Pressing device and pressing method

Abstract

To provide a press device and press method which can improve a yield in a forging-press for shaping an alloy having high intensity.SOLUTION: A press device estimates a temperature of a shaping object on the basis of a measurement result of a temperature measuring instrument in a shaping operation in which the shaping object is deformed, and controls a slide speed so that a Z parameter of the shaping object in the shaping operation is maintained within a predetermined range (steps S9-S11).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a press device and a pressing method.

Background Art

[0002] Patent Document 1 describes a method for manufacturing an aluminum alloy material for a structural member under hot working conditions considering the Z parameter. Patent Document 1 shows that an aluminum alloy material for a high-strength structural member can be manufactured by the manufacturing method.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional processing device that attempts to control the Z parameter, the yield may decrease. This was considered to be due to the processing device only considering the temperature of the workpiece before the forming operation.

[0005] An object of the present invention is to provide a press device and a pressing method capable of improving the yield in a forging press that forms a high-strength alloy.

Means for Solving the Problems

[0006] A press device according to one aspect of the present invention During the forming operation in which the workpiece is deformed, The temperature of the molded object, and the temperature of the mold. Based on The aforementioned Of the workpiece absolute Estimate the temperature, Based on the absolute temperature Control the speed of the slide so that the Z parameter of the workpiece during the forming operation is maintained within a predetermined range.

[0007] Another embodiment of the present invention is a press apparatus, Based on the input molding parameters, the system calculates a sliding motion in which the Z-parameter of the molded object is maintained within a predetermined range during the molding operation in which the molded object deforms. The speed of the slide during the molding operation is controlled based on the calculation results of the aforementioned slide movement. death, The molding parameters include the temperature of the workpiece and the absolute temperature of the workpiece during the molding operation, estimated based on the temperature related to the mold temperature. .

[0008] One aspect of the present invention is a pressing method, During the molding process in which the molded object deforms, The temperature of the molded object, and the temperature of the mold. Based on the molded product absolute To estimate the temperature, Based on the absolute temperature The slide speed is controlled so that the Z-parameter of the workpiece during the molding operation is maintained within a predetermined range.

[0009] One aspect of the present invention is a pressing method, Based on the input molding parameters, the system calculates a sliding motion in which the Z-parameter of the molded object is maintained within a predetermined range during the molding operation in which the molded object deforms. The speed of the slide during the molding operation is controlled based on the calculation results of the aforementioned slide movement. death, The molding parameters include the temperature of the workpiece and the absolute temperature of the workpiece during the molding operation, estimated based on the temperature related to the mold temperature. . [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a press apparatus and a press method that can improve yield. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram showing the configuration of a press apparatus according to Embodiment 1 of the present invention, where (a) is a front view and (b) is a top view. [Figure 2] This is a block diagram showing the configuration of the control system of the press device according to Embodiment 1. [Figure 3]It is a graph showing the generation region of the sub-grain structure. [Figure 4] It is a flowchart of the press control process of Embodiment 1. [Figure 5] It is a graph explaining the operations of steps S9 to S12 in FIG. 4. [Figure 6] It is a block diagram showing the configuration of the control system of the press device of Embodiment 2. [Figure 7] It is a flowchart showing the press control process of Embodiment 2.

Mode for Carrying Out the Invention

[0012] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. Hereinafter, "material" means the workpiece to be formed, and "during the forming operation" means the period during which the material is deformed under the load from the mold 20.

[0013] (Embodiment 1) FIG. 1 is a configuration diagram showing the press device of Embodiment 1 of the present invention, (a) is a front view, and (b) is a plan view. FIG. 2 is a block diagram showing the configuration of the control system of the press device of Embodiment 1.

[0014] The press device 1 according to Embodiment 1 is a forging press and includes a bed 23, four uprights 22, a crown 21, a bolster 24, a slide 18, a drive unit 10, and a control unit (computer) 100.

[0015] The bed 23, the four uprights 22, and the crown 21 constitute the frame of the press device 1. The four uprights 22 are erected at the four corners of the front, rear, left, and right of the bed 23 and the crown 21. The bed 23, the four uprights 22, and the crown 21 have tie rods 25a inserted therein and are fastened to each other by being tightened with tie rod nuts 25b. The bolster 24 is fixed on the bed 23, and a lower mold 20D is fixed to the upper part thereof.

[0016] The slide 18 is supported so as to be able to move up and down by guides 19 provided on each of the four uprights 22. The upper die 20U is fixed to the lower part of the slide 18. As the slide 18 descends, the upper die 20U and the lower die 20D come into close proximity, and the material is subjected to load and forged between them. Hereinafter, the upper die 20U and the lower die 20D will be referred to collectively as the die 20.

[0017] The drive unit 10 comprises a motor 11, a transmission shaft 12, a reduction gear 13, an eccentric shaft 14, and a connecting rod 15. The drive unit 10 is supported by the crown 21. When the motor 11 is driven, its rotational motion is transmitted in the order of the transmission shaft 12, the reduction gear 13, and the eccentric shaft 14, and the rotational motion of the eccentric shaft 14 is converted into translational motion of the slide 18 via the connecting rod 15. This causes the slide 18 to move up and down. The motor 11 is a servo motor, and by controlling the amount of rotation, the speed at which the slide 18 moves up and down can be controlled.

[0018] The control unit 100 is a computer that executes a control program. It receives detection results and measurement results from various detection units and measuring instruments (described later), performs calculation processing, and performs various control processing, including drive control of the motor 11.

[0019] <Strain rate estimation configuration> As shown in Figures 1 and 2, the press machine 1 includes a speed detection unit 31 for detecting the speed of the slide 18, a material height detection unit 32 for detecting the height of the material, and a strain rate estimation unit 33 for estimating the strain rate of the material. The strain rate estimation unit 33 is a functional module (software) realized by the control unit 100 executing a control program.

[0020] The speed detection unit 31 is, for example, a linear encoder provided on the guide 19. The linear encoder detects the position of a predetermined part of the slide 18, and the speed of the slide 18 is calculated by the time derivative of that position. The speed detection unit 31 is not limited to the above example, and any configuration that can detect the speed of the slide 18 may be adopted. For example, the rotational speed of the eccentric shaft 14 or the motor 11 may be detected, and the speed of the slide 18 may be detected from that rotational speed.

[0021] The material height detection unit 32 detects the height of the material (the thickness of the material in the height direction) during the molding operation. Specifically, the material height detection unit 32 detects the material height based on the output of the linear encoder that detects the position of the slide 18 and the dimensional data of the mold 20. That is, once the position of the slide 18 is determined, the distance between the top surface of the cavity of the upper mold 20U and the bottom surface of the cavity of the lower mold 20D can be calculated from the dimensional data of the mold 20. The material height detection unit 32 performs this calculation and detects the above distance as the material height.

[0022] In this embodiment, the material height is detected as a single value, assuming that the material height is constant within the cavity of the mold 20. However, if there are differences in material height at different locations within the cavity of the mold 20, the material height detection unit 32 may detect the material height at each location separately.

[0023] The material height detection unit 32 is not limited to the above specific examples, and various configurations may be adopted as long as the material height during the molding operation can be detected, such as a configuration in which the material height is detected by a camera and an image analysis device that analyzes the video acquired by the camera.

[0024] The strain rate estimation unit 33 estimates the strain rate of the material during the molding operation. The strain rate estimation unit 33 calculates the strain rate as the nominal strain rate, as shown in equation (1) below. Strain rate [1 / sec] = Slide speed [mm / sec] / Material height [mm] ...(1)

[0025] The strain rate estimation unit 33 may calculate the strain rate of the material during the molding operation as the true strain rate from the slide speed and the material height. Furthermore, if the material height differs from place to place, the strain rate estimation unit 33 may estimate the strain rate for each place.

[0026] <Temperature estimation configuration> As shown in Figures 1 and 2, the press apparatus 1 includes a first temperature measuring instrument 34 and a second temperature measuring instrument 35 that measure temperatures related to the absolute temperature T of the material, and an absolute temperature estimation unit 36 ​​that estimates the absolute temperature T of the material. The absolute temperature estimation unit 36 ​​is a functional module (software) realized by the control unit 100 executing a control program. The absolute temperature T of the material refers to the temperature (absolute temperature) of the main part of the material.

[0027] The first temperature measuring instrument 34 measures the temperature of a predetermined location in the material. Hereinafter, the temperature of a predetermined location in the material will simply be referred to as the "material temperature." The location where the first temperature measuring instrument 34 measures temperature may be a location outside the main part of the material, for example, the surface of the material's edge. More specifically, the above location may be an exposed surface of the material visible from between the molds 20, or a material surface in contact with the inner surface of the cavity of the mold 20. The temperature of the exposed surface can be measured by a non-contact thermometer such as a radiation thermometer, and the temperature of the material surface in contact with the inner surface of the cavity can be measured by a contact thermometer such as a thermocouple thermometer. The first temperature measuring instrument 34 measures the material temperature in real time throughout the molding process.

[0028] The absolute temperature T of the material often closely matches the material temperature measured by the first temperature measuring instrument 34, but differences may occur depending on the measurement location. In particular, when the material temperature is the surface temperature of the material, the difference may be relatively large because it is easily affected by the mold temperature.

[0029] The second temperature measuring instrument 35 measures the temperature of the mold 20 or the vicinity of the mold 20. The mold 20 is equipped with a heater, and the mold 20 may be heated both before and during the molding process, or both. Based on the measurement results of the second temperature measuring instrument 35, the temperature of the mold 20 that changes due to heating can be detected or estimated. The second temperature measuring instrument 35 measures the temperature in real time throughout the molding process. The second temperature measuring instrument 35 may be a non-contact thermometer such as a radiation thermometer, or a contact thermometer such as a thermocouple thermometer.

[0030] The absolute temperature estimation unit 36 ​​estimates the absolute temperature T of the material during the molding operation, mainly based on the measurement results of the first temperature measuring instrument 34 and the measurement results of the second temperature measuring instrument 35. Since the material temperature measured by the first temperature measuring instrument 34 is determined by the influence of the absolute temperature T of the material and the mold temperature, the absolute temperature T of the material can be calculated from the material temperature and the mold temperature as shown in equation (2) below. The absolute temperature of the material T = material temperature - correction factor K / mold temperature ... (2) Here, the correction factor K is a constant. The correction factor K can be determined by testing or simulation.

[0031] The method for estimating the absolute temperature T of the material by the absolute temperature estimation unit 36 ​​is not limited to the above example. For example, the first temperature measuring instrument 34 is not limited to a configuration that measures the material temperature in real time during the molding process, but may also be configured to measure the material temperature before the molding process, for example, the surface temperature of the material coming out of the material heating device. The material heating device is a device that heats the material before it is set in the mold 20. In this case, the absolute temperature estimation unit 36 ​​may estimate the material temperature during the molding process based on the measured material temperature and the elapsed time since the end of heating, as shown in equation (3) below. Material temperature = Measured temperature at the heating device outlet - Correction factor C × elapsed time ... (3) Here, the correction factor C is a constant. The correction factor C can be determined by testing or simulation.

[0032] Then, the absolute temperature estimation unit 36 may calculate the absolute temperature T of the material by correcting the material temperature estimated by Equation (3) according to Equation (2).

[0033] <Z Parameter Control Configuration> As shown in FIG. 2, the press device 1 according to Embodiment 1 further includes a Z parameter calculation unit 37, a Z parameter control unit 38, a slide speed control unit 39, and a slide operation planning unit 40. Each of these components is a functional module (software) realized by the control unit 100 executing a control program.

[0034] As a parameter related to the formation of subgrain structures in the plastic processing of alloys (such as aluminum alloys and titanium alloys), the Z parameter (Zenner - Hollomon factor) has been known for some time. The generation of subgrain structures means that the density of dislocations during plastic processing decreases, the recrystallization in the heat treatment process is suppressed, and thus the strength of the molded product is improved.

[0035] The Z parameter is calculated from the strain rate ε of the material, the absolute temperature T of the material, and a constant as shown in the following Equation (4). Z = ε×exp(Q / RT) ···(4) Here, ε is the strain rate [1 / sec], T is the absolute temperature [K], Q is the activation energy of the material [J / mol], and R is the gas constant [J / mol·K]. The activation energy Q is a constant determined by the composition of the material, and when the material is an aluminum alloy, it means the activation energy of Al.

[0036] The range of possible values ​​for the Z parameter includes the range in which a sub-grained structure is generated and the range in which a sub-grained structure is not generated. Here, "no sub-grained structure is generated" does not mean that a sub-grained structure is not generated at all, but rather that a sub-grained structure sufficient to obtain the required strength for the molded product is not generated. Below, the boundary between the range in which a sub-grained structure is generated and the range in which it is not generated is denoted as the threshold THz. In this case, it means that a sub-grained structure is generated to the extent that the required strength for the molded product is obtained in the range Z ≤ THz.

[0037] The press apparatus 1 of Embodiment 1 is a device for stably producing high-strength molded products with a sub-granular structure. Therefore, the speed of the slide 18 is controlled so that the Z-parameter of the material during the molding operation is maintained within a predetermined range. In Embodiment 1, the above predetermined range corresponds to a range below the threshold THz at which a sub-granular structure is generated.

[0038] Figure 3 is a graph showing the region where sub-granular textures are formed. In this graph, the threshold THz of the Z parameter is shown as a curve.

[0039] The Z parameter becomes smaller as the absolute temperature T of the material increases. On the other hand, the absolute temperature T of the material is equal to the melting temperature T of the material. Z0、 Furthermore, the cracking induction temperature T that induces cracking of the material. Z1 It needs to be lower than this. Therefore, maintaining the material's Z parameter below the threshold THz during the molding operation means maintaining the material's absolute temperature T and strain rate ε in region A1 (the shaded area in the graph in Figure 3) during the molding operation. Region A1 is where the absolute temperature T is below the cracking induction temperature T. Z1 This is the region where the value is less than the threshold THz and the Z parameter is below the threshold THz. Hereafter, the absolute temperature T and strain rate ε of the material will also be referred to as "parameter(T, ε)".

[0040] The slide motion planning unit 40 creates an initial plan for the slide motion (motion pattern and initial speed of the slide 18). The slide motion planning unit 40 assumes that the material has been heated to a specified temperature by the heat treatment before the molding operation, and creates an initial plan for the slide motion such that the parameters (T, ε) are located within region A1 at least at the start of molding. The above motion pattern and specified temperature may be input by the operator.

[0041] The Z-parameter calculation unit 37 receives the estimation results from the strain rate estimation unit 33 and the absolute temperature estimation unit 36 ​​throughout the molding operation, and calculates the material's Z-parameter from these.

[0042] The Z-parameter control unit 38 monitors whether the parameter (T, ε) deviates from region A1 throughout the molding operation, and if a deviation is predicted, it corrects the molding parameter before the deviation occurs. More specifically, if the plot position of the parameter (T, ε) is displaced from near the center of region A1 to near the boundary, the Z-parameter control unit 38 corrects the molding parameter so that the plot position moves away from the boundary of region A1. The molding parameter to be corrected is mainly the slide speed, which determines the strain rate ε. Note that the molding parameter to be corrected is not limited to the slide speed, but may also be the absolute temperature T of the material. If there is a heater that heats the mold 20 or the material during the molding operation, the absolute temperature T of the material can be increased by increasing the amount of heat from the heater, thereby returning the plot position of the parameter (T, ε) to near the center of region A1.

[0043] The slide speed control unit 39 controls the speed of the slide 18 by controlling the motor 11 according to the motion pattern and initial speed created by the slide motion planning unit 40. On the other hand, if the Z parameter control unit 38 issues a command to correct the slide speed during the molding operation, the speed of the slide 18 is corrected by controlling the motor 11 according to the correction command.

[0044] Furthermore, the slide speed control unit 39 may be configured to control the speed of the slide 18 in at least two stages. In addition, when the Z parameter control unit 38 outputs a slide speed correction command, the slide speed control unit 39 may perform control to reduce the slide speed by one stage based on the correction command.

[0045] By reducing the speed of slide 18, if the parameter (T, ε) approaches the boundary of region A1 during the molding operation, it is possible to move the parameter (T, ε) away from the boundary of region A1, thereby suppressing the parameter (T, ε) from deviating from region A1.

[0046] <Press control processing> Next, the press control process performed by the control unit 100 will be described. Figure 4 is a flowchart of the press control process.

[0047] When the forging process begins, the control unit 100 controls the motor 11 so that the slide 18 is driven according to the initial slide operation plan created by the slide operation planning unit 40 (step S1).

[0048] Then, the control unit 100 receives the slide speed detection result from the speed detection unit 31 (step S2), the material height detection result from the material height detection unit 32 (step S3), and estimates the material strain rate ε in real time through processing by the strain rate estimation unit 33 (step S4).

[0049] Furthermore, in parallel with the processing in steps S2 to S4, the control unit 100 inputs the measurement result of the material temperature from the first temperature measuring instrument 34 (step S5), inputs the measurement result of the mold temperature 20 from the second temperature measuring instrument 35 (step S6), and estimates the absolute temperature T of the material in real time through processing by the absolute temperature estimation unit 36 ​​(step S7).

[0050] Note that the process in step S5 may be replaced with a process that inputs real-time estimated material temperature data, rather than a process that inputs the measured material temperature results. The material temperature can be estimated from the elapsed time after heating using the estimation method described above. Similarly, the process in step S6 may be replaced with a process that inputs real-time estimated temperature data of the mold 20, rather than a process that inputs the measured mold temperature results. The temperature of the mold 20 can be estimated from the temperature of the vicinity of the mold 20, for example, as it correlates with the temperature of the vicinity of the mold 20. Alternatively, if the mold 20 is heated by a mold heating device, the temperature of the mold 20 may be estimated based on the output of the mold heating device and the elapsed time after heating, etc.

[0051] Next, the control unit 100 calculates the material's Z-parameters in real time using the processing of the Z-parameter calculation unit 37 (step S8), and then, the Z-parameter control unit 38 determines whether the material's Z-parameters are near the threshold THz and are expected to exceed the threshold THz (step S9). If the determination result in step S9 is NO, the operation of the slide 18 is kept as originally planned (step S10). If the determination result in step S9 is YES, the Z-parameter control unit 38 outputs a speed correction command, and the control unit 100 reduces the speed of the slide 18 from the originally planned speed based on the correction command (step S11).

[0052] Subsequently, the control unit 100 determines whether one cycle of the press operation has finished (step S12). If it has not finished, it repeats the loop processing from steps S2 to S12. On the other hand, if it determines in step S12 that the operation has finished, the control unit 100 terminates one cycle of press control processing.

[0053] Figure 5 is a graph illustrating the operation of steps S9 to S12 in Figure 4. In the press control process in Figure 4, the loop processing of steps S2 to S12 is repeated, allowing real-time monitoring to ensure that the material parameters (T, ε) do not deviate from region A1 during the pressing process. If deviation is likely, the determination result in step S9 becomes YES, and the speed of slide 18 is reduced. Through this process, the material parameters (T, ε) are maintained within region A1.

[0054] Figure 5(A) shows the transition curve H1 of the parameters (T, ε) during the molding operation when the slide 18 is lowered according to the initial plan set by the slide motion planning unit 40. One end e1 of the transition curve H1 represents the start of the molding operation, and the other end e2 represents the end of the molding operation. The example in Figure 5(A) shows that as time progresses, the material is molded and the material height decreases, so even if the speed of the slide 18 is constant, the strain rate ε increases, and furthermore, the absolute temperature T of the material gradually decreases due to the amount of heat absorbed from the material to the mold 20, etc. In this example, at the beginning of the molding operation, the parameters (T, ε) are within region A1, and the Z parameter is below the threshold THz. However, from the middle of the molding operation onward, the transition curve H1 deviates from region A1, the Z parameter becomes larger than the threshold THz, and a molded product with a low degree of subcrystalline structure formation is formed.

[0055] In other words, even if only the initial parameters of the molding operation (slide speed and material temperature) are controlled to the desired values ​​that cause the formation of a subcrystalline structure in order to manufacture a high-strength molded product, the parameters (T, ε) may change as shown in the transition curve H1 in Figure 5(A), resulting in press molding with a low yield.

[0056] Figure 5(B) shows an example of a transition curve H2 of the parameters (T, ε) during the molding operation of the press control process of Embodiment 1. One end f1 of the transition curve H1 represents the start of the molding operation, and the other end f2 represents the end of the molding operation. In the example in Figure 5(B), although the absolute temperature T of the material gradually decreases over time, control is applied at various points to correct the speed of the slide 18 to a lower value. Through this correction control of the speed of the slide 18, the parameters (T, ε) are maintained within region A1 throughout the molding operation, a subcrystalline structure is generated, and molded products with high strength can be stably obtained. Therefore, the yield of molded products can be improved.

[0057] As described above, according to the press apparatus 1 of Embodiment 1, the absolute temperature estimation unit 36 ​​estimates the absolute temperature T of the material based on the measurement results of the first temperature measuring instrument 34 and the second temperature measuring instrument 35 during the molding operation in which the material deforms. The Z parameter control unit 38 and the slide speed control unit 39 then control the speed of the slide 18 so that the Z parameter of the material during the molding operation is below the threshold THz. Therefore, the problem of the Z parameter being at a desired value at the beginning of the molding operation but deviating from the desired value in the middle or end of the molding operation is solved, and high-strength molded products with a subcrystalline structure can be stably manufactured by controlling the Z parameter to a desired value during the molding operation. Consequently, the yield of molded products can be improved.

[0058] Furthermore, according to the press apparatus 1 of Embodiment 1, the first temperature measuring instrument 34 measures the material temperature. Therefore, by using the measurement results of the first temperature measuring instrument 34, the absolute temperature estimation unit 36 ​​can estimate the absolute temperature T of the material with high accuracy, and consequently, the Z parameter calculation unit 37 can calculate the Z parameter with high accuracy.

[0059] Furthermore, according to the press apparatus 1 of Embodiment 1, the second temperature measuring instrument 35 measures a temperature related to the temperature of the mold 20 (the temperature of the mold 20 itself or the temperature near the mold 20). The temperature of the mold 20 affects the absolute temperature T of the material, while it can take on various temperatures due to heating by the mold heating device. Therefore, the absolute temperature estimation unit 36 ​​can estimate the absolute temperature T of the material that determines the Z parameter with high accuracy by using the measurement results of the second temperature measuring instrument 35, and consequently, the Z parameter calculation unit 37 can calculate the Z parameter with high accuracy.

[0060] Furthermore, according to the press apparatus 1 of Embodiment 1, the Z-parameter control unit 38 corrects the speed of the slide 18 when the parameters (T, ε) are about to deviate from region A1. That is, the parameters (T, ε) are maintained within region A1 by changing the speed of the slide 18 in at least two stages. Reducing the speed of the slide 18 is relatively easy, and furthermore, as the height of the material decreases in the middle or final stages of the molding operation, the degree to which the speed of the slide 18 affects the Z-parameter of the material increases. Therefore, by changing the speed of the slide 18, the Z-parameter during the molding operation can be efficiently controlled to be below the threshold THz.

[0061] (Embodiment 2) Figure 6 is a block diagram showing the configuration of the control system of the press device in Embodiment 2. The control unit 100 of Embodiment 1, described above, calculated the Z parameter in real time during the molding operation and controlled the speed of the slide 18 so that the Z parameter was maintained below the threshold THz. On the other hand, the control unit 100A of Embodiment 2 simulates the state of the material during the molding operation before the molding operation and creates the movement (motion pattern and initial speed) of the slide 18 so that the Z parameter is maintained below the threshold THz during the molding operation. Then, by moving the slide 18 with this movement, a molding operation is realized in which the Z parameter of the material does not exceed the threshold THz during the molding operation. The mechanism of the press device in Embodiment 2 is the same as the mechanism of Embodiment 1 shown in Figure 1.

[0062] The control unit 100A of Embodiment 2 includes a molding parameter input unit 41 for inputting predetermined molding parameters in order to accurately simulate the state of the material during the molding operation, a slide motion planning unit 42 for creating the operation of the slide 18 by simulating the state of the material, and a slide speed control unit 39 for controlling the speed of the slide 18. The slide speed control unit 39, the molding parameter input unit 41, and the slide motion planning unit 42 are functional modules (software) realized by the control unit 100 executing a control program.

[0063] The molding parameter input unit 41 inputs the heating temperature of the material by the material heating device, the heating temperature of the mold 20 by the mold heating device, mold information, and material information. The material heating device is a device that heats the material before it is put into the mold 20. The mold heating device is a device that heats the mold 20 before the molding operation. The mold information includes the cavity shape of the mold 20, the overall dimensions of the mold 20, its shape, and material information. The material information includes the composition, weight, and volume information of the material. This information is entered, for example, by the operator based on actual conditions.

[0064] The slide motion planning unit 42 calculates the temperature change of the material during the molding operation by simulating the amount of heat conducted from the material to the mold 20 during the molding operation based on the heating temperature of the material, material information, the heating temperature of the mold 20, and mold information. Furthermore, the slide motion planning unit 42 may calculate the temperature change of the material more precisely by simulating the amount of heat generated by the material due to the pressure applied to the mold 20 and the deformation of the material during the molding operation.

[0065] Furthermore, the slide motion planning unit 42 calculates the strain rate of the material during the molding operation by simulating the deformation of the material based on the mold information and the slide motion data.

[0066] The slide motion planning unit 42 then calculates the Z-parameter during the molding operation from the temperature change and strain rate of the material, and determines the motion pattern and initial speed of the slide 18 so that the Z-parameter is below the threshold THz. The motion pattern of the slide 18 is such that the speed of the slide 18 changes in at least two stages.

[0067] The operator may also input a proposed motion for the slide 18 via the molding parameter input unit 41. The slide motion planning unit 42 may then determine the modified motion (motion pattern and initial velocity) of the slide 18 by adopting the motion of the slide 18 according to the proposed motion input by the operator in the simulation, while modifying the velocity of the slide 18 in the proposed motion so that the Z parameter does not exceed the threshold THz.

[0068] <Press control processing> Figure 7 is a flowchart showing the press control process performed by the control unit of Embodiment 2.

[0069] In the press control process, the control unit 100A first inputs mold information, material information, material heating temperature, and mold heating temperature information as initial data via the molding parameter input unit 41. This data is pre-input by the operator (step S21). The initial data input in step S21 may include a proposed motion for the slide 18 (proposal for motion pattern and initial speed).

[0070] Next, the control unit 100A, using the slide motion planning unit 42, simulates the material during the molding operation and creates a motion plan (motion pattern and initial velocity) for the slide 18 (step S22). In the simulation, the temperature and strain rate of the material during the molding operation are calculated, and the motion plan for the slide 18 is calculated so that the parameters (T, ε) are maintained in region A1 (Figure 3) during the molding operation.

[0071] Once steps S21 and S22 are completed, the actual molding process becomes possible, and the control unit 100A waits for input of a press start command (step S23). When material is loaded into the mold 20 and a press start command is input, the control unit 100A drives the slide 18 according to the motion plan (motion pattern and initial speed) created in step S22 (step S24). The molding of one piece of material is completed by the process in step S24.

[0072] Once step S24 is completed, the control unit 100A returns the process to step S23. If multiple molding operations are to be performed on multiple materials, the molding process in step S24 can be performed on the new materials by loading new material into the mold 20 and inputting the press start command again.

[0073] In press forming, variations are likely to occur in the time interval between when the material and mold 20 are heated to the specified temperature and when the forming operation begins. If this time interval is long, the material and mold 20 will cool down during that time, causing their temperatures to deviate from the initial temperatures in the simulation. In this case, the accuracy of the simulation calculated by the slide motion planning unit 42 will decrease.

[0074] Therefore, in the press apparatus of Embodiment 2, the time from the end of heating of the material and mold 20 to the start of the molding operation may be controlled to be within a specified time. For example, the control unit 100A may measure this time and provide a notification unit that, if it exceeds the specified time, notifies the user to restart the heating process. Alternatively, the control unit 100A may measure the temperature of the material and the temperature of the mold 20 when the molding operation starts and provide a notification unit that, if the measured temperature deviates from the heating temperature input from the molding parameter input unit 41, notifies the user to restart the heating process.

[0075] As described above, according to the press apparatus of Embodiment 2, based on the molding parameters input via the molding parameter input unit 41, the slide motion planning unit 42 performs a simulation to create a motion plan (motion pattern and initial speed) for the slide 18 so that the Z parameter of the material during the molding operation is below the threshold THz. Then, the material is molded by driving the slide 18 according to the motion plan. Therefore, the problem of the Z parameter being at a desired value at the beginning of the molding operation but deviating from the desired value in the middle or end of the molding operation is solved, and high-strength molded products with a subcrystalline structure can be stably manufactured by controlling the Z parameter to a desired value during the molding operation. Consequently, the yield of molded products can be improved.

[0076] Furthermore, according to the press apparatus of Embodiment 2, the forming parameters input via the forming parameter input unit 41 include the heating temperature of the material, the heating temperature of the mold 20, and mold information including the cavity shape. These forming parameters enable the slide motion planning unit 42 to simulate the absolute temperature T of the material during the forming operation, as well as the strain rate of the material during the forming operation. Therefore, the slide motion planning unit 42 can successfully perform the process of creating a motion plan (motion pattern and initial speed) for the slide 18 so that the Z parameter of the material is below the threshold THz during the forming operation, through simulation.

[0077] Furthermore, according to the press apparatus of Embodiment 2, the speed of the slide 18 changes in at least two stages in the motion pattern created by the slide motion planning unit 42. Reducing the speed of the slide 18 is relatively easy, and furthermore, as the height of the material decreases in the middle or final stages of the molding operation, the degree to which the speed of the slide 18 affects the Z parameter of the material increases. Therefore, by generating a motion pattern in which the speed of the slide 18 changes, it is possible to efficiently achieve a slide 18 operation that keeps the Z parameter below the threshold THz during the molding operation.

[0078] Furthermore, according to the press apparatus of Embodiment 2, the forming parameters input via the forming parameter input unit 41 include a proposed operation for the slide 18. On the other hand, the operation of the slide 18 created by the slide operation planning unit 42 and executed in the subsequent press process differs from the proposed operation. That is, the operator creates a proposed operation for the slide 18 without considering the Z parameter in detail, and by inputting this proposed operation, a modified operation plan for the slide 18 is created to satisfy the Z parameter requirements. Then, the press process can be performed according to this operation plan. Therefore, as long as the Z parameter is maintained below the threshold THz, the slide 18 can be moved according to the proposed operation specified by the operator, and during the period when the Z parameter exceeds the threshold THz in the proposed operation, the modified operation of the slide 18 can maintain the Z parameter below the threshold THz.

[0079] The embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above. For example, in the above embodiments, a press device in which the slide is driven by a servo motor to control the speed of the slide was shown, but a fluid pressure press (e.g., a hydraulic press) in which the slide is moved back and forth by fluid pressure from a servo pump may be used as long as the speed of the slide can be controlled. Furthermore, if the speed of the slide can be controlled in at least two stages, the Z-parameter of the material can be controlled, so a press device that does not use a servo motor as a drive source may also be used.

[0080] Furthermore, Embodiment 1 described above shows an example equipped with both a first temperature measuring instrument 34 that measures the material temperature in real time and a second temperature measuring instrument 35 that measures the temperature related to the mold temperature in real time. However, one of them may be omitted. Even if one is omitted, it is possible to estimate the absolute temperature T of the material during the molding operation from the measured value of one of the material temperature and mold temperature, the heating temperature of the material at the beginning of the molding operation, the heating temperature of the mold at the beginning of the molding operation, and information such as the elapsed time since heating. Other details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0081] 1 Pressing device 10 Drive unit 11 Motor 18 slides 20 molds 20U upper mold 20D lower mold 31 Speed ​​detection unit 32 Material height detection unit 33. Strain rate estimation unit 34. First temperature measuring instrument 35. Second temperature measuring instrument 36 Absolute Temperature Estimation Unit 37 Z-parameter calculation section 38 Z-parameter control unit 39 Slide speed control unit 40 Slide motion planning unit 41 Molding parameter input section 42 Slide motion planning unit 100, 100A control unit THz threshold A1 area T: Absolute temperature (temperature of the molded object) ε Strain rate

Claims

1. During the molding process in which the molded object deforms, the absolute temperature of the molded object is estimated based on the temperature of the molded object and the temperature of the mold. A press device that controls the speed of the slide so that the Z parameter of the workpiece during the molding operation is maintained within a predetermined range based on the absolute temperature.

2. The system comprises a first temperature measuring instrument for measuring the temperature of the molded object, and a second temperature measuring instrument for measuring temperatures related to the mold temperature. The press apparatus according to claim 1.

3. The press apparatus according to claim 1, wherein the speed of the slide changes in at least two stages.

4. Based on the input molding parameters, the system calculates a sliding motion in which the Z-parameter of the molded object is maintained within a predetermined range during the molding operation in which the molded object deforms. Based on the calculation results of the aforementioned sliding motion, the speed of the slide during the molding operation is controlled. A press apparatus in which the molding parameters include the temperature of the workpiece and the absolute temperature of the workpiece during the molding operation, estimated based on the temperature related to the mold temperature.

5. The press apparatus according to claim 4, wherein the molding parameters include at least the heating temperature of the workpiece, the heating temperature of the mold, and mold information including the cavity shape.

6. The sliding motion is calculated such that the speed of the slide changes in at least two stages. The press apparatus according to claim 4.

7. The molding parameters include a proposed sliding motion. The movement of the slide during the molding operation differs from the proposed slide movement. The press apparatus according to claim 4.

8. During the molding process in which the molded object deforms, the absolute temperature of the molded object is estimated based on the temperature of the molded object and the temperature of the mold. A pressing method that controls the speed of a slide so that the Z-parameter of the workpiece during the molding operation is maintained within a predetermined range based on the absolute temperature.

9. Based on the input molding parameters, the system calculates a sliding motion in which the Z-parameter of the molded object is maintained within a predetermined range during the molding operation in which the molded object deforms. Based on the calculation results of the aforementioned sliding motion, the speed of the slide during the molding operation is controlled. A pressing method wherein the molding parameters include the temperature of the workpiece and the absolute temperature of the workpiece during the molding operation, estimated based on the temperature related to the mold temperature.

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