease of the load on punch 1 to 0 after reaching maximum value P0 is that punch 1 has punched workpiece 5 and the resistance to punch 1 is eliminated.

[0100] When the load related to punch 1 has become 0 at time C2, negative reaction force P2 in the direction opposite to the direction of positive reaction force P1 is applied to punch 1. Thereafter, positive reaction force P1 is applied to punch 1 as a reaction to negative reaction force P2. The load waveform of FIG. 13 illustrates that positive reaction force P1 and negative reaction force P2 are alternately generated with respect to punch 1 between time C2 and time C6.

[0101] As illustrated in FIG. 10, load sensors 6a to 6d are fixed to punch 1 by free shank 20. A gap is formed between the flange reception portion of free shank 20 and the flange reception portion of free shank holder 22. When the cutting of workpiece 5 is completed, the loads applied to load sensors 6a to 6d, specifically, positive reaction force P1 applied to punch 1 becomes 0. Due to the gap between the flange reception portion of free shank 20 and the flange reception portion of free shank holder 22, the flange reception portion of free shank 20 comes into contact with or separates from the flange reception portion of free shank holder 22 in response to punch 1 punching workpiece 5. Further, the top surface of free shank 20 comes into contact with or separates from backing plate 21. At this time, as illustrated in between time C2 and time C6 of the load waveform in FIG. 13, a load larger than 0 (positive reaction force P1) and a load smaller than 0 (negative reaction force P2) are alternately generated with respect to punch 1.

[0102] Thereafter, the load applied to punch 1 gradually converges to 0 at time C6. The vibration waveform of FIG. 13 indicates that the vibration of die 2 is generated between time C2 and time C6 as described above. In the vibration generated between time C2 and time C6, punch 1 vibrates because of application of positive reaction force P1 and negative reaction force P2 to punch 1, and the vibration of punch 1 is transmitted to die 2 via workpiece 5.

[0103] After the working on workpiece 5 is completed, as illustrated in FIG. 5D, workpiece 5 cut by punch 1 is pushed into hollow portion 2a of die 2. From time C6 to the time when punch 1 illustrated in FIG. 5E reaches the bottom dead center, that is, until time C3, positive reaction force P1 may be applied to punch 1. This is because side surface 1b of punch 1 and workpiece 5 interfere with each other as illustrated in FIGS. 5D and 5E. Positive reaction force P1 generated because of the interference between side surface 1b of punch 1 and workpiece 5 is generated between time C6 and time C3 in FIG. 13, and the load applied to punch 1 becomes 0 at time C3.

[0104] In FIG. 13, punch 1 stops at the bottom dead center from time C3 to time C4. Thus, the load applied to punch 1 is 0. When punch 1 starts to rise from the bottom dead center at time C4, negative reaction force P2 may be applied to punch 1 because of the pulling out of punch 1 from hollow portion 2a of die 2. This is because when punch 1 is pulled out from hollow portion 2a of die 2, side surface 1b of punch 1 and workpiece 5 interfere with each other and a compressive load is applied to punch 1. As illustrated in FIG. 5G, when punch 1 continues to rise and is separated from workpiece 5, the load applied to punch 1 becomes 0. In FIG. 13, the time point when the load applied to punch 1 becomes 0 is time C5.

[0105] Similarly to the vibration waveform described in the first exemplary embodiment, when the wear amount of punch 1 is small, the load waveforms generated based on the loads detected by load sensors 6a to 6d have substantially the same shape. The load waveforms of load sensors 6a to 6d may be slightly different because of a slight difference in clearance between punch 1 and die 2.

[0106] As described above, in the load waveform of FIG. 13, a load is applied to punch 1 because of the interference between side surface 1b of punch 1 and workpiece 5 between time C6 and time C3 and between time C4 and time C5. Calculation unit 16 calculates second wear amount b and third wear amount c of side surface 1b of punch 1 based on the load waveform in this period.

[0107] The description returns to FIG. 12. In step S16, calculation unit 16 calculates second wear amount b of side surface 1b of punch 1 based on the load waveform in the period from the completion of working on workpiece 5 until the punch reaches the bottom dead center, that is, from time C6 to time C3, in the load waveform.

[0108] As described above, a load is mainly applied to side surface 1b of punch 1 from time C6 to time C3. Thus, calculation unit 16 calculates second wear amount b of side surface 1b of punch 1 based on maximum value Ps0 of the load in period Ts0 from time C6 to time C3.

[0109] FIG. 14 is a graph in which a load waveform and a vibration waveform generated when the wear of punch 1 has not progressed are superimposed on a load waveform and a vibration waveform generated when the wear of punch 1 has progressed in FIG. 13. In FIG. 14, the load waveform (broken line) of load sensor 6a and the vibration waveform (broken line) based on vibration sensor 19a generated when the wear of punch 1 has not progressed are superimposed on the vibration waveform (broken line) based on load sensor 6a (solid line) and vibration sensor 19a (solid line) generated when the wear of punch 1 has progressed.

[0110] As illustrated in FIG. 13, the maximum value of the load applied to punch 1 in period Ts0 is maximum value Ps0. When the wear of punch 1, in particular, the wear of side surface 1b of punch 1 has progressed, the maximum value of the load applied to punch 1 in period Ts0 becomes maximum value Ps1.

[0111] When the wear of side surface 1b has progressed, maximum value Ps1 of the load applied to punch 1 in period Ts0 becomes larger than maximum value Ps0 of the load applied to punch 1 when the wear of side surface 1b has not progressed. In this manner, the maximum value of the load applied to punch 1 in period Ts0 changes depending on the state of progress of the wear of side surface 1b. Thus, calculation unit 16 can calculate second wear amount b of side surface 1b of punch 1 based on the maximum value of the load applied to punch 1 in period Ts0.

[0112] For example, as in the first exemplary embodiment, when workpiece 5 is a stainless-steel plate made of SUS301-EH material having a thickness of 0.03 mm, punching is performed under the conditions of an instantaneous speed of punch 1 at the time of punching of 3 mm / s and with no press oil. Under this condition, the relationship of Formula (2) shown below is established between maximum value Ps of the load applied to punch 1 in period Ts0 and second wear amount b of side surface 1b of punch 1.Ps=6.667×b3-2×10-12×b2+8.3333×b+5(2)

[0113] FIG. 15 is a graph illustrating an example of a relationship between maximum value Ps of the load applied to punch 1 in period Ts0 and second wear amount b of side surface 1b of punch 1. According to Formula (2) and FIG. 15, for example, when maximum value Ps of the load applied to punch 1 in period Ts0 is 29 N, second wear amount b of side surface 1b of punch 1 is calculated to be 1.27 μm.

[0114] In the first exemplary embodiment, first wear amount d is calculated based on the maximum value of the vibration of die 2 in period Tsb0, but in the present exemplary embodiment, calculation unit 16 calculates third wear amount c of side surface 1b of punch 1 based on the maximum value of the load applied to punch 1 in period Tsb0.

[0115] As illustrated in FIG. 13, in period Tsb0, the load applied to punch 1 is negative reaction force P2. Thus, as illustrated in the load waveform in FIG. 13, the load applied to punch 1 in period Tsb0 has a value smaller than 0. In period Tsb0, the maximum value of the load applied to punch 1 is maximum value Psb0. The maximum value of the load of punch 1 in period Tsb0 is the maximum value of the absolute value of the load of punch 1. When the wear of punch 1, in particular, the wear of side surface 1b of punch 1 has progressed, the maximum value of the load applied to punch 1 in period Tsb0 becomes maximum value Psb1.

[0116] When the wear of side surface 1b has progressed, maximum value Psb1 of the load applied to punch 1 in period Tsb0 becomes larger than maximum value Psb0 of the load applied to punch 1 when the wear of side surface 1b has not progressed. In this manner, the maximum value of the load applied to punch 1 in period Tsb0 changes depending on the state of progress of the wear of side surface 1b. Thus, calculation unit 16 can calculate third wear amount c of side surface 1b of punch 1 based on the maximum value of the load applied to punch 1 in period Tsb0.

[0117] For example, as in the first exemplary embodiment, when workpiece 5 is a stainless-steel plate made of SUS301-EH material having a thickness of 0.03 mm, punching is performed under the conditions of an instantaneous speed of punch 1 at the time of punching of 3 mm / s and with no press oil. Under this condition, the relationship of Formula (3) shown below is established between maximum value Psb of the load applied to punch 1 in period Tsb0 and third wear amount c of side surface 1b of punch 1.Psb=20×c3+25×c+15(3)

[0118] FIG. 16 is a graph illustrating an example of the relationship between maximum value Psb of the load of punch 1 and third wear amount c of side surface 1b of punch 1 in period Tsb0. According to Formula (3) and FIG. 16, for example, when maximum value Psb of the load applied to punch 1 in period Tsb0 is 87 N, third wear amount c of side surface 1b of punch 1 is calculated to be 1.25 μm.

[0119] When calculation unit 16 calculates the wear amount of side surface 1b in steps S15 to S17, determination unit 17 determines whether polishing of punch 1 is necessary in step S18.

[0120] In the present exemplary embodiment, as described above, the wear amounts of side surfaces 1b are calculated such that first wear amount d is 1.20 μm, second wear amount b is 1.27 μm, and third wear amount c is 1.25 μm. For example, determination unit 17 can determine that polishing of punch 1 is necessary based on the fact that the largest value among first wear amount d, second wear amount b, and third wear amount c has exceeded a predetermined threshold value. By using the largest value among first wear amount d, second wear amount b, and third wear amount c, it is possible to determine whether polishing of punch 1 is necessary in consideration of the calculation error of the wear amount.

[0121] Alternatively, determination unit 17 may determine whether polishing of punch 1 is necessary based the magnitude of the allowable wear amount. For example, it is assumed that the size of the burr allowed for the product manufactured with press working apparatus 100A is 5 μm. As a result of calculating the wear amount when a burr of 5 μm was generated in the product, first wear amount d of side surface 1b of punch 1 was 1.20 μm, second wear amount b was 1.27 μm, and third wear amount c was 1.25 μm. Thus, the allowable wear amount of side surface 1b is such that first wear amount d is 1.20 μm, second wear amount b is 1.27 μm, and third wear amount c is 1.25 μm. Determination unit 17 may use the smallest allowable wear amount among first wear amount d, second wear amount b, and third wear amount c to determine whether polishing of punch 1 is necessary. In this case, determination unit 17 determines whether polishing of punch 1 is necessary using first wear amount d having the smallest allowable wear amount. For example, determination unit 17 can determine that polishing of punch 1 is necessary based on first wear amount d exceeding a predetermined threshold value.

[0122] Further, determination unit 17 may determine that polishing of the punch is necessary when at least one of second wear amount b and third wear amount c has exceeded the second threshold value.

[0123] Which one of first wear amount d, second wear amount b, and third wear amount c is used to determine whether polishing of punch 1 is necessary may be determined in advance depending on, for example, working conditions such as the material or thickness of workpiece 5, the materials of punch 1 and die 2, the punching speed, and the presence or absence of press oil.

[0124] When determination unit 17 has determined in step S18 that polishing of punch 1 is necessary, the driving of press working apparatus 100A is stopped by press controller 14, the punching is interrupted, and the processing ends.

[0125] When determination unit 17 has determined in step S4 that polishing of punch 1 is not necessary, the punching continues, and the processing returns to step S11.Effects

[0126] According to the exemplary embodiment described above, it is possible to provide press working apparatus 100A capable of more accurately calculating the wear amount of side surface 1b of punch 1. The wear amount of side surface 1b of punch 1 is calculated using the load waveform generated based on the load applied to punch 1 in addition to the vibration waveform. Whether polishing of punch 1 is necessary can be determined based on first wear amount d of side surface 1b of punch 1 based on the vibration waveform and second wear amount b or third wear amount c of side surface 1b of punch 1 based on the load waveform having higher calculation accuracy.

[0127] In the exemplary embodiment described above, an example in which load sensor 6 includes four load sensors 6a to 6d has been described, but the present disclosure is not limited to this configuration. Load sensor 6 may include one or two or more load sensors.

[0128] In the exemplary embodiment described above, an example in which calculation unit 16 calculates second wear amount b and third wear amount c based on the load waveform has been described, but the present disclosure is not limited to this configuration. Calculation unit 16 may calculate second wear amount b based on the load waveform, and determination unit 17 may determine whether polishing of punch 1 is necessary based on first wear amount d and second wear amount b.Overview of Exemplary Embodiments(1) A press working apparatus of the present disclosure is a press working apparatus that performs press working on a workpiece, including a punch including a press surface and a side surface connected to the press surface, a die on which the workpiece is placed, the die including a hollow portion in which the punch is to be inserted, a position sensor that detects a position of the punch, a vibration sensor that detects a vibration of the die, and a controller that controls the punch, the die, the position sensor, and the vibration sensor, wherein the controller generates a vibration waveform indicating a relationship between the vibration detected by the vibration sensor and a time after the punch reaches a bottom dead center, and calculates a first wear amount of the side surface of the punch based on the vibration waveform.

[0130] (2) In the press working apparatus according to (1), the vibration waveform may indicate a change in vibration in a predetermined period from when the punch starts to rise from the bottom dead center as detected by the position sensor.

[0131] (3) In the press working apparatus according to (1) or (2), the controller may determine that polishing of the punch is necessary when the first wear amount has exceeded a first threshold value.

[0132] (4) In the press working apparatus according to any one of (1) to (3), the press working apparatus may further include a load sensor that detects a load applied to the punch, wherein the controller may generate a load waveform indicating a relationship between the load detected by the load sensor and a time from a start of press working and calculate a second wear amount of the side surface of the punch based on a part of the load waveform during a period from completion of working on the workpiece until the punch reaches the bottom dead center.

[0133] (5) In the press working apparatus according to (4), whether polishing of the punch is necessary may be determined based on the first wear amount or the second wear amount.

[0134] (6) In the press working apparatus according to (4) or (5), the controller may calculate a third wear amount of the side surface of the punch based on a part of the load waveform in a predetermined period from when the punch starts to rise from the bottom dead center and determine whether polishing of the punch is necessary based at least any one of the first wear amount, the second wear amount, and the third wear amount.

[0135] (7) In the press working apparatus according to (6), the controller may determine that polishing of the punch is necessary when at least one of the second wear amount and the third wear amount has exceeded a predetermined second threshold value.

[0136] (8) In the press working apparatus according to (6) or (7), the controller may determine that polishing of the punch is necessary when a largest value among the first wear amount, the second wear amount, and the third wear amount has exceeded a predetermined threshold value.

[0137] (9) In the press working apparatus according any one of (1) to (8), the vibration sensor may include a plurality of vibration sensors.

[0138] (10) In the press working apparatus according to (9), the plurality of vibration sensors may be disposed at equal intervals around the hollow portion of the die.

[0139] (11) In the press working apparatus according to (9) or (10), the controller may calculate a wear position of the punch based on a plurality of load waveforms each indicating a relationship between the vibration detected by corresponding one of the plurality of vibration sensors and time.

[0140] (12) In the press working apparatus according to any one of (4) to (11), the load sensor may include a plurality of load sensors.

[0141] According to the present invention, it is possible to provide a press working apparatus capable of improving calculation accuracy of a wear amount of a punch.INDUSTRIAL APPLICABILITY

[0142] The press working apparatus of the present disclosure is useful as an apparatus for punching any workpiece used for home electric appliances, medical devices, or the like.REFERENCE MARKS IN THE DRAWINGS1 punch

[0144] 1a press surface

[0145] 1b side surface

[0146] 2 die

[0147] 2a hollow portion

[0148] 3 stripper plate

[0149] 4 die plate

[0150] workpiece

[0151] 6, 6a to 6d load sensor

[0152] 7 slide

[0153] 8 bolster

[0154] 9 press apparatus body

[0155] shaft

[0156] 11 servomotor

[0157] 13 position sensor

[0158] 14 press controller

[0159] sensor controller

[0160] 16 calculation unit

[0161] 17 determination unit

[0162] 18 controller

[0163] 19, 19a to 19d vibration sensor

[0164] free shank

[0165] 21 backing plate

[0166] 22 free shank holder

[0167] 100, 100A press working apparatus

Examples

first exemplary embodiment

[Overall Configuration]

[0035]FIG. 1 is a schematic diagram illustrating press working apparatus 100 according to a first exemplary embodiment of the present disclosure. FIG. 2 is a schematic view illustrating a bottom dead center state of punch 1 of press working apparatus 100 of FIG. 1. FIG. 3 is a top view illustrating vibration sensor 19 of press working apparatus 100 of FIG. 1. In FIGS. 2 to 3, some components are not illustrated. With reference to FIGS. 1 to 3, press working apparatus 100 according to the present exemplary embodiment will be described.

[0036]The X-Y-Z coordinate system illustrated in each drawing is provided to facilitate the understanding of the exemplary embodiments, and is not intended to limit the scope of the exemplary embodiments in any way. In each drawing, an X direction is a width direction of press working apparatus 100, a Y direction is a depth direction of press working apparatus 100, and a Z direction is a height direction of press working apparatus...

second exemplary embodiment

[0086]With reference to FIGS. 9 to 11, a second exemplary embodiment will be described. The second exemplary embodiment includes components identical or equivalent to those in the first exemplary embodiment, the components being denoted by the same reference marks as those in the first exemplary embodiment. The description already given for the first exemplary embodiment is omitted for the second exemplary embodiment.

[0087]FIG. 9 is a schematic diagram illustrating press working apparatus 100A according to the second exemplary embodiment. FIG. 10 is a schematic diagram illustrating a state in which punch 1 of press working apparatus 100A of FIG. 9 is at the bottom dead center. FIG. 11 is a top view illustrating load sensor 6 of press working apparatus of FIG. 9. The second exemplary embodiment is different from the first exemplary embodiment in that press working apparatus 100A includes load sensor 6 that detects a load applied to punch 1. In addition, the second exemplary embodimen...

TECHNICAL FIELD

[0001] The present disclosure relates to a press working apparatus.BACKGROUND ART

[0002] In press working for punching a plate-shaped workpiece, there has been known a device for measuring working resistance generated when the workpiece is punched.

[0003] In a punching characteristic measurement apparatus described in PTL 1, a temporal change in deformation of a frame at the time of punching is converted into an electric signal to measure a punching force.CITATION LISTPatent Literature

[0004] PTL 1: Unexamined Japanese Patent Publication No. S62-40938SUMMARY OF THE INVENTION

[0005] A press working apparatus according to one aspect of the present disclosure is a press working apparatus that performs press working on a workpiece, the press working apparatus including: a punch including a press surface and a side surface connected to the press surface; a die on which the workpiece is placed, the die including a hollow portion in which the punch is to be inserted; a position sensor that detects a position of the punch; a vibration sensor that detects a vibration of the die; and a controller that controls the punch, the die, the position sensor, and the vibration sensor, wherein the controller: generates a vibration waveform indicating a relationship between the vibration detected by the vibration sensor and a time after the punch reaches a bottom dead center; and calculates a first wear amount of the side surface of the punch based on the vibration waveform.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a schematic diagram illustrating a press working apparatus according to a first exemplary embodiment of the present disclosure.

[0007] FIG. 2 is a schematic diagram illustrating a bottom dead center state of a punch of the press working apparatus in FIG. 1.

[0008] FIG. 3 is a top view illustrating a vibration sensor of the press working apparatus in FIG. 1.

[0009] FIG. 4 is a flowchart for describing processing of calculating the wear amount of a side surface of the punch in the press working apparatus.

[0010] FIG. 5A is a schematic diagram illustrating a step of punching a workpiece with a press working apparatus.

[0011] FIG. 5B is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0012] FIG. 5C is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0013] FIG. 5D is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0014] FIG. 5E is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0015] FIG. 5F is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0016] FIG. 5G is a schematic diagram illustrating a step of punching the workpiece with the press working apparatus.

[0017] FIG. 6 is a graph illustrating a relationship between a load (left vertical axis) detected by four vibration sensors, a position (right vertical axis) from a bottom dead center of punch 1, and time in punching.

[0018] FIG. 7A is a graph illustrating a vibration waveform generated when wear of the punch of FIG. 6 has not progressed.

[0019] FIG. 7B is a graph illustrating a vibration waveform generated when wear of the punch of FIG. 6 has progressed.

[0020] FIG. 8 is a graph illustrating an example of a relationship between maximum value Asb of vibration of a die and a first wear amount of a side surface of the punch in period Tsb0.

[0021] FIG. 9 is a schematic diagram illustrating a press working apparatus according to a second exemplary embodiment.

[0022] FIG. 10 is a schematic diagram illustrating a state where a punch of the press working apparatus in FIG. 9 is at a bottom dead center.

[0023] FIG. 11 is a top view illustrating a load sensor of the press working apparatus in

[0024] FIG. 9.

[0025] FIG. 12 is a flowchart for describing processing of calculating the wear amount of a side surface of the punch in the press working apparatus in FIG. 9.

[0026] FIG. 13 is a graph in which load waveforms generated based on loads detected by four load sensors and vibration waveforms generated based on vibrations detected by the four vibration sensors illustrated in FIG. 6 are arranged.

[0027] FIG. 14 is a graph in which a load waveform and a vibration waveform generated when the wear of the punch has not progressed are superimposed on a load waveform and a vibration waveform generated when the wear of the punch has progressed in FIG. 13.

[0028] FIG. 15 is a graph illustrating an example of a relationship between maximum value Ps of the load applied to the punch and a second wear amount of the side surface of the punch in period Ts0.

[0029] FIG. 16 is a graph illustrating an example of a relationship between maximum value Psb of the load of the punch and a third wear amount of the side surface of the punch in period Tsb0.DESCRIPTION OF EMBODIMENTBackground to Present Disclosure

[0030] Press working of performing punching on a plate-shaped workpiece is generally a technique capable of obtaining a predetermined shape by pressing a workpiece loaded on a die with a stripper, pushing a part of the workpiece into the die with a punch, and performing punching. Press working by punching is generally used in a wide variety of fields such as home appliances, precision machines, and automobile parts.

[0031] In press working by punching, as in a punching characteristic measurement apparatus described in PTL 1, there is known a punching characteristic measurement apparatus that measures a punching force at the time of punching by converting a temporal change in frame deformation at the time of punching into an electric signal.

[0032] In the punching characteristic measurement apparatus described in PTL 1, frame deformation at the time of punching is converted into an electric signal, and a punching force at the time of punching is measured. The punching force is a resistance force when a laminate is punched with a mold. Since the punching force increases as the mold wears, it has been studied to use the punching force to calculate the wear state of the mold and determine the necessity of re-polishing the tool.

[0033] However, in the punching characteristic measurement apparatus described in PTL 1, the deformation of the frame at a position more distant than the working position of the mold is detected, there is a problem that the wear state of the mold cannot be calculated with high accuracy. The punching characteristic measurement apparatus described in PTL 1 still has room for improvement in terms of improvement in calculation accuracy of the wear amount of the tool.

[0034] The inventor(s) of the present invention have studied a press working apparatus capable of accurately calculating the wear amount of the punch, and have reached the following disclosure. The present disclosure provides a press working apparatus capable of improving calculation accuracy of a wear amount of a punch.First Exemplary Embodiment[Overall Configuration]

[0035] FIG. 1 is a schematic diagram illustrating press working apparatus 100 according to a first exemplary embodiment of the present disclosure. FIG. 2 is a schematic view illustrating a bottom dead center state of punch 1 of press working apparatus 100 of FIG. 1. FIG. 3 is a top view illustrating vibration sensor 19 of press working apparatus 100 of FIG. 1. In FIGS. 2 to 3, some components are not illustrated. With reference to FIGS. 1 to 3, press working apparatus 100 according to the present exemplary embodiment will be described.

[0036] The X-Y-Z coordinate system illustrated in each drawing is provided to facilitate the understanding of the exemplary embodiments, and is not intended to limit the scope of the exemplary embodiments in any way. In each drawing, an X direction is a width direction of press working apparatus 100, a Y direction is a depth direction of press working apparatus 100, and a Z direction is a height direction of press working apparatus 100.

[0037] Press working apparatus 100 is an apparatus that performs punching on plate-shaped workpiece 5, and the apparatus is, for example, a servo screw press machine that can be controlled with high accuracy. In the present exemplary embodiment, press working apparatus 100 includes press apparatus body 9 and controller 18. Press apparatus body 9 includes punch 1, die 2, position sensor 13, and vibration sensor 19.

[0038] Press apparatus body 9 and controller 18 may be accommodated in one housing. Alternatively, controller 18 may be a control circuit such as a CPU mounted on an apparatus different from press apparatus body 9, for example, an electronic device or the like. Even when controller 18 is mounted on an apparatus different from press apparatus body 9, press apparatus body 9 and controller 18 are collectively referred to as “press working apparatus”. Alternatively, when controller 18 is mounted on an apparatus different from press apparatus body 9, press apparatus body 9 and controller 18 may be collectively referred to as “press working system”.

[0039] Press working apparatus 100 includes punch 1, die 2, position sensor 13, vibration sensor 19, and controller 18.

[0040] As illustrated in FIG. 1, press apparatus body 9 of press working apparatus 100 has an upper die including punch 1 attached to slide 7 and a lower die including die 2 attached to bolster 8. Press apparatus body 9 rotates ball screw 12 connected to servomotor 11 based on a command from controller 18 to vertically drive slide 7 in a pressing direction (Z direction) at a predetermined speed along shaft 10. Workpiece 5 can be punched through such an operation of press apparatus body 9.<Punch>

[0041] Punch 1 is a tool for punching workpiece 5 by moving in the pressing direction (Z direction). As illustrated in FIG. 2, punch 1 has press surface 1a facing workpiece 5 and side surface 1b connected to press surface 1a. Punch 1 is attached to slide 7 together with stripper plate 3 that presses workpiece 5 against die 2 at the time of punching. With the movement of slide 7, punch 1 is pressed against workpiece 5, and punching is performed. In the present exemplary embodiment, punch 1 has circular press surface 1a. Thus, workpiece 5 can be punched into a circular shape.

[0042] In the present exemplary embodiment, punch 1 is formed in a columnar shape having circular press surface 1a with a diameter of 4.5 mm, and a round hole is punched into workpiece 5. Punch 1 is made of, for example, a cemented carbide material. Examples of the cemented carbide material include an artificial metal (alloy) in which nine carbides of tungsten (W), chromium (Cr), molybdenum (Mo), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), and tantalum (Ta) are bonded with an Fe-group metal (Fe, Co, or Ni). As the cemented carbide material, for example, an alloy corresponding to VM-40 of the cemented carbide tool standard (CIS) can be adopted.<Die>

[0043] As illustrated in FIG. 2, workpiece 5 is placed on die 2 at the time of punching. Hollow portion 2a into which punch 1 is inserted is formed in die 2. Hollow portion 2a is a through hole penetrating die 2 in the Z direction. Die 2 is attached to bolster 8 together with die plate 4 for holding die 2. Similarly to punch 1, die 2 is made of, for example, a cemented carbide material. As illustrated in FIG. 3, vibration sensor 19 that detects vibration of die 2 is disposed in die 2.<Position Sensor>

[0044] Position sensor 13 is a sensor that detects the position of punch 1. More specifically, position sensor 13 can detect that punch 1 illustrated in FIG. 2 is in the lowest possible position, that is, in a bottom dead center state. Further, position sensor 13 can detect how much punch 1 has risen from the bottom dead center state. In the present exemplary embodiment, the degree of rise from the bottom dead center state is detected as the position of punch 1. Position sensor 13 can be made up of, for example, a variation sensor that measures a minute distance interval from a measurement object in a non-contact manner.

[0045] Position sensor 13 can be mounted in any position of the lower die of press working apparatus 100 including die 2, die plate 4, and bolster 8, for example. Position sensor 13 detects contact between position sensor 13 and the upper mold including punch 1, stripper plate 3, and slide 7 to detect that punch 1 is in the bottom dead center state, and detects the position of punch 1 by measuring the distance between the upper mold and position sensor 13.

[0046] Based on the position of punch 1 detected by position sensor 13, the start timing of the detection of the vibration of die 2 with vibration sensor 19 can be determined. Specifically, the detection start timing can be determined based on the gap of position sensor 13 and the position from the bottom dead center of punch 1 so that the vibration of die 2 can be detected at the same timing at the shot time of the punching. Thus, position sensor 13 can be used as a trigger for vibration detection of die 2 with vibration sensor 19. Further, for example, by disposing position sensor 13 at each of the four corners of the lower mold, whether the upper mold and the lower mold are disposed in parallel can also be detected.<Vibration Sensor>

[0047] Vibration sensor 19 is a sensor that detects vibration of die 2. Vibration sensor 19 detects the vibration transmitted from workpiece 5 to die 2 when workpiece 5 is punched. As illustrated in FIG. 3, in the present exemplary embodiment, vibration sensor 19 includes four vibration sensors 19a to 19d. In the present exemplary embodiment, four vibration sensors 19a to 19d are disposed at equal intervals around hollow portion 2a of die 2. Specifically, vibration sensor 19a and vibration sensor 19b are disposed symmetrically in the X direction, vibration sensor 19c and vibration sensor 19d are disposed symmetrically in the Y direction, and four vibration sensors 19a to 19d are disposed concentrically. By disposing four vibration sensors 19a to 19d like this, which portion of punch 1 is worn is more easily grasped.<Controller>

[0048] Controller 18 controls punch 1, die 2, position sensor 13, and vibration sensor 19. In the present exemplary embodiment, controller 18 includes press controller 14, sensor controller 15, calculation unit 16, and determination unit 17. Controller 18 includes a digital circuit such as a microcomputer, a CPU, an MPU, a GPU, a DSP, an FPGA, or an ASIC, for example.

[0049] Press controller 14 drives servomotor 11 to rotate ball screw 12, thereby vertically driving slide 7 in the pressing direction (Z direction) at a predetermined speed.

[0050] Sensor controller 15 is electrically connected to position sensor 13 and vibration sensor 19 and outputs detection values of sensors 13 and 19 to calculation unit 16.

[0051] Calculation unit 16 generates a vibration waveform indicating the relationship between the vibration of die 2 and the time after punch 1 reaches the bottom dead center based on the vibration detected by vibration sensor 19, and calculates a first wear amount of side surface 1b of punch 1 based on the vibration waveform. When the punching is repeated, punch 1 gradually wears. In the present exemplary embodiment, calculation unit 16 calculates the wear amount of side surface 1b of punch 1. The generation of the vibration waveform and the calculation of the wear amount will be described later in detail.

[0052] Determination unit 17 determines whether polishing of punch 1 is necessary based on the first wear amount of side surface 1b calculated by calculation unit 16. When the wear amount of punch 1 has increased, the accuracy of the punching dimension of workpiece 5 gradually deteriorates. Thus, it is preferable to polish punch 1 at a timing when the wear amount has exceeded a predetermined threshold value. When determination unit 17 determines to polish punch 1, determination unit 17 outputs a signal to press controller 14 to interrupt the punching. After receiving the signal, press controller 14 stops servomotor 11 and interrupts the punching. Determination unit 17 is not an essential component, and controller 18 does not have to determine whether polishing of punch 1 is necessary.<Workpiece>

[0053] Workpiece 5 is a plate-shaped material to be worked by press working apparatus 100. A plurality of workpieces 5 are conveyed in the X direction or the Y direction by a conveyance unit (not illustrated) in accordance with the pressing operation of press apparatus body 9, and the workpieces 5 are sequentially subjected to punching.

[0054] In the present exemplary embodiment, workpiece 5 is made of SUS301-EH material which is a steel type classified as austenitic stainless steel. The SUS301-EH material is, for example, a material used as a mainspring or a spring of an automobile component. In the present exemplary embodiment, the thickness of workpiece 5 is 0.03 mm, the hardness is 529 HV, and the tensile strength is 1,679 N / mm2.[Calculation of Wear Amount]

[0055] FIG. 4 is a flowchart for describing processing of calculating the wear amount of side surface 1b of punch 1 in press working apparatus 100. The calculation of the wear amount of side surface 1b of punch 1 will be described with reference to FIG. 4.

[0056] When press working apparatus 100 starts punching, vibration sensor 19 detects vibration of die 2 in step S1. In the present exemplary embodiment, punching is started in press working apparatus 100, and detection of vibration of die 2 is started by vibration sensor 19 when position sensor 13 has detected that punch 1 has reached the bottom dead center. In the present exemplary embodiment, the vibration of die 2 is detected by each of four vibration sensors 19a to 19d.

[0057] In step S2, calculation unit 16 generates a vibration waveform indicating a relationship between vibration of die 2 and time. The vibration of die 2 detected in step S1 is output to calculation unit 16 by sensor controller 15 of controller 18, and a vibration waveform is generated by calculation unit 16.

[0058] FIGS. 5A to 5G are schematic diagrams illustrating steps of punching workpiece 5 with press working apparatus 100. FIG. 6 is a graph illustrating a relationship between a load (left vertical axis) detected by four vibration sensors 19a to 19d, a position (right vertical axis) from a bottom dead center of punch 1, and time in punching. FIG. 6 is a graph in which four vibration waveforms generated based on the vibration of die 2 detected by each of four vibration sensors 19a to 19d are superimposed. FIG. 6 illustrates the vibration waveform formed when side surface 1b of punch 1 has not worn much yet.

[0059] When the punching has started, punch 1 lowers in the Z direction from the top dead center state, and punch 1 comes into contact with workpiece 5 as illustrated in FIG. 5A. The top dead center state refers to a state in which punch 1 is at the highest possible position. In FIG. 6, time C1 indicates the time when punch 1 starts to come into contact with workpiece 5.

[0060] When punch 1 comes into contact with workpiece 5, punching to workpiece 5 is started by punch 1 as illustrated in FIG. 5B. Thereafter, as illustrated in FIG. 5C, a part of workpiece 5 is cut off by punch 1, and the cutting of workpiece 5 is completed. In the graph of FIG. 6, time C2 indicates the time when the cutting of workpiece 5 is completed by punch 1. At the time of punching workpiece 5 with punch 1, positive reaction force P1 in the −Z direction illustrated in FIG. 2 is applied to punch 1.

[0061] When the cutting of workpiece 5 is completed, as illustrated in FIG. 5D, punch 1 pushes a portion cut from workpiece 5 into the hollow portion of die 2. At this time, the load applied to punch 1 changes from positive reaction force P1 to negative reaction force P2 in the direction (+Z direction) opposite to the direction of positive reaction force P1 illustrated in FIG. 2. After the cutting of workpiece 5 is completed, positive reaction force P1 and negative reaction force P2 are alternately applied to punch 1, and thus punch 1 vibrates. The vibration of punch 1 is transmitted to die 2 via workpiece 5. Region R1 in FIG. 6 illustrates the detected vibration of die 2 after the cutting of workpiece 5 is completed.

[0062] Thereafter, as illustrated in FIG. 5E, punch 1 reaches the bottom dead center. In FIG. 6, the time when punch 1 has reached the bottom dead center is time C3. As illustrated in region R2 in FIG. 6, vibration may be detected before punch 1 reaches the bottom dead center. This vibration is generated because of transmission of vibration from workpiece 5 to die 2 when workpiece 5 cut from the tip of punch 1 is separated and falls.

[0063] When punch 1 reaches the bottom dead center at time C3, punch 1 stops at the bottom dead center until time C4. At time C4, punch 1 starts to rise from the bottom dead center. When punch 1 rises from the bottom dead center, punch 1 and workpiece 5 may interfere with each other as illustrated in FIG. 5F, and vibration is transmitted from punch 1 to die 2 via workpiece 5. This vibration continues until punch 1 rises and comes out of the hollow portion of die 2 completely, as illustrated in FIG. 5F. The vibration of die 2 generated when punch 1 rises from the bottom dead center is illustrated in region R3 in FIG. 6. As illustrated in FIG. 5G, when punch 1 completely comes out of hollow portion 2a of die 2, the vibration of die 2 is not detected.

[0064] When the wear amount of punch 1 is small, for example, when punch 1 has just been polished, the vibration waveforms of respective vibration sensors 19a to 19d have substantially the same shape as illustrated in FIG. 6. The vibration waveforms of vibration sensors 19a to 19d may be slightly different because of a slight difference in clearance between punch 1 and die 2.

[0065] In FIG. 6, for the sake of explanation, the vibration waveform from when punch 1 starts to lower from the top dead center to when punch 1 reaches the bottom dead center and then returns to the top dead center again is illustrated. However, as described later, in the present exemplary embodiment, it is sufficient that at least the vibration waveform after punch 1 reaches the bottom dead center is generated.

[0066] The description returns to FIG. 4. After calculation unit 16 generates the vibration waveform in step S2, calculation unit 16 calculates the wear amount of side surface 1b of punch 1 in step S3. The wear amount of side surface 1b of punch 1 is calculated based on each vibration waveform illustrated in FIG. 6.

[0067] When punch 1 rises, as illustrates in FIG. 5F, side surface 1b of punch 1 and workpiece 5 interfere with each other. Thus, the vibration of punch 1 is transmitted to die 2 via workpiece 5. As side surface 1b of punch 1 wears because of repeating punching, the vibration of die 2 increases.

[0068] As the wear of side surface 1b of punch 1 progresses, the vibration waveform of die 2 generated when punch 1 is pulled out from hollow portion 2a of die 2 changes after punch 1 reaches the bottom dead center. Thus, in the present exemplary embodiment, the first wear amount of side surface 1b of punch 1 is calculated from time C4 to time C5, that is, using a vibration waveform indicating a change in vibration in a predetermined period from when punch 1 starts to rise from the bottom dead center. The predetermined period from when the punch 1 starts to rise from the bottom dead center can be a period from when punch 1 starts to rise from the bottom dead center at time C4 to when punch 1 completely comes out of hollow portion 2a of die 2 at time C5. Alternatively, the predetermined period may be a time from time C4 until punch 1 reaches the top dead center.

[0069] FIG. 7A is a graph illustrating a vibration waveform generated when wear of punch 1 of FIG. 6 has not progressed. FIG. 7B is a graph illustrating a vibration waveform generated when wear of punch 1 of FIG. 6 has progressed.

[0070] As illustrated in FIG. 7A, the maximum value of the vibration of die 2 in period Tsb0 is maximum value Asb0. As illustrated in FIG. 7B, when the wear of side surface 1b of punch 1 has progressed, the maximum value of the vibration of die 2 in period Tsb0 becomes maximum value Asb1. As illustrated in FIGS. 6 to 7B, vibration sensor 19 detects vibration larger than 0 and vibration smaller than 0 depending on the direction of vibration. Thus, maximum value Asb of vibration may be the maximum value of the absolute value of vibration in period Tsb0.

[0071] When the wear of side surface 1b has progressed, maximum value Asb1 of the vibration of die 2 in period Tsb0 becomes larger than maximum value Asb0 of the vibration of die 2 when the wear of side surface 1b has not progressed. In this manner, the maximum value of the vibration of die 2 in period Tsb0 changes depending on the state of progress of the wear of side surface 1b. Thus, calculation unit 16 can calculate first wear amount d of side surface 1b of punch 1 based on the maximum value of the vibration of die 2 in period Tsb0.

[0072] For example, when workpiece 5 is a stainless-steel plate made of SUS301-EH material having a thickness of 0.03 mm, punching is performed under the conditions of an instantaneous speed of punch 1 at the time of punching of 3 mm / s and with no press oil. Under the conditions, the relationship of Formula (1) shown below is established between maximum value Asb of the vibration of die 2 in period Tsb0 and first wear amount d of side surface 1b of punch 1.Asb=20×d3+50×d2+20×d+50(1)

[0073] FIG. 8 is a graph illustrating an example of the relationship between maximum value Asb of vibration of die 2 and first wear amount d of side surface 1b of punch 1 in period Tsb0. According to Formula (1) and FIG. 8, for example, when maximum value Asb of the vibration of die 2 in period Tsb0 is 180 m / s2, first wear amount d of side surface 1b of punch 1 is calculated to be 1.20 μm.

[0074] As described above, calculation unit 16 calculates first wear amount d of side surface 1b of punch 1 based on maximum value Asb of the vibration of die 2 in period Tsb0 in the vibration waveform. In the present exemplary embodiment, press working apparatus 100 includes four vibration sensors 19a to 19d, and four vibration waveforms illustrated in FIG. 6 are generated. Thus, first wear amount d is calculated for each of the four vibration waveforms. Calculation unit 16 can calculate the wear position of punch 1 by calculating first wear amount d for each of the four vibration waveforms. For example, first wear amount d with respect to the vibration waveform generated by the detection value of vibration sensor 19a indicates the wear amount of the portion of side surface 1b of punch 1 facing vibration sensor 19a when punch 1 reaches the bottom dead center. In the present exemplary embodiment, four vibration sensors 19a to 19d are disposed. Thus, it is possible to specify a portion where wear has progressed or a portion where wear has not progressed in side surface 1b of punch 1 to some extent.

[0075] For example, in multilayer punching in which a plurality of workpieces 5 are stacked in multiple layers and simultaneously punched, the load on the side surface of punch 1 increases. Thus, when side surface 1b of punch 1 has worn with repeating punching, maximum value Asb of the vibration of die 2 in period Tsb0 significantly increases. Therefore, by using maximum value Asb of the vibration of die 2 in period Tsb0, first wear amount d of side surface 1b of punch 1 can be accurately calculated.

[0076] The description returns to FIG. 4. After first wear amount d of side surface 1b of punch 1 is calculated, determination unit 17 determines in step S4 whether polishing of punch 1 is necessary.

[0077] When first wear amount d of side surface 1b of punch 1 has exceeded a first threshold value, determination unit 17 determines that polishing of punch 1 is necessary. In the present exemplary embodiment, when at least one of first wear amounts d calculated by the four vibration waveforms is larger than the first threshold value, determination unit 17 determines to polish punch 1.

[0078] For example, when a burr of 5 μm was generated in the punched product, first wear amount d of side surface 1b of punch 1 was 1.20 μm. Assuming that the allowable range of the size of the burr is 5 μm, the maximum value of allowable first wear amount d of side surface 1b can be defined as 1.20 μm. Thus, the first threshold value can be set to 1.20 μm. The magnitude of the first threshold value may be set based on the magnitude of the allowable burr. Alternatively, the magnitude of the first threshold value may be set based on working conditions such as materials of workpiece 5, punch 1, and die 2, a punching speed, and presence or absence of press oil.

[0079] When determination unit 17 has determined in step S4 that polishing of punch 1 is necessary, the driving of press working apparatus 100 is stopped by press controller 14, the punching is interrupted, and the processing ends.

[0080] When determination unit 17 has determined in step S4 that polishing of punch 1 is not necessary, the punching continues, and the processing returns to step S1.Effects

[0081] According to the exemplary embodiment described above, it is possible to provide press working apparatus 100 capable of accurately calculating the wear amount of side surface 1b of punch 1. In press working apparatus 100, the vibration of die 2 is detected by vibration sensor 19. A vibration waveform is generated based on the detected vibration. The vibration waveform is a waveform indicating the relationship between the vibration detected by vibration sensor 19 and the time after punch 1 reaches the bottom dead center. First wear amount d of side surface 1b of punch 1 is calculated based on the vibration waveform. When punch 1 rises toward the top dead center after reaching the bottom dead center, a load is applied to side surface 1b of punch 1. Thus, by using the vibration waveform generated after punch 1 reaches the bottom dead center, first wear amount d of side surface 1b of punch 1 can be accurately calculated.

[0082] In the exemplary embodiment described above, an example in which press working apparatus 100 includes four vibration sensors 19a to 19d has been described, but the present disclosure is not limited to this configuration. The number of vibration sensors 19 may be one or two or more.

[0083] In the exemplary embodiment described above, an example has been described in which controller 18 includes determination unit 17, and determination unit 17 determines whether polishing of punch 1 is necessary based on first wear amount d calculated by calculation unit 16. However, the present disclosure is not limited to this configuration. Controller 18 does not have to include determination unit 17 as long as calculation unit 16 can calculate first wear amount d of side surface 1b of punch 1 based on the vibration waveform with vibration sensor 19 in press working apparatus 100.

[0084] In the exemplary embodiment described above, an example in which the material of workpiece 5 is the SUS301-EH material has been described, but the present disclosure is not limited to this configuration. Workpiece 5 can be made of various metal materials. The thickness of workpiece 5 is not limited to 0.03 mm but may be any thickness.

[0085] In the exemplary embodiment described above, an example in which punch 1 has circular press surface 1a has been described, but the present disclosure is not limited to this configuration. The shape of press surface 1a is not limited to a circular shape, but may be any shape such as a polygonal shape or an elliptical shape.Second Exemplary Embodiment

[0086] With reference to FIGS. 9 to 11, a second exemplary embodiment will be described. The second exemplary embodiment includes components identical or equivalent to those in the first exemplary embodiment, the components being denoted by the same reference marks as those in the first exemplary embodiment. The description already given for the first exemplary embodiment is omitted for the second exemplary embodiment.

[0087] FIG. 9 is a schematic diagram illustrating press working apparatus 100A according to the second exemplary embodiment. FIG. 10 is a schematic diagram illustrating a state in which punch 1 of press working apparatus 100A of FIG. 9 is at the bottom dead center. FIG. 11 is a top view illustrating load sensor 6 of press working apparatus of FIG. 9. The second exemplary embodiment is different from the first exemplary embodiment in that press working apparatus 100A includes load sensor 6 that detects a load applied to punch 1. In addition, the second exemplary embodiment is different from the first exemplary embodiment in that the wear amount of side surface 1b of punch 1 is calculated based on the load waveform indicating the relationship between the load detected by the load sensor and time.

[0088] As illustrated in FIGS. 9 and 10, press working apparatus 100A includes load sensor 6. Load sensor 6 is a sensor that detects a load applied to punch 1. In the present exemplary embodiment, load sensor 6 detects a load applied in the pressing direction (Z direction) of punch 1 when workpiece 5 is punched with punch 1. As illustrated in FIG. 10, the load applied in the pressing direction of punch 1 includes positive reaction force P1 in the −Z direction and negative reaction force P2 in the +Z direction. Positive reaction force P1 is a load applied to punch 1 mainly when punch 1 punches workpiece 5 (FIGS. 5A to 5C). Negative reaction force P2 is a load applied to punch 1 mainly when punch 1 rises from the bottom dead center (FIGS. 5D to 5F).

[0089] In the present exemplary embodiment, to detect the load applied to punch 1 with load sensor 6, punch 1, load sensor 6, and free shank 20 on the upper side of load sensor 6 are fixed by a fastening bolt (not illustrated) or the like. Thus, load sensor 6 can detect both positive reaction force P1 in the −Z direction when workpiece 5 is punched out and negative reaction force P2 in the +Z direction when punch 1 rises from the bottom dead center.

[0090] As illustrated in FIG. 11, in the present exemplary embodiment, load sensor 6 includes four load sensors 6a to 6d. In the present exemplary embodiment, load sensor 6a and load sensor 6b are disposed symmetrically in the Y direction, and load sensor 6c and load sensor 6d are disposed symmetrically in the X direction. In the present exemplary embodiment, four load sensors 6a to 6d are disposed concentrically at equal intervals. The disposition of four sensors 6a to 6d like this makes it easier to grasp which part of punch 1 is worn.

[0091] As illustrated in FIG. 9, in the present embodiment, sensor controller 15 of controller 18 is electrically connected to load sensor 6, position sensor 13, and vibration sensor 19, and the sensor controller 15 outputs detection values of respective sensors 6, 13, and 19 to calculation unit 16 of controller 18.

[0092] In addition to the vibration waveform described in the first exemplary embodiment, calculation unit 16 generates a load waveform indicating the relationship between the load detected by load sensor 6 and the time from the start of working based on the load of punch 1 detected by load sensor 6. Calculation unit 16 calculates first wear amount d of the side surface of punch 1 based on the vibration waveform. Calculation unit 16 calculates second wear amount b of side surface 1b of punch 1 based on the load waveform in the time from when the working on workpiece 5 is completed to when punch 1 reaches the bottom dead center in the generated load waveform. Further, calculation unit 16 calculates third wear amount c of side surface 1b of punch 1 based on the load waveform in a predetermined period from when punch 1 starts to rise from the bottom dead center in the generated load waveform.

[0093] Determination unit 17 determines whether polishing of punch 1 is necessary based on at least one of first wear amount d, second wear amount b, and third wear amount c of side surface 1b calculated by calculation unit 16. For example, when at least one of second wear amount b and third wear amount c has exceeded the second threshold value, determination unit 17 may determine that polishing of punch 1 is necessary. Alternatively, determination unit 17 may determine that polishing of punch 1 is necessary when the largest value among first wear amount d, second wear amount b, and third wear amount c has exceeded a predetermined threshold value.[Calculation of Wear Amount]

[0094] FIG. 12 is a flowchart for describing processing of calculating the wear amount of side surface 1b of punch 1 in press working apparatus 100A of FIG. 9. The calculation of the wear amount of side surface 1b of punch 1 in the present exemplary embodiment will be described with reference to FIG. 12. Step S11, step S13, and step S15 in FIG. 12 are the same processing as step S1, step S2, and step S3 in FIG. 4, respectively, and thus description thereof is omitted.

[0095] In step S12, load sensor 6 detects a load applied to punch 1. In the present exemplary embodiment, each of four load sensors 6a to 6d detects a load. The load detected by load sensor 6 is output to calculation unit 16 via sensor controller 15 of controller 18. In step S14, calculation unit 16 generates a load waveform indicating the relationship between the load applied to punch 1 and time.

[0096] FIG. 13 is a graph in which load waveforms generated based on the loads detected by four load sensors 6a to 6d and vibration waveforms generated based on the vibrations detected by four vibration sensors 19a to 19d illustrated in FIG. 6 are arranged. In FIG. 13, the load waveform and the vibration waveform are arranged with the horizontal axis aligned. FIG. 13 illustrates a load waveform and a vibration waveform at the time when side surface 1b of punch 1 has not worn much yet.

[0097] As illustrated in FIG. 5A, when the punching has started, punch 1 works in the +Z direction from the top dead center, and punch 1 comes into contact with workpiece 5. In the graph of FIG. 13, the position from the bottom dead center of punch 1 comes at height H at time C1. When punch 1 is positioned at height H from the bottom dead center, that is, at time C1, punch 1 is in contact with the upper surface of workpiece 5 as illustrated in FIG. 5A. When punch 1 comes into contact with workpiece 5, positive reaction force P1 starts to be applied to punch 1. Thus, time C1 in the graph of FIG. 13 is a time point when punch 1 comes into contact with workpiece 5 and positive reaction force P1 applied to punch 1 has become larger than 0. In the load waveform of FIG. 13, positive reaction force P1 is indicated by a value larger than 0, and negative reaction force P2 to be described later is indicated by a value smaller than 0.

[0098] When punch 1 comes into contact with workpiece 5, punching of workpiece 5 is started by punch 1 as illustrated in FIG. 5B. Thus, a load starts to be applied to punch 1 from time C1, and the load on punch 1 rapidly increases. The load applied to punch 1 reaches maximum value P0 at time m1.

[0099] As illustrated in FIG. 5C, when workpiece 5 is cut by punch 1, the load on punch 1 decreases to 0, and the working on workpiece 5 is completed. In FIG. 13, the time point when the working on the workpiece is completed is time C2. Time C2 represents a time point when the load related to punch 1 has decreased to 0 after the load of punch 1 reaches maximum value P0. The reason for the decrease of the load on punch 1 to 0 after reaching maximum value P0 is that punch 1 has punched workpiece 5 and the resistance to punch 1 is eliminated.

[0100] When the load related to punch 1 has become 0 at time C2, negative reaction force P2 in the direction opposite to the direction of positive reaction force P1 is applied to punch 1. Thereafter, positive reaction force P1 is applied to punch 1 as a reaction to negative reaction force P2. The load waveform of FIG. 13 illustrates that positive reaction force P1 and negative reaction force P2 are alternately generated with respect to punch 1 between time C2 and time C6.

[0101] As illustrated in FIG. 10, load sensors 6a to 6d are fixed to punch 1 by free shank 20. A gap is formed between the flange reception portion of free shank 20 and the flange reception portion of free shank holder 22. When the cutting of workpiece 5 is completed, the loads applied to load sensors 6a to 6d, specifically, positive reaction force P1 applied to punch 1 becomes 0. Due to the gap between the flange reception portion of free shank 20 and the flange reception portion of free shank holder 22, the flange reception portion of free shank 20 comes into contact with or separates from the flange reception portion of free shank holder 22 in response to punch 1 punching workpiece 5. Further, the top surface of free shank 20 comes into contact with or separates from backing plate 21. At this time, as illustrated in between time C2 and time C6 of the load waveform in FIG. 13, a load larger than 0 (positive reaction force P1) and a load smaller than 0 (negative reaction force P2) are alternately generated with respect to punch 1.

[0102] Thereafter, the load applied to punch 1 gradually converges to 0 at time C6. The vibration waveform of FIG. 13 indicates that the vibration of die 2 is generated between time C2 and time C6 as described above. In the vibration generated between time C2 and time C6, punch 1 vibrates because of application of positive reaction force P1 and negative reaction force P2 to punch 1, and the vibration of punch 1 is transmitted to die 2 via workpiece 5.

[0103] After the working on workpiece 5 is completed, as illustrated in FIG. 5D, workpiece 5 cut by punch 1 is pushed into hollow portion 2a of die 2. From time C6 to the time when punch 1 illustrated in FIG. 5E reaches the bottom dead center, that is, until time C3, positive reaction force P1 may be applied to punch 1. This is because side surface 1b of punch 1 and workpiece 5 interfere with each other as illustrated in FIGS. 5D and 5E. Positive reaction force P1 generated because of the interference between side surface 1b of punch 1 and workpiece 5 is generated between time C6 and time C3 in FIG. 13, and the load applied to punch 1 becomes 0 at time C3.

[0104] In FIG. 13, punch 1 stops at the bottom dead center from time C3 to time C4. Thus, the load applied to punch 1 is 0. When punch 1 starts to rise from the bottom dead center at time C4, negative reaction force P2 may be applied to punch 1 because of the pulling out of punch 1 from hollow portion 2a of die 2. This is because when punch 1 is pulled out from hollow portion 2a of die 2, side surface 1b of punch 1 and workpiece 5 interfere with each other and a compressive load is applied to punch 1. As illustrated in FIG. 5G, when punch 1 continues to rise and is separated from workpiece 5, the load applied to punch 1 becomes 0. In FIG. 13, the time point when the load applied to punch 1 becomes 0 is time C5.

[0105] Similarly to the vibration waveform described in the first exemplary embodiment, when the wear amount of punch 1 is small, the load waveforms generated based on the loads detected by load sensors 6a to 6d have substantially the same shape. The load waveforms of load sensors 6a to 6d may be slightly different because of a slight difference in clearance between punch 1 and die 2.

[0106] As described above, in the load waveform of FIG. 13, a load is applied to punch 1 because of the interference between side surface 1b of punch 1 and workpiece 5 between time C6 and time C3 and between time C4 and time C5. Calculation unit 16 calculates second wear amount b and third wear amount c of side surface 1b of punch 1 based on the load waveform in this period.

[0107] The description returns to FIG. 12. In step S16, calculation unit 16 calculates second wear amount b of side surface 1b of punch 1 based on the load waveform in the period from the completion of working on workpiece 5 until the punch reaches the bottom dead center, that is, from time C6 to time C3, in the load waveform.

[0108] As described above, a load is mainly applied to side surface 1b of punch 1 from time C6 to time C3. Thus, calculation unit 16 calculates second wear amount b of side surface 1b of punch 1 based on maximum value Ps0 of the load in period Ts0 from time C6 to time C3.

[0109] FIG. 14 is a graph in which a load waveform and a vibration waveform generated when the wear of punch 1 has not progressed are superimposed on a load waveform and a vibration waveform generated when the wear of punch 1 has progressed in FIG. 13. In FIG. 14, the load waveform (broken line) of load sensor 6a and the vibration waveform (broken line) based on vibration sensor 19a generated when the wear of punch 1 has not progressed are superimposed on the vibration waveform (broken line) based on load sensor 6a (solid line) and vibration sensor 19a (solid line) generated when the wear of punch 1 has progressed.

[0110] As illustrated in FIG. 13, the maximum value of the load applied to punch 1 in period Ts0 is maximum value Ps0. When the wear of punch 1, in particular, the wear of side surface 1b of punch 1 has progressed, the maximum value of the load applied to punch 1 in period Ts0 becomes maximum value Ps1.

[0111] When the wear of side surface 1b has progressed, maximum value Ps1 of the load applied to punch 1 in period Ts0 becomes larger than maximum value Ps0 of the load applied to punch 1 when the wear of side surface 1b has not progressed. In this manner, the maximum value of the load applied to punch 1 in period Ts0 changes depending on the state of progress of the wear of side surface 1b. Thus, calculation unit 16 can calculate second wear amount b of side surface 1b of punch 1 based on the maximum value of the load applied to punch 1 in period Ts0.

[0112] For example, as in the first exemplary embodiment, when workpiece 5 is a stainless-steel plate made of SUS301-EH material having a thickness of 0.03 mm, punching is performed under the conditions of an instantaneous speed of punch 1 at the time of punching of 3 mm / s and with no press oil. Under this condition, the relationship of Formula (2) shown below is established between maximum value Ps of the load applied to punch 1 in period Ts0 and second wear amount b of side surface 1b of punch 1.Ps=6.667×b3-2×10-12×b2+8.3333×b+5(2)

[0113] FIG. 15 is a graph illustrating an example of a relationship between maximum value Ps of the load applied to punch 1 in period Ts0 and second wear amount b of side surface 1b of punch 1. According to Formula (2) and FIG. 15, for example, when maximum value Ps of the load applied to punch 1 in period Ts0 is 29 N, second wear amount b of side surface 1b of punch 1 is calculated to be 1.27 μm.

[0114] In the first exemplary embodiment, first wear amount d is calculated based on the maximum value of the vibration of die 2 in period Tsb0, but in the present exemplary embodiment, calculation unit 16 calculates third wear amount c of side surface 1b of punch 1 based on the maximum value of the load applied to punch 1 in period Tsb0.

[0115] As illustrated in FIG. 13, in period Tsb0, the load applied to punch 1 is negative reaction force P2. Thus, as illustrated in the load waveform in FIG. 13, the load applied to punch 1 in period Tsb0 has a value smaller than 0. In period Tsb0, the maximum value of the load applied to punch 1 is maximum value Psb0. The maximum value of the load of punch 1 in period Tsb0 is the maximum value of the absolute value of the load of punch 1. When the wear of punch 1, in particular, the wear of side surface 1b of punch 1 has progressed, the maximum value of the load applied to punch 1 in period Tsb0 becomes maximum value Psb1.

[0116] When the wear of side surface 1b has progressed, maximum value Psb1 of the load applied to punch 1 in period Tsb0 becomes larger than maximum value Psb0 of the load applied to punch 1 when the wear of side surface 1b has not progressed. In this manner, the maximum value of the load applied to punch 1 in period Tsb0 changes depending on the state of progress of the wear of side surface 1b. Thus, calculation unit 16 can calculate third wear amount c of side surface 1b of punch 1 based on the maximum value of the load applied to punch 1 in period Tsb0.

[0117] For example, as in the first exemplary embodiment, when workpiece 5 is a stainless-steel plate made of SUS301-EH material having a thickness of 0.03 mm, punching is performed under the conditions of an instantaneous speed of punch 1 at the time of punching of 3 mm / s and with no press oil. Under this condition, the relationship of Formula (3) shown below is established between maximum value Psb of the load applied to punch 1 in period Tsb0 and third wear amount c of side surface 1b of punch 1.Psb=20×c3+25×c+15(3)

[0118] FIG. 16 is a graph illustrating an example of the relationship between maximum value Psb of the load of punch 1 and third wear amount c of side surface 1b of punch 1 in period Tsb0. According to Formula (3) and FIG. 16, for example, when maximum value Psb of the load applied to punch 1 in period Tsb0 is 87 N, third wear amount c of side surface 1b of punch 1 is calculated to be 1.25 μm.

[0119] When calculation unit 16 calculates the wear amount of side surface 1b in steps S15 to S17, determination unit 17 determines whether polishing of punch 1 is necessary in step S18.

[0120] In the present exemplary embodiment, as described above, the wear amounts of side surfaces 1b are calculated such that first wear amount d is 1.20 μm, second wear amount b is 1.27 μm, and third wear amount c is 1.25 μm. For example, determination unit 17 can determine that polishing of punch 1 is necessary based on the fact that the largest value among first wear amount d, second wear amount b, and third wear amount c has exceeded a predetermined threshold value. By using the largest value among first wear amount d, second wear amount b, and third wear amount c, it is possible to determine whether polishing of punch 1 is necessary in consideration of the calculation error of the wear amount.

[0121] Alternatively, determination unit 17 may determine whether polishing of punch 1 is necessary based the magnitude of the allowable wear amount. For example, it is assumed that the size of the burr allowed for the product manufactured with press working apparatus 100A is 5 μm. As a result of calculating the wear amount when a burr of 5 μm was generated in the product, first wear amount d of side surface 1b of punch 1 was 1.20 μm, second wear amount b was 1.27 μm, and third wear amount c was 1.25 μm. Thus, the allowable wear amount of side surface 1b is such that first wear amount d is 1.20 μm, second wear amount b is 1.27 μm, and third wear amount c is 1.25 μm. Determination unit 17 may use the smallest allowable wear amount among first wear amount d, second wear amount b, and third wear amount c to determine whether polishing of punch 1 is necessary. In this case, determination unit 17 determines whether polishing of punch 1 is necessary using first wear amount d having the smallest allowable wear amount. For example, determination unit 17 can determine that polishing of punch 1 is necessary based on first wear amount d exceeding a predetermined threshold value.

[0122] Further, determination unit 17 may determine that polishing of the punch is necessary when at least one of second wear amount b and third wear amount c has exceeded the second threshold value.

[0123] Which one of first wear amount d, second wear amount b, and third wear amount c is used to determine whether polishing of punch 1 is necessary may be determined in advance depending on, for example, working conditions such as the material or thickness of workpiece 5, the materials of punch 1 and die 2, the punching speed, and the presence or absence of press oil.

[0124] When determination unit 17 has determined in step S18 that polishing of punch 1 is necessary, the driving of press working apparatus 100A is stopped by press controller 14, the punching is interrupted, and the processing ends.

[0125] When determination unit 17 has determined in step S4 that polishing of punch 1 is not necessary, the punching continues, and the processing returns to step S11.Effects

[0126] According to the exemplary embodiment described above, it is possible to provide press working apparatus 100A capable of more accurately calculating the wear amount of side surface 1b of punch 1. The wear amount of side surface 1b of punch 1 is calculated using the load waveform generated based on the load applied to punch 1 in addition to the vibration waveform. Whether polishing of punch 1 is necessary can be determined based on first wear amount d of side surface 1b of punch 1 based on the vibration waveform and second wear amount b or third wear amount c of side surface 1b of punch 1 based on the load waveform having higher calculation accuracy.

[0127] In the exemplary embodiment described above, an example in which load sensor 6 includes four load sensors 6a to 6d has been described, but the present disclosure is not limited to this configuration. Load sensor 6 may include one or two or more load sensors.

[0128] In the exemplary embodiment described above, an example in which calculation unit 16 calculates second wear amount b and third wear amount c based on the load waveform has been described, but the present disclosure is not limited to this configuration. Calculation unit 16 may calculate second wear amount b based on the load waveform, and determination unit 17 may determine whether polishing of punch 1 is necessary based on first wear amount d and second wear amount b.Overview of Exemplary Embodiments(1) A press working apparatus of the present disclosure is a press working apparatus that performs press working on a workpiece, including a punch including a press surface and a side surface connected to the press surface, a die on which the workpiece is placed, the die including a hollow portion in which the punch is to be inserted, a position sensor that detects a position of the punch, a vibration sensor that detects a vibration of the die, and a controller that controls the punch, the die, the position sensor, and the vibration sensor, wherein the controller generates a vibration waveform indicating a relationship between the vibration detected by the vibration sensor and a time after the punch reaches a bottom dead center, and calculates a first wear amount of the side surface of the punch based on the vibration waveform.

[0130] (2) In the press working apparatus according to (1), the vibration waveform may indicate a change in vibration in a predetermined period from when the punch starts to rise from the bottom dead center as detected by the position sensor.

[0131] (3) In the press working apparatus according to (1) or (2), the controller may determine that polishing of the punch is necessary when the first wear amount has exceeded a first threshold value.

[0132] (4) In the press working apparatus according to any one of (1) to (3), the press working apparatus may further include a load sensor that detects a load applied to the punch, wherein the controller may generate a load waveform indicating a relationship between the load detected by the load sensor and a time from a start of press working and calculate a second wear amount of the side surface of the punch based on a part of the load waveform during a period from completion of working on the workpiece until the punch reaches the bottom dead center.

[0133] (5) In the press working apparatus according to (4), whether polishing of the punch is necessary may be determined based on the first wear amount or the second wear amount.

[0134] (6) In the press working apparatus according to (4) or (5), the controller may calculate a third wear amount of the side surface of the punch based on a part of the load waveform in a predetermined period from when the punch starts to rise from the bottom dead center and determine whether polishing of the punch is necessary based at least any one of the first wear amount, the second wear amount, and the third wear amount.

[0135] (7) In the press working apparatus according to (6), the controller may determine that polishing of the punch is necessary when at least one of the second wear amount and the third wear amount has exceeded a predetermined second threshold value.

[0136] (8) In the press working apparatus according to (6) or (7), the controller may determine that polishing of the punch is necessary when a largest value among the first wear amount, the second wear amount, and the third wear amount has exceeded a predetermined threshold value.

[0137] (9) In the press working apparatus according any one of (1) to (8), the vibration sensor may include a plurality of vibration sensors.

[0138] (10) In the press working apparatus according to (9), the plurality of vibration sensors may be disposed at equal intervals around the hollow portion of the die.

[0139] (11) In the press working apparatus according to (9) or (10), the controller may calculate a wear position of the punch based on a plurality of load waveforms each indicating a relationship between the vibration detected by corresponding one of the plurality of vibration sensors and time.

[0140] (12) In the press working apparatus according to any one of (4) to (11), the load sensor may include a plurality of load sensors.

[0141] According to the present invention, it is possible to provide a press working apparatus capable of improving calculation accuracy of a wear amount of a punch.INDUSTRIAL APPLICABILITY

[0142] The press working apparatus of the present disclosure is useful as an apparatus for punching any workpiece used for home electric appliances, medical devices, or the like.REFERENCE MARKS IN THE DRAWINGS1 punch

[0144] 1a press surface

[0145] 1b side surface

[0146] 2 die

[0147] 2a hollow portion

[0148] 3 stripper plate

[0149] 4 die plate

[0150] workpiece

[0151] 6, 6a to 6d load sensor

[0152] 7 slide

[0153] 8 bolster

[0154] 9 press apparatus body

[0155] shaft

[0156] 11 servomotor

[0157] 13 position sensor

[0158] 14 press controller

[0159] sensor controller

[0160] 16 calculation unit

[0161] 17 determination unit

[0162] 18 controller

[0163] 19, 19a to 19d vibration sensor

[0164] free shank

[0165] 21 backing plate

[0166] 22 free shank holder

[0167] 100, 100A press working apparatus

Examples

first exemplary embodiment

[Overall Configuration]

[0035]FIG. 1 is a schematic diagram illustrating press working apparatus 100 according to a first exemplary embodiment of the present disclosure. FIG. 2 is a schematic view illustrating a bottom dead center state of punch 1 of press working apparatus 100 of FIG. 1. FIG. 3 is a top view illustrating vibration sensor 19 of press working apparatus 100 of FIG. 1. In FIGS. 2 to 3, some components are not illustrated. With reference to FIGS. 1 to 3, press working apparatus 100 according to the present exemplary embodiment will be described.

[0036]The X-Y-Z coordinate system illustrated in each drawing is provided to facilitate the understanding of the exemplary embodiments, and is not intended to limit the scope of the exemplary embodiments in any way. In each drawing, an X direction is a width direction of press working apparatus 100, a Y direction is a depth direction of press working apparatus 100, and a Z direction is a height direction of press working apparatus...

second exemplary embodiment

[0086]With reference to FIGS. 9 to 11, a second exemplary embodiment will be described. The second exemplary embodiment includes components identical or equivalent to those in the first exemplary embodiment, the components being denoted by the same reference marks as those in the first exemplary embodiment. The description already given for the first exemplary embodiment is omitted for the second exemplary embodiment.

[0087]FIG. 9 is a schematic diagram illustrating press working apparatus 100A according to the second exemplary embodiment. FIG. 10 is a schematic diagram illustrating a state in which punch 1 of press working apparatus 100A of FIG. 9 is at the bottom dead center. FIG. 11 is a top view illustrating load sensor 6 of press working apparatus of FIG. 9. The second exemplary embodiment is different from the first exemplary embodiment in that press working apparatus 100A includes load sensor 6 that detects a load applied to punch 1. In addition, the second exemplary embodimen...

Claims

1. A press working apparatus that performs press working on a workpiece, the press working apparatus comprising:a punch including a press surface and a side surface connected to the press surface;a die on which the workpiece is placed, the die including a hollow portion in which the punch is to be inserted;a position sensor that detects a position of the punch;a vibration sensor that detects a vibration of the die; anda controller that controls the punch, the die, the position sensor, and the vibration sensor,wherein the controller:generates a vibration waveform indicating a relationship between the vibration detected by the vibration sensor and a time after the punch reaches a bottom dead center; andcalculates a first wear amount of the side surface of the punch based on the vibration waveform.

2. The press working apparatus according to claim 1, wherein the vibration waveform indicates a change in vibration in a predetermined period from when the punch starts to rise from the bottom dead center as detected by the position sensor.

3. The press working apparatus according to claim 1, wherein the controller determines that polishing of the punch is necessary when the first wear amount has exceeded a first threshold value.

4. The press working apparatus according to claim 1, further comprising a load sensor that detects a load applied to the punch,wherein the controller:generates a load waveform indicating a relationship between the load detected by the load sensor and a time from a start of press working; andcalculates a second wear amount of the side surface of the punch based on a part of the load waveform during a period from completion of working on the workpiece until the punch reaches the bottom dead center.

5. The press working apparatus according to claim 4, wherein whether polishing of the punch is necessary is determined based on one or two wear amounts selected from the first wear amount and the second wear amount, the one or two wear amounts including at least the second wear amount.

6. The press working apparatus according to claim 5, whereinthe controller:calculates a third wear amount of the side surface of the punch based on a part of the load waveform in a predetermined period from when the punch starts to rise from the bottom dead center; anddetermines whether polishing of the punch is necessary based on one or two or more wear amounts selected from the first wear amount, the second wear amount, and the third wear amount, the one or two or more wear amounts including at least the third wear amount.

7. The press working apparatus according to claim 6, wherein the controller determines that polishing of the punch is necessary when at least one of the second wear amount and the third wear amount has exceeded a predetermined second threshold value.

8. The press working apparatus according to claim 6, wherein the controller determines that polishing of the punch is necessary when a largest value among the first wear amount, the second wear amount, and the third wear amount has exceeded a predetermined threshold value.

9. The press working apparatus according to claim 1, wherein the vibration sensor includes a plurality of vibration sensors.

10. The press working apparatus according to claim 9, wherein the plurality of vibration sensors is disposed at equal intervals around the hollow portion of the die.

11. The press working apparatus according to claim 9, wherein the controller calculates a wear position of the punch based on a plurality of load waveforms each indicating a relationship between the vibration detected by corresponding one of the plurality of vibration sensors and time.

12. The press working apparatus according to claim 4, wherein the load sensor includes a plurality of load sensors.

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