Path setting method, control device and program

Abstract

To provide a molding method and a molding apparatus in which a path of a tool is efficiently configured to obtain a finished article with high dimensional accuracy in an incremental forming, and a program which can efficiently configure the path.SOLUTION: A path setting method in which a path that is a movement path of a tool T is set to process a workpiece W in an incremental forming to obtain a finished article comprises steps of: setting a first path P1 and measuring dimension of the finished object obtained by moving the tool T along the first path P1; calculating the difference between the measured value of the dimension of the finished article through the first path P1 and a design value of the dimension of the finished article having a desired shape; and setting a second path P2 different from the first path P1 based on the first path P1 and the difference between the measured value and the design value without generating a new plane other than the plane generated when setting the first path P1.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a method for setting a path of a tool used in incremental forming (also called sequential forming, the same applies below), a control device for setting the path, and a program for setting the path. [Background technology]

[0002] A method of manufacturing a press die is known in which a pressed product having a specified quality and each part of a press die used to form the pressed product are measured, the measured values ​​are compared, the parameters of the press die that highly contribute to the quality of the pressed product are selected, the tendency that changes in the parameters will have on the quality of the pressed product is statistically calculated, and from the calculated tendency, an estimated die amount for absorbing springback that occurs during press processing is determined, and when a new press die is manufactured, the determined estimated die amount is incorporated into the processing data of the press die (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-94842 Summary of the Invention [Problem to be solved by the invention]

[0004] If the above-mentioned conventional technology, which uses a die during processing, is used in incremental forming, which does not use a die during processing, a surface corresponding to the shape of the formed product, which takes springback into account, is created, as in the case of creating a press die, and the path along which the tool moves is changed based on the shape of that surface. Therefore, a process is required to convert the shape of the surface, which takes into account the expected amount of the die that will absorb springback, into the path of the tool, which is a complicated and inefficient process.

[0005] The problem that the present invention aims to solve is to provide a path setting method that can efficiently set the path of a tool in incremental forming, a control device that sets the path, and a program that can efficiently set the path. [Means for solving the problem]

[0006] The present invention solves the above problem by, when setting a path, which is the movement path of a tool for machining a workpiece by incremental forming to obtain a machined product, setting a first path, measuring the dimensions of the machined product obtained by moving the tool along the first path, calculating the difference between the measured dimensions of the machined product obtained by the first path and design values, which are the dimensions of the machined product having a desired shape, and setting a second path different from the first path using the first path and the difference, without generating any new surfaces other than those generated to set the first path. Effect of the Invention

[0007] According to the present invention, since there is no need to generate a surface and convert the shape of the surface into a path, the tool path can be set efficiently. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing one embodiment of a molding device according to the present invention. [Diagram 2] FIG. 2 is a plan view showing an example of the fixing device of FIG. 1. [Diagram 3] FIG. 2 is a plan view showing an example of the molding apparatus of FIG. [Figure 4] FIG. 4 is a side view of the molding device shown in FIG. [Figure 5A] FIG. 2 is a side view showing an example of a workpiece. [Figure 5B] FIG. 2 is a side view showing an example of a processed product. [Figure 6A] FIG. 5C is a plan view showing an example of a path for forming the workpiece shown in FIG. 5B. [Figure 6B] FIG. 5C is a side view showing an example of a path for forming the workpiece shown in FIG. 5B. [Figure 7] FIG. 2 is a perspective view showing an example of an element model used in the finite element method. [Figure 8] FIG. 11 is a side view showing an example of a method for measuring the dimensions of a processed product. [Figure 9] 9 is a side view for explaining an example of a method for calculating the difference between the measured value of the dimension of the processed product and the design value of the dimension of the processed product in the case of FIG. 8. FIG. [Figure 10A] FIG. 1 is a plan view for explaining an example of a method for identifying a first element and a second element according to the present embodiment (part 1). [Figure 10B] FIG. 2 is a plan view for explaining an example of a method for identifying a first element and a second element in the present embodiment (part 2). [Figure 11] 10 is a side view showing an example of a method for setting a new path based on the difference calculated in FIG. 9. [Figure 12] 12 is a side view showing an example of a method for setting a new path based on the path set in FIG. 11. [Figure 13A] FIG. 9 is a side view (part 1) showing another example of a method for calculating the difference between the measured value of the dimension of the processed product and the design value of the dimension of the processed product in the case of FIG. 8; [Figure 13B] FIG. 9 is a side view (part 2) showing another example of a method for calculating the difference between the measured value of the dimension of the processed product and the design value of the dimension of the processed product in the case of FIG. 8; [Figure 14] 2 is a flowchart showing an example of an information processing procedure in the molding device of FIG. 1. [Figure 15] 10 is a flowchart showing another example of the information processing procedure in the molding apparatus of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] [Molding equipment configuration] FIG. 1 is a block diagram showing a forming apparatus 1 according to the present invention. The forming apparatus 1 is an apparatus for processing a workpiece with a tool by incremental forming to form a processed product. Incremental forming is a forming method for forming a workpiece (also called a workpiece; the same applies below) by sequentially applying local plastic deformation to the workpiece without using a forming die. Incremental forming is classified into incremental bulge forming, incremental reverse bulge forming, and incremental compression forming. In particular, in incremental bulge forming, the outer periphery of the workpiece is fixed with a blank holder (wrinkle suppressor), the workpiece is pressed into by a rod-shaped tool, and bulge forming is sequentially performed from the outer periphery to the center.

[0011] The workpiece is also called a blank material, and any suitable material can be used as long as it can be processed (for example, plastically deformed by pressing) with a tool. For example, it is a plate material such as stainless steel, aluminum alloy, copper alloy, titanium, etc., and the thickness of the plate material is, for example, 1 to 20 mm, and the dimensions of the plate material are, for example, 50 to 3000 mm in length and 50 to 3000 mm in width. For the tool, a material normally used for tools, such as carbon tool steel, high-speed tool steel, cemented carbide, cermet, ceramics, diamond, etc., can be used. In addition, the shape of the tool is, for example, rod-like, the size of the tool is, for example, 10 to 30 mm in diameter, and the tip of the tool is, for example, spherical (approximately Φ5 to 25 mm) so as not to damage the surface of the workpiece. A processed product is an item obtained by deforming a workpiece with a tool, and includes not only a final product but also a semi-finished product that is further processed. Usually, a design value is set for the dimensions of the processed product, and a processed product having the dimensions of the design value has a desired shape.

[0012] As shown in FIG. 1, the molding apparatus 1 includes a fixing device 11, a processing device 12, a display device 13, an input device 14, and a control device 15. The devices included in the molding apparatus 1 are connected by wired or wireless LAN, and can exchange information with each other. In the molding apparatus 1, the display device 13, the input device 14, and the control device 15 do not need to be installed together with other devices, and may be installed in a location away from the other devices. For example, the fixing device 11 and the processing device 12 may be installed in a factory where the workpiece is processed, the display device 13 and the input device 14 may be installed in a location away from the factory (for example, a user's office), and the control device 15 may be installed in a server in a remote location away from the factory and the office.

[0013] The fixing device 11 is a device for fixing a workpiece such as a metal plate during processing. The fixing device 11 is made of a steel material that can be used for dies, such as pre-hardened steel, quenched and tempered steel, or aging treated steel, or ceramics, and the dimensions of the fixing device 11 can be set to any appropriate value as long as it is larger than the size of the workpiece and within a range in which the outer periphery of the workpiece can be appropriately fixed.

[0014] FIG. 2 is a plan view showing an example of the fixing device 11. As shown in the lower left, the horizontal direction in FIG. 2 is the x-axis direction, the vertical direction in FIG. 2 is the y-axis direction, and the direction perpendicular to FIG. 2 is the z-axis direction. The fixing device 11 shown in FIG. 2 includes a support member 111 for supporting the workpiece, and a plurality of bolts 112 for fixing the workpiece placed on the support member 111. The support member 111 has screw holes for inserting the bolts 112 at positions corresponding to the bolts 112. In the fixing device 11 shown in FIG. 2, the workpiece is fixed by sandwiching it between the support member 111 and the heads of the bolts 112 (also called bolt caps or bolt heads). The support member 111 also has openings 113 corresponding to the range in which the workpiece is processed by a tool. By making the processing range the openings, it is possible to prevent the workpiece pushed out in the z-axis direction from coming into contact with the support member 111. The number and arrangement of the bolts 112 can be set appropriately within a range in which the workpiece can be fixed. Moreover, the bolt 112 may be replaced by a clamp.

[0015] FIG. 3 is a plan view showing an example of the forming device 1, and shows a state in which the workpiece W is fixed to the fixing device 11 in FIG. 2. The workpiece W shown in FIG. 3 is a metal plate, and a processing device 12 is provided above it. The processing device 12 is a device for moving a tool used for incremental forming in the x-axis direction, the y-axis direction, and the z-axis direction, and is, for example, a multi-axis controlled robot arm. The tool is attached to a robot hand at the tip of the robot arm. The moving direction and the moving amount when the processing device 12 moves the tool are controlled by the control device 15 so as to follow a moving path (path) for moving the tool inputted from the input device 14. Note that, instead of the multi-axis controlled robot arm, an NC machine tool having a tool attached to a tool head may be used.

[0016] FIG. 4 is a side view of the forming apparatus 1 shown in FIG. 3. As shown in FIG. 4, the robot arm, which is the processing device 12, uses the attached tool T to push the workpiece W in the negative direction of the z-axis and plastically deform it. The tip of the tool T is coated with a hard film made of industrial diamond, diamond-like carbon (DLC), or the like in order to reduce the frictional force between the workpiece W and the tool T. In addition, the processing device 12 may rotate the tool T around the central axis of the tool T or spray a lubricant onto the surface of the workpiece W. The workpiece W processed by the tool T becomes a processed product, and unnecessary parts such as the part held by the support member 111 and the bolt 112 are cut off. Note that, in the forming device 1 shown in FIG. 4, either the x-axis direction or the z-axis direction may be vertical. That is, the workpiece W may be fixed horizontally to the ground and processed, or the workpiece W may be fixed vertically to the ground and the tool T may be pressed against it from the side.

[0017] When the workpiece W is plastically deformed by the tool T, the workpiece W tries to return to its original shape due to the elastic recovery of the metal. This is called springback. In this embodiment, the dimensions of the machined product are measured by a three-dimensional coordinate measuring machine, and the measured dimensions of the machined product are compared with the passing position of the tool T to obtain the amount of springback. Then, the path of the tool T is adjusted using the obtained amount of springback to obtain a machined product having a desired shape. The measurement result of the three-dimensional coordinate measuring machine is, for example, coordinate data of a three-dimensional orthogonal coordinate system consisting of the x-axis, y-axis, and z-axis shown in FIG. 4. The coordinate data obtained as point cloud data may be input by the user from the input device 14, or may be automatically acquired by the control device 15.

[0018] 1, the display device 13 is a device for providing a user with information for operating the molding apparatus 1, and is a liquid crystal display, a projector, etc. The input device 14 is a device for a user to input instructions for operating the molding apparatus 1, and examples of the input device include a keyboard, a mouse, and a touch panel.

[0019] The control device 15 is a device for controlling the devices included in the molding device 1 to cooperate with each other. Specifically, it obtains instructions from the input device 14, sets a path for moving the tool T, controls the processing device 12 so that the tool T moves along the set path, obtains and processes measurement results of the dimensions of the processed product, and outputs necessary information to the display device 13. The control device 15 is, for example, a computer, and includes a CPU (Central Processing Unit) 151 which is a processor, a ROM (Read Only Memory) 152 in which a program is stored, and a RAM (Random Access Memory) 153 which functions as an accessible storage device. The CPU 151 is an operating circuit, and functions as the control device 15 by executing a program stored in the ROM 152.

[0020] [Control unit functions] The program used by the control device 15 includes a control unit 2, which is a functional block that causes the control device 15 to cooperate with and control the devices included in the molding device 1 and function as the molding device 1. The control unit 2 includes a setting unit 21, a measurement unit 22, a calculation unit 23, and an output unit 24. Each unit is illustrated in Fig. 1 for convenience. The function of each functional block will be described below.

[0021] The setting unit 21 has a function of setting a path, which is a moving route of the tool T, for machining the workpiece W by incremental forming to obtain a machined product. The path, which is the moving route of the tool T, is a route through which the tool passes when moving from a position set as a starting point to a position set as an end point, and in particular, refers to a route through which the tip part of the tool T that comes into contact with the workpiece W passes. The path is set, for example, as a trajectory of the intersection between the surface of the tip part of the tool T and the central axis of the tool T. That is, the first position of the intersection is set as the starting point, the position where the intersection finally reaches is set as the end point, and the starting point, the end point, and the trajectory indicating the positions through which the intersection passes from the starting point to the end point are set as the path.

[0022] The path of the tool T is set according to the desired shape of the machined product. For example, when the tool T is moved from the outer periphery to the center so as to follow the desired shape, the path is set to the trajectory drawn by the intersection of the surface of the tip of the tool T and the central axis of the tool T. Also, taking into consideration the springback of the machined product, a shape that will give the machined product the desired shape after springback may be generated, and when the tool T is moved from the outer periphery to the center so as to follow the generated shape, the path may be set to the trajectory drawn by the intersection of the surface of the tip of the tool T and the central axis of the tool T.

[0023] For example, when machining the workpiece W shown in FIG. 5A to produce a workpiece W0 having a rectangular recess as shown in FIG. 5B, the path is set as a path drawn by the intersection of the surface of the tip of the tool T and the central axis of the tool T when the tool T moves from the outer periphery to the center along the surfaces S1 and S2 in FIG. 5B. An example of the path to be set is shown in FIGS. 6A and 6B. FIG. 6A is a plan view of the set path P, and FIG. 6B is a side view of the set path P. The start point of the set path P is A0, and the end point is B. When the workpiece W is viewed in plan, the tool T moves from the start point A0 to point A1, moves from point A1 to point A2, and moves from point A3 to the start point A0, as shown in FIG. 6A. While moving clockwise from A0 to A1 to A2 to A3 to A0, the position of the tool T in the z-axis direction is kept constant as shown in FIG. 6B.

[0024] After returning to the starting point A0, the tool moves from the starting point A0 to point A4 as shown in FIG. 6A. While moving from the starting point A0 to point A4, the position of the tool T in the z-axis direction moves in the negative direction of the z-axis as shown in FIG. 6B. When the tool T moves to the position of point A4 shown in FIG. 6B, the tool T moves along the rectangular trajectory shown in FIG. 6A while keeping the position of the tool T in the z-axis direction constant. However, if the tool T continues to move in the same direction, the workpiece W will be twisted, so the tool T moves counterclockwise from point A4 to point A5, from point A5 to point A6, from point A6 to point A7, and from point A7 to point A4. After that, the tool T moves to the inner trajectory, moves clockwise along the rectangular trajectory, moves further to the inner trajectory, and moves counterclockwise along the rectangular trajectory, repeating the process. Finally, when the tool T reaches the end point B, the machining of the workpiece W is completed.

[0025] When the tool T is moved along a certain shape (for example, the surfaces S1 and S2 in FIG. 5B) as shown in FIGS. 6A and 6B, and the path is set as the path P, the path is calculated geometrically from the shapes of the surfaces S1 and S2 using software such as Tebis (registered trademark). Alternatively, the path P of the tool T is set based on the movement path of the cutting tool from the simulation result of the cutting process using a cutting tool having the same dimensions as the tool T using cutting software such as AdvantEdge FEM. The set path P is expressed using absolute coordinates in a global coordinate system, for example, and is output to the display device 13 by the function of the output unit 24. The user checks the path P displayed on the display device 13, and when performing processing according to the path P, inputs an instruction to execute the processing from the input device 14. When the control device 15 acquires the input instruction, it controls the processing device 12 based on the set path P, and moves the tool T so that the intersection point between the surface of the tip portion of the tool T and the central axis of the tool T moves along the path shown in FIGS. 6A and 6B. The moving speed of the tool T is set according to the performance of the processing device 12.

[0026] Returning to FIG. 1, the measuring unit 22 has a function of measuring the dimensions of the processed product obtained by moving the tool T along the path P. The control device 15 acquires the dimensions of the processed product measured using a three-dimensional measuring machine through the function of the measuring unit 22. The measuring unit 22 automatically acquires coordinate data, which is the measurement result, from the three-dimensional measuring machine, or acquires data input by the user from the input device 14. The coordinate data acquired from the three-dimensional measuring machine are absolute coordinates in a global coordinate system. The measuring unit 22 also has a function of calculating the shape of the processed product obtained by moving the tool T along the path P through numerical analysis such as the finite element method. Numerical analysis refers to solving problems that are difficult to solve algebraically or analytically, or problems that require such a large amount of calculation that manual calculation is impossible, mainly using a computer, and the finite element method is one of the numerical analysis methods. In the present invention, instead of actually machining the workpiece W with the tool T, measuring the shape of the machined product obtained with a three-dimensional measuring machine, and calculating the difference between the measured values ​​of the machined product obtained from the coordinate data of the measurement result and the design values, which are the dimensions of the machined product having the desired shape, the shape of the machined product may be obtained by numerical analysis and the difference between the measured values ​​of the machined product's dimensions and the design values ​​may be calculated. This makes it possible to obtain the difference between the measured values ​​and the design values ​​without actually machining the workpiece W, thereby reducing the time and cost required for machining and measurement. The measured values ​​of the machined product's dimensions obtained by numerical analysis are also called analytical values.

[0027] The finite element method is a method for numerically analyzing the stress, strain, deformation, etc. that occur in a complex structure under the operating environment, dividing the analysis target into small elements that are mathematically easy to handle, applying boundary conditions between the elements, and analyzing the overall behavior by solving partial differential equations and simultaneous equations. Many general-purpose software for the finite element method are commercially available, and the machining of a workpiece W by a tool T can be simulated using appropriate general-purpose software such as ABAQUS, LS-DYNA (registered trademark), and PAM-CRASH.

[0028] When performing a numerical analysis using the finite element method, an element model to be used in the numerical analysis is generated from data showing the shape of the analysis target. Then, analysis conditions are set for the generated model, and calculations are performed by a computer using the above-mentioned software. The measurement unit 22 includes a generation unit 221 and an analysis unit 222, which are functional blocks for executing these processes.

[0029] The generating unit 221 has a function of generating an element model to be used in numerical analysis from the shape data of the analysis target. The shape data of the analysis target is three-dimensional CAD data in a format such as IGES, STEP, or STL. These data are input by the user through the input device 14 and acquired by the generating unit 221. The user generates an element model to be used in numerical analysis from the three-dimensional CAD data, which is the shape data of the analysis target, using the functions of a commercially available preprocessor such as ANSA (registered trademark), LS-PrePost, and HyperMesh (registered trademark). An element model is a model in which the shape of the analysis target is divided (discretized) into elements, which are small regions, and expressed. By discretizing, it becomes possible to perform numerical analysis by computer even for complex shapes.

[0030] The elements include two-dimensional elements (also called shells, the same applies below) and three-dimensional elements (also called solids, the same applies below). Examples of two-dimensional elements include triangular elements and quadrangular elements, and examples of three-dimensional elements include tetrahedral elements and hexahedral elements. A node (also called nodes, the same applies below) is provided at the vertex of each element, and each node has coordinate information. The coordinates may be absolute coordinates or relative coordinates, and the coordinate system may be an orthogonal coordinate system or a polar coordinate system. The length of the side of the generated element can be set to an appropriate value within a range in which the machining of the workpiece W can be appropriately simulated, and is, for example, 0.5 to 20 mm. In addition, when stably analyzing the part where the tool T and the workpiece W contact each other as in the present invention, for example, the three-dimensional shape of the analysis target is contracted in the thickness direction to generate an element model expressed by two-dimensional elements. This makes it easier to determine contact than when using three-dimensional elements, and also reduces the time required for calculation.

[0031] A user generates at least an element model of the workpiece W and the tool T by operating the preprocessor via the input device 14. FIG. 7 shows an example of the element model of the workpiece W and the tool T. In the element model of FIG. 7, the workpiece W and the tool T are expressed using quadrilateral elements. Each quadrilateral element has a node at its vertex, and each node has coordinate information. The user inputs and sets analysis conditions for the numerical analysis of the generated element model via the input device 14. For example, the element is set so that the part of the workpiece W that is restrained by the fixing device 11 does not move. In addition, in order to simulate the contact between the tool T and the workpiece W, a contact condition between the tool T and the workpiece W is set. For example, the contact is determined to occur when the distance between the node of the workpiece W and the node of the tool T is equal to or less than a predetermined value (for example, 0.1 to 5 mm). In addition, a trajectory corresponding to a path that is the movement route of the tool T is input, and the tool T is set to move along the path. In addition to this, physical property data (elastic modulus, stress-strain curve, etc.) corresponding to the materials of the tool T and the workpiece W are set.

[0032] Returning to Fig. 1, the analysis unit 222 has a function of causing a computer or the like to perform numerical analysis using the element model generated by the generation unit 221. When a user inputs an instruction to execute an analysis from the input device 14, the analysis unit 222 acquires the element model generated by the generation unit 221, and causes hardware such as the CPU 151 and RAM 153 to execute calculations using software stored in the ROM 152. The calculation results are output from the analysis unit 222 to the calculation unit 23. The calculation results include the stress value, strain amount, deformation amount, surface state of the workpiece W, etc. in each element in addition to coordinate information of each node of the element model.

[0033] The calculation unit 23 has a function of calculating the difference between the measured value of the dimension of the processed product and the design value of the dimension of the processed product. When the dimension of the processed product is measured by a coordinate measuring machine, the control device 15 acquires the measured value from the measurement unit 22 by the function of the calculation unit 23, compares it with the design value inputted by the input device 14, and calculates the difference between the measured value and the design value. On the other hand, when the shape of the processed product machined by the tool T is calculated by numerical analysis, the difference between the measured value and the design value is calculated using the result of the numerical analysis acquired from the analysis unit 222. The design value means the dimension set when the processed product is designed, and a predetermined allowable error (for example, ±0.5 to 5%) is set for each dimension.

[0034] In particular, when calculating the measured dimensions of a processed product from the results of a numerical analysis using the finite element method, the distance between coordinates is calculated from the coordinate information of each node of the element model, which is the calculation result, and used as the measured value. For example, as shown in Fig. 8, when the analysis result shows that the workpiece W is deformed to become the processed product W1 when the tool T is moved along the path P1, to measure the depth of the processed product W1 in the z-axis direction, the node Z1 with the smallest coordinate value in the z-axis direction and the node Z2 with the largest coordinate value in the z-axis direction are extracted from the nodes of the processed product W1, and the distance Lz corresponding to the depth of the processed product W1 is calculated by subtracting the z-coordinate value of the node Z1 from the z-coordinate value of the node Z2.

[0035] On the other hand, for the design value, the shape data of the processed product having the dimensions of the design value is input from the input device 14, the shape of the processed product having the dimensions of the design value is expressed by elements used in the finite element method, and the coordinate information of the nodes of each element is obtained. Then, the design value is calculated from the obtained coordinate information. For example, when the shape of the processed product W1 is the same as the dimensions of the design value, in order to calculate the design value of the length in the y-axis direction of the processed product W1, the node Z2 having the largest coordinate value in the y-axis direction and the node Z3 having the smallest coordinate value in the y-axis direction are extracted from the nodes of the processed product W1, and the y-coordinate value of the node Z3 is subtracted from the y-coordinate value of the node Z2 to calculate the distance Ly corresponding to the length in the vertical direction of the processed product W1. In the same case, in order to calculate the design value of the depth in the z-axis direction of the processed product W1, the node having the largest coordinate value in the z-axis direction and the node having the smallest coordinate value in the z-axis direction are extracted from the nodes of the processed product W1, and the smaller value of the z-coordinate values ​​of the two nodes is subtracted from the larger value to calculate the design value of the depth of the processed product W1. In this way, the control device 15, by using the function of the calculation unit 23, determines the measurement value and the design value using the coordinate information of the node calculated by numerical analysis and the design value dimensions obtained as the coordinate information of the node of the element, and calculates the difference between the measurement value and the design value (for example, the value obtained by subtracting the distance Lz from the design value of the depth).

[0036] After calculating the difference between the measured value and the design value, the setting unit 21 sets a path different from the path P1 using the path P1 set when processing the workpiece W to produce the processed product W1 and the difference between the measured value and the design value. In this embodiment, in order to distinguish between the two paths, the path P1 set when processing the workpiece W to produce the processed product W1 is referred to as the first path, and the path different from the first path P1, which is set using the first path P1 and the difference between the measured value and the design value, is referred to as the second path. In the following, the second path is also referred to as a correction path.

[0037] As described in Figs. 5A-5B and 6A-6B, when a path is set, information on some surface is used, and the path is set as a trajectory drawn by the intersection of the surface of the tip portion of the tool T and the central axis of the tool T when the tool T moves on the surface. Usually, when a machined product is manufactured, the shape of the machined product having the dimensions of the design value is given, so that the first path P1 can be set using information on the shape, but for the second path, a new surface needs to be generated. In the forming device 1 of this embodiment, the calculation unit 23 calculates the difference between the measured value and the design value at the position where the tool T has passed, so that the setting unit 21 can set the second path without newly generating a surface other than the surface generated to set the first path P1. More specifically, the setting unit 21 sets the second path only from the first path P1 and the difference between the measured value and the design value. In this case, the measured value may be either one measured by a three-dimensional measuring machine or one obtained by numerical analysis. The setting of the second path will be described below.

[0038] FIG. 9 is a side view of the workpiece W and the tool T when the workpiece W and the tool T are viewed from the same direction as FIG. 4. In FIG. 9, the shape D shown by the dashed line is the shape of the workpiece having the dimensions of the design value, and the trajectory when the tool T moves along the surface of the shape D is set as the first path P1 using the surface of the shape D. Then, a simulation is performed by moving the tool T along the first path P1 by a numerical analysis using a finite element method using general-purpose software, and an analysis result is obtained that the workpiece W is formed into the workpiece W1. The difference between the shape D, which is the design value, and the shape of the workpiece W1 is caused by springback due to elastic recovery. In this case, the tool T is assumed to have passed the position shown in FIG. 9, and the difference between the measured value and the design value at the position of the tool T in FIG. 9 is calculated.

[0039] First, the first pass P1 is represented by a node string using the function of the calculation unit 23. By replacing the first pass P1, which is a trajectory, with nodes, it is possible to calculate the difference between the measured value and the design value at the position where the tool T passed by using coordinate information of the nodes of the element model of the processed product W1 and the nodes of the element model of the shape D, which is the dimension of the design value. The interval between the nodes in the node string can be set to an appropriate value (for example, 0.5 to 20 mm) within the range in which the trajectory of the first pass P1 can be obtained from the node string.

[0040] Next, the difference between the measured value and the design value is calculated from the coordinate information of the node of the element model of the processed product W1 at the position where the tool T passed (the position of the node of the node row) and the coordinate information of the node of the element model of the shape D, which is the dimension of the design value. Here, as in the element model shown in FIG. 7, the elements of the tool T and the workpiece W do not necessarily correspond to each other, and at least one of the nodes of the element model of the processed product W1 and the nodes of the element model of the shape D, which is the dimension of the design value, may not exist at the position where the tool T passes. Therefore, the function of the calculation unit 23 specifies a first element that includes a node of the node row when the first pass P1 is viewed in a plane among the elements defined by the nodes of the processed product W1. Similarly, a second element that includes a node of the node row when the first pass P1 is viewed in a plane among the elements generated when the dimension of the design value is obtained as coordinate information is specified.

[0041] Once the first element and the second element are specified, an equation expressing the plane of the first element and an equation expressing the plane of the second element can be calculated from the coordinate information of the nodes of the first element and the second element. By substituting the coordinates of the nodes of the node row into the equations expressing these planes, the coordinates of the processed product W1 at the positions of the nodes of the node row and the coordinates of the shape D, which are the dimensions of the design value, can be obtained. Then, from these obtained coordinates, the difference between the measured value and the design value is calculated. Note that the element model of the processed product W1 can be obtained as a result of numerical analysis using the finite element method, or it can be generated from the coordinate information of the point cloud obtained as a measurement result by actually machining the workpiece W and measuring the dimensions of the processed product W1 obtained by a three-dimensional measuring machine.

[0042] A method for identifying the first element and the second element will be described with reference to Figs. 10A and 10B. The element E shown in Fig. 10A is an element of an element model when the workpiece W1 is viewed in a plane, and the node Nx is a node of a node string indicating the position where the tool T passes. In this case, a half line X is drawn from the node Nx of the node string in the horizontal direction (the positive direction of the x-axis in Figs. 10A and 10B) when the first path P1 is viewed in a plane by the function of the calculation unit 23. As shown in Fig. 10A, when the node Nx is included inside the element E, the number of intersections Y1 between the half line X and the side constituting the element E is 1. On the other hand, as shown in Fig. 10B, when the node of the node string indicating the position where the tool T passes exists outside the element E, such as the nodes Ny, Nz, and Nz', the number of intersections Y2, Y3 between the half line X and the side constituting the element E is 2 (in the case of the node Ny) or 0 (in the case of the nodes Nz and Nz'). In this way, when a half line X is drawn from a certain node in the horizontal direction when the processed product W1 is viewed in a plane, the number of intersections with the sides constituting the element E is 1 only when the node is inside the element E. The calculation unit 23 identifies the first element and the second element using the number of intersections between the half line X and the sides constituting the element E. The direction in which the half line X is drawn may be any direction on the xy plane in Figures 10A and 10B, for example, the vertical direction when the processed product W1 is viewed in a plane (the y-axis direction in the case of Figures 10A and 10B).

[0043] 9, the calculation unit 23 identifies an element in which the number of intersections between the half line X and the side constituting the element E of the processed workpiece W1, which is defined by the nodes calculated by numerical analysis, is one, as the first element. From the identified nodes of the first element, an equation expressing the plane of the first element is obtained, and the x-coordinate value and the y-coordinate value of the node corresponding to the position through which the tool T passes are substituted into the obtained equation to obtain the z-coordinate value at the position through which the tool T passes. This makes it possible to calculate the coordinates of a point N1 on the first element that exists at a position corresponding to a node included in the first element when the first path P1 is viewed in a plane (i.e., a position where the x-coordinate and the y-coordinate values ​​are the same).

[0044] Similarly, the calculation unit 23 specifies an element having one intersection between the half line X and the side constituting the element of the processed product of the shape D, which was generated when obtaining the coordinate information of the dimension of the design value D, as the second element. From the nodes of the specified second element, an equation expressing the plane of the second element is obtained, and the x-coordinate value and the y-coordinate value of the node corresponding to the position where the tool T passes are substituted into the obtained equation to obtain the z-coordinate value at the position where the tool T passes. This makes it possible to calculate the coordinates of the point N2 on the second element, which exists at a position corresponding to the node included in the second element when the first path P1 is viewed in a plane (i.e., a position where the x-coordinate and the y-coordinate values ​​are the same). Hereinafter, the coordinates of the point N1 are referred to as the first coordinates, and the coordinates of the point N2 are referred to as the second coordinates.

[0045] Then, the calculation unit 23 calculates the distance L1 between the points N1 and N2 in a direction perpendicular to the surface of the workpiece W machined by the tool T (z-axis direction in the case of FIG. 9) as the difference between the measured value and the design value. Specifically, the z-coordinate value of the second coordinate of the point N2 is subtracted from the z-coordinate value of the first coordinate of the point N1. After the calculation unit 23 determines the distance L1, the setting unit 21 moves the nodes of the node string of the first pass P1 by the distance L1 in a direction from the first element to the second element (negative direction of the z-axis in the case of FIG. 11) along a direction perpendicular to the surface of the workpiece W machined by the tool T (z-axis direction in the case of FIG. 11). In the case of FIG. 11, the first pass P1 was set using the shape D, so the tool T passes through the position of the point N2. That is, a node of the node string is present at the position of the point N2. Therefore, the node at point N2 is moved by a distance L1 in the negative direction of the z-axis to generate a node at point N3. The same process is performed for each node in the node string to generate a node string consisting of the moved nodes. By using these new nodes, the second path P2 shown in Figure 11 can be set without generating a new surface.

[0046] The above-mentioned method of setting the paths can be repeated until the shape of the processed product has dimensions within a range of a predetermined error from the design value. The predetermined error is set, for example, within a range of ±0.5 to 5% of the design value. As an example of the repetition, the setting of the third path P3 shown in FIG. 12 will be described. As shown in FIG. 12, when the workpiece W is processed in the second path P2 to produce the processed product W2, the control unit 2 judges whether the dimensions of the processed product W2 by the second path P2 are within the range of the design value D and the predetermined error. When it is judged that the dimensions of the processed product W2 by the second path P2 are within the range of the design value D and the predetermined error, the second path P2 is output as the final path from the output unit 24 described later to the display device 13.

[0047] On the other hand, if it is determined that the dimension of the machined product W2 by the second pass P2 is not within the range of the design value D and the predetermined error, the calculation unit 23 identifies the first element from the elements E of the machined product W2, obtains an equation expressing the plane of the first element from the nodes of the identified first element, and substitutes the x-coordinate value and the y-coordinate value of the node corresponding to the position where the tool T passes into the obtained equation to calculate the coordinate of the node N1a. Then, from the second coordinate of the node N2 included in the second element already calculated, the distance L2 between the point N1a and the point N2 in the z-axis direction is obtained, and the node at the position of the point N3 is moved by the distance L2 in the negative direction of the z-axis to generate a node at the position of the point N4. By performing the same process for each node in the node row, the third pass P3 shown in FIG. 12 can be set without generating a new surface.

[0048] The third pass P3 is also processed in the same manner as the second pass P2. That is, it is determined whether the dimensions of the processed product measured by processing the workpiece W in the third pass P3 are within the range of the design value D and the specified error. If it is determined that the dimensions of the processed product by the third pass P3 are within the range of the design value D and the specified error, the third pass P3 is output to the display device 13 as the final pass. On the other hand, if it is determined that the dimensions of the processed product by the third pass P3 are not within the range of the design value D and the specified error, a fourth pass is newly set in the same manner as the method for setting the third pass P3. In this manner, the setting of new passes is repeated until the nth pass (n is a natural number) at which the dimensions of the processed product by the newly set pass are within the range of the design value D and the specified error. That is, the measurement of the dimensions of the processed product by the nth pass, the calculation of the difference between the measured values ​​of the dimensions of the processed product by the nth pass and the design value D, and the setting of the n+1th pass are repeated until the dimensions of the processed product by the set pass are within the range of the design value D and the specified error. Then, the path that results in the dimension of the processed product being within a predetermined error range from the design value D is output to the display device 13 as the final path to be used in manufacturing the processed product having the desired shape.

[0049] Here, instead of setting the dimension of the machined product by the set path to be within a predetermined error range from the design value D, the setting of a new path may be repeated until the dimension of the machined product by the set path becomes the design value D or until the dimension of the machined product by the set path becomes within an error range of 0 to 0.5% from the design value D. The measured value of the dimension of the machined product may be measured by a three-dimensional measuring machine or may be obtained by numerical analysis, or may be a combination of both. For example, the n-th pass and the n+2-th pass may be set using the measured value of the dimension of the machined product obtained by numerical analysis, and the n+1-th pass may be set using the measured value of the dimension of the machined product measured by a three-dimensional measuring machine. In this embodiment, a new workpiece W (blank material) is prepared for each set pass and processed.

[0050] The calculation unit 23 can also consider the amount of deformation in the x-axis direction and the y-axis direction as the difference between the measured value and the design value. In this case, the calculation unit 23 specifies the second element by the above-mentioned method, and then calculates the second coordinate of the point N2. Next, as shown in FIG. 13A, the calculation unit 23 calculates the coordinate of the point N1b corresponding to the point N2 of the second coordinate in the workpiece W1 machined by the first path P1. Then, the calculation unit 23 calculates a movement vector for moving the first path P1 from the distance and direction in which the point N2 moves to the point N1b. In the case of FIG. 13A, the point N2 has moved to the position of the point N1b due to springback, so the calculation unit 21 obtains a vector V2 that starts from the point N1b and ends at the point N2, which is a vector in the opposite direction of the vector V1 from the point N2 to the point N1b. The setting unit 21 moves the node at the position of the point N2 along the movement vector V2 to generate a new node at the position of the point N3a. By performing similar processing on each node in the node series, a node series is calculated by moving the node series of the first path P1 along the movement vector obtained for each node, and a second path P2a is set based on the calculated node series.

[0051] A calculation method of the coordinates of the point N1b will be described with reference to FIG. 13B. First, the shape of the workpiece W is represented by elements used in the finite element method using coordinate information of the dimensions of the workpiece W measured by a three-dimensional measuring machine or a three-dimensional CAD model of the workpiece W. From the generated elements, the dimensions of the workpiece W are obtained as coordinate information of the nodes of the elements. Next, among the elements representing the shape of the workpiece W, a third element Ea that includes a node of the node row when the first path P1 is viewed in a plane is specified. Then, the coordinates of a point N5 on the third element Ea that exists at a position corresponding to a node of the node row included in the third element Ea (i.e., a position where the x coordinate and y coordinate values ​​are the same) when the first path P1 is viewed in a plane is calculated. Next, the tool T is moved along the first path P1, the coordinates of the nodes of the third element Eb after the workpiece W is deformed are calculated, and the movement amount of each node of the third element Ea accompanying the deformation of the third element Ea is calculated. Next, the coordinates of point N6 in the deformed third element Eb, which corresponds to point N5, are calculated using the calculated movement amounts of each node of the third element Ea. The movement amounts may be absolute movement amounts in the global coordinate system or relative movement amounts with respect to the third element Ea.

[0052] The coordinates of the point N6 are calculated as a relative position with respect to each node of the element. In the case of FIG. 13B, first, the relative position of the point N5 with respect to each node arranged at the corner of the third element Ea of the quadrangular element is obtained. Next, the point whose relative position with respect to each node arranged at the corner of the third element Eb after deformation is the same relative position as the point N5 of the third element Ea before deformation is set as the point N6. Then, the coordinates of each node of the third element Eb after deformation are used to calculate the coordinates of the point N6. When the positions of the nodes of the node row in FIG. 13B are the same as those in FIG. 13A, the coordinates of the point N6 in FIG. 13B and the coordinates of the point N1b in FIG. 13A coincide. In this embodiment, the coordinates of the point N5 are also referred to as the third coordinates, and the coordinates of the point N6 (point N1b) are also referred to as the fourth coordinates.

[0053] 1, the output unit 24 has a function of outputting to the display device 13 the path set by the setting unit 21, the measurement value and the design value measured or calculated by the measurement unit 22, the difference between the measurement value and the design value D calculated by the calculation unit 23, etc. The output information is displayed on the display device 13.

[0054] [Processing in molding equipment] The procedure for the control device 15 to process information will be described with reference to Figures 14 and 15. Figure 14 is an example of a flowchart showing information processing in the molding device 1 of this embodiment. The process described below is executed by the control device 15 when the user requests the setting of a path.

[0055] First, in step S1, the function of the generation unit 221 is used to acquire shape data of a processed product having dimensions of the design value D, and in the subsequent step S2, a finite element model is generated from the shape data of the processed product having dimensions of the design value D. In the subsequent step S3, the function of the calculation unit 23 is used to acquire coordinate information from the finite element model of the processed product having dimensions of the design value D. In the subsequent step S4, the function of the generation unit 221 is used to acquire shape data of the workpiece W and the tool T, and in the subsequent step S5, a finite element model is generated from the shape data of the workpiece W and the tool T.

[0056] After the finite element model is generated, in step S6, the generation unit 221 sets analysis conditions such as the fixing conditions of the workpiece W and the contact conditions between the workpiece W and the tool T, and in the following step S7, the setting unit 21 sets a first pass P1 using the finite element model generated from the shape data of the processed product having the dimensions of the design value D. In the following step S8, the analysis unit 222 executes a numerical analysis by the finite element method.

[0057] After performing the numerical analysis by the finite element method, in step S9, the function of the measurement unit 22 is used to acquire coordinate information of the nodes calculated by the numerical analysis. In the following step S10, the function of the calculation unit 23 is used to identify the first element and the second element. In the following step S11, the z coordinate of the first coordinate corresponding to the point N1 included in the plane of the first element and the z coordinate of the second coordinate corresponding to the point N2 included in the plane of the second element are calculated using the x coordinate and y coordinate of the node of the node row corresponding to the position passed by the tool T. In the following step S12, the distance between the points N1 and N2 in the z-axis direction is calculated from the z coordinate of the points N1 and N2.

[0058] After the difference between the measured value and the design value D is calculated, in step S13, the setting unit 21 functions to move the path by the calculated distance in a direction perpendicular to the surface machined by the tool (z-axis direction). The direction of movement is from the first element to the second element. In the following step S14, a second path P2, which is a corrected path, is set based on the moved node string. In step S15, the analysis unit 222 functions to execute a numerical analysis by the finite element method using the second path. The conditions of the numerical analysis in step S15 are the same as those set in step S6. In the following step S16, the measurement unit 22 functions to acquire coordinate information of the nodes calculated by the numerical analysis, and measure the dimensions of the machined product.

[0059] After performing the numerical analysis using the finite element method, in step S17, the control unit 2 determines whether the difference between the analytical value, which is the measured value, and the design value is within a predetermined error. If the difference between the measured value and the design value is within the predetermined error, the process proceeds to step S18, where the output unit 24 outputs the second path P2 (corrected path) as the final path to the display device 13, and the execution of the routine ends. On the other hand, if the difference between the measured value and the design value exceeds the predetermined error, the process returns to step S10, and an attempt is made to set a path again.

[0060] In step S12, the distance between node N1 and node N2 in the z-axis direction was calculated as the difference between the measured value and the design value D, but the distance between node N1 and the second element in the z-axis direction may be calculated as the difference, or the distance between the first element and node N2 in the z-axis direction may be calculated as the difference. Also, the distance between the first element and the second element in the z-axis direction may be calculated as the difference. These measured values ​​can be obtained using a commercially available general-purpose post-processor.

[0061] Next, Fig. 15 is another example of a flowchart showing information processing in the molding apparatus 1 of this embodiment. Steps S1 to S9 are similar to the steps in the flowchart shown in Fig. 14, so a description thereof will be omitted.

[0062] First, in step S10a, the function of the calculation unit 23 is used to identify the second element and the third element which is an element of the workpiece W. In the following step S11a, the function of the calculation unit 23 is used to calculate the z coordinate (i.e., the z coordinate of the second coordinate) corresponding to the position of the x coordinate and the y coordinate in the plane of the second element, using the x coordinate and the y coordinate of the node of the node row corresponding to the position where the tool T passed. Similarly, the function of the calculation unit 23 is used to calculate the z coordinate (i.e., the z coordinate of the third coordinate) corresponding to the position of the x coordinate and the y coordinate in the plane of the third element. In the following step S11b, the function of the analysis unit 222 is used to calculate the coordinate of each node of the third element Eb deformed after machining and the movement amount of each node before and after the deformation. In the following step S12a, the movement amount of each node of the third element Ea before and after the deformation is used to calculate the fourth coordinate, which is the coordinate of the point N6 corresponding to the point N5 located in the third coordinate. Then, in step S12b, a movement vector V2 is calculated, the start point of which is point N6 (point N1b) located at the fourth coordinate system and the end point of which is point N2 located at the second coordinate system.

[0063] After calculating the movement vector V2, in step S13a, the node row of the first pass is moved along the movement vector V2 by the function of the setting unit 21, and in step S14, a second pass (corrected pass) is set based on the moved node row. Steps S15 to S18 are similar to the steps in the flowchart shown in FIG. 14, and therefore a description thereof will be omitted. Note that, before performing the numerical analysis, nodes may be generated in the finite element model of the workpiece W at positions corresponding to the node row of the first pass. In other words, the x and y coordinates of each node in the node row may be obtained, and nodes may be generated in advance in the finite element model of the workpiece W at positions corresponding to the obtained x and y coordinates.

[0064] [Embodiments of the present invention] As described above, according to the present embodiment, in a method for setting a path P, which is a moving path of a tool T, for machining a workpiece W by incremental forming to obtain a machined product, a first path P1 is set, the tool T is moved along the first path P1 to measure the dimensions of the machined product obtained, a difference is calculated between the measured value of the dimensions of the machined product by the first path P1 and a design value which is the dimension of the machined product having a desired shape, and a second path P2 different from the first path P1 is set using the first path P1 and the difference, without generating a new surface other than the surface generated to set the first path P1. This makes it possible to efficiently set the path P of the tool T, since it is not necessary to generate a surface and convert the shape of the surface into the path P.

[0065] According to the method for setting the path P of the present embodiment, the second path P2 is set only from the first path P1 and the difference, which makes it possible to set the path P of the tool T more efficiently.

[0066] According to the method for setting the path P of this embodiment, the dimensions of the processed product by the first path P1 are obtained as coordinate information, the shape of the processed product having the dimensions of the design value D is expressed by elements used in the finite element method, the design value D is obtained as coordinate information of the nodes of the element, and the difference is calculated using the coordinate information of the processed product by the first path P1 and the coordinate information of the nodes of the element. This makes it possible to set the path P by numerical analysis without actually producing a processed product or by reducing the number of times that the processed product is actually produced.

[0067] According to the method for setting the path P of the present embodiment, the first path P1 is represented by a node string, the shape of a processed product by the first path P1 is represented by elements used in the finite element method, a first element that includes a node of the node string when the first path P1 is viewed in a plane among the elements that represent the shape of the processed product by the first path P1 is specified, a second element that includes a node of the node string when the first path P1 is viewed in a plane among the elements that represent the shape of the processed product having the dimensions of the design value is specified, and a first element that exists at a position corresponding to the node of the node string included in the first element when the first path P1 is viewed in a plane is specified. and a second coordinate of a point on the second element that exists at a position corresponding to a node of the node series included in the second element when the first path P1 is viewed in a plane, and the distance between the point corresponding to the first coordinate and the point corresponding to the second coordinate in a direction perpendicular to the surface of the workpiece W that is machined by the tool T is calculated as the difference, and the nodes of the node series of the first path P1 are moved by the distance in a direction from the first element to the second element along the perpendicular direction, and the node series consisting of the moved nodes is set as the second path P2. This allows the path P to be updated using numerical analysis, and the dimensional accuracy of the machined product to be improved.

[0068] According to the method for setting the path P of this embodiment, a half line X is drawn from the nodes of the node row in the horizontal direction when the first path P1 is viewed in a plane, and among the elements expressing the shape of the machined product by the first path P1, an element having one intersection point Y1 between the half line and a side constituting the element is identified as the first element, and among the elements expressing the shape of the machined product having the dimension of the design value D, an element having one intersection point between the half line X and a side constituting the element is identified as the second element. This makes it possible to accurately determine the difference between the measured value and the design value D even if there is no node at the position where the tool T passes.

[0069] Further, according to the method for setting the path P of this embodiment, the first path P1 is expressed by a node string, and among elements expressing the shape of the processed product having the dimension of the design value D, a second element including a node of the node string when the first path P1 is viewed in a plane is identified, second coordinates of points on the second element that exist at positions corresponding to the nodes of the node string included in the second element when the first path P1 is viewed in a plane are calculated, the shape of the workpiece is expressed by elements used in a finite element method, the dimensions of the workpiece are obtained as coordinate information of the nodes of the element, a third element including a node of the node string when the first path P1 is viewed in a plane is identified, and a third element including a node of the node string when the first path P1 is viewed in a plane is identified. a third coordinate of a point on the third element that exists at a position corresponding to a node of the node series included in the element, a movement of the tool T along the first path P1, a coordinate of the node of the third element after the workpiece is deformed, a movement amount of each node of the third element due to the deformation of the third element is calculated, a fourth coordinate which is a coordinate of a point in the deformed third element corresponding to the third coordinate is calculated using the calculated movement amount of each node of the third element, a movement vector is calculated with a point located at the fourth coordinate as a start point and a point located at the second coordinate as an end point, the nodes of the node series of the first path are moved along the movement vector, and a node series consisting of the moved nodes is set as the second path P2. This allows the path P to be updated using numerical analysis, and the dimensional accuracy of the machined product to be improved.

[0070] According to the path setting method of the present embodiment, the dimensions of the machined product obtained by moving the tool T along the second path P2 are measured, and it is determined whether the dimensions of the machined product obtained by the second path P2 are within a range of a predetermined error from the design value. If it is determined that the dimensions of the machined product obtained by the second path P2 are not within a range of a predetermined error from the design value, a new path different from the first path P1 and the second path P2 is set using the second path P2 and the difference between the measured dimensions of the machined product obtained by the second path P2 and the design value, and the measurement of the dimensions of the machined product obtained by the new path, the calculation of the difference between the measured dimensions of the machined product and the design value, and the setting of the new path are repeated until the dimensions of the machined product obtained by the new path are within a range of a predetermined error from the design value. This makes it possible to manufacture a machined product having dimensions within a range of a predetermined error from the design value.

[0071] According to the present embodiment, there is provided a control device 15 including a processor for setting a path P, which is a moving path of a tool T, for machining a workpiece W by incremental forming to obtain a machined product. The processor sets a first path P1, measures the dimensions of the machined product obtained by moving the tool T along the first path P1, calculates the difference between the measured value of the dimension of the machined product by the first path P1 and a design value, which is the dimension of the machined product having a desired shape, and sets a second path P2 different from the first path P1 by using the first path P1 and the difference, without generating a new surface other than the surface generated to set the first path P1. This makes it possible to efficiently set the path P of the tool T, since it is not necessary to generate a surface and convert the shape of the surface into the path P.

[0072] According to the present embodiment, a program is provided for causing a computer to execute the following steps in a program for setting a path P, which is a moving path of a tool T, for machining a workpiece W by incremental forming to obtain a machined product: setting a first path P1, measuring the dimensions of the machined product obtained by moving the tool T along the first path P1, calculating the difference between the measured value of the dimension of the machined product by the first path P1 and a design value, which is the dimension of the machined product having a desired shape, and setting a second path P2 different from the first path P1 by using the first path P1 and the difference, without generating a new surface other than the surface generated to set the first path P1. This makes it possible to efficiently set the path P of the tool T, since it is not necessary to generate a surface and convert the shape of the surface into the path P. [Explanation of symbols]

[0073] 1…Forming equipment 11...Fixing device 111...Support member 112…Volts 113…Opening 12...Processing equipment 13...Display device 14...Input device 15...Control device 151...CPU 152...ROM 153...RAM 2...Control section 21. Setting section 22…Measuring part 221...Generation section 222…Analysis Department 23...Calculation section 24...Output section A0...Start point A1, A2, A3, A4, A5, A6, A7... points B…End point D: Design value E, Ea, Eb...elements L1, L2, Ly, Lz…distance N1, N1a, N1b, N2, N3, N3a, N4, N5, N6... points Nx, Ny, Nz, Nz'... nodes P1, P2, P2a, P3…パス S1, S2... T…Tools V1, V2…ベクトル W…Workpiece W0, W1, W2, W3… processed products X…half straight line Y1, Y2, Y3…intersection point Z1, Z2, Z3...nodes

Claims

1. A method for setting a path, which is a tool movement path, for machining a workpiece by incremental forming to obtain a machined product, comprising: Set up the first pass, measuring a dimension of the workpiece obtained by moving the tool along the first path; Calculating a difference between a measured value of a dimension of the processed product by the first pass and a design value which is a dimension of the processed product having a desired shape; A path setting method for setting a second path different from the first path by using the first path and the difference, without generating any new faces other than the faces generated to set the first path.

2. 2. The path setting method according to claim 1, wherein the second path is set based only on the first path and the difference.

3. Obtaining dimensions of the workpiece processed by the first pass as coordinate information; A shape of a processed product having dimensions of the design value is expressed by elements used in a finite element method; The design value is obtained as coordinate information of a node of the element; 3. The path setting method according to claim 1, further comprising the step of calculating the difference using coordinate information of the workpiece machined by the first path and coordinate information of the nodes of the element.

4. The first path is represented by a sequence of nodes; expressing the shape of the workpiece by the first pass using elements used in a finite element method; Identifying a first element that includes a node of the node row when the first pass is viewed in a plan view among elements that represent a shape of a product processed by the first pass; Identifying a second element that includes a node of the node row when the first path is viewed in a plan view among elements that represent a shape of a processed product having the design value dimensions; calculating first coordinates of a point on the first element, the point existing at a position corresponding to a node of the node string included in the first element when the first path is viewed in a plane, and second coordinates of a point on the second element, the point existing at a position corresponding to a node of the node string included in the second element when the first path is viewed in a plane; Calculating, as the difference, a distance between a point corresponding to the first coordinates and a point corresponding to the second coordinates in a direction perpendicular to a surface of the workpiece that is machined by the tool; 4. A method for setting a path as described in claim 3, further comprising: moving the nodes of the node series of the first path by the distance along the perpendicular direction in a direction from the first element toward the second element; and setting the node series consisting of the moved nodes as the second path.

5. a half-line is drawn from each node of the node row in a horizontal direction when the first path is viewed in a plane; Among the elements representing the shape of the product processed by the first pass, an element having a number of intersections between the half line and a side constituting the element that is one is identified as the first element; The path setting method according to claim 4, further comprising identifying an element having one intersection between the half line and a side constituting the element and among the elements representing the shape of the processed product having the dimensions of the design value, as the second element.

6. The first path is represented by a sequence of nodes; Identifying a second element that includes a node of the node row when the first path is viewed in a plan view among elements that represent a shape of a processed product having the design value dimensions; calculating second coordinates of a point on the second element that exists at a position corresponding to a node of the node string included in the second element when the first path is viewed in a plane; The shape of the workpiece is represented by elements used in a finite element method; Obtaining dimensions of the workpiece as coordinate information of nodes of the element; Identifying a third element that includes a node of the node row when the first pass is viewed in a plan view among elements that represent the shape of the workpiece; calculating third coordinates of a point on the third element that exists at a position corresponding to a node of the node string included in the third element when the first path is viewed in a plane; Moving the tool along the first path and calculating coordinates of the nodes of the third element after the workpiece is deformed; Calculating the amount of movement of each node of the third element due to the deformation of the third element; calculating fourth coordinates, which are coordinates of a point in the third element after deformation corresponding to the third coordinates, using the calculated movement amounts of each node of the third element; Calculating a movement vector having a start point at the point located at the fourth coordinates and an end point at the point located at the second coordinates; 4. The path setting method according to claim 3, further comprising the steps of: moving the nodes of said node string of said first path along said movement vector; and setting a node string consisting of the moved nodes as said second path.

7. measuring a dimension of the workpiece obtained by moving the tool along the second path; determining whether or not a dimension of the product machined by the second pass is within a predetermined error range with respect to the design value; when it is determined that the dimension of the processed product by the second pass is not within a predetermined error range with respect to the design value, a new pass different from the first pass and the second pass is set using the second pass and a difference between the measured value of the dimension of the processed product by the second pass and the design value; A path setting method according to any one of claims 1 to 6, further comprising repeating steps of measuring the dimension of the processed product by the new path, calculating the difference between the measured dimension of the processed product and the design value, and setting the new path, until the dimension of the processed product by the new path falls within the specified error range with respect to the design value.

8. A control device including a processor and configured to set a path, which is a movement path of a tool, for machining a workpiece by incremental forming to obtain a machined product, comprising: The processor, Set up the first pass, measuring a dimension of the workpiece obtained by moving the tool along the first path; Calculating a difference between a measured value of a dimension of the processed product by the first pass and a design value which is a dimension of the processed product having a desired shape; a control device that sets a second path different from the first path by using the first path and the difference, without generating any new faces other than the faces generated to set the first path.

9. In a program for setting a path, which is a movement path of a tool, for machining a workpiece by incremental forming to obtain a machined product, setting up a first path; measuring a dimension of an artefact obtained by moving the tool along the first path; A step of calculating a difference between a measured value of a dimension of a processed product by the first pass and a design value which is a dimension of a processed product having a desired shape; and a step of setting a second path different from the first path by using the first path and the difference, without generating any new faces other than the faces generated to set the first path.

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