JP3676139B2 - Control data creation method for push-through bending machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a push-through bending machine capable of bending a long material passing through a fixed mold and a movable mold one after another through relative displacement of the movable mold with respect to the fixed mold, and in particular, such a push-bending machine. The present invention relates to a control data generation method for generating control data used for control of the control.
[0002]
[Prior art]
Generally, the push-through bending machine includes a fixed mold and a movable mold that is disposed in front of the fixed mold and is displaced relative to the fixed mold. For example, when the movable mold moves in a plane perpendicular to the traveling direction of the profile while the aluminum profile passes through the fixed mold and the movable mold one after another, bending deformation (plastic deformation) is caused in the profile. In such a push-bending machine, it is possible to relatively easily realize bending of various shapes regardless of two-dimensional or three-dimensional through a movable movement along one plane. .
[0003]
[Problems to be solved by the invention]
Similar to a general machine tool, the operation of the push-through bending machine can be controlled by a control program such as an NC (numerical control) program. In such a control program, for example, control data such as a movable displacement amount must be defined. So far, such control data has been created based on the intuition and rules of thumb of skilled workers. The trial production of the product was repeated using such control data, and the control data was rewritten every time the trial production was carried out. As a result of such trial production being repeated several tens of times, finally, control data capable of realizing bending deformation as desired was established.
[0004]
For example, Japanese Patent Application Laid-Open No. 9-327727 and Japanese Patent Application Laid-Open No. 10-166604 disclose attempts to create control data without relying on the intuition and rule of thumb of a skilled worker. According to these attempts, a prototype roughly resembling the final shape can be formed at the initial prototype stage. Therefore, it is not necessary to rely on the operator's intuition and empirical rules from the beginning, and labor and labor for trial manufacture and rewriting of control data are reduced.
[0005]
In the control data creation methods described in these publications, the x coordinate axis of the three-dimensional coordinate system is used to calculate the movable position. The x-coordinate axis specifies the traveling direction of the profile, that is, the axis. The movable moving plane is orthogonal to the x coordinate axis. However, in practice, the axial direction of the shape subjected to bending deformation cannot be uniformly expressed by one straight line. Therefore, even if the movable movement plane is orthogonal to the x coordinate axis, the movable movement plane cannot be accurately pushed through and reflect the machine coordinate system of the bending machine. As a result, even if the position of the movable mold is specified on such a moving plane, the shape accuracy after processing cannot be increased to the extent that it can withstand general practical use.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control data creation method for a push-bending machine capable of generating control data that realizes push-bending with high accuracy.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the first invention, a step of obtaining shape data representing the shape of a long product according to the global coordinate system, and a fixed die of a push-through bending machine based on the shape data For a push-through bending machine, comprising: a step of setting a specified local coordinate system for each cross section of a long product; and a step of calculating a movable die position of the push-bending machine based on the local coordinate system A method for creating control data is provided.
[0008]
According to such a control data creation method, a long product extending forward from the fixed mold can be reproduced in the local coordinate system set in the cross section of the long product. When the movable mold is virtually superimposed on the long product on the local coordinate system, the position of the movable mold can be specified on the local coordinate system. The position of the movable mold reflects the bending deformation of the long product formed between the fixed mold and the movable mold. If the movement amount of the movable type is calculated based on the position of the movable type thus specified, an ideal movement amount of the movable type can be obtained. Control data of the push-through bending machine may be created based on the obtained movement amount. If the control data created in this way is supplied to a push bending machine, it is possible to realize an ideal movable movement that accurately reflects the shape of the long product.
[0009]
Such a push-bending machine control data creation method includes a step of identifying at least one parametric curve representing the bending degree of the long product based on shape data, and each control point specified on the parametric curve. The method may further include a step of calculating a tangent vector for the parametric curve, and a step of specifying the cross section for each control point of the parametric curve based on the calculated tangent vector.
[0010]
In general, in a parametric curve, the number of control points increases as the curvature of the curve to be expressed increases, and conversely, the number of control points decreases as the curvature of the curve decreases. Therefore, if each section of a long product is defined while taking advantage of the features of such a parametric curve, the number of sections increases as the curvature of the long product increases, and as a result, it can be moved finely according to the size of the curvature. The movement of the mold can be controlled.
[0011]
In calculating the position of the movable mold, the control data creation method for the push-through bending machine includes the step of identifying the approach distance between the fixed mold and the movable mold on the local coordinate system and the identified approach distance. The method may further comprise defining a movable movement plane on the local coordinate system and specifying an intersection of the movement plane and the parametric curve on the local coordinate system. When the above-described parametric curve is used, the movable position can be identified relatively easily by simply identifying the movable moving plane on the local coordinate system.
[0012]
According to the second invention, the local coordinate system specified based on the fixed type of the push-through bending machine is defined as the global coordinate system for specifying the shape of the long product. A control data creation method is provided. According to this control data creation method, the position of the movable type can be specified according to the local coordinate system specified with reference to the fixed type, as in the first aspect of the invention. The position of the movable mold reflects the bending deformation of the long product formed between the fixed mold and the movable mold. Therefore, if the movable movement amount is calculated based on the movable position specified in this way, the ideal movable movement can be realized.
[0013]
In calculating the movable position, the local coordinate system may be redefined for each feed position defined in the longitudinal direction of the long product. If the local coordinate system is redefined for each feed position in this way, it becomes possible to specify the movable displacement continuously along the longitudinal direction of the long product. Based on the continuous displacement thus identified, a movable continuous movement can be realized.
[0014]
Further, according to the third invention, the step of acquiring the shape data of the long product from the computer-aided design system, and the push bending process for each feed position defined in the longitudinal direction of the long product based on the acquired shape data And a step of generating control data for specifying the position of the movable type of the machine.
[0015]
In recent years, so-called computer-aided design (CAD) has been remarkably developed in the field of product design. However, so far, in the field of plastic working, product data created by such CAD has not been used efficiently. According to such a control data creation method, it is possible to create control data for a push-bending machine easily and efficiently using shape data created by CAD. Here, it is desirable that the shape data defines at least one curve expressing the bending state of the long product.
[0016]
The above push-bending machine control data creation method may be configured as a software program executed by a computer. Such a software program may be loaded into a computer through a portable recording medium such as an FD (floppy disk), a CD (compact disk), or a DVD (digital video disk), or may be a LAN (private network) or WAN (wide area communication). Network) or the Internet.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
[0018]
FIG. 1 schematically shows the overall configuration of a push-through bending machine. The push-through bending machine 10 is a pair of front and rear molds that guide the forward movement of the long material 11, that is, a fixed mold 12 and a movable mold 13, and a feed that feeds the long material 11 toward the fixed mold 12 and the movable mold 13. And a mechanism 14. In the push-through bending machine 10, as will be described later, when the movable mold 13 moves in a plane orthogonal to the traveling direction of the long material 11, bending deformation (plastic deformation) is caused in the long material 11.
[0019]
The feed mechanism 14 includes, for example, a pusher that contacts the rear end of the long material 11, that is, a slider 15, and a screw shaft 17 that converts the rotational force of the feed motor 16 into the propulsive force of the slider 15. When the screw shaft 17 rotates in the forward direction through the action of the feed motor 16, the slider 15 moves forward according to the rotation, and when the screw shaft 17 rotates in the reverse direction, the slider 15 can move backward. The advance of the slider 15 causes the long material 11 to advance. The advance amount of the slider 15, that is, the feed amount of the long material 11 can be determined according to the rotation amount of the screw shaft 17, that is, the rotation amount of the feed motor 16. A so-called servo motor may be used as the feed motor 16.
[0020]
In such a push-bending machine 10, a solid long material or a hollow long material 11 can be processed. The hollow long material 11 can be represented by, for example, an extruded material made of aluminum, that is, a shape material or an iron pipe material. In general, the long material 11 defines a common cross-sectional shape over its entire length. However, the cross-sectional shape need not always be constant over the entire length of the long material 11.
[0021]
The feed mechanism 14 and the fixed mold 12 are supported by a so-called pendulum member 19. As apparent from FIG. 2, the columnar outer peripheral surface of the pendulum member 19 is supported by the support base 21 through a bearing 20 disposed along the semi-cylindrical surface. According to the function of the pendulum member 19, the long material 11 can rotate around the central axis 22 of the fixed mold 12 together with the fixed mold 12. Such rotation is useful, for example, in causing torsional deformation in the long material 11. The rotation of the pendulum member 19 may be realized through the operation of the drive motor 23 configured by, for example, a servomotor.
[0022]
As shown in FIG. 2, the fixed mold 12 is formed with a through hole 24 that is shaped like the outer shape of the long material 11. The forward movement of the long material 11 is guided by the through hole 24. As apparent from the through hole 24 shown in FIG. 2, the cross-sectional shape of the long material 11 may be a simple shape such as a circle, an ellipse, a triangle, and other polygons, as well as other complicated shapes. Even if it is a shape, it does not interfere. The shape of the through hole 24 may be adjusted to the cross-sectional shape of the long material 11.
[0023]
As is clear from FIG. 2, when the hollow long material 11 is processed, it is desirable that the core metal, that is, the core 25 is inserted into the hollow space of the long material 11 surrounded by the fixed mold 12. As is well known, in such a push-through bending machine 10, the largest bending stress acts on the long material 11 in the vicinity of the exit of the fixed mold 12 side through hole 24. At this time, if the long material 11 is hollow, the cross-sectional shape of the long material 11 may be crushed by the edge of the through hole 24. As a result, a large error occurs in the deformation amount of the bending deformation with respect to the long material 11, and unnecessary dents are formed on the outer peripheral surface of the long material 11. If the core 25 comes into contact with the inside of the long material 11, such crushing of the long material 11 can be avoided as much as possible.
[0024]
As is clear from FIG. 1, a control motor 26 that moves the core 25 back and forth is connected to the core 25. The core 25 is moved in and out of the long material 11 by the action of the control motor 26. Moreover, in this embodiment, a control motor 27 that rotates the core 25 around the central axis 22 of the fixed mold 12 is connected to the core 25. The control motor 27 can rotate the core 25 around the central axis 22 in response to the rotation of the fixed mold 12 around the central axis 22 as the pendulum member 19 rotates as described above. For example, servo motors may be used as the control motors 26 and 27.
[0025]
With reference to FIGS. 1 and 3, the movable die 13 is formed with a through-hole 28, which is similar to the fixed die 12, and is shaped like the long material 11. The forward movement of the long material 11 is guided by the through hole 28. The shape of the through hole 28 preferably matches the shape of the fixed mold 12 side through hole 24, for example.
[0026]
The movable mold 13 can move in a moving plane orthogonal to the extension line of the central axis 22 of the fixed mold 12. The movement of the movable mold 13 is realized by, for example, a combination of the vertical movement of the vertical movement member 29 and the horizontal movement of the horizontal movement member 30. The vertical movement member 29 is guided to the horizontal movement member 30 so as to be displaceable in the vertical direction, that is, the vertical direction. At the same time, the horizontal moving member 30 is supported by the guide member 31 so as to be displaceable in the horizontal direction. The displacement of the vertical movement member 29 may be realized by the action of the vertical movement motor 32, for example, and the displacement of the horizontal movement member 30 may be realized by the action of the horizontal movement motor 33, for example. For example, the vertical movement motor 32 and the horizontal movement motor 33 may be configured by a servo motor or other drive source capable of controlling the rotation amount of the rotation shaft with a minute rotation angle.
[0027]
Moreover, the movable mold 13 can change its posture while changing its position on the above-described moving plane. Such a change in the posture of the movable mold 13 is realized through the action of a rotating member 35 formed with a rotating shaft 34 extending in the vertical direction and a swinging member 37 formed with a pair of swinging shafts 36 extending in the horizontal direction. . When the rotation shaft 34 is received in the support hole 38 formed in the vertical movement member 29, the rotation member 35 can rotate about the vertical axis. On the other hand, when the two swing shafts 36 are received in the support holes 39 formed in the rotating member 35, the swing member 37 can swing around the horizontal axis. The rotation of the rotating member 35 and the swinging of the swinging member 37 may be realized individually by the action of a drive motor (not shown) composed of, for example, a servomotor. Here, it is desirable that the swing center of the swing shaft 36 is orthogonal to the rotation center of the rotary shaft 34 on the extension line of the central shaft 22.
[0028]
FIG. 4 schematically shows an overall configuration of a push-through bending system 41 in which the push-through bending machine 10 as described above is incorporated. In this push-through bending system 41, the operation of the push-through bending machine 10 is controlled by the NC controller 42. In realizing this control, the NC controller 42 sets a three-dimensional machine coordinate system xyz for the push-bending machine 10 as shown in FIG. 5, for example. The machine coordinate system xyz includes, for example, a z-coordinate axis that overlaps the central axis 22 of the fixed mold 12 and an x-coordinate axis and a y-coordinate axis that define the horizontal direction and the vertical direction of the fixed mold 12 on one plane where the exit of the through hole 24 faces. With.
[0029]
It is desirable that the moving plane HV of the movable mold 13 be held in a posture parallel to the xy plane of the machine coordinate system xyz. According to the setting of the moving plane HV, the position of the movable mold 13 can be easily specified by the x coordinate value and the y coordinate value specified according to the machine coordinate system xyz. At this time, the z coordinate value of the movable mold 13 may be specified based on the so-called approach distance, that is, the distance between the fixed mold 12 and the movable mold 13. This approach distance is kept constant regardless of the movement of the movable mold 13.
[0030]
For example, the intersection of the moving plane HV of the movable mold 13 and the extension line of the central axis 22 (the z coordinate axis of the mechanical coordinate system xyz) can be set as the reference position of the movable mold 13. When the movable mold 13 is positioned at this reference position, the restraining force of the movable mold 13 along the moving plane HV is not applied to the profile 11 that passes through the two through holes 24 and 28 one after another. That is, the straight shape member 11 goes straight, and no bending deformation is caused to the shape member 11 at this time. When the reference position of the movable mold 13 is specified in this way, the attitude of the movable mold 13 is, for example, the rotation angle B around the y axis (V axis) or the rotation angle A around the x axis (H axis) specified according to the machine coordinate system xyz. Can be specified by.
[0031]
Referring to FIG. 4 again, the NC processing program calculated by the computer device 43 such as an engineering workstation (EWS) or a personal computer (personal computer) is supplied to the NC controller 42. In this NC machining program, for example, control data such as the position and orientation of the movable mold 13 associated with each feed position of the long material 11 is defined. When the x-coordinate value and y-coordinate value of the movable mold 13 are designated according to the above-described mechanical coordinate system xyz, the NC controller 42 establishes such an x-coordinate value and y-coordinate value of the horizontal motion motor 33 and the vertical motion motor 32. A drive command value that defines the amount of rotation is pushed through and output to the bending machine 10. When the rotation angle B around the y-axis and the rotation angle A around the x-axis of the movable mold 13 are designated according to the machine coordinate system xyz, the NC controller 42 rotates the rotation member 35 and the swinging member 37 that establish these rotation angles. The drive command value of the drive motor to be driven is pushed through and output to the bending machine 10.
[0032]
The computer apparatus 43 incorporates NC machining program creation software for realizing the control data creation method for a push-bending machine according to the present invention. This NC machining program creation software can function as one module (so-called add-on software) of CAD software that realizes a computer-aided design (CAD) system, for example. If incorporated in the CAD software in this way, the NC machining program creation software can divert the existing functions incorporated in the CAD software in realizing the control data creation method. However, the NC machining program creation software does not necessarily have to be incorporated into the CAD software, and all necessary functions may be provided by the NC machining program creation software alone. The NC processing program creation software may be taken into the computer device 43 from, for example, an FD (floppy disk) 44, a CD (compact disk) 45, a DVD (digital video disk), or other portable recording medium, and may be wireless or wired. Regardless, it may be incorporated into the computer device 43 through a network.
[0033]
In realizing the control data creation method for a push-bending machine according to the present invention, the NC machining program creation software uses the shape of a long product through a network 46 such as a LAN (local area communication network), a WAN (wide area communication network), or the Internet. Get the data. Using the acquired shape data, the NC machining program creation software creates the NC machining program as described above.
[0034]
The shape data may be fetched from a product database constructed in the server computer 47, for example. For example, CAD data of products designed on the CAD terminal 48 may be stored in the product database. Such CAD data may be taken into the product database from, for example, FD (floppy disk), CD (compact disk), DVD (digital video disk), and other portable recording media, as described above. Regardless, it may be incorporated into the product database through the network 49.
[0035]
Now, for example, as shown in FIG. 6, a scene is assumed in which a long product 51 formed by bending a shape having a uniform cross section is formed. The long product 51 designed on the CAD system is stored in the product database as CAD data. Such CAD data includes at least shape data representing the shape of the long product 51 in accordance with a single global coordinate system XYZ. For example, a representation method such as a wire frame model, a surface model, or a solid model may be used for the shape data. The shape data may specify the cross-sectional shape of the long product 51 and the bending state of the long product 51 associated with the cross-sectional shape in a single data structure. You may specify.
[0036]
The operator first launches NC machining program creation software on the computer device 43. The NC machining program creation software captures the shape data of the long product 51 from the product database based on the operator's input operation. For example, a keyboard or a mouse may be used for the input operation. Based on the captured shape data, a three-dimensional image of the long product 51 can be reproduced on the screen of the computer device 43. For this reproduction, for example, an image processing function of CAD software may be used.
[0037]
When the three-dimensional shape of the long product 51 is confirmed in this way, the NC machining program creation software pushes and bends the entire coordinate system XYZ that specifies the three-dimensional shape of the long product 51, for example, as shown in FIG. A local coordinate system, that is, a machine coordinate system xyz specified based on the fixed die 12 of the processing machine 10 is defined. Such a machine coordinate system xyz may be set for each of the specific cross sections 52 a to 52 f of the long product 51. Details of the method of setting the cross section will be described later. The machine coordinate system xyz is associated with each of the cross sections 52a to 52f on the basis of the shape of the through hole 24 of the fixed mold 12.
[0038]
In associating the machine coordinate system xyz with each of the cross sections 52a to 52f, the NC machining program creation software acquires the positional relationship between the through hole 24 of the fixed mold 12 and the machine coordinate system xyz. For this acquisition, for example, a GUI (graphical user interface) may be used. That is, for example, as shown in FIG. 8, the operator may align the machine coordinate system xyz with the cross-sectional shape of the long product 51 drawn on the screen of the computer device 43. At this time, the orientation of the x coordinate axis and the y coordinate axis of the machine coordinate system xyz is set according to the shape of the through hole 24 formed in the fixed mold 12, that is, the orientation around the central axis 22. The direction of the z coordinate axis coincides with the central axis 22 of the fixed mold 12. It is desirable that the center axis 22 of the fixed mold 12 coincides with the gravity center position G specified by the cross-sectional shape of the long product 51, for example.
[0039]
When the position and orientation of the fixed mold 12 are specified for each of the cross sections 52a to 52f of the long product 51 based on the machine coordinate system xyz, the position and attitude of the movable mold 13 on the basis of the fixed mold 12 are determined based on the machine coordinate system xyz. Can be read in accordance with. When reading the position of the movable mold 13, the NC machining program creation software specifies a position vector related to the movable mold 13 on the machine coordinate system xyz. Such a position vector is, for example, a first vector defined by the magnitude of the approach distance from the origin of the machine coordinate system xyz along the z coordinate axis, and parallel to the y coordinate axis of the machine coordinate system xyz from the tip of the first vector. What is necessary is just to specify by the combination of the 2nd vector prescribed | regulated, and the 3rd vector prescribed | regulated in parallel with the x coordinate axis of the machine coordinate system xyz from the front-end | tip of a 2nd vector.
[0040]
For example, when the movement plane HV of the movable mold 13 is specified on the machine coordinate system xyz, the sizes of the second vector and the third vector related to the movable mold 13 are determined according to the cross-sectional shape of the long product 51 that intersects the movement plane HV. Can be specified. As shown in FIG. 9, when the three-dimensional image of the long product 51 is projected onto the yz plane of the machine coordinate system xyz, the magnitude of the second vector is based on the intersection of the projected three-dimensional image and the moving plane HV. That is, the y-coordinate value of the movable mold 13 can be specified. At this time, if the tangential direction 53 of the long product 51 is specified on the moving plane HV, the rotation angle A around the x-axis of the movable mold 13 can be derived. As shown in FIG. 10, when the three-dimensional image of the long product 51 is projected onto the xz plane of the machine coordinate system xyz, similarly, the third product 51 is based on the intersection of the projected three-dimensional image and the moving plane HV. The magnitude of the vector, i.e. the x-coordinate value of the movable mold 13 can be specified. At the same time, if the tangential direction 54 of the long product 51 is specified on the moving plane HV, the rotation angle B around the y axis of the movable mold 13 can be derived. The horizontal movement motor 33 is controlled according to the specified x coordinate value, and the vertical movement motor 32 is controlled according to the specified y coordinate value.
[0041]
Subsequently, the NC machining program creation software calculates the feed position of the long material 11 that is the material of the long product 51 for each of the cross sections 52a to 52f in which the machine coordinate system xyz is set. The feed position may be calculated based on the distance from the tip of the long product 51 to each of the cross sections 52a to 52f measured along the longitudinal direction of the long product 51. Each calculated feed position is associated with the x-coordinate value and y-coordinate value of the movable mold 13, the y-axis rotation angle B, and the x-axis rotation angle A. Control data is thus created. When the description of the NC program header and NC program footer is added to the control data, the NC machining program is completed as shown in FIG. 11, for example.
[0042]
The completed NC machining program is finally supplied to the NC controller 42. The NC controller 42 operates the push-bending machine 10 according to the NC machining program. According to the NC machining program shown in FIG. 11, the long material 11 has a constant feed rate. F Pass through the fixed mold 12 and the movable mold 13 at 6000 mm / min. For example, when the feed position W = −1424.0000 mm is established, the movable mold 13 has the x coordinate value X = 0.000 mm and the y coordinate value Y = 0.446 mm from the reference position, that is, the origin position of the xy plane. Move to the specified coordinate position. At this time, the posture of the movable mold 13 is specified by a rotation angle B around the y axis B = 0.000 degrees and a rotation angle A around the x axis A = 0.159 degrees. Subsequently, when the long material 11 reaches the feed position W = −1504.072 mm, the movable mold 13 moves to the coordinate position specified by the x coordinate value X = 0.000 mm and the y coordinate value Y = 4.409 mm. . At this time, the posture of the movable mold 13 changes to a posture defined by a rotation angle B around the y axis B = 0.000 degrees and a rotation angle A around the x axis A = 3.157 degrees. Thus, each time the feed position W is passed, the movable mold 13 moves to a position defined by the x coordinate value X or the y coordinate value Y, and is defined by the rotation angle B around the y axis or the rotation angle A around the x axis. Change to a posture. Between the adjacent feed positions W, the x-coordinate value X, the y-coordinate value Y, the y-axis rotation angle B, and the x-axis rotation angle A may be changed at a constant speed, for example. However, the feed position W here is defined along the z coordinate axis based on the origin position of the slider 15. The origin position of the slider 15 refers to, for example, a position where the slider 15 starts to advance during push-through bending and a standby position before processing.
[0043]
As described above, according to the control data generation method according to the present invention, the position of the movable die 13 is determined according to the machine coordinate system xyz specified based on the fixed die 12 of the push-through bending machine 10, that is, the local coordinate system. Moreover, the local coordinate system is redefined every time the feed position defined in the longitudinal direction of the long product 51 changes. Therefore, after the bending deformation of the long product 51 formed between the fixed mold 12 and the movable mold 13 is always included, the x coordinate value and the y coordinate value of the movable mold 13 are specified. As a result, an ideal amount of movement of the movable mold 13 is obtained. Such an ideal amount of movement can greatly help the bending of the long material 11 as designed.
[0044]
In determining the cross-sections 52a to 52f associated with the machine coordinate system xyz as described above, the NC machining program creation software determines the bending state of the long product 51 based on the above-described shape data, for example, as shown in FIG. At least one parametric curve 55 to be expressed is specified. Such a parametric curve 55 may be directly specified by, for example, a ridge line or a centroid line (a curve connecting the centroids of each cross section one after another) of the long product 51 reproduced by CAD software. Based on the NC machining program creation software, it may be newly created.
[0045]
The parametric curve 55 can be expressed by an expression method such as a Bezier curve, a B-spline curve, or a NURBS (non-uniform rational B-spline) curve. In such a representation method, for example, as shown in FIG. 13, the bending state of the curve 56 can be defined by a plurality of control points 57 and 58. These control points 57 and 58 always include knots 57 that give coordinate values on the curve 56 to be expressed. The arrangement of the knots 57 is determined based on the difference between the straight line 59 connecting the adjacent knots 57 and the expressed curve 56, that is, the tolerance TOL. As a result of maintaining the tolerance TOL constant, the interval between the knots 57 is narrowed in the curved portion 56 having a large curvature, and conversely, the spacing between the knots 57 is expanded in the curved portion 56 having a small curvature. Moreover, when the tolerance TOL is increased, the interval between the knots 57 is increased, and when the tolerance TOL is decreased, the interval between the knots 57 is decreased.
[0046]
When the coordinate value of each knot 57 is specified on the parametric curve 55 in this way, the NC machining program creation software calculates the tangent vector 60 for the parametric curve 55 for each knot 57 as shown in FIG. . As a result, in each knot 57, the cutting plane 61 in which the tangent vector 60 is orthogonal can be specified. The cross sections 52a to 52f can be specified by the cross sectional shape of the long product 51 drawn on the cutting plane 61. As a result of using the parametric curve 55 in this way, as the curvature of the long product 51 increases, the number of cross sections 52a to 52f increases, and the movement of the movable mold 13 can be finely controlled. Moreover, if the size of the tolerance TOL is intentionally changed, the number of the cross-sections 52a to 52f can be changed intentionally according to the dimensional accuracy required for the long product 51.
[0047]
Such a parametric curve 55 can be used to calculate the position of the movable mold 13 at each feed position W, that is, the amount of movement. For example, as described above, a scene in which the machine coordinate system xyz is set in the cross sections 52a to 52f defined for each knot 57 of the parametric curve 55 is assumed. At this time, the NC machining program creation software specifies the approach distance L between the fixed mold 12 and the movable mold 13 on the machine coordinate system xyz, for example, as shown in FIG. This approach distance L is measured along the direction of the central axis 22 of the fixed mold 12 between the outlet of the fixed mold 12 side through hole 24 and the movable mold 13 positioned at the reference position. Such an approach distance L may be taken into the NC machining program creation software in advance through, for example, an operator's input operation.
[0048]
Based on the identified approach distance L, a moving plane HV of the movable mold 13 is defined on the machine coordinate system xyz. In defining the moving plane HV, the NC machining program creation software may define the z coordinate value on the machine coordinate system xyz based on the approach distance L. As a result, the xy plane of the machine coordinate system xyz is translated by the approach distance L along the z coordinate axis. When the movement plane HV is thus defined, the NC machining program creation software calculates the x coordinate value and the y coordinate value at the intersection 63 between the movement plane HV and the parametric curve 55. Since the z coordinate value is specified in advance by the approach distance L, the x coordinate value and the y coordinate value of the intersection 63 can be easily derived. The position of the movable mold 13 as described above can be specified by the calculated x coordinate value and y coordinate value.
[0049]
As described above, when the z coordinate axis of the machine coordinate system xyz overlaps the central axis 22 of the fixed mold 12, the parametric curve 55 is always fixed at the outlet of the fixed mold 12 side through hole 24, as is apparent from FIG. It is desirable to overlap the 12 central axes 22. Such a parametric curve 55 passes through the center position of the fixed mold 12 at each of the cross sections 52 a to 52 f of the long product 51. Here, the parametric curve 55 is referred to as a “neutral axis”. Such a neutral axis can be specified as follows, for example.
[0050]
For example, as shown in FIGS. 16 and 17, two-dimensional data representing the cross-sectional shape 65 of the long product 51 and three-dimensional data representing a ridge line corresponding to each vertex of the cross-sectional shape 65 are individually CAD data. Suppose a scene included in However, in making each vertex of the cross-sectional shape 65 correspond to each ridgeline, the chamfering formed at each vertex is ignored. That is, the ridge line is drawn by the vertices before the cornering used in the process of drawing the cross-sectional shape 65.
[0051]
First, the NC machining program creation software acquires the correspondence between each vertex of the cross-sectional shape 65 specified by the two-dimensional data and the ridge line specified by the three-dimensional data. For example, a GUI may be used for this acquisition. That is, as shown in FIG. 17, the operator designates the first and second guide lines 66a and 66b based on the three-dimensional image of the ridge line drawn on the screen of the computer apparatus 43, and similarly, FIG. As shown in FIG. 5, for example, the first and second guide points 67a and 67b are designated based on the cross-sectional shape 65 drawn on the screen. Here, according to the specified order, the first guide line 66a and the first guide point 67a are associated with each other, and the second guide line 66b and the second guide point 67b are associated with each other. For such designation, for example, a mouse operation may be used.
[0052]
When the two-dimensional data and the three-dimensional data are associated in this way, the NC machining program creation software acquires the positional relationship between the two guide points 67a and 67b and the center position 68 of the fixed mold 12. For example, a GUI may be used for this acquisition. That is, the operator may superimpose the xy coordinate system on the cross-sectional shape 65 of the long product 51 drawn on the screen of the computer device 43 as shown in FIG. At this time, the operator makes the coordinate origin (0, 0) of the xy coordinate system coincide with the center position 68 of the fixed mold 12. The orientation of the xy coordinate system may be specified according to the machine coordinate system xyz described above. When the xy coordinate system is set in this way, the NC machining program creation software calculates the x coordinate value and the y coordinate value of the first and second guide points 67a and 67b according to the xy coordinate system.
[0053]
Subsequently, as shown in FIG. 18, the NC machining program creation software defines a plurality of cutting planes 70a to 70f with respect to two edge lines defined by the three-dimensional data, that is, the first and second guide lines 66a and 66b. To do. In setting the cutting planes 70a to 70f, the first and second guide lines 66a and 66b may be equally divided into the same number of partial lines. Each of the cutting planes 70a to 70f is orthogonal to the tangent line of the first and second guide lines 66a and 66b at the dividing points 71a to 71f of the partial lines. In each of the cutting planes 70a to 70f, the first guide point 67a can be specified at a position where the first guide line 66a and the cutting planes 70a to 70f intersect, and the second guide line 66b and the cutting planes 70a to 70f The second guide point 67b can be specified at the position where the two intersect.
[0054]
When the positions of the first and second guide points 67a and 67b are specified on the respective cutting planes 70a to 70f in this way, the NC machining program creation software determines that the two guide points 67a and 67b and the fixed mold 12 are Based on the positional relationship with the center position 68, the center position 68 is specified on the cutting planes 70a to 70f. When the calculated center positions 68 are connected in order, the parametric curve 55 can be drawn.
[0055]
When connecting the center positions 68 in order, the NC machining program creation software may refer to the first guide line 66a expressed by a parametric curve, for example. First, the NC machining program creation software specifies the direction vector of the first guide line 66a on each of the cutting planes 70a to 70f. These direction vectors are translated to the center position 68. As a result, a start point vector and an end point vector are specified between two adjacent cutting planes 70a to 70f. A first guide line 6 between the start point vector and the end point vector thus identified. 6 A parametric curve of the same order as a is drawn. The parametric curve can change the curvature at an equal change rate from the start point vector to the end point vector. As a result of drawing these parametric curves one after the other, a smooth and highly accurate neutral axis can be obtained. In addition, in order to improve the accuracy of the parametric curve obtained in this way, it is desirable to narrow the interval between the dividing points 71a to 71f, that is, the interval between the cutting planes 70a to 70f.
[0056]
Note that in the push-through bending machine 10, in addition to the bending deformation described above, twist deformation may be realized at the same time. Such torsional deformation may be realized by rotation of the pendulum member 19. At this time, the NC machining program supplied to the NC controller 42 may include control data such as the rotation position of the pendulum member 19 associated with each feed position of the long material 11 as described above. The NC controller 42 pushes through and outputs a drive command value that defines the amount of rotation of the drive motor 23 that establishes such a rotational position to the bending machine 10.
[0057]
【The invention's effect】
As described above, according to the present invention, it is possible to realize the ideal movement of the movable type while reflecting the bending deformation of the long product formed between the fixed type and the movable type.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing an overall configuration of a push-through bending machine.
FIG. 2 is an enlarged front view of a fixed mold.
FIG. 3 is an enlarged front view of a movable type.
FIG. 4 is a schematic diagram schematically showing an overall configuration of a push-through bending processing system.
FIG. 5 is a fixed perspective view showing the concept of a machine coordinate system.
FIG. 6 is a perspective view schematically showing the configuration of a long product.
FIG. 7 is a perspective view showing a machine coordinate system associated with each cross section of the long product.
FIG. 8 is a diagram schematically showing a GUI (Graphical User Interface) used for setting the orientation of the machine coordinate system with respect to a cross section.
FIG. 9 is a conceptual diagram illustrating a process of calculating a y-coordinate value from a long product projected on a yz plane.
FIG. 10 is a conceptual diagram showing a process of calculating an x-coordinate value from a long product projected on an xz plane.
FIG. 11 is a diagram showing a specific example of an NC machining program.
FIG. 12 is a conceptual diagram showing a parametric curve expressing the bending state of a long product.
FIG. 13 is a conceptual diagram showing control points specified by a parametric curve.
FIG. 14 is a conceptual diagram showing a cross section of a long product specified based on a parametric curve.
FIG. 15 is a conceptual diagram showing a movable position specified based on a parametric curve.
FIG. 16 is a plan view showing a cross-sectional shape of a long product expressed by two-dimensional data.
FIG. 17 is a conceptual diagram showing a ridge line of a long product expressed by three-dimensional data.
FIG. 18 is a conceptual diagram showing a neutral axis specified based on two guide lines.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Push bending machine, 12 Fixed type, 13 Movable type, 44 Floppy disk (FD) as a recording medium, 45 Compact disk (CD) as a recording medium, 51 Long product, 52a-52f The cross section of a long product, 55 parametric curve, 57 knot as control point, 60 tangent vector, 63 intersection, HV movable moving plane, L approach distance.

Claims (3)

Obtaining the shape data representing the shape of the long product according to the global coordinate system; identifying at least one parametric curve representing the bending of the long product based on the shape data; and the parametric A step of calculating a tangent vector to the parametric curve for each control point specified according to the curvature of the curve, and a step of specifying a cross section of the long product for each control point of the parametric curve based on the calculated tangent vector When, further comprising the step of setting a local coordinate system specified on the basis of the fixed-type push-through bending machine for each of the cross-section, and a step of calculating the position of the movable die bending pushed through on the basis of the local coordinate system machine Control data creation method for push-through bending machine characterized by the above. In the control data creation method for the push-through bending machine according to claim 1 , a step of specifying an approach distance between the fixed mold and the movable mold on the local coordinate system in calculating the position of the movable mold; A step of defining a movable movement plane on the local coordinate system based on the specified approach distance, and a step of specifying an intersection of the movement plane and the parametric curve on the local coordinate system. Control data creation method for push-through bending machine. Obtaining the shape data representing the shape of the long product according to the global coordinate system; identifying at least one parametric curve representing the bending of the long product based on the shape data; and the parametric A step of calculating a tangent vector to the parametric curve for each control point specified according to the curvature of the curve, and a step of specifying a cross section of the long product for each control point of the parametric curve based on the calculated tangent vector When the steps of setting a local coordinate system specified on the basis of the fixed-type push-through bending machine for each of the cross-section, and a step of calculating the position of the movable type based push-through bending machine in the local coordinate system to the computer A computer-readable recording medium storing a program to be realized.

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