FILLING TIMING DETERMINATION APPARATUS, FILLING TIMING DETERMINATION METHOD, AND NON-TRANSITORY STORAGE MEDIUM

Abstract

A processor is configured to: generate analysis meshes constituting a die model and a formed-object model; calculate a distance between the die model and the formed-object model; calculate a difference between the calculated distance and a distance between the die model and the formed-object model obtained by immediately previous analysis; when the difference is a predetermined threshold value or more, calculate an approximation line based on a predetermined number of distance history data pieces starting from a time at which the distance between the die model and the formed-object model becomes zero; when the difference is less than the predetermined threshold value, calculate an approximation line based on calculated distance history data starting from a time immediately preceding the time at which the difference is determined to be less than the predetermined threshold value; and calculate, from the approximation line, a time at which the distance becomes zero.

Claims

1. A filling timing determination apparatus comprising a processor configured to calculate a distance between a die model and a formed-object model at each forming time in forging, and determine a filling timing, based on the distance, wherein the processor is configured to calculate distance history data from the distance between corresponding nodes, one of the corresponding nodes being a node on a plurality of analysis meshes that constitutes the die model, the other of the corresponding nodes being a node on a plurality of analysis meshes that constitutes the formed-object model, calculate an approximation line, based on the distance history data, and determine, based on the approximation line, a timing at which the formed-object model fills the die model.

2. The filling timing determination apparatus according to claim 1, wherein the processor is configured to calculate a distance difference between a first distance calculated at a first forming time and a second distance calculated at a second forming time immediately preceding the first forming time, determine, based on the distance difference, whether a change in the distance is normal, and change, based on a result of the determination of whether a change in the distance is normal, the distance history data to be used to calculate the approximation line.

3. The filling timing determination apparatus according to claim 2, wherein the processor is configured to, in response to a fact that the distance difference is a predetermined threshold value or more, calculate the approximation line by using a predetermined number of pieces of the distance history data starting from a time at which the distance becomes zero.

4. The filling timing determination apparatus according to claim 2, wherein the processor is configured to, in response to a fact that the distance difference is less than a predetermined threshold value, calculate the approximation line by using a predetermined number of pieces of the distance history data starting from a second time immediately preceding a first time at which the distance difference becomes less than the predetermined threshold value.

5. The filling timing determination apparatus according to claim 2, wherein the processor is configured to, in response to a fact that the distance obtained from the approximation line becomes zero, determine a filling timing at which the formed-object model fills the die model.

6. A filling timing determination method for a filling timing determination apparatus, the filling timing determination apparatus including a processor configured to calculate a distance between a die model and a formed-object model at each forming time in forging, and determine a filling timing, based on the distance, the filling timing determination method comprising: calculating distance history data from the distance between a node on a plurality of analysis meshes that constitutes the die model, and a node on a plurality of analysis meshes that constitutes the formed-object model; calculating an approximation line, based on the distance history data; and determining, based on the approximation line, a timing at which the formed-object model fills the die model.

7. A non-transitory storage medium storing instructions that cause a processor to perform functions, the processor being included in a filling timing determination apparatus, the processor being configured to calculate a distance between a die model and a formed-object model at each forming time in forging, and determine a filling timing, based on the distance, the functions comprising: calculating distance history data from the distance between a node on a plurality of analysis meshes that constitutes the die model, and a node on a plurality of analysis meshes that constitutes the formed-object model; calculating an approximation line, based on the distance history data; and determining, based on the approximation line, a timing at which the formed-object model fills the die model.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Features, advantages, and technical and industrial significance of exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein:

[0017] FIG. 1A shows an outline of a filling timing determination apparatus according to an embodiment;

[0018] FIG. 1B shows the outline of the filling timing determination apparatus according to the embodiment;

[0019] FIG. 2 is a functional block diagram showing a configuration of the filling timing determination apparatus shown in FIG. 1B;

[0020] FIG. 3 shows an example of generation of analysis mesh;

[0021] FIG. 4A is an explanatory diagram for describing a change, occurring when remeshing is performed, in distance between a node of a die model and a node of a formed-object model;

[0022] FIG. 4B is an explanatory diagram for describing the change, occurring when remeshing is performed, in distance between the node of the die model and the node of the formed-object model;

[0023] FIG. 5 is an explanatory diagram (No. 1) for describing determination of a filling timing;

[0024] FIG. 6 is an explanatory diagram (No. 2) for describing determination of a filling timing;

[0025] FIG. 7 is a flowchart showing a procedure for processing by the filling timing determination apparatus shown in FIG. 2;

[0026] FIG. 8 is a flowchart showing a procedure for processing in a distance calculation process shown in FIG. 7; and

[0027] FIG. 9 shows an example of a hardware configuration.

DETAILED DESCRIPTION OF EMBODIMENTS

[0028] Hereinafter, an embodiment of a filling timing determination apparatus, a filling timing determination method, and a filling timing determination program according to the present disclosure is described in detail based on the drawings.

[0029] An outline of the filling timing determination apparatus according to the present embodiment is described. FIGS. 1A, 1B show the outline of the filling timing determination apparatus according to the embodiment.

Outline of Filling Timing Determination Apparatus 10

[0030] As shown in FIG. 1A, in manufacture of a product by using forging technology, forming of the product is performed through a plurality of forming processes. FIG. 1A shows a state in which forming is performed with the passage of time in a forming process. Specifically, the state is shown in which preparation of a formed object is made at forming time 1, forming is repeated for each portion at each forming time, and via forming time 30, forming is completed at forming time 100. A time at which the distance between a die and a formed object becomes zero or less during forging is referred to as "filling timing". In general, determination of a filling timing is performed using analysis.

[0031] In analysis, when the shape of an analysis-target region greatly changes during analysis, remeshing that reconstructs mesh to adapt to the changed shape is performed to improve accuracy of the analysis. Due to such remeshing, in some cases, the distance between a node on an analysis mesh of a die model and a node on an analysis mesh of a formed-object model after remeshing becomes discontinuous from those before remeshing, resulting in determination of a filling timing being unable to be accurately performed.

[0032] In the present disclosure, as shown in FIG. 1B, the following is performed in each forming process of forging: numerical analysis is conducted based on the formed-object model; a distance between nodes of the die model and the formed-object model is calculated; and a filling timing is determined based on the distance. The filling timing determination apparatus 10 generates analysis mesh including a plurality of nodes that constitutes the formed-object model. The filling timing determination apparatus 10 conducts numerical analysis while performing remeshing as necessary. In the numerical analysis, a distance from a node on analysis mesh constructed on the inner surface of the die model to a corresponding node on the analysis mesh of the formed-object model is calculated at each forming time.

[0033] Thereafter, the filling timing determination apparatus 10 determines a filling timing, based on the distance. Specifically, a difference is calculated between the calculated distance from the node of the die model to the node of the formed-object model and a distance between the node of the die model to the node of the formed-object model calculated at the immediately preceding forming time. When there is included a forming time at which the difference is a predetermined threshold value or more, the filling timing determination apparatus 10 calculates an approximation line, based on a predetermined number of distance history data pieces, starting from a time at which the distance between the nodes of the die model and the formed-object model has become zero or less, then calculates, from the approximation line, a time at which the distance becomes zero, and then determines that the calculated time is a filling timing.

[0034] When there is included a forming time at which the difference is less than the predetermined threshold value, the filling timing determination apparatus 10 calculates an approximation line starting from a time immediately preceding the time at which the difference is determined to be less than the predetermined threshold value, based on the predetermined number of distance history data pieces calculated before the starting-point time, then calculates, from the approximation line, a time at which the distance becomes zero, and then determines that the calculated time is a filling timing. Note that the predetermined threshold value is, for example, 0.4 mm.

[0035] As described above, when there occurs a forming time at which the distance, or a change in distance, indicates an abnormal value in the course of the distance uniformly decreasing as forming time progresses, the filling timing determination apparatus 10 executes processing of reviewing a filling timing. When the reduced amount suddenly decreases at a certain forming time, the filling timing determination apparatus 10 can obtain an approximation line based on distances at a plurality of forming times before the certain forming time without including the forming time at which the reduced amount indicates an abnormal value, and thus can determine a filling timing from the approximation line. The filling timing determination apparatus 10 sets a threshold value for detecting an abnormality of the reduced amount of distance, detects an abnormality as described above, and determines a filling timing.

Configuration of Filling Timing Determination Apparatus 10

[0036] Next, a configuration of the filling timing determination apparatus 10 shown in FIG. 1B is described. FIG. 2 is a functional block diagram showing the configuration of the filling timing determination apparatus 10 shown in FIG. 1B. The filling timing determination apparatus 10 includes a display unit 11, an input unit 12, a storage unit 14, and a control unit 15. The display unit 11 is a display device, such as a liquid crystal display, that displays various information. The input unit 12 is an input device, such as a mouse or a keyboard.

[0037] The storage unit 14 is a storage device, such as a hard disk device or a non-volatile memory, and stores forging process data 14a, mesh data 14b, and distance history data 14c. The forging process data 14a is data on a formed-object model in each forming process using forging technology. The mesh data 14b is data on analysis meshes that include a plurality of nodes and are generated, to conduct analysis, with respect to surfaces of the die model and the formed-object model.

[0038] The distance history data 14c is data indicating the distance between each node on the analysis mesh of the formed-object model and each corresponding node on the analysis mesh of the die model. In the distance history data 14c, a period of time passing (hereinafter, referred to as "period of time") from forming time 1 until each forming time, and a distance between each pair of corresponding nodes of the formed-object model and the die model calculated at each forming time are stored in association with each other. Note that when remeshing is performed, a node, among nodes on an analysis mesh of the formed-object model after the remeshing, that has the shortest distance from a node on the analysis mesh of the die model is set as the node corresponding to the node of the die model.

[0039] The control unit 15 is a control unit that controls the filling timing determination apparatus 10 as a whole, and includes a mesh generation section 15a, a numerical analysis section 15b, a distance calculation section 15c, a distance difference calculation section 15d, a distance difference determination section 15e, an approximation line calculation section 15f, and a determination section 15g. In actual practice, programs for the sections are loaded on and executed by a CPU, whereby the mesh generation section 15a, the numerical analysis section 15b, the distance calculation section 15c, the distance difference calculation section 15d, the distance difference determination section 15e, the approximation line calculation section 15f, and the determination section 15g are caused to execute respective corresponding processes.

[0040] The mesh generation section 15a is a processing section that generates analysis mesh 40 including a plurality of nodes for analysis, with respect to each of a die model and a formed-object model 60. As to the size of the analysis mesh 40 to be generated, density is changed according to the shapes of the die model and the formed-object model 60. For example, as shown in FIG. 3, the finer analysis mesh 40 is generated in a region where changes in shape of the formed-object model 60 occur.

[0041] The numerical analysis section 15b is a processing section that conducts numerical analysis, based on nodes on the generated analysis mesh. For the numerical analysis, for example, Finite Element Method or the like is used.

[0042] The distance calculation section 15c is a processing section that calculates a distance between a node of the die model and a corresponding node of the formed-object model 60. Specifically, the distance between a node on the analysis mesh 40 of the die model and a node on the analysis mesh 40 of the formed-object model 60 is calculated, with the node on the analysis mesh 40 of the die model used for a starting point. Then, the distance calculation section 15c stores the calculated distance as the distance history data 14c in the storage unit 14. The die model is not deformed, so remeshing of the analysis mesh 40 of the die model is not performed even if forming time progresses. Accordingly, when a distance is calculated, a node on the analysis mesh 40 of the die model is used for a starting point, whereby accuracy of the calculated distance is also maintained when remeshing of the analysis mesh 40 of the formed-object model 60 is performed.

[0043] The distance difference calculation section 15d is a processing section that calculates a difference between a first distance calculated at a predetermined forming time and a second distance calculated at a forming time immediately preceding the predetermined forming time. Specifically, the first distance and the second distance are read from the distance history data 14c in the storage unit 14, and the difference is calculated by subtracting the first distance from the second distance.

[0044] The distance difference determination section 15e is a processing section that determines whether the distance difference calculated by the distance difference calculation section 15d is a predetermined threshold value or more. Specifically, "normality" is determined when the distance difference is the predetermined threshold value or more, and "abnormality" is determined when the distance difference is less than the predetermined threshold value.

[0045] The approximation line calculation section 15f is a processing section that calculates a coefficient of an approximation line through the least-squares method or the like by using a predetermined number of distance history data pieces before a predetermined time in the distance history data 14c. For example, assuming that the approximation line is expressed as y = ax + b, the approximation line calculation section 15f calculates coefficients a, b by using the predetermined number of distance history data pieces. Based on a result of the determination by the distance difference determination section 15e, when the result of the determination is "normality", the approximation line calculation section 15f calculates the coefficients, based on the predetermined number of distance history data pieces, starting from a time at which the distance has become zero. When the result of the determination is "abnormality", the approximation line calculation section 15f uses, for the starting point, a time immediately preceding the time at which "abnormality" is determined, and calculates the coefficients, based on the predetermined number of distance history data pieces before the starting-point time. The predetermined number is, for example, ten.

[0046] The determination section 15g is a processing section that calculates a time at which the distance becomes zero, and determines that the time is a timing at which the formed object fills the die. Specifically, the determination section 15g calculates the time at which the distance becomes zero, from an equation of the approximation line calculated by the approximation line calculation section 15f. For example, when the approximation line is expressed as y = ax + b, the determination section 15g calculates x that satisfies y = 0, and determines that the calculated value of x is a filling timing.

Change in Distance between Die Model and Formed-object Model When Remeshing Is Performed

[0047] Next, a description is given of a change in distance between a node of the die model and a node of the formed-object model occurring when remeshing is performed. FIGS. 4A, 4B are explanatory diagrams for describing a change in distance between a node of the die model and a node of the formed-object model occurring when remeshing is performed. As shown in FIG. 4A, forming time in forging progresses, and at certain forming time N, a distribution of distances between nodes of the die model and nodes of the formed-object model is obtained. Then, as shown in FIG. 4B, when remeshing is performed at forming time (N + 1), analysis mesh 40 that has a new node in a region A is generated. FIG. 4B shows a state in which the new node generated in the region A has a larger value of distance than a distance at forming time N.

Determination of Filling Timing

[0048] Next, determination of a filling timing for the die and the formed object is described. FIGS. 5 and 6 are explanatory diagrams for describing determination of a filling timing. As shown in FIG. 5, when the distance between a node of the die model and a corresponding node of the formed-object model simply decreases, the coefficients a and b of the equation (y = ax + b) of the approximation line are calculated based on the predetermined number of distance history data pieces starting from a time (here t.sub.n+5) at which the distance has become zero, then x that satisfies y = 0 is obtained from the approximation line, and then it is determined that the obtained value of x is a filling timing.

[0049] In contrast, as shown in FIG. 6, when a discontinuous situation appears in decreases of the distance between a node of the die model and a node of the formed-object model, the coefficients a and b of the equation (y = ax + b) of the approximation line are calculated based on the predetermined number of distance history data pieces starting from time t.sub.n+3 immediately preceding time.sub.t+4 at which discontinuity occurs, then x that satisfies y = 0 is obtained from the approximation line, and then it is determined that the obtained value of x is a filling timing. Note that time.sub.t+4 at which discontinuity occurs in decreases of the distance between the die model and the formed-object model is a time at which "abnormality" is determined by the distance difference determination section 15e.

Procedure for Processing by Filling Timing Determination Apparatus 10

[0050] Next, a procedure for processing by the filling timing determination apparatus 10 is described. FIG. 7 is a flowchart showing the procedure for processing by the filling timing determination apparatus 10 shown in FIG. 2. As shown in FIG. 7, the filling timing determination apparatus 10 generates analysis mesh for a die model and a formed-object model (step S101).

[0051] Then, the filling timing determination apparatus 10 performs a distance calculation process (step S102). Thereafter, the filling timing determination apparatus 10 calculates a distance difference (step S103). Then, the filling timing determination apparatus 10 determines whether the distance difference is a predetermined threshold value or more (step S104).

[0052] When the distance difference is less than the predetermined threshold value (step S104: No), the filling timing determination apparatus 10 calculates an approximation line by using a predetermined number of distance history data pieces starting from a time immediately preceding the time at which the distance difference is less than the predetermined threshold value (step S105), and moves to step S108. When the distance difference is the predetermined threshold value or more (step S104: Yes), the filling timing determination apparatus 10 determines whether the distance has become zero (step S106).

[0053] When the distance is not zero (step S106: No), the filling timing determination apparatus 10 moves to step S104. When the distance is zero (step S106: Yes), the filling timing determination apparatus 10 calculates an approximation line by using the predetermined number of distance history data pieces starting from the time at which the distance becomes zero (step S107).

[0054] Then, the filling timing determination apparatus 10 calculates a time at which the distance becomes zero, based on the approximation line (step S108). Thereafter, the filling timing determination apparatus 10 determines that the calculated time at which the distance becomes zero is a filling timing (step S109).

Procedure for Processing in Distance Calculation Process

[0055] Next, a procedure for processing in the distance calculation process shown in FIG. 7 is described. FIG. 8 is a flowchart showing the procedure for processing in the distance calculation process shown in FIG. 7. As shown in FIG. 8, the distance calculation process conducts numerical analysis by using Finite Element Method or the like (step S201).

[0056] Then, the distance calculation process calculates a distance between a node on analysis mesh of the die model and a corresponding node on analysis mesh of the formed-object model (step S202). Thereafter, the distance calculation process determines whether a forming time at which numerical analysis is conducted is the final forming time (step S203). When the forming time at which numerical analysis is conducted is not the final forming time (step S203: No), the distance calculation process reads data on the formed-object model for a next forming time (step S204), and moves to step S201.

[0057] When the forming time at which numerical analysis is conducted is the final forming time (step S203: Yes), the distance calculation process moves to step S103 shown in FIG. 7.

[0058] As described above, in the present embodiment, the filling timing determination apparatus 10 generates analysis mesh including a plurality of nodes that constitutes a formed-object model. Then, the filling timing determination apparatus 10 conducts numerical analysis, and calculates a distance between a die model and the formed-object model at nodes on the respective analysis meshes, based on the respective analysis meshes. Thereafter, the filling timing determination apparatus 10 calculates a difference between the calculated distance between the die model and the formed-object model and a distance between the die model and the formed-object model at the immediately preceding forming time, and, when the difference is a predetermined threshold value or more, calculates an approximation line based on a predetermined number of distance history data pieces starting from a time at which the distance between the die model and the formed-object model has become zero or less. When the difference is less than the predetermined threshold value, the filling timing determination apparatus 10 calculates an approximation line based on history of the calculated distances starting from a time immediately preceding the time at which the difference is determined to be less than the predetermined threshold value, calculates, from the approximation line, a time at which the distance becomes zero, and determines that the calculated time is a filling timing.

[0059] Note that the embodiment describes a case in which when the distance difference is the predetermined threshold value or more, an approximation line is also calculated and a filling timing is determined from the approximation line. However, when the distance difference is the predetermined threshold value or more, it may be determined that a time at which the calculated distance is zero is a filling timing.

[0060] Moreover, although the embodiment describes an example in which an abnormality is detected by comparing the difference in distance between forming times with a threshold value, a detection method is not limited as long as it can be detected that an abnormal value is indicated for the distance that gradually decreases between a die and a formed object as forming time progresses. For example, an abnormality may be detected by comparing differences in distance, or an abnormality may be detected by calculating a differential value for a change in distance.

[0061] Furthermore, although the embodiment describes a case in which in analysis, an approximation line is calculated when the distance has become zero, an approximation line may be calculated when the distance has become a predetermined threshold value of distance or less. The predetermined threshold value of distance is, for example, 0.01 mm.

Relation to Hardware

[0062] Next, correspondences between the filling timing determination apparatus 10 according to the present embodiment and a major hardware configuration of a computer are described. FIG. 9 shows an example of the hardware configuration.

[0063] In general, a computer is configured such that a CPU 81, a ROM 82, a RAM 83, a non-volatile memory 84, and the like are connected by a bus 85. A hard disk device may be provided instead of the non-volatile memory 84. For convenience of description, FIG. 9 shows only basic hardware components.

[0064] Here, a program and the like required to start an operating system (hereinafter, simply referred to as "OS") are stored in the ROM 82 or the non-volatile memory 84, and the CPU 81 loads, from the ROM 82 or the non-volatile memory 84 at power-on, and executes the OS program.

[0065] On the other hand, various application programs to be executed on the OS are stored in the non-volatile memory 84, and the CPU 81 executes an application program while using the RAM 83 for a main memory, whereby a process corresponding to the application is executed.

[0066] In addition, a filling timing determination program for the filling timing determination apparatus 10 according to the present embodiment, similarly to other application programs, is also stored in the non-volatile memory 84 or the like, and the CPU 81 loads and executes the filling timing determination program. In the case of the filling timing determination apparatus 10 according to the present embodiment, the filling timing determination program including routines corresponding to the mesh generation section 15a, the numerical analysis section 15b, the distance calculation section 15c, the distance difference calculation section 15d, the distance difference determination section 15e, the approximation line calculation section 15f, and the determination section 15g shown in FIG. 2 is stored in the non-volatile memory 84 or the like. The filling timing determination program is loaded and executed by the CPU 81, whereby filling timing determination processes corresponding to the mesh generation section 15a, the numerical analysis section 15b, the distance calculation section 15c, the distance difference calculation section 15d, the distance difference determination section 15e, the approximation line calculation section 15f, and the determination section 15g are generated.

[0067] Each configuration depicted in the embodiment is a functional and schematic one, and the depicted configurations do not necessarily need to be physically made. In other words, a way in which the individual devices are distributed or integrated is not limited to those depicted, and a configuration can be made by functionally or physically distributing or integrating all, or one or some, of the devices in any units, depending on various loads, usage situations, or the like.

[0068] The filling timing determination apparatus, the filling timing determination method, and the filling timing determination program according to the present disclosure are suitable when a filling timing is correctly and efficiently determined when forging is performed.