Scrap drop simulation method, simulation program, and press equipment quality assessment method

Abstract

To provide a simulation method of scrap falling and a simulation program, capable of suppressing increase of a calculation amount in simulation and predicting accurately, falling operation of scrap in a press device, and a quality determining method of a press device using the simulation method.SOLUTION: There is provided a simulation method of scrap falling comprising a step of making a three-dimension model from, a press die 54 of a press device 50, a scrap 72 generated from workpiece 70 processed on the press die and a scrap chute 56 for guiding the scrap to outside of the press device, and predicting a mode in which the scrap is fallen to the scrap chute and is discharged to outside. In initial falling in which the scrap generated from the workpiece is fallen to the scrap chute, to the scrap, gravity force and force F which is random magnitude force in a prescribed magnitude range, are acted.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and a program for simulating the dropping of scrap generated in a press machine, and a method for evaluating the quality of a press machine using the simulation method. [Background technology]

[0002] The manufacturing process of press products includes a trimming process in which a scrap portion of a workpiece is cut off and discarded after the workpiece is pressed and formed using a press device.

[0003] In the trimming process, scrap cut from the workpiece is dropped into a scrap chute installed in the press machine. However, if the scrap remains in the press machine due to an unpredictable movement, it can cause defective products in the subsequent processing of pressed products or damage to the press die.

[0004] To solve this problem, a technique has been developed to simulate the action of scrap falling into a scrap chute when designing a press device.

[0005] For example, Patent Document 1 describes a simulation method in which a press device and scrap generated from a workpiece pressed by the press device are virtually created within a computer, and the action of the scrap falling into a scrap chute and being discharged to the outside is virtually reproduced. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-134174 A Summary of the Invention [Problem to be solved by the invention]

[0007] In conventional simulation methods, scrap is generated by allowing it to fall freely under the action of gravity alone. Therefore, scrap of the same shape generated at the same part of the press machine falls in the same manner, but in an actual press machine, the falling action of the scrap changes each time. This is thought to be because, when scrap is generated, forces other than gravity act on it, such as the pressing force from the upper die of the press die during cutting, the restoring force due to the elastic deformation of the plate material itself, the moment of inertia of the scrap itself, and air resistance.

[0008] However, since the magnitude of these forces is small compared to gravity and changes slightly each time scrap is generated, it is difficult to numerically calculate these forces and add them to the simulation. Also, adding each force to the simulation equation results in a huge amount of calculation.

[0009] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a simulation method and simulation program for scrap falling that can accurately predict the falling motion of scrap in a press device while suppressing an increase in the amount of calculations in the simulation, and a quality assessment method for a press device using the simulation method. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, one embodiment of the present invention is a simulation method for scrap falling, which three-dimensionally models a press die of a press machine, scrap generated from a workpiece machined by the press die, and a scrap chute that guides the scrap to the outside of the press machine, and predicts how the scrap will fall into the scrap chute and be discharged to the outside, and is characterized in that it includes a step of applying gravity and a force of a random magnitude within a predetermined range to the scrap at the initial stage of the scrap generated from the workpiece falling into the scrap chute.

[0011] According to this configuration, in the simulation, when the scrap is virtually dropped into the scrap chute, a force of random magnitude within a predetermined range is applied, so that the dropping behavior of the scrap generated in the press changes each time. This makes it possible to reproduce the manner in which the dropping behavior of the scrap changes each time when the scrap is generated without individually calculating various forces other than gravity acting on the scrap, so that it is possible to accurately predict the dropping behavior of the scrap in the press while suppressing an increase in the amount of calculation in the simulation.

[0012] Moreover, one embodiment of the present invention is characterized in that, in the simulation method, a step of performing a deceleration process for the scrap when the falling speed of the scrap exceeds a predetermined threshold value is included.

[0013] According to this configuration, it is possible to perform a highly accurate simulation while suppressing an increase in the amount of calculation required for the simulation. Specifically, if the time interval for calculating the falling speed of the scrap is lengthened in order to reduce the amount of calculation required for the simulation, a phenomenon occurs in the simulation where the scrap is wedged into the scrap chute. If the reaction force that the scrap receives from the chute is calculated in this state, the reaction force becomes excessively large, and the accuracy of the simulation decreases. Furthermore, if the time interval for calculating the falling speed is shortened in order to resolve this situation, the amount of calculation becomes enormous. In response to this, by slowing down the falling speed, it is possible to lengthen the interval for calculating the falling speed to suppress an increase in the amount of calculation, while suppressing an excessive reaction force when the scrap hits the scrap chute, thereby improving the accuracy of the simulation.

[0014] Moreover, one embodiment of the present invention is characterized in that, in the simulation method, the force of random magnitude is set in each of an X direction, a Y direction, and a Z direction which are perpendicular to each other.

[0015] With this configuration, forces of random magnitude act on the falling scrap in each of the X, Y, and Z directions, making it possible to reproduce the various falling motions that may occur when the scrap falls into the scrap chute.

[0016] Moreover, one embodiment of the present invention is a scrap falling simulation program that three-dimensionally models a press die of a press machine, scrap generated from a workpiece machined by the press die, and a scrap chute that guides the scrap to the outside of the press machine, and predicts the operation of the scrap being discharged to the outside via the scrap chute, and is characterized in that it includes a step of applying gravity and a force of a random magnitude within a predetermined range to the scrap at the initial stage of the scrap generated from the workpiece falling into the scrap chute.

[0017] According to this configuration, it is possible to reproduce the way in which the falling motion of the scrap changes each time it is generated without having to individually numerically calculate the various forces other than gravity acting on the scrap. This makes it possible to accurately predict the falling motion of the scrap in the press device while suppressing an increase in the amount of calculations in the simulation.

[0018] Moreover, one embodiment of the present invention is a quality assessment method for a press apparatus using the simulation method, the method including: an iterative step of repeating an operation of dropping the scrap into the scrap chute a predetermined number of times using the simulation method; a probability calculation step of calculating a probability that the scrap has been discharged to the outside through the scrap chute in the iterative step; and a assessment step of determining that the design quality of the press apparatus is low if the probability is less than a predetermined threshold value.

[0019] According to this configuration, by repeating the dropping motion of the scrap a predetermined number of times using the above-mentioned simulation method, it is possible to predict whether scrap with different dropping motions will get stuck in the scrap chute. Also, if the probability that the scrap is discharged to the outside through the scrap chute is less than a predetermined threshold, i.e., if the probability that the scrap is not discharged to the outside due to clogging in the scrap chute or the like is relatively high, it is determined that the design quality of the press device is low, and by making design changes to the press device based on this determination result, it is possible to improve the design quality of the press device. Effect of the Invention

[0020] According to the scrap falling simulation method and simulation program of the present invention, and the quality assessment method for a press machine using the simulation method, it is possible to accurately predict the falling motion of scrap in a press machine while suppressing an increase in the amount of calculations in the simulation. [Brief description of the drawings]

[0021] [Figure 1] FIG. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] 1 is a block diagram showing a simulation system for executing a simulation method and a method for determining design quality of a press apparatus according to an embodiment of the present invention. [Figure 4] 1 is a flowchart showing the steps of a method for simulating scrap dropping. [Diagram 5] FIG. 13 is a diagram illustrating a deceleration process for the scrap. [Figure 6] FIG. 1 is a diagram illustrating a random force acting on scrap. [Figure 7] 4 is a flowchart showing the steps of a method for determining the design quality of a press apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] An embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a schematic diagram showing a press device 50. The press device 50 presses a workpiece 70, which is a plate material, and also performs trimming to cut off a scrap portion of the workpiece 70. As shown in Fig. 1, the press device 50 includes a press die 54 and a scrap chute 56 that guides scrap 72 cut from the workpiece 70 to the outside of the press device 50.

[0023] The press die 54 is a part where trimming is performed on the workpiece 70, and includes a lower die 66 fixed at the installation site, and an upper die 61 that is movable up and down relative to the lower die 66. The lower die 66 includes a lower cutting edge 68 supported on a lower die body 67. The upper die 61 includes a pad 62 that holds down the workpiece 70 placed on the lower die 66, a cam slider 64, and an upper cutting edge 65. The cam slider 64 moves forward toward the workpiece 70 by abutting against a cam driver 69 provided on the lower die body 67 as the upper die 61 descends, and moves backward as the upper die 61 ascends. The upper cutting edge 65 is provided on the cam slider 64 so as to face the lower cutting edge 68.

[0024] The workpiece 70 is cut by the upper cutting edge 65 and the lower cutting edge 68 of the press die 54, and a part of the cut workpiece 70 falls into the scrap chute 56 of the press device 50 as scrap 72.

[0025] The scrap chute 56 is disposed below the lower cutting edge 68 of the press die 54, and extends at an incline with respect to the vertical direction. In the illustrated example, the scrap chute 56 and the lower die body 60 are integrally formed. As shown in FIG. 2, the scrap chute 56 has both side walls 56a, 56b extending in the vertical direction, and a bottom wall 56c connecting the lower ends of the both side walls 56a, 56b, and is open at the top. The upper surface of the bottom wall 56c is formed smooth, and the scrap 72 slides downward in the inclined direction along this upper surface and is discharged to the outside of the press device 50.

[0026] The method for simulating scrap dropping according to this embodiment simulates the process in which scrap 72 generated when workpiece 70 is cut by press device 50 falls into scrap chute 56 and passes through scrap chute 56 until it is discharged to the outside of press device 50. By simulating the manner in which scrap 72 falls and is discharged based on setting data for press device 50 at the design stage of press device 50, it becomes possible to eliminate the problem of scrap 72 remaining inside press device 50 at the design stage. The method for simulating scrap dropping according to this embodiment will be described below.

[0027] 3 is a block diagram showing a simulation system 10 for executing the scrap dropping simulation method of this embodiment. The simulation system 10 of this embodiment has a function of judging the design quality of the press device 50 using the simulation results in addition to simulating the scrap dropping. This simulation system 10 is composed of a single computer such as a microcomputer or a personal computer, or a plurality of computers connected to each other via a network.

[0028] The simulation system 10 includes an input device 12 serving as information input means, an external storage device 14 serving as storage means, a calculation device 16 serving as control means, and a display device 18 serving as display means.

[0029] The input device 12 can be configured using input means such as a keyboard, a mouse, and / or a touch panel.

[0030] The external storage device 14 is an external memory connected to the arithmetic device 16, and can be composed of a magnetic disk, an optical disk, or the like.

[0031] The arithmetic device 16 is a calculator including a microcomputer, and includes a central processing unit (CPU) which is an information processing unit, internal memories such as RAM and ROM, and an input / output interface for communicating with other devices, etc. The information processing unit of the arithmetic device 16 is not limited to a CPU, and can be, for example, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), an application specific standard product (ASSP), a system on chip (SOC), etc.

[0032] The arithmetic device 16 can execute, on a CPU, a scrap dropping simulation program stored in the internal memory or the external storage device 14, a scrap dropping simulation program recorded on a recording medium readable by the arithmetic device 16, or a scrap dropping simulation program loaded from the outside via a network or communication device (not shown). Using this simulation program, the arithmetic device 16 simulates pressing and trimming of the press machine 50 and workpiece 70 that are the analysis targets specified by the input device 12, and simulates the manner in which scrap 72 generated from the workpiece 70 falls into the scrap chute 56 and is discharged to the outside.

[0033] The flow simulation described above includes a model constructing unit 22 , a random force setting unit 24 , a deceleration processing unit 26 , a probability calculating unit 30 , and a determining unit 32 , which are provided in the computing device 16 .

[0034] The model construction unit 21 reads shape data of the press device 50, the workpiece 70, and the scrap 72, and constructs a three-dimensional model thereof. The shape data can be input to the calculation device 16 via the input device 12 or the external storage device 14. In this embodiment, the three-dimensional model is created using CAD data used in carrying out the design of these.

[0035] The random force setting unit 24 sets a force F of random magnitude within a predetermined range to be applied at the initial stage of the fall of the scrap 72. This force F of random magnitude (hereinafter also referred to as "random force F") can be expressed by a random function shown in the following formula (1). force = (upper limit, lower limit) formula (1)

[0036] In this embodiment, as shown in the following equations (2), (3), and (4), a random force F is set in each of the X direction, Y direction, and Z direction which are perpendicular to each other. X-direction force = (upper limit x up , lower limit x low )...Equation (2) Y direction force = (upper limit y up , lower limit y low )...Equation (3) Z direction force = (upper limit z up , lower limit z low )...Equation (4)

[0037] In this embodiment, as an example, the positive Y direction is set to the direction of gravity, and the lower limit value y low = 0. Also, the upper limit x up , upper limit y up and upper limit z up Set to a positive value and lower limit x low and the lower limit z low is set to a negative value. The random force F acting on the scrap 72 is the resultant force of the forces in the X direction, Y direction, and Z direction set by the formulas (2) to (4). The range of the force magnitude of the random force F is set so that it is smaller than the magnitude of gravity acting on the scrap 72.

[0038] The deceleration processing unit 26 detects whether the falling speed V of the scrap 72 is a predetermined threshold value V th (Hereinafter, "speed threshold V th In this embodiment, the scrap 72 is decelerated when the speed exceeds a speed threshold value V thIf the falling speed V of the scrap 72 exceeds the threshold value, a process is performed to halve the falling speed V of the scrap 72 as shown in the following equation (5). V=V / 2...Formula (5)

[0039] The probability calculation unit 30 calculates, based on the results of the scrap drop simulation, the probability that the scrap 72 is properly discharged outside the press device 50 in the simulation. The determination unit 30 determines, based on the probability calculated by the probability calculation unit 30, whether or not the design quality of the press device 50 is low.

[0040] The scrap falling simulation results analyzed by the arithmetic unit 16 are displayed on the display unit 18. The display unit 18 is a device capable of visually displaying information, and can be configured, for example, with a liquid crystal display, an organic EL display, a plasma display, and / or a cathode ray tube display. The display unit 18 can display not only the simulation results but also the simulation process.

[0041] Next, a method for simulating a scrap drop using the simulation system 10 will be described with reference to the flowchart of FIG.

[0042] As shown in FIG. 4, in step S10, various shape data and calculation condition data are read from the external storage device 14 and / or the internal memory of the computing device 16. The shape data includes shape data of the press device 50, the workpiece 70, and the scrap 70, and also includes data on the shape change caused by processing the workpiece 70. The calculation condition data includes the moving cycle time (e.g., 6 seconds) of the upper die 61 of the press die 54, the pressure force of the press die 54, the time Te for dropping the scrap 72 (e.g., 4 seconds), the number of frames N (N is an integer of 2 or more) of the scene into which the drop time Te is equally divided, the upper and lower limits of the random function described above, the magnitude of gravity, and the condition of the reaction force received from the scrap chute 56 when the scrap 70 abuts against the scrap chute 56. In the next step S12, the model construction unit 22 creates a three-dimensional model from the read shape data.

[0043] In the next step S14, the number of times M (M is an integer equal to or greater than 1) to perform the dropping operation of the scraps 72 is set. The number of times M can be a number specified by the input device 12. In the next step S16, the number of times m to perform the dropping operation of the scraps 72 is reset, and the number of times m is set to 1.

[0044] In the next step S18, scene n=1 is set for the dropping operation of the scrap 72. Here, n is the number of each scene of the frame number N read in the numerical condition data, and is an integer from 1 to N. Scene 1 is set to the scene where the scrap 72 is generated by cutting the workpiece 70, that is, the scene at the beginning of the drop of the scrap 72.

[0045] In the next step S20, the random force setting unit 24 sets a random force F based on the random functions of the above-mentioned formulas (2) to (4). In the next step S22, gravity and the random force F are applied to the scrap 72 in scene 1. These forces start the falling motion of the scrap 72.

[0046] In the next step S24, the falling speed V of the scrap 72 is set to a predetermined speed threshold V th It is determined whether the speed threshold V th If it exceeds this value, the deceleration processing unit 26 executes a process of decelerating the falling speed V in the following step S26.

[0047] FIG. 5 is a diagram for explaining the deceleration process of the scrap 72. When the deceleration process is not performed on the scrap 72, if the time interval for calculating the falling speed of the scrap 72 is lengthened (i.e., the value of the number of frames N is reduced) in order to reduce the amount of calculation for the simulation, a phenomenon may occur in which the scrap 72 is wedged into the scrap chute 56 in scene n during the simulation, as shown by the scrap 72 shown by the imaginary line in FIG. 5. This wedged phenomenon does not occur in the actual press device 50, but if the reaction force that the scrap 72 receives from the scrap chute 56 is calculated in the simulation based on this wedged state, the reaction force may become excessively large, and the scrap 72 may bounce back from the scrap chute 56 (hereinafter also referred to as the "bounce back phenomenon"). In order to eliminate the occurrence of the bounce back phenomenon, it is effective to shorten the time interval for calculating the falling speed (i.e., the value of the number of frames N is increased), but if the number of frames N is increased, the amount of calculation becomes enormous.

[0048] Since the falling speed V of the scrap 72 becomes maximum immediately before the scrap 72 comes into contact with the scrap chute 56, in this embodiment, a threshold is set for the falling speed V, and the falling speed V is set to the speed threshold V th When the speed exceeds , the speed is decelerated to prevent the above-mentioned bouncing phenomenon from occurring, while the interval for calculating the falling speed V of the scraps 72 is lengthened to suppress an increase in the amount of calculation. This makes it possible to prevent the scraps 72 from receiving an excessive reaction force when they hit the scrap chute 56, thereby improving the accuracy of the simulation.

[0049] After the deceleration process is performed, in the next step S28, it is determined whether or not the falling time of the scrap 72 exceeds the set falling time Te of the scrap 72. The falling time Te is set to the time until the scrap 72 does not remain in the press device 50 and is discharged to the outside via the scrap chute 56. Note that in step S24, when the falling speed V exceeds the speed threshold value V th In the following cases, the deceleration process is not performed and the process proceeds to step S28.

[0050] If it is determined in step S28 that the time Te has not been exceeded, then in step S30, scene n is counter-processed, and processing continues again from step S24. If it is determined in step S28 that the time Te has been exceeded, then in step S32, it is determined whether the number m of times the scrap 72 has been dropped is equal to or greater than the set number M. If the number m is less than the set number M, then in step S34, the number m is counter-processed, and processing continues again from step S18 (i.e., the process of dropping the scrap 72 from the initial drop position of scene 1 is newly continued).

[0051] 6 is a diagram illustrating the random force F acting on the scrap 72. In a dropping operation with the number of times m=1, a random force F1 is applied using a random function at the beginning of the dropping of the scrap 72. Also, in a dropping operation with the number of times m=2, a random force F2 is applied at the beginning of the dropping of the scrap 72. In this way, by using a random function, the random force F acting on the scrap 72 changes every time the number of times m changes. Note that the gravity acting on the scrap 72 at the beginning of the dropping is constant.

[0052] On the other hand, if the number of times m is equal to or greater than the set number of times M in step S32, the process proceeds to step S36, and the results of the simulation (presence or absence of clogging of the scraps 72, the trajectory of the falling of the scraps 72, etc.) are displayed on the display of the display device 18 or the like. In this embodiment, if a clogging of the scraps 72 occurs, the state in which the scraps 72 are stuck inside the press device 50 is displayed on the display. In the example shown in FIG. 1, the scraps 72 stuck in the scrap chute 56 are shown by virtual lines, which makes it possible to visually identify the location of the clogging.

[0053] As described above, in the simulation method and simulation program according to the present embodiment, when the scrap 72 is virtually dropped into the scrap chute 56 in the scrap drop simulation, a force F of random magnitude within a predetermined range is applied, thereby making it possible to change the dropping behavior of the scrap 72 each time. This makes it possible to reproduce in the simulation the dropping behavior of the scrap 72 that changes each time due to forces other than gravity acting on the scrap 72 when the scrap 72 is generated in the actually manufactured press machine 50 (for example, the pressing force from the upper die 61 of the press die 54 during cutting, the restoring force due to the elastic deformation of the workpiece 70 and the scrap 72, the moment of inertia of the scrap 72 itself, air resistance, and the force due to the shear angles of the upper cutting edge 64 and the lower cutting edge 68).

[0054] Furthermore, since the random force F is set using a random function, the falling motion of the scrap 72 can be changed each time without individually calculating forces other than gravity acting when the scrap 72 is generated, so that the falling motion of the scrap 72 in the press device 50 can be accurately predicted while suppressing an increase in the amount of calculations in the simulation. Furthermore, in this embodiment, forces of random magnitude are applied to the scrap 72 in each of the X-, Y-, and Z-directions, so that a variety of falling motions that may occur when the scrap 72 falls into the scrap chute 46 can be reproduced.

[0055] In the simulation method and the simulation program of the present embodiment, the falling speed of the scrap 72 is a predetermined speed threshold V th By performing a deceleration process on the scrap 72 when the speed exceeds this value, it is possible to reduce the amount of calculation required for the simulation while suppressing the occurrence of the bouncing phenomenon of the scrap 72 in the simulation, thereby enabling a highly accurate simulation to be performed.

[0056] Next, a method for determining the design quality of the press machine 50 by the simulation system 10 will be described with reference to the flowchart of FIG.

[0057] 7, in step S50, the number of times M for performing the dropping operation of the scraps 72 is set. The number of times M is set to an integer equal to or greater than 2. The number of times M can be a number specified by the input device 12. In the next step S52, the number of times m for the dropping operation of the scraps 72 is reset, and the number of times m is set to 1.

[0058] In the next step S54, a scrap drop simulation is performed by the above-mentioned simulation method. The process of step S54 is similar to the process of steps S18 to S28 and the process of step S30 of the above-mentioned simulation method, so the details will be omitted here.

[0059] In the next step S56, it is determined whether the number m of times of the dropping operation of the scrap 72 is equal to or greater than the set number M. If the number m is less than the set number M, the number m is counted in the next step S34, and the process continues from step S18 again (i.e., the process of dropping the scrap 72 from the initial drop position of scene 1 is newly continued). In this way, the simulation of the scrap dropping is repeated a predetermined number of times until the set number M is reached (repetitive process).

[0060] On the other hand, in step S56, if the number of times m is equal to or greater than the set number of times M, the process proceeds to step S60, where the probability calculation unit 30 calculates the probability R that the scrap 72 has been discharged to the outside of the press device 50 through the scrap chute 56 in the above-mentioned repetitive process (probability calculation process). For example, if the number of times M=200 and the number of times Q that the scrap 72 has been properly discharged to the outside (i.e., the number of times that scrap 72 was left behind=20), then the probability R=180 / 200*100(%).

[0061] In the next step S62, the calculated probability R is compared with a predetermined threshold value R th It is determined whether the threshold value R th can be appropriately set by the input device 12. In step S62, the probability R is set to a threshold value Rth If the probability R is less than the threshold value R in step S62, the design quality is determined to be low in step S64 (determination step). th If so, the design quality is judged to be good in the following step S66 (judgment step). After the judgment in step S64 or step S66 is performed, the process proceeds to the next step S68, where the judgment result is displayed on the display of the display device 18 together with the simulation result.

[0062] As described above, in the method for determining the design quality of the press apparatus 50 of this embodiment, the above-mentioned scrap drop simulation method is used to repeat the dropping action of the scrap 72 a predetermined number of times, making it possible to predict whether or not scrap 72 with different dropping actions will get stuck in the scrap chute 56. In addition, the design quality of the press apparatus 50 can be improved by calculating the probability that the scrap 72 is discharged to the outside of the press apparatus 50 through the scrap chute 56 and determining the design quality based on this probability. For example, if there is a relatively high probability that the scrap 72 will not be discharged to the outside of the press apparatus 50 due to, for example, getting stuck in the scrap chute 56, the design quality of the press apparatus 50 is determined to be low, and the design of the press apparatus 50 can be modified based on this determination result.

[0063] For example, if the design quality is determined to be low, the design can be modified to change the shape of the bottom of scrap chute 56 to a V-shape to make it easier to drop, as shown in Fig. 2. Also, for example, a rod-shaped member for changing the falling attitude of scrap 72 can be installed between the position where scrap 72 starts to fall and scrap chute 56, and the falling action can be controlled so that scrap 72 comes into contact with this rod-shaped member to be discharged appropriately without clogging.

[0064] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the invention. [Explanation of symbols]

[0065] 10 Simulation System 12 Input Devices 14 External storage device 16 Arithmetic unit 18 Display device 50 Press equipment 54 Press mold 56 Scrap Shoot 61 Upper mold 66 Lower mold 70 Work 72 Scrap F1,F2 random forces

Claims

1. A simulation method for scrap dropping, which comprises creating a three-dimensional model of a press die of a press machine, scrap generated from a workpiece machined by the press die, and a scrap chute that guides the scrap to the outside of the press machine, and predicting how the scrap drops into the scrap chute and is discharged to the outside, comprising: A simulation method comprising the steps of: applying gravity and a force of a random magnitude within a predetermined range to the scrap generated from the workpiece at the initial stage of the scrap falling into the scrap chute.

2. 2. The simulation method according to claim 1, further comprising the step of performing a deceleration process for the scrap when the falling speed of the scrap exceeds a predetermined threshold value.

3. 3. The simulation method according to claim 1, wherein the force of random magnitude is set in each of an X direction, a Y direction, and a Z direction perpendicular to each other.

4. A scrap dropping simulation program for three-dimensionally modeling a press die of a press device, scrap generated from a workpiece machined by the press die, and a scrap chute that guides the scrap to the outside of the press device, and predicting an operation of the scrap being discharged to the outside through the scrap chute, A simulation program comprising a step of applying gravity and a force of a random magnitude within a predetermined range to the scrap generated from the workpiece at the initial stage of the scrap falling into the scrap chute.

5. A quality assessment method for a press machine using the simulation method according to any one of claims 1 to 3, a repeating step of dropping the scrap into the scrap chute a predetermined number of times using the simulation method; a probability calculation step of calculating a probability that the scrap is discharged to the outside through the scrap chute in the repetitive step; a determining step of determining that the design quality of the press apparatus is low when the probability is less than a predetermined threshold value; A method for evaluating the quality of a press machine, comprising:

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