Press machine and press machine control method

Abstract

To achieve both of processing speed and process tolerance in a press machine.SOLUTION: A press machine (10) comprises: two opposite metal molds (11a, 11b) for pressing a work-piece; and a first drive part and a second drive part for driving at least one of two metal molds. The first drive part can be driven at a high speed compared to the second drive part, the second drive part can be driven with high accuracy compared to the first drive part, and a stop position of the metal mold, which is driven by the second drive part, is changed on the basis of drive situation of the first drive part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a press. [Background technology]

[0002] There are press machines that process workpieces by clamping them between upper and lower dies and applying compressive force. There are various drive mechanisms and press mechanisms for press machines, each with its own advantages and disadvantages.

[0003] Patent Document 1 discloses a press machine in which a servo motor is used to move a die up and down at high speed to press a workpiece. Furthermore, if the load measured by the load cell is insufficient, a hydraulic cylinder attached to the tip of the servo motor applies additional pressure. In other words, the press machine is disclosed in which servo motors and hydraulic cylinders are connected in multiple stages, with each mechanism playing a different role.

[0004] Patent Document 2 discloses a press machine in which a workpiece is clamped between dies having a gap therein to confine the workpiece, and then the workpiece in the gap is punched out with a punch driven by a separate drive mechanism.

[0005] Patent Document 3 discloses a press machine in which multiple servo motors are synchronously controlled to move the entire die up and down and drive some of the drive parts within the die at high speed.

[0006] As described above, press machines using multiple interlocking drive mechanisms have been disclosed, and these press machines are used when moving the entire mold up and down, or when moving the entire mold and parts of the mold separately. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-55932 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-224576 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-142374 Summary of the Invention [Problem to be solved by the invention]

[0008] Conventional presses include a cam type in which a cam is driven by a motor to move a die up and down at high speed, and a servo press type in which a servo motor is used to move a die up and down.

[0009] The cam method makes it possible to speed up the press cycle, but because the bottom dead center position of the die is mechanically determined by the cam, it is difficult to perform a press adjusted with a profile that corresponds to the workpiece or environment.

[0010] In contrast, the servo press method allows for highly accurate control of the stop position, which corresponds to the bottom dead center of the die, making it possible to perform pressing adjusted with a profile that suits the workpiece or environment.However, in order to operate the servo press method at high speed, the lead of the ball screw must be large, which leads to a decrease in accuracy.

[0011] In other words, there is a trade-off between the processing speed and processing accuracy in a press. Therefore, an object of one aspect of the present invention is to realize a press that achieves both processing speed and processing accuracy. [Means for solving the problem]

[0012] In order to solve the above problems, a press machine according to one embodiment of the present invention comprises two opposing dies for pressing a workpiece, a first drive unit and a second drive unit for driving at least one of the two dies, and a control unit for controlling the first drive unit and the second drive unit, wherein the first drive unit can be driven at a higher speed than the second drive unit, and the second drive unit can be driven with a higher degree of precision than the first drive unit, and the control unit changes the stopping position of the die driven by the second drive unit based on the driving status of the first drive unit.

[0013] According to the above configuration, one of the two dies can be driven at high speed by the first drive unit. However, the accuracy of the stop position of the die driven by the first drive unit is low. Therefore, the stop position of the die driven by the second drive unit is changed based on the driving status of the first drive unit. This improves the accuracy of the gap between the two dies. As a result, the press machine can achieve both high processing speed and high processing accuracy.

[0014] One of the two molds may be driven by the first drive unit, and the other of the two molds may be driven by the second drive unit.

[0015] According to the above configuration, the two molds can be driven individually by the first drive unit and the second drive unit, respectively.

[0016] One of the two molds may be driven by the first drive unit and the second drive unit, and the other of the two molds may be fixed.

[0017] According to the above configuration, one of the two dies is driven by the first drive unit and the second drive unit, and can be pressed toward the other fixed die.

[0018] The driving condition of the first driving unit may be a position or a speed of the mold driven by the first driving unit.

[0019] According to the above configuration, the stop position of the second driving unit can be changed based on the position or speed of the mold as the driving condition of the first driving unit.

[0020] The control unit may stop the second driving unit after the first driving unit has stopped.

[0021] According to the above configuration, after the first driving unit stops, the second driving unit, which can operate with higher precision, can reduce the gap error that occurs in the first driving unit.

[0022] The control unit may change the stopping position of the mold driven by the second drive unit based on at least one of the yield stress or proof stress of the workpiece, the temperature of each of the two molds, the temperature of the workpiece, and the ambient temperature.

[0023] According to the above configuration, by taking into consideration various temperatures and individual differences in thickness of the workpieces, the stopping position can be adjusted to be different for each workpiece, thereby making it possible to produce high-precision products.

[0024] The control unit may change a stop position of the die driven by the second drive unit at least once during one pressing operation.

[0025] According to the above configuration, the stop position can be dynamically changed and finely adjusted during pressing.

[0026] The control unit may be capable of controlling a stop position of the mold driven by the first drive unit.

[0027] According to the above configuration, the stop position of the mold driven by the first drive unit can also be controlled, which makes it easier to control the gap between the two molds.

[0028] In order to solve the above-mentioned problems, another aspect of the present invention provides a method for controlling a press machine, which is a method for controlling a press machine having two opposing dies for pressing a workpiece, the press machine including a first drive unit and a second drive unit for driving at least one of the two dies, and a control unit for controlling the first drive unit and the second drive unit, wherein the first drive unit can be driven at a higher speed than the second drive unit and the second drive unit can be driven with a higher degree of accuracy than the first drive unit, and the method includes the steps of acquiring the drive status of the first drive unit and changing the stop position of the second drive unit based on the drive status.

[0029] According to the above control method, the same effects as those described above can be achieved. [Effects of the Invention]

[0030] According to one aspect of the present invention, a press machine that achieves both high processing speed and high processing accuracy can be provided. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a block diagram showing the configuration of a main part of a press machine according to a first embodiment. [Figure 2] 1 is a schematic diagram illustrating a mechanical configuration of a press machine according to a first embodiment. [Figure 3] 4 is a flowchart showing the flow of operations of the press machine according to the first embodiment. [Figure 4] 4 is a graph showing changes in the positions of a first mold and a second mold according to the first embodiment. [Figure 5] 10 is another graph showing changes in the positions of the first mold and the second mold according to the first embodiment. [Figure 6] FIG. 10 is a schematic diagram illustrating the mechanical configuration of a press machine according to a second embodiment. [Figure 7] FIG. 10 is a block diagram showing the configuration of a main part of a press machine according to a third embodiment. [Figure 8] FIG. 10 is a schematic diagram showing the mechanical configuration of a press machine according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] [Embodiment 1] Hereinafter, an embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0033] §1. Application Examples Fig. 1 is a block diagram showing the configuration of the main parts of a press machine 10 according to embodiment 1. Fig. 2 is a schematic diagram showing the mechanical configuration of the press machine 10 according to embodiment 1. The press machine 10 presses the workpiece 40 from above and below using a first die 11a facing the top surface of the workpiece 40 and a second die 11b facing the bottom surface of the workpiece.

[0034] The press 10 is equipped with a first thermometer 14a that measures the temperature of the first die 11a, a second thermometer 14b that measures the temperature of the second die 11b, a work thermometer 15 that measures the temperature of the workpiece, an environmental thermometer 16 that measures the environmental temperature, and a workpiece thickness sensor 17 that measures the thickness of the workpiece before and after pressing (before and after processing). Therefore, during pressing, the press 10 precisely adjusts the amount of pressure applied to the workpiece 40 based on various temperatures and the thickness of the workpiece before processing, thereby processing products with high precision.

[0035] The first mold 11a and / or the second mold 11b can be driven by a first drive unit and a second drive unit. The first drive unit and the second drive unit have different drive speeds and positional accuracy. The first drive unit has low positional accuracy but a high drive speed. In contrast, the second drive unit has a slow drive speed but high positional accuracy. By using the first drive unit and the second drive unit, which have different characteristics, the press 10 can compress the workpiece 40 at high speed with the first drive unit, and then control the second drive unit to adjust the dimensions to the desired accuracy, thereby processing the workpiece into a product.

[0036] §2. Configuration example (Outline of Press Machine 10) The press machine 10 includes a first mold 11a, a second mold 11b, a first servo motor 12a, a second servo motor 12b, a first ball screw 13a, a second ball screw 13b, a first thermometer 14a, a second thermometer 14b, a work thermometer 15, an environmental thermometer 16, a work thickness sensor 17, a main body 19, and a press controller 20.

[0037] 2, the first die 11a faces the upper surface of the workpiece 40, the second die 11b faces the lower surface of the workpiece 40, the workpiece 40 is sandwiched between the first die 11a and the second die 11b, and external forces are applied from above and below to press the workpiece 40. In other words, the first die 11a and the second die 11b face each other.

[0038] (Mechanical configuration of press machine 10) The main body 19 is a so-called housing, and non-moving parts are fixed thereto.

[0039] The first die 11a and the second die 11b are dies that actually press the workpiece 40, and are formed in a shape that allows an appropriate external force to be applied to the workpiece 40.

[0040] The first servo motor 12a and the second servo motor 12b are motors whose stop positions can be controlled, and are fixed to the main body 19. The first ball screw 13a and the second ball screw 13b are fixed in a direction perpendicular to the motor shafts of the first servo motor 12a and the second servo motor 12b, respectively, and each ball screw rotates in response to the rotation of the motors. The movable part of the first ball screw 13a is fixed to the first mold 11a, and the movable part of the second ball screw 13b is fixed to the second mold 11b.

[0041] The first mold 11a moves up and down by a first drive unit. That is, the first servo motor 12a rotates, causing the first ball screw 13a to rotate, and the first mold 11a is driven up and down by the first ball screw 13a. The second mold 11b moves up and down by a second drive unit. That is, the second servo motor 12b rotates, causing the second ball screw 13b to rotate, and the second mold 11b is driven up and down by the second ball screw 13b.

[0042] The first servo motor 12a and the first ball screw 13a together correspond to a first drive unit, and the second servo motor 12b and the second ball screw 13b together correspond to a second drive unit.

[0043] The first ball screw 13a and the second ball screw 13b are not limited to ball screws, but may be any means for transmitting driving force such as a chain, pulleys and a belt.

[0044] The lead of the second ball screw 13b is shorter than the lead of the first ball screw 13a. Furthermore, the accuracy of the second ball screw 13b is higher than the accuracy of the first ball screw 13a. Therefore, the accuracy of the second mold 11b using the second ball screw 13b has finer resolution and higher repeatability than the accuracy of the first mold 11a using the first ball screw 13a. In other words, it can be said that the second drive unit has higher accuracy than the first drive unit. Furthermore, the second servo motor 12b may be able to be controlled with higher accuracy (higher resolution and / or higher repeatability) than the first servo motor 12a.

[0045] (Measuring instrument for press 10) The first thermometer 14a and the second thermometer 14b are thermometers that measure the temperatures of the first mold 11a and the second mold 11b, respectively. The work thermometer 15 is a thermometer that measures the temperature of the workpiece 40, and the environmental thermometer 16 is a thermometer that measures the environmental temperature of the installation environment of the press machine 10. Furthermore, the work thickness sensor 17 measures the thickness of the workpiece 40 before and after processing.

[0046] (Configuration of press controller 20) The press controller 20 includes a position acquisition unit 21, a temperature acquisition unit 22, a thickness acquisition unit 23, a drive control unit 24, and a control unit 30. The control unit 30 includes a sheet processing unit 31 and a stop position command unit 32.

[0047] The position acquisition unit 21 acquires the positions of the first servo motor 12a and the second servo motor 12b from their respective encoders, and acquires the positions of the first mold 11a and the second mold 11b taking into account the relationship with the respective ball screws.

[0048] The position acquisition unit 21 is not limited to acquiring positions from an encoder. That is, the positions may be acquired from a potentiometer or resolver attached to the first servo motor and the second servo motor. The positions of the first mold 11a and the second mold 11b may also be acquired directly from a linear encoder attached to the movable ends of the first drive unit and the second drive unit (or the movable parts of the first ball screw 13a and the second ball screw 13b). The position acquisition unit 21 outputs the acquired positions to the stop position command unit 32. The position acquisition unit 21 also outputs the positions of each servo motor for feedback to the drive control unit 24. The position acquisition unit 21 also outputs the positions to the single wafer processing unit 31 and the stop position command unit 32.

[0049] The temperature acquisition unit 22 acquires the temperatures at the respective locations from the first thermometer 14a, the second thermometer 14b, the workpiece thermometer 15, and the environment thermometer 16. The temperature acquisition unit 22 outputs the acquired temperatures to the single wafer processing unit 31.

[0050] The thickness acquisition unit 23 acquires the thickness of the workpiece 40 from the workpiece thickness sensor 17. The thickness acquisition unit 23 outputs the acquired thickness of the workpiece 40 to the sheet processing unit 31.

[0051] The drive control unit 24 is a so-called servo driver that controls the first servo motor 12a and the second servo motor 12b to the input positions. In other words, it stops the first drive unit and the second drive unit or the first mold 11a and the second mold 11b at the specified positions. The drive control unit 24 also acquires the torques output by the first servo motor 12a and the second servo motor 12b and estimates the loads on each servo motor. The drive control unit 24 then outputs the estimated loads to the single-wafer processing unit 31.

[0052] (Configuration of control unit 30) The single-wafer processing unit 31 is a functional block that uses single-wafer processing to reflect the results of the previous press of the press machine 10 in the next press. Specifically, it estimates the amount of wear and thermal deformation of the mold under the current temperature conditions based on the change in thickness of the workpiece 40 before and after processing, the temperature of each part, the load on each servo motor, and the relationship between stress and strain for each material. Here, single-wafer processing is processing performed on each workpiece individually, rather than batch processing in which multiple workpieces are processed together.

[0053] Furthermore, if the relationship between stress and strain for each material cannot be provided in advance to the press 10, the relationship between stress and strain may be estimated from the change in load and thickness before and after processing. In addition, the elastic modulus, plastic modulus, yield stress or proof stress, etc. may also be estimated.

[0054] The sheet processing unit 31 also inputs the thickness of the workpiece 40 before processing. The sheet processing unit 31 outputs to the stop position command unit 32 information summarizing the amount of wear and thermal deformation of the mold, the elastic modulus, plastic modulus, yield stress or proof stress of the workpiece 40, and the thickness of the workpiece 40.

[0055] The stop position command unit 32 is a functional block that determines the stop positions of the first drive unit and the second drive unit based on information about the sheet processing unit 31 for each press, as well as information about the positions of the first mold 11a and the second mold 11b during pressing. The stop position command unit 32 outputs the determined stop positions to the drive control unit 24.

[0056] §3. Example FIG. 3 is a flowchart showing the flow of operations of the press machine 10 according to the first embodiment.

[0057] In S11, the single-substrate processing unit 31 measures the thickness and temperature of the new workpiece 40. Based on the measurement results, the single-substrate processing unit 31 derives the elastic modulus of the new workpiece 40 and outputs the elastic modulus and the thickness to the stop position command unit 32.

[0058] In S12, the stop position command unit 32 acquires various information, such as the amount of wear and thermal deformation of the previous mold, and the elastic coefficient, plastic coefficient, proof strength or yield stress, and thickness of the workpiece 40, from the sheet processing unit 31. In addition to the various information, the stop position command unit 32 determines the stop positions of the first mold and the second mold from the positions of the first servo motor 12a and the second servo motor 12b acquired from the position acquisition unit 21. Thereafter, the stop position command unit 32 outputs the stop positions to the drive control unit 24. Next, the processes of S21 and S23 are performed in parallel.

[0059] In S21, the drive control unit 24 controls the first servo motor 12a with the input stop position as the target position.

[0060] In S22, the position acquisition unit 21 acquires the position of the first servo motor from the encoder of the first servo motor, and measures the position of the first mold 11a.

[0061] In S23, the drive control unit 24 controls the second servo motor 12b with the input stop position as the target position.

[0062] In S24, the position acquisition unit 21 acquires the position of the second servo motor from the encoder of the second servo motor, and measures the position of the second mold 11b.

[0063] In S31, the stop position command unit 32 determines whether both the first mold 11a and the second mold 11b have reached their target positions based on the positions of the first mold 11a and the second mold 11b. If they have reached their target positions (Yes in S31), the process proceeds to S32. If they have not reached their target positions (No in S31), the process returns to S12. That is, the stop position command unit 32 causes the first drive unit and the second drive unit to drive the first mold 11a and the second mold 11b until both the first mold 11a and the second mold 11b reach their target positions. The second drive unit also continues to dynamically change the target positions. Here, whether the target positions have been reached is determined by whether the deviation between the position of each mold and the target position in each drive unit is equal to or less than a predetermined threshold.

[0064] In S32, the first mold 11a and the second mold 11b are made to wait at the target positions for a predetermined time, which is defined as a waiting time Twait.

[0065] In S33, the single-wafer processing unit 31 calculates the gap between the first mold 11a and the second mold 11b from the positions of the first mold 11a and the second mold 11b acquired from the position acquisition unit 21.

[0066] In S34, the single-wafer processing section 31 estimates the loads applied to the workpiece 40 by the first mold 11a and the second mold 11b from the torques of the first servo motor 12a and the second servo motor 12b.

[0067] In S35, the drive control unit 24 operates the first mold 11a and the second mold 11b to open the molds.

[0068] In S36, the thickness acquisition unit 23 acquires the measured thickness of the workpiece 40 after machining.

[0069] In S37, the temperature acquisition unit 22 measures the first thermometer 14a, the second thermometer 14b, and the environmental thermometer 16. If the workpiece temperature is measured again using the workpiece thermometer 15, the measurement amount and the amount of workpiece deformation due to temperature can be corrected, which has the effect of improving the accuracy of calculating the amount of die wear and thermal deformation, the accuracy of deriving the local elastic modulus or plastic modulus, etc.

[0070] In S38, the single-wafer processing section 31 calculates the amount of wear and the amount of thermal deformation of the first mold 11a and the second mold 11b.

[0071] In S39, the workpiece 40 is discharged and preparations are made for the next workpiece 40 to be loaded.

[0072] §4. Action and Effects By repeating the processes from S12 to S31 until the condition of S31 is met, the first mold 11a and the second mold 11b can be stopped at the target positions. Here, the first drive unit that drives the first mold 11a has a faster drive speed than the second drive unit that drives the second mold 11b, but has the characteristic of being poor in resolution and / or repeatability.

[0073] Therefore, the first die 11a is stopped first, and the stop position of the second die can be determined taking into consideration the stop position of the first die 11a. Therefore, errors occurring in the first drive unit can be corrected by the second drive unit, and the gap between the first die and the second die can be controlled with high precision. Because the gap is highly precise, the product (workpiece 40) pressed by the press 10 is also highly precise.

[0074] Fig. 4 is a graph showing changes in the positions of the first mold 11a and the second mold 11b according to embodiment 1. Fig. 5 is another graph showing changes in the positions of the first mold 11a and the second mold 11b according to embodiment 1.

[0075] In Figures 4 and 5, the dashed lines represent the ideal change in target position. As shown by the dashed lines in Figures 4 and 5, the first mold 11a and the second mold 11b start operating at the same time, with the first mold descending and the second mold ascending. At the target position, the first mold 11a and the second mold 11b simultaneously stop at the stop position. After the first mold 11a and the second mold 11b stop, they stop operating for a predetermined time and apply an external force to the workpiece 40. After that, the first mold ascends and the second mold descends to open the molds and allow the workpiece 40 to be removed.

[0076] In Figure 4, the solid line represents the actual change in position. As the solid line in Figure 4 shows, the first mold stops at the first mold stop position in a state where it has moved too far below the ideal target position. Therefore, the second mold corrects its target position to be lower than the ideal target position and stops at the second mold stop position. Therefore, the second mold stops later than the first mold.

[0077] In Figure 5, the solid line represents the actual position change. As the solid line in Figure 5 shows, the first mold does not reach the ideal target position change and stops at the upper first mold stop position. Therefore, the second mold corrects its target position to be higher than the ideal target position and stops at the second mold stop position. Therefore, the second mold stops later than the first mold.

[0078] As shown in FIGS. 4 and 5, the first drive unit has a high drive speed and is less accurate than the second drive unit, which causes the first die to stop at a first die stop position that is offset from the target position. Therefore, to eliminate the error between the target position of the first die and the first die stop position, the second drive unit continues to operate after the first drive unit stops, based on the drive status of the first drive unit, and stops the second die at the second die stop position. This operation allows the press 10 according to the first embodiment to achieve both high processing speed and high processing accuracy. To achieve both high processing speed and high processing accuracy, the first drive unit and the second drive unit have different characteristics.

[0079] Here, the driving status of the first drive unit refers to information such as the position or speed of the first die driven by the first drive unit. The second drive unit corrects the stop position by causing the position of the second die to follow the first die so as to reduce error, in accordance with the driving status of the first drive unit. In other words, rather than changing the target position of the second drive unit only once the first die is stopped by the first drive unit, the target position of the second drive unit is changed dynamically during pressing to reduce error.

[0080] The differences between the first and second drive units are, for example, the length of the ball screw lead or the machining precision of the ball screw. If the ball screw lead is long, the drive speed increases, but the resolution of the stop position decreases accordingly. In contrast, if the ball screw lead is short, the drive speed decreases, but the resolution of the stop position improves accordingly. Furthermore, the higher the machining precision of the ball screw, the higher the repeatability and the more precisely the product can be manufactured with less variation.

[0081] Here, the relationship between the drive speed or accuracy (resolution and repeatability) of the first drive unit and the second drive unit may be different from that described above. That is, the first drive unit may be able to drive with higher accuracy than the second drive unit, and the second drive unit may be able to drive with higher speed than the first drive unit. In other words, it is sufficient that the first drive unit drives one of the two molds and the second drive unit drives the other mold, and that one of the first drive unit and the second drive unit can be driven at a higher speed than the other and the other can be driven with higher accuracy than the other.

[0082] In addition, by measuring various temperatures and the thickness of the workpiece before and after processing and reflecting this information in each press, high-precision products can be produced.

[0083] Furthermore, the load can be estimated from the torque of the first servo motor 12a and the second servo motor 12b during pressing, and the relationship between stress and strain, including the yield stress or proof stress of the workpiece 40, can be estimated from the amount of deformation before and after processing of each workpiece 40, and applied to the next press for correction. Therefore, high-precision products can be produced through correction. At this time, instead of estimating the load from the torque of the first servo motor 12a and the second servo motor 12b, the load can also be actually measured using a load cell or the like.

[0084] (Compensation according to mold temperature) By correcting the target position in accordance with the temperature of the first mold measured by the first thermometer 14a and the temperature of the second mold measured by the second thermometer 14b in the single wafer processing section 31, it is possible to produce highly accurate products.

[0085] The higher the temperature of the first and second molds, the more the molds themselves thermally expand, so by narrowing the required gap (the distance between the first and second molds), a product of the specified dimensions can be obtained.

[0086] (Compensation according to ambient temperature) The first ball screw 13a and the second ball screw 13b also thermally expand in accordance with the environmental temperature measured by the environmental thermometer 16 in the single wafer processing section 31. Therefore, in order to produce high-precision products, it is necessary to correct the target position (required gap) in accordance with the environmental temperature.

[0087] The higher the environmental temperature, the greater the lead of the first ball screw 13a and the second ball screw 13b. Therefore, by narrowing the required gap, a product of predetermined dimensions can be obtained.

[0088] Furthermore, the relationship between stress and strain in the workpiece 40 itself changes with temperature, and the yield stress or proof stress also changes with temperature. Therefore, the higher the workpiece temperature, the lower the elastic modulus in the elastic region of the workpiece 40 itself and the yield stress or proof stress in the plastic region. By taking these changes into consideration, it is possible to obtain a product with the specified dimensions.

[0089] (correction according to the elastic modulus of the workpiece 40) The higher the elastic modulus of the workpiece 40, the higher the stress that must be applied, so the smaller the required gap must be. Also, the higher the elastic modulus of the workpiece 40, the longer it takes to plastically deform the workpiece 40, so the longer the stopping time Twait must be. By making these corrections, a product of the specified dimensions can be obtained.

[0090] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0091] (Mechanical configuration of press machine 10a) 6 is a schematic diagram showing the mechanical configuration of a press machine 10a according to embodiment 2. The press machine 10a differs from the press machine 10 in that the second drive unit drives a different target, and the second drive unit drives the first drive unit. Also, unlike the press machine 10, the press machine 10a has a second die 11b facing the underside of the workpiece 40, which is fixed to the main body 19. The first die 11a remains driven by the first drive unit.

[0092] Specifically, the second servo motor is fixed to the main body 19, and the first servo motor is not fixed to the main body 19. The second ball screw 13b is assembled to drive the first servo motor 12a. Therefore, when the second servo motor 12b rotates the second ball screw 13b, the first servo motor 12a, the first ball screw 13a, and the first mold 11a move up and down. Also, when the first servo motor 12a rotates the first ball screw 13a, the first mold 11a moves up and down. Therefore, the first mold 11a is driven by the first drive unit and the second drive unit, and its movement amount is the sum of the movement amounts of the first drive unit and the second drive unit.

[0093] (Actions and Effects of Press Machine 10a) Similarly to the press 10, the first and second drive units of the press 10a are different in drive speed, resolution, repeatability, etc. The second drive unit is characterized by higher resolution and repeatability (higher accuracy) than the first drive unit. In contrast, the first drive unit is characterized by a faster drive speed than the second drive unit.

[0094] Therefore, in the press 10a, as in the press 10, the gap between the first mold 11a and the second mold 11b is quickly reduced by a first drive unit with a high drive speed. Thereafter, the gap between the first mold 11a and the second mold 11b is precisely adjusted by a second drive unit with high drive accuracy, resulting in a highly precise gap.

[0095] Therefore, the press machine 10a according to embodiment 2 can also achieve both high processing speed and high processing accuracy, similar to the press machine 10 according to embodiment 1. Furthermore, in the press machine 10a, since both the first drive unit and the second drive unit operate to lower the first die 11a from above to below, it has the characteristic that rattles caused by backlash generated in the ball screw are unlikely to occur.

[0096] Here, the relationship between the drive speed or accuracy (resolution and repeatability) of the first drive unit and the second drive unit may be different from that described above. That is, the first drive unit may be driven with higher accuracy than the second drive unit, and the second drive unit may be driven at a higher speed than the first drive unit. That is, it is sufficient that one of the two molds is driven by the first drive unit and the second drive unit that are connected to each other, and the other mold is fixed. Here, it is sufficient that one of the first drive unit and the second drive unit can be driven at a higher speed than the other, and the other can be driven with higher accuracy than the other.

[0097] [Embodiment 3] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0098] (Mechanical configuration of press machine 10b) Fig. 7 is a block diagram showing the configuration of the main parts of a press machine 10b according to embodiment 3. Fig. 8 is a schematic diagram showing the mechanical configuration of the press machine 10b according to embodiment 3. The press machine 10b differs from the press machine 10 in that it includes a gap sensor 18 and a press controller 20b instead of the press controller 20. Unlike the press controller 20, the press controller 20b includes a gap acquisition unit 25.

[0099] The gap sensor 18 is a sensor that measures the distance (gap) between the first mold 11a and the second mold 11b. The gap sensor 18 may be a micrometer or the like.

[0100] The gap acquisition unit 25 acquires the gap measured by the gap sensor 18. The gap acquisition unit 25 outputs the acquired gap to the single wafer processing unit 31 and the stop position command unit 32.

[0101] (Operation of press machine 10b) In the first embodiment, the single-wafer processing unit 31 estimates the gap from the positions of the first mold 11a and the second mold 11b acquired from the position acquisition unit 21 and uses the estimated gap for correction, but in the third embodiment, the gap is actually measured and used for correction. This makes it possible to perform correction based on actual measurements of the mechanical backlash generated in the first drive unit and the second drive unit and the influence of thermal expansion of the molds, thereby enabling the production of products with higher precision.

[0102] The stop position command unit 32 can drive the first drive unit and the second drive unit by controlling the gap between the first die 11a and the second die 11b, rather than by controlling the positions of the first die 11a and the second die 11b, as in the single wafer processing unit 31. This makes it possible to correct the effects of mechanical backlash occurring in the first drive unit and the second drive unit and thermal expansion of the dies by actually measuring them, allowing for the production of products with higher precision.

[0103] (Variation 1) In the press machine 10b according to the third embodiment, control is performed based on the gap between the first mold 11a and the second mold 11b, so the first drive unit may be a cylinder that does not perform position control. Even in this case, the second drive unit operates to compensate for errors generated by the first drive unit. Therefore, even if the first drive unit does not perform position control, the gap between the first mold 11a and the second mold 11b can be controlled by the gap sensor 18 and the second drive unit, allowing for the production of highly accurate products.

[0104] (Variation 2) In the press machine according to the embodiment described above, the first and second dies are configured to press the workpiece in the vertical direction, but the press machine is not limited to this configuration. For example, the press machine may be configured to press the workpiece in the horizontal direction by the first and second dies.

[0105] Specifically, the opposing surfaces of the first and second dies are stepped, with an upper and lower step. The upper step of the first die is brought into contact with the upper step of the second die, and the lower step of the first die is brought into contact with the lower step of the second die, and the first and second dies are slid laterally toward each other. This causes the workpiece to be pressed laterally between the lower step of the first die and the upper step of the second die.

[0106] Furthermore, in the above-described embodiment, the first mold and the second mold are configured to move in the vertical direction, but this is not limited to this, and for example, the first mold and the second mold may be configured to move in a direction diagonal to the vertical direction.

[0107] Furthermore, in the above-described embodiment, the first mold and the second mold are configured so that their opposing surfaces are provided on a horizontal plane, but this is not limited thereto, and they may be provided, for example, on a vertical plane.

[0108] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0109] 10, 10a, 10b Press 11a First mold 11b Second mold 12a First servo motor (first drive unit) 12b Second servo motor (second drive unit) 13a First ball screw (first drive unit) 13b Second ball screw (second drive unit) 14a 1st thermometer 14b 2nd thermometer 15 Work thermometer 16 Environmental thermometer 17 Work thickness sensor 18 Gap sensor 19 Main Unit 20, 20b Press Controller 21 Position acquisition part 22 Temperature acquisition section 23 Thickness acquisition unit 24 Drive unit 25 Gap acquisition section 30 Control Unit 31 Single wafer processing section 32 Stop position command section 40 Work

Claims

1. Two opposing dies for pressing the workpiece; a first driving unit and a second driving unit for driving at least one of the two molds; a control unit that controls the first drive unit and the second drive unit, The first driving unit can be driven at a higher speed than the second driving unit, The second driving unit can be driven with higher accuracy than the first driving unit, The control unit changes the stop position of the die driven by the second drive unit during one press cycle based on the drive status of the first drive unit during that press cycle.

2. Two opposing dies for pressing a workpiece; a first driving unit and a second driving unit for driving at least one of the two molds; a control unit that controls the first drive unit and the second drive unit, The first driving unit can be driven at a higher speed than the second driving unit, The second driving unit can be driven with higher accuracy than the first driving unit, the control unit changes a stop position of the mold driven by the second drive unit based on a drive status of the first drive unit; A press machine, wherein one of the two dies is driven by the first drive unit, and the other of the two dies is driven by the second drive unit.

3. one of the two molds is driven by the first drive unit and the second drive unit; 2. The press according to claim 1, wherein the other of the two dies is fixed.

4. The press machine according to claim 1 , wherein the driving condition of the first driving unit is a position or a speed of the die driven by the first driving unit.

5. The press machine according to claim 1 , wherein the control unit stops the second drive unit after the first drive unit stops.

6. 6. The press machine according to claim 1, wherein the control unit changes the stop position of the die driven by the second drive unit based on at least one of the elastic modulus, plastic modulus, yield stress or proof stress of the workpiece, the temperature of each of the two dies, the temperature of the workpiece, and the ambient temperature.

7. The press machine according to claim 1 , wherein the control unit changes a stop position of the die driven by the second drive unit at least once during one pressing operation.

8. The press machine according to claim 1 , wherein the control unit is capable of controlling a stop position of the die driven by the first drive unit.

9. A method for controlling a press machine having two opposing dies for pressing a workpiece, comprising: The press machine is a first driving unit and a second driving unit for driving at least one of the two molds; a control unit that controls the first drive unit and the second drive unit, The first driving unit can be driven at a higher speed than the second driving unit, The second driving unit can be driven with higher accuracy than the first driving unit, acquiring a driving status of the first driving unit; and changing, during one pressing, a stop position of the second drive unit based on the driving status during the pressing.

10. A method for controlling a press machine having two opposing dies for pressing a workpiece, comprising: The press machine is a first driving unit and a second driving unit for driving at least one of the two molds; a control unit that controls the first drive unit and the second drive unit, The first driving unit can be driven at a higher speed than the second driving unit, The second driving unit can be driven with higher accuracy than the first driving unit, one of the two molds is driven by the first drive unit, and the other of the two molds is driven by the second drive unit; acquiring a driving status of the first driving unit; and changing the stop position of the second drive unit based on the drive status.

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