JP4622987B2 - Tool reference plane data creation device and creation method - Google Patents

Description

  The present invention relates to a technique for creating a tool reference surface used in NC machining technique (numerical control machining technique) or the like. In particular, the present invention relates to a technique for creating tool reference plane data describing a tool reference plane for processing a material into a product shape based on data describing the product shape.

The NC processing technology processes a material into a predetermined product shape by relatively moving the tool and the material along a movement path taught in advance. The product shape is represented by data created using a three-dimensional CAD (Computer Aided Design) device or the like. In order to process a material into a product shape using an NC machine tool, it is necessary to determine a tool movement path based on data describing the product shape.
In the NC machining technique, a reference point is defined for a tool in order to describe the position of the tool with coordinates. Thereby, the movement path of the tool is determined by the movement path of the reference point of the tool. The movement path of the tool is equal to the path along which the tool reference point moves when the tool cutting edge surface is moved in contact with the boundary surface of the product shape. That is, the movement path of the tool is located on a surface that is offset from the boundary surface of the product shape by the amount corresponding to the tool shape. In order to determine the movement path of the tool, it is necessary to obtain a tool reference surface that is offset from the boundary surface of the product shape by the amount of the tool shape based on data describing the product shape.
Patent Document 1 describes a technique for obtaining a tool reference surface using an inverse offset method. In the inverse offset method, each tool reference point is a virtual reversing tool that approximates the boundary surface of the product shape with an approximate element such as a point cloud or a small plane group (STL: Stereo lithography), and is reversed with respect to the posture during processing. Arrange it so that it is located in the approximate element. Then, by obtaining the envelope surface of the arranged virtual reversal tool shape group, an offset surface model that is offset from the boundary surface of the product shape by the tool shape is created.
JP-A-4-133103

In the technique of Patent Document 1, a curved surface cannot be directly handled, and a tool reference plane is created after creating an approximate model that approximates a boundary surface of a product shape with an approximate element group. For this reason, an error caused by the approximation process occurs on the created tool reference surface. In order to reduce this error, it is necessary to closely approximate the boundary surface of the product shape, but the calculation load increases as finer approximation processing is performed. There is a need for a technique for accurately creating a tool reference surface without excessively increasing the calculation load.
The present invention solves the above problems. The present invention provides a technique for accurately creating a tool reference surface without increasing a calculation load.

  The technology of the present invention is embodied in an apparatus that creates tool reference plane data describing a tool reference plane for processing a material into a product shape based on product shape data describing the product shape. An apparatus embodied by the present invention includes a storage unit for product shape data describing a product shape arranged in xyz space, and tool shape data describing a tool shape arranged in xyz space with a tool reference point as an origin. Storage means. Thereby, product shape data and tool shape data created by an external three-dimensional CAD device or the like can be stored.

  The apparatus according to the present invention sets lattice point groups arranged in the xyz direction at predetermined intervals in an xyz space in which product shape data describes a product shape, and a sphere having a predetermined radius centered on each set lattice point. Means for partitioning the area, a grid point near the product boundary that is the central grid point of the sphere area through which the product shape boundary surface passes, and a point on the boundary surface of the product shape that is closest to the grid point near the product boundary A product boundary closest point is specified, and product shape grid point data describing a data group of a pair of coordinates of a product boundary neighboring grid point and a product boundary closest point coordinate is prepared. Thereby, product shape grid point data expressing the product shape described by the product shape data as a set of product boundary neighboring lattice points close to the boundary surface of the product shape can be obtained.

  The apparatus according to the present invention sets a grid point group arranged in the xyz direction at the predetermined interval in an xyz space in which tool shape data describes a tool shape, and the predetermined radius centered on each set grid point. On the boundary surface of the tool shape that is located closest to the tool boundary lattice point that is the center lattice point of the sphere region through which the tool shape boundary surface passes, and the tool boundary boundary lattice point A tool boundary closest point which is a point is specified, and tool shape grid point data describing a data group of a pair of coordinates of a tool boundary neighboring grid point and a tool boundary closest point coordinate is prepared. Thereby, tool shape lattice point data expressing the tool shape described by the tool shape data as a set of tool boundary vicinity lattice points close to the boundary surface of the tool shape can be obtained.

  The apparatus according to the present invention provides a tool reference point from at least one of the lattice points near the product boundary described in the product shape lattice point data among the lattice points located above the lattice point near the product boundary in the z direction. , The tool-shaped boundary surface passes through the sphere region of at least one product boundary vicinity lattice point, and the lattice point with the largest z coordinate is specified as the temporary reference surface vicinity lattice point, and the specified temporary reference surface vicinity lattice point is identified. Means for creating temporary reference plane lattice point data describing the coordinates of The temporary reference plane neighboring grid points specified by this means are candidates for reference plane neighboring grid points located in the vicinity of the tool reference plane. Note that the grid point group where the tool shape boundary surface passes the vicinity when the tool reference point is arranged at an arbitrary point in the xyz space is the tool boundary neighboring grid point group described in the tool shape grid point data. It can be obtained by translating only the coordinates of the grid points where the reference points are arranged.

The apparatus according to the present invention performs a first determination as to whether or not the temporary reference surface vicinity lattice points described in the temporary reference surface lattice point data are reference surface vicinity lattice points located in the vicinity of the tool reference surface. Means for performing This determination means first determines each coordinate of the arrangement tool boundary vicinity lattice point group that is the center lattice point of the spherical region through which the tool shape boundary surface that is arranged by positioning the tool reference point at the temporary reference surface vicinity lattice point passes. Identify. Next, with respect to the product boundary grid point group described in the product shape grid point data for the placement tool boundary grid point group,
(1) In all xy coordinates, the minimum z coordinate of the grid point near the placement tool boundary is not less than the minimum z coordinate of the grid point near the product boundary, and
(2) There is at least one lattice point near the product boundary that matches the lattice point near the placement tool boundary.
It is determined whether or not the first condition is satisfied. When the requirement (1) is not satisfied, it can be determined that the determined temporary reference surface vicinity lattice points are too close to the boundary surface of the product shape. When the requirement (2) is not satisfied, it can be determined that the determined temporary reference plane vicinity lattice points are too far apart from the boundary surface of the product shape. In the first determination, the interference between the product shape and the tool shape is determined at an approximation level based on a grid point group.

The apparatus according to the present invention includes a second determination unit for determining whether or not the temporary reference surface vicinity lattice point satisfying the first condition is a reference surface vicinity lattice point located in the vicinity of the tool reference surface. Yes. The determination means reads from the product shape grid point data the product boundary nearest point with respect to the product boundary neighborhood grid point that coincides with the placement tool border neighborhood grid point for the temporary reference plane neighborhood grid point that satisfies the first condition, and the product A reversal tool boundary closest point that is a point on the boundary surface of the tool shape that is reversed and arranged with the tool reference point positioned at the boundary closest point and that is closest to the grid point near the temporary reference surface is calculated. And the temporary reference plane vicinity grid point and the calculated reversal tool boundary nearest point,
(3) Temporary reference plane vicinity grid points are located outside the reversed tool shape, or all reverse tool boundary nearest points exist in the spherical area of temporary reference plane vicinity grid points, and
(4) At least one reversing tool boundary nearest point exists in the spherical region of the temporary reference plane vicinity lattice point,
It is determined whether or not the second condition is satisfied. When the requirement (3) is not satisfied, it can be determined that the determined temporary reference plane neighboring lattice points are too close to the boundary surface of the product shape. When the requirement (4) is not satisfied, it can be determined that the determined temporary reference plane neighboring lattice points are too far apart from the boundary surface of the product shape. In the second determination, the interference between the product shape and the tool shape is accurately determined using the points on the respective boundary surfaces.

The apparatus according to the present invention is the product boundary closest point used to calculate the reversal tool boundary closest point from the reversal tool boundary closest points for the temporary reference plane neighboring lattice points satisfying the second condition. Is provided with means for identifying the closest reversal tool boundary closest to the temporary reference surface vicinity grid point and creating tool reference surface data describing the identified reversal tool boundary closest point. The temporary reference surface vicinity lattice points satisfying the second condition can be determined as regular reference surface vicinity lattice points located in the vicinity of the tool reference surface. The reversing tool boundary closest point specified as described above from one or a plurality of reversing tool boundary closest points is a point closest to the boundary surface of the product shape. Even if the tool reference point is arranged in the tool shape, the tool shape does not interfere with the product shape. Therefore, it can be used for defining the tool reference plane.
The apparatus according to the present invention includes means for adding a grid point adjacent to a temporary reference plane neighboring grid point (that is, a regular reference plane neighboring grid point) satisfying the second condition to the temporary reference plane grid point data. Yes. Since the temporary reference plane vicinity lattice point satisfying the second condition is located in the vicinity of the tool reference surface, the lattice point adjacent to the temporary reference surface vicinity lattice point satisfying the second condition is also set to the tool. It can be a point located in the vicinity of the reference plane. Therefore, by adding the grid point group adjacent to the regular reference plane neighboring grid points to the temporary reference plane grid point data, the grid points located near the tool reference plane and the points defining the tool reference plane are leaked. You can search without.
According to this apparatus, it is possible to obtain tool reference plane data that represents a tool reference plane with respect to a product shape as a point cloud. By expressing the product shape and tool shape by the grid point set in the xyz space and the nearest point on the boundary surface with respect to the grid point, the tool reference plane can be accurately created without increasing the calculation load. it can.

The technology of the present invention may also be embodied in a method for creating tool reference plane data that describes a tool reference plane for processing a material into a product shape based on product shape data describing the product shape. it can. In this method, the electronic computer is caused to execute the following processing.
First, processing for storing product shape data describing the product shape arranged in the xyz space and tool shape data describing the tool shape arranged in the xyz space with the tool reference point as the origin are stored in the electronic computer. Execute the process.
Next, a process of setting lattice point groups arranged in the xyz direction at predetermined intervals in the xyz space in which the product shape data describes the product shape, and partitioning a spherical region having a predetermined radius around each set lattice point Near the product boundary, which is the center grid point of the sphere region through which the product shape boundary surface passes, and the product boundary closest to the product shape boundary point located near the product boundary grid point. A point is specified, and a process of creating product shape grid point data describing a data group of a pair of coordinates of a grid point in the vicinity of the product boundary and the coordinates of the nearest point of the product boundary is executed.
Next, in the xyz space in which the tool shape data describes the tool shape, a grid point group arranged in the xyz direction at the predetermined interval is set, and the spherical area having the predetermined radius centered on each set grid point is defined. The tool boundary near the tool boundary that is the center grid point of the sphere region through which the tool shape boundary surface passes, and the tool boundary that is the point on the boundary surface of the tool shape that is closest to the tool boundary grid point The closest point is specified, and a process of creating tool shape grid point data describing a data group of a pair of the coordinate of the grid point near the tool boundary and the coordinate of the closest point of the tool boundary is executed.

Next, when a tool reference point is arranged from among the lattice points located above the product boundary lattice point in the z direction for at least one of the product boundary lattice points described in the product shape lattice point data, the tool shape The grid surface of the grid passes through the spherical region of at least one product boundary grid point, and the grid point with the largest z coordinate is specified as the temporary reference plane grid point, and the coordinates of the specified temporary reference plane grid point are described. A process of creating temporary reference plane lattice point data is executed. Also, for each temporary reference plane neighboring grid point described in the temporary reference plane grid point data, the center of the sphere area through which the tool-shaped boundary surface arranged by positioning the tool reference point at the temporary reference plane neighboring grid point passes Specify each coordinate of the grid point group near the placement tool boundary that is a grid point, and the grid point group near the tool boundary is described in the product shape grid point data,
(1) In all xy coordinates, the minimum z coordinate of the grid point near the placement tool boundary is not less than the minimum z coordinate of the grid point near the product boundary, and
(2) There is at least one lattice point near the product boundary that matches the lattice point near the placement tool boundary.
To determine whether or not the first condition is satisfied.

Next, for the temporary reference plane neighboring grid point satisfying the first condition, the product boundary nearest point for the product boundary neighboring grid point that coincides with the placement tool boundary neighboring grid point is read from the product shape grid point data, and the nearest product boundary is obtained. Calculate the closest reference point of the reversal tool boundary, which is a point on the boundary surface of the tool shape that is reversely arranged with the tool reference point positioned at the point, and that is the closest point from the lattice point near the temporary reference surface. The nearest grid point and the calculated reversing tool boundary nearest point are
(3) Temporary reference plane vicinity grid points are located outside the reversed tool shape, or all reverse tool boundary nearest points exist in the spherical area of temporary reference plane vicinity grid points, and
(4) At least one reversing tool boundary nearest point exists in the spherical region of the temporary reference plane vicinity lattice point,
To determine whether or not the second condition is satisfied.

And, for the temporary reference surface vicinity lattice points satisfying the second condition, the product boundary closest point used to calculate the reverse tool boundary closest point is the temporary reference surface vicinity near the reverse tool boundary closest point. Identifying the closest point to the grid point, creating a tool reference plane data describing the specified reverse tool boundary closest point, and a grid point adjacent to the temporary reference plane neighboring grid point satisfying the second condition, A process of adding to the temporary reference plane lattice point data is executed.
According to this method, it is possible to obtain tool reference plane data that expresses a tool reference plane for a product shape with a point cloud.

  According to the present invention, a tool reference surface can be created with high accuracy. By creating a tool movement path using the created tool reference surface, it is possible to improve the accuracy of product processing by the NC machine tool.

The main features of the embodiments described below are listed.
(Feature 1) Product shape data is created using a three-dimensional CAD device.
(Feature 2) The lattice point groups arranged in the xyz space are arranged at equal intervals in the xyz direction.
(Characteristic 3) The diameter of the spherical region of the lattice point is set to 3 ^1/2 times the interval of the lattice point group.

FIG. 1 shows a functional configuration of a tool reference plane data creation device 10 (hereinafter simply referred to as a creation device) that implements the present invention. The creation device 10 is a device that creates tool reference plane data that describes a tool reference plane for processing a material into a product shape based on the product shape data 22 describing the product shape. The tool reference plane data created by the creation device 10 can be used to create a tool movement path taught to a numerical control (NC) machine tool.
As shown in FIG. 1, the creation device 10 functionally includes a data storage unit 20, a data creation unit 50, and an input / output unit 70. The creation device 10 is configured using a computer device, and the data storage unit 20, the data creation unit 50, and the input / output unit 70 are configured by hardware of the computer device, a program stored in the computer device, and the like.

The data storage unit 20 includes product shape data 22, tool shape data 24, product shape grid point data 26, tool shape grid point data 28, temporary reference plane grid point data 30, and reference plane grid point data 32. The tool reference plane data 34 can be stored. The product shape data 22 is CAD data describing a product shape, and describes a product shape arranged in an xyz space in which xyz orthogonal coordinates are defined. The tool shape data 24 is CAD data describing a tool shape, and describes a tool shape arranged in an xyz space in which xyz orthogonal coordinates are defined. The product shape data 22 and the tool shape data 24 are taught to the creation apparatus 10 from the outside via the input / output unit 70. On the other hand, the product shape grid point data 26, the tool shape grid point data 28, the temporary reference plane grid point data 30, the reference plane grid point data 32, and the tool reference plane data 34 are data created by the data creation unit 50.
The data creation unit 50 includes a grid point setting unit 52, a grid point data creation unit 54, a temporary reference plane grid point data creation unit 56, a first grid point determination unit 58, a second term viewpoint determination unit 60, A reference plane point determination unit 62 is provided. The data creation unit 50 performs various arithmetic processes based on the product shape data 22 and the tool shape data 24 and finally creates the tool reference plane data 34. The tool reference plane data 34 is data describing a tool reference plane for processing the product shape described in the product shape data 22 with the tool described in the tool shape data 24. The tool reference surface is an offset surface that is offset from the boundary surface of the product shape by the tool shape (tool radius). The data creation unit 50 creates product shape grid point data 26, tool shape grid point data 28, temporary reference plane grid point data 30, reference plane grid point data 32, and the like in the process of creating tool reference plane data.

FIG. 2 is a flowchart showing a flow of processing in which the creation device 10 creates the tool reference plane data 34. A processing procedure in which the creation apparatus 10 creates the tool reference plane data 34 based on the product shape data 22 and the tool shape data 24 taught from the outside will be described along the flow shown in FIG.
In step S <b> 2, the creation apparatus 10 stores the product shape data 22 and the tool shape data 24 in the data storage unit 20. The product shape data 22 and the tool shape data 24 are input to the creation device 10 via the input / output unit 70.
FIG. 3 shows an example of the product shape 22 a described by the product shape data 22. As illustrated in FIG. 3, the product shape data 22 describes a boundary surface 22b of the product shape 22a arranged in the xyz space by a set of basic shapes. As the basic shape, for example, a vertex V, a ridge line C, a surface S, or the like is used. For example, a straight line or a curved line is used for the ridge line C, and a flat surface, a cylindrical surface, a spherical surface, a free curved surface, or the like is used for the surface S. The ridge line C is described by a curve expression C (t) using a parameter t. The surface S is described by a surface expression S (u, v) using parameters u and v. Each basic shape V, C, and S describing the product shape 22a is assigned an identifier ID that can be identified.
FIG. 4 shows an example of the tool shape 24 a described by the tool shape data 24. As illustrated in FIG. 4, the tool shape data 24 is described by arranging the tool shape 24 in an xyz space with the tool reference point 24c as the origin. As shown in FIG. 4, the tool shape data 24 describes the shape of a tip spherical tool (so-called ball end mill) having a radius r. Similarly to the product shape data 22, the tool shape data 24 describes the boundary surface 24b of the tool shape 24a by a set of basic shapes (vertex V, ridge line C, and surface S).
The product shape data 22 and the tool shape data 24 are approximate representations of the product shape 22a and the tool shape 24a by point groups arranged in the xyz space and minute plane groups (STL: Stereo lithography) arranged in the xyz space. It may be data.

  In step S <b> 4 of FIG. 2, the grid point setting unit 52 and the grid point data creation unit 54 create product shape grid point data 26 based on the product shape data 22. FIG. 5 schematically shows the product shape grid point data 26. The product shape grid point data 26 will be described with reference to FIG. In creating the product shape grid point data 26, the grid point setting unit 52 first sets a predetermined value in the xyz space described by the product shape data 22, that is, the xyz space in which the boundary surface 22b of the product shape 22a is arranged. A group of lattice points g arranged in the xyz direction at an interval b is set. The lattice point setting unit 52 partitions a spherical region R having a predetermined radius a with each set lattice point g as the center. When the lattice point setting unit 52 divides the sphere region R centered on each lattice point g, the lattice point data creation unit 54 then identifies the sphere region R group through which the product shape boundary surface 22b passes. Further, for each specified sphere region R, the nearest point p on the product shape boundary surface 22b located closest to the center lattice point (hereinafter referred to as a product boundary vicinity lattice point) gm is calculated. Then, a data group of a pair of the coordinates (i, j, k) of the specified product boundary neighboring grid point gm and the coordinates (x, y, z) of the nearest point p on the calculated product shape boundary surface 22b is described. Product shape grid point data 26 to be created is created. The position of the lattice point g can be expressed by integer coordinates (i, j, k) indicating the arrangement position in the lattice point group, or can be expressed by xyz system coordinates (x, y, z). In this case, x = b × i, y = b × j, and z = b × k are satisfied. Here, in the product shape grid point data 26, the identifier ID of the basic shape (vertex V, ridge line C, surface S) to which each nearest point p belongs, and the product boundary grid point gm are inside the product shape boundary surface 22b. An internal / external flag indicating whether the image is located outside or outside is also recorded. The inside / outside flag is “−1” if the product boundary grid point gm is located inside the product shape boundary surface 22b, and “+1” if the product boundary grid point gm is located outside the product shape boundary surface 22b. To do.

  Here, a procedure in which the lattice point data creation unit 54 creates the product shape lattice point data 26 from the product shape data 22 will be described. As described above, in the product shape data 22, the boundary surface 22b of the product shape 22a is described by the basic shape group such as the vertex V, the ridge line C, and the surface S arranged in the xyz space. Therefore, as illustrated in FIGS. 6A to 6C, the lattice point data creation unit 54 first specifies the product boundary neighboring lattice point gm with respect to the vertex V constituting the product shape boundary surface 22b, and then the product shape. The product boundary vicinity lattice point gm is specified for the ridge line C constituting the boundary surface 22b, and finally the product boundary vicinity lattice point gm is specified for the surface S forming the product shape boundary surface 22b.

  FIG. 7 shows a lattice point g where the vertex V exists in the spherical region R. As shown in FIG. 7, the lattice point g where the vertex V exists in the spherical region R has a distance from the vertex V equal to or less than the radius a of the spherical region R. Accordingly, the distance from the vertex V is calculated for all the lattice points g, and the vertex V is present in the sphere region R by specifying the lattice point g whose calculated distance is less than or equal to the radius a of the sphere region R. The grid point g to be identified can be specified.

  FIG. 8 shows a lattice point g where a ridge line C exists in the spherical region R. As shown in FIG. 8, the lattice point g where the ridge line C exists (passes) in the sphere region R has a distance from the nearest point Ca on the ridge line C that is less than or equal to the radius a of the sphere region R. The nearest point Ca on the ridge line C with respect to the lattice point g is a Newton-Raphson method with the constraint that the vector connecting the lattice point g and the nearest point Ca is perpendicular to the tangent vector C ′ at the nearest point Ca. This can be obtained by executing the analysis operation. However, in the analysis calculation for obtaining the nearest point Ca, if the given initial point is inappropriate, the correct nearest point Ca may not be calculated. In addition, it is not practical to perform the analysis operation on all the lattice points g because the calculation load increases remarkably. Therefore, the lattice point data creation unit 54 first arbitrarily determines at least one initial point on the ridge line C, and specifies the lattice point g where the initial point is located in the sphere region R. Then, with respect to the specified grid point g, an analysis calculation is performed using the initial point on the ridge line C determined in advance, and the nearest point Ca is calculated. Thereby, one lattice point g and the nearest point Ca on the ridge line C can be correctly specified. If the distance between the specified lattice point g and the nearest point Ca is equal to or less than the radius a of the sphere region R, it can be determined that the ridge line C passes through the sphere region R of the lattice point g. If even one grid point g through which the ridge line C passes within the sphere region R can be specified, the nearest point Ca specified above is used as the initial point for the 26 grid points g adjacent to the grid point g. Analytical operations can be performed. Similarly, every time the grid point g through which the ridge line C passes through the sphere region R is specified, the lattice point g adjacent to the grid point g is set as the object of the analysis calculation process, so that The lattice point g group through which the ridge line C passes can be searched for along the ridge line C. Thereby, the grid point g group in which the ridge line C exists (passes) in the spherical region R can be specified without omission.

  FIG. 9 shows a lattice point g where the surface S exists (passes) in the spherical region R. As shown in FIG. 9, the lattice point g where the surface S exists (passes) in the sphere region R has a distance from the nearest point Sa on the surface S equal to or less than the radius a of the sphere region R. The nearest point Sa on the plane S with respect to the lattice point g is such that the vector connecting the lattice point g and the nearest point Sa is perpendicular to the tangential vector Su in the s direction and the tangent vector Su in the u direction at the nearest point Sa. It can be obtained by executing analytical operations of the Newton-Raphson method with a certain condition as a constraint. As in the case of the edge line C, the lattice point data creation unit 54 first determines at least one initial point on the surface S and specifies the lattice point g in which the initial point is located in the sphere region R. Then, with respect to the specified lattice point g, an analytical calculation is performed using the initial point on the surface S previously determined, and the nearest point Sa is calculated. Thereby, one lattice point g and the nearest point Sa on the surface S can be correctly specified. If the distance between the specified lattice point g and the nearest point Sa is equal to or less than the radius a of the sphere region R, it can be determined that the surface S passes through the sphere region R of the lattice point g. If even one grid point g through which the surface S passes within the sphere region R can be specified, with respect to the 26 grid points g adjacent to the grid point g, the closest point Sa specified above is used as the initial point. Analytical operations can be performed. Similarly, every time a lattice point g through which the surface S passes through the sphere region R is specified, the lattice point g adjacent to the lattice point g is set as the object of the analysis calculation process, so that the inside of the sphere region R The lattice point g group through which the surface S passes can be searched along the surface S. Thereby, the lattice point g group where the surface S exists (passes) in the spherical region R can be specified without omission.

  In step S <b> 6 of FIG. 2, the lattice point setting unit 52 and the lattice point data creating unit 54 create the tool shape lattice point data 28 based on the tool shape data 24. FIG. 10 schematically shows the tool shape grid point data 28. The tool shape grid point data 28 will be described with reference to FIG. In creating the tool shape grid point data 28, first, the grid point setting unit 52 sets a predetermined value in the xyz space described by the tool shape data 24, that is, the xyz space in which the boundary surface 24 b of the tool shape 24 a is arranged. A group of lattice points g arranged in the xyz direction at an interval b is set. The lattice point setting unit 52 partitions a spherical region R having a predetermined radius a with each set lattice point g as the center. When the lattice point setting unit 52 divides the sphere region R centered on each lattice point g, the lattice point data creation unit 54 then identifies the sphere region R group through which the tool shape boundary surface 24b passes. For each specified sphere region R, the nearest point q on the tool shape boundary surface 24b located closest to the center lattice point (hereinafter referred to as a tool boundary vicinity lattice point) gz is calculated. Then, a data group of a pair of the coordinates (i, j, k) of the specified tool boundary neighboring grid point gz and the coordinates (x, y, z) of the nearest point q on the calculated tool shape boundary surface 24b is described. Tool shape grid point data 28 to be created is created. Here, in the tool shape lattice point data 28, the identifier ID of the basic shape (vertex V, ridge line C, surface S) to which each nearest point q belongs and the tool boundary neighboring lattice point gz are inside the tool shape boundary surface 24b. An internal / external flag indicating whether the image is located outside or outside is also recorded. The specific procedure for creating the tool shape grid point data 28 is the same as the procedure for creating the product shape grid point data 26.

  In step S <b> 8, the temporary reference plane grid point data creation unit 56 creates temporary reference plane grid point data 30 using the product shape grid point data 26 and the tool shape grid point data 28. FIG. 11 schematically shows provisional reference plane lattice point data 30. The temporary reference plane grid point data creation unit 56 first sets a tool axis zh that passes through the product boundary grid point gm described in the product shape grid point data 26. Next, when the tool reference point 24c is arranged from each lattice point on the tool axis zh, that is, each lattice point located in the z direction above the lattice point near the product boundary, the tool-shaped boundary surface 24b has at least one product. A lattice point that passes through the spherical region R of the lattice point gm near the boundary and has the largest z coordinate is specified. Specifically, first, a grid point for arranging the tool reference point is determined from the grid points on the tool axis zh. Next, the coordinates of the grid points near the tool boundary described in the tool shape grid point data 28 are read, and the coordinates of the grid points near the tool boundary set as the tool reference point arrangement positions are read out. Translate. The coordinate group moved in parallel indicates each coordinate of the lattice point group in which the tool-shaped boundary surface 24b in which the tool reference point is arranged at the previously determined lattice point passes through the spherical area. Then, the coordinates of the coordinate group moved in parallel and the coordinates of the lattice point gm group near the product boundary are compared, and it is determined whether or not there is a matching lattice point. By sequentially performing this determination process from a sufficiently upper lattice point on the tool axis zh, the temporary reference plane vicinity lattice point gf can be specified. The temporary reference plane grid point data creation unit 56 specifies one temporary reference plane neighboring grid point gf for each product boundary neighboring grid point gm described in the product shape grid point data 26. Then, temporary reference plane grid point data 30 describing the coordinates of the specified temporary reference plane neighboring grid point gf is created. The provisional reference plane vicinity grid point gf does not need to be specified for all the product boundary vicinity grid points gm, and may be obtained for at least one product boundary vicinity grid point gm.

  In steps S10, S12, and S14 of FIG. 2, the first grid point determination unit 56 and the second grid point determination unit 58 perform the process for each temporary reference plane neighboring grid point gf described in the temporary reference plane grid point data 30. It is determined whether or not the grid point is located in the vicinity of the tool reference plane. Each of the temporary reference surface lattice points gf group obtained in the previous step S8 can be a lattice point located in the vicinity of the tool reference surface with respect to the product shape boundary surface 22b. On the other hand, each of the temporary reference surface vicinity lattice points gf group is not necessarily a lattice point located in the vicinity of the tool reference surface. In the processes of steps S10, S12, and S14, regular reference plane neighboring grid points located in the vicinity of the tool reference plane are selected from the temporary reference plane neighboring grid points gf described in the temporary reference plane grid point data 30. Extract.

In step S <b> 10 of FIG. 2, the first grid point determination unit 58 selects one temporary reference plane neighboring grid point gf from the temporary reference plane grid point data 30.
In step S12, the first grid point determination unit 58 performs a first determination process on the selected temporary reference plane vicinity grid point gf. The first determination process will be described with reference to FIG. As shown in FIG. 12, the first grid point determination unit 58 sets each of the spherical region R groups through which the tool shape boundary surface 24b passes when the tool reference point 24c is arranged at the selected temporary reference plane vicinity grid point gf. A center grid point (hereinafter referred to as a grid point near the placement tool boundary) gz is specified. The arrangement tool boundary vicinity lattice point gz can be obtained by translating the tool boundary vicinity lattice point gz described in the tool shape lattice point data 28 by the coordinate of the selected temporary reference plane vicinity lattice point gf. Next, the first lattice point determination unit 58 determines that the specified arrangement tool boundary vicinity lattice point gz group is the product boundary vicinity lattice point gm group described in the product shape lattice point data 26.
(1) In all xy coordinates, the minimum z coordinate of the grid point gz near the tool boundary is equal to or greater than the minimum z coordinate of the grid point gm near the product boundary, and (2) the grid point gm near the tool boundary and the product boundary There is at least one temporary processing point neighboring lattice point gmz that coincides with the lattice point gz.
It is determined whether or not the first condition is satisfied. If the grid point gz near the placement tool boundary satisfies the first condition (in the case of OK), the coordinates of the grid point gmz near the temporary machining point in (2) are held, and the second grid point determination in step S14. The process proceeds to the determination process by the unit 60. When the placement tool boundary vicinity grid point gz does not satisfy the second condition (in the case of NG), the selected temporary reference plane vicinity grid point gf is determined not to be a grid point located in the vicinity of the tool reference plane; Return to step S10. Here, when the arrangement tool boundary vicinity lattice point gz group does not satisfy the requirement (1), it can be determined that the selected temporary reference surface vicinity lattice point gf is too close to the product shape boundary surface 22b. When the arrangement tool boundary vicinity lattice point gz group does not satisfy the requirement (2), it can be determined that the selected temporary reference surface vicinity lattice point gf is too far from the product shape boundary surface 22b.

In step S14 of FIG. 2, the second grid point determination unit 60 performs the second determination process on the temporary reference plane neighboring grid point gf that has passed the first determination process by the first grid point determination unit 58. . The first determination process will be described with reference to FIG. First, the second grid point determination unit 60 reads, from the product shape grid point data 26, the nearest point p on the product shape boundary surface 22b with respect to the temporary machining point neighboring grid point gmz specified in the previous step S12. Next, when the tool reference point 24c is disposed at the closest point p and the tool shape 24a is reversed, the closest point hr on the boundary surface 24b of the reversed tool shape located closest to the temporary reference plane vicinity grid point gf. Is calculated. Here, the calculation of the nearest point hr is performed according to the following procedure. First, the relative coordinates gf-gmz between the temporary reference plane vicinity grid point gf and the temporary processing point vicinity grid point gmz are calculated. Next, from the tool shape grid point data 28, the coordinates of the tool boundary neighboring grid point gz matching the coordinate obtained by reversing the relative coordinates gf-gmz and the nearest point q corresponding thereto are read out. Next, a tangent plane U that touches the boundary surface 24b of the inverted tool shape is obtained in the vicinity of the temporary reference surface vicinity lattice point gf from the tool boundary vicinity lattice point gz and the nearest point q. Here, the normal vector of the tangent plane U is obtained by the relative coordinates gz-q between the tool boundary neighboring lattice point gz and the nearest point q. Finally, the nearest point hr on the nearest tangent plane U is calculated from the temporary reference plane vicinity grid point gf, and the distance d from the temporary reference plane vicinity grid point gf to the closest point hr is calculated. Here, the distance d from the temporary reference plane neighboring grid point gf to the nearest point hr is a positive value when the reference plane neighboring grid point gf is located outside the tangent plane U, and the reference plane neighboring grid point gf is When it is located inside the tangent plane U, it is a negative value and is a signed distance value. The second grid point determination unit 60 calculates the nearest point hr and the signed distance value d for all the temporary machining point neighboring grid points gmz specified in step S12. Next, the second grid point determination unit 60 determines that the data group of a pair of the temporary processing point neighboring grid point gmz and the nearest point hr is
(3) The temporary machining point vicinity grid point gmz is located outside the tangent plane U, or the temporary machining point vicinity grid point gmz is located inside the sphere vicinity R of the temporary reference plane vicinity grid point gf, and
(4) At least one nearest point hr is located in the sphere vicinity R of the temporary reference plane vicinity lattice point gf.
It is determined whether or not the second condition is satisfied. When the data group of the pair of the temporary processing point neighboring grid point gmz and the nearest point hr satisfies the second condition (in the case of OK), the second grid point determination unit 60 selects the temporary reference plane neighboring grid point. gf is determined to be a regular reference plane neighboring grid point. Then, the process proceeds to step S16. On the other hand, when the data group of the pair of the temporary machining point vicinity lattice point gmz and the nearest point hr does not satisfy the second condition (in the case of NG), the temporary reference surface vicinity lattice point gf is located near the tool reference surface. It is determined that the grid point is not located, and the process returns to step S10. Here, when the data group of the pair of the temporary processing point vicinity lattice point gmz and the nearest point hr does not satisfy the requirement (3), the temporary reference surface vicinity lattice point gf is close to the product shape boundary surface 22b. It can be judged that it is too much. When the data group of the pair of the temporary processing point neighboring grid point gmz and the nearest point hr does not satisfy the requirement (4), the selected temporary reference plane neighboring grid point gf is too far from the product shape boundary surface 22b. Can be judged.
In step S16 of FIG. 2, the second grid point determination unit 60 sets the temporary reference plane vicinity grid point gf that satisfies the second condition in step S14 as a normal reference plane vicinity grid point located in the vicinity of the tool reference plane. The reference plane lattice point data 32 is recorded. At this time, the second grid point determination unit 60 records the nearest point hr calculated for each temporary processing point neighboring grid point gmz and the signed distance value d together with the reference plane grid point data 32.

In step S18 of FIG. 2, the reference surface upper point determination unit 62 determines each closest point hr from among the closest points hr on the boundary surface 24b of the inverted tool shape calculated in the second determination process of step S14. A point on the tool reference plane that defines the tool reference plane is determined based on the distance value d. Specifically, the nearest point hr having the smallest distance value d is determined as a point on the tool reference plane.
In step S <b> 20, the reference surface upper point determination unit 62 records the tool reference surface upper point hr determined in step S <b> 18 in the tool reference surface data 34.
Through the processing from step S10 to step S20 described above, one tool reference plane neighboring grid point gf located in the vicinity of the tool reference plane and the nearest point on the tool reference plane located closest to the tool reference plane neighboring grid point gf. A point hr is determined. The tool reference plane neighboring grid point gf is recorded in the reference plane grid point data 32, and the nearest point hr on the tool reference plane is recorded in the tool reference plane data 34.

In step S22 of FIG. 2, the temporary reference plane grid point data creation unit 56 sets the 26 grid point g groups adjacent to the determined tool reference plane vicinity grid point gf as new temporary reference plane vicinity grid points gf. To the temporary reference plane lattice point data 30. Since the tool reference plane continuously spreads, the grid point g adjacent to the tool reference plane vicinity grid point gf can also be a grid point located in the vicinity of the tool reference plane. Therefore, by recording the 26 grid points g adjacent to the tool reference plane neighboring grid points gf in the temporary reference plane grid point data 30, and executing the above-described determination processing also on those adjacent grid points g, The tool reference plane neighboring grid point gf and the nearest point hr on the tool reference plane can be calculated without omission.
In step S24, it is determined whether or not the processing of steps S10 to S22 has been executed for all temporary reference plane neighboring grid points gf described in the temporary reference plane grid point data 30. If the process is not executed for all the reference plane neighboring grid points gf, the process returns to step S10, and the processes of steps S10 to S24 are repeatedly executed. Finally, all the reference surface vicinity lattice points gf through which the tool reference surface passes through the sphere vicinity R are specified, and the closest point hr on the tool reference surface is determined for each reference surface vicinity lattice point gf. The The specified reference plane neighboring grid point gf group is recorded in the reference plane grid point data 32, and the determined closest point hr group on the tool reference plane is recorded in the tool reference plane data 34. Thereby, tool reference surface data 34 describing the tool reference surface with respect to the boundary surface 22b of the product shape 22a in the nearest point hr group is obtained. Based on the tool reference surface described by the tool reference surface data 34, a tool path for processing the material into the product shape 22a can be created.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The block diagram which shows the structure of the preparation apparatus of tool reference plane data. The figure which shows the processing flow which the preparation apparatus of tool reference plane data performs. The figure which shows an example of the product shape which product shape data describes. The figure which shows an example of the tool shape which tool shape data describes. The figure which shows product shape grid point data typically. The figure which shows the procedure which produces product shape grid point data. The figure which shows the lattice point in which a vertex exists in a spherical area. The figure which shows the lattice point in which a ridgeline exists in a spherical area. The figure which shows the lattice point in which a surface exists in a spherical area. The figure which shows tool shape grid point data typically. The figure which shows typically temporary reference plane vicinity lattice point data. The figure for demonstrating a 1st determination process. The figure for demonstrating a 2nd determination process.

Explanation of symbols

10. ・ Tool reference plane data creation device 20 ・ ・ Data storage unit 22 ・ ・ Product shape data 24 ・ ・ Tool shape data 26 ・ ・ Product shape grid point data 28 ・ ・ Tool shape grid point data 30 ・ ・ Temporary reference plane Grid point data 32... Reference plane grid point data 34... Tool reference plane data 50... Data creation unit 52... Grid point setting unit 54. 58 .. First grid point determination unit 60.. Second grid point determination unit 62.. Reference plane point determination unit 70.

Claims (2)

An apparatus for creating tool reference plane data that describes a tool reference plane for processing a material into a product shape based on product shape data describing a product shape,
storage means for product shape data describing the product shape arranged in the xyz space;
Storage means for tool shape data describing the tool shape arranged in the xyz space with the tool reference point as the origin;
Means for setting a grid point group arranged in the xyz direction at predetermined intervals in the xyz space in which the product shape data describes the product shape, and partitioning a spherical region having a predetermined radius centered on each set grid point;
The near-product-boundary grid point, which is the center grid point of the sphere area through which the product-shaped boundary surface passes, and the product boundary nearest point, which is the point on the product-shaped boundary surface that is closest to the product-boundary grid point Means for creating product shape grid point data that identifies and describes a pair of data sets of the coordinates of the grid points near the product boundary and the coordinates of the nearest product boundary;
Means for setting lattice point groups arranged in the xyz direction at the predetermined intervals in the xyz space in which the tool shape data describes the tool shape and partitioning the spherical region having the predetermined radius centered on each set lattice point When,
The tool boundary near grid point that is the center grid point of the sphere area through which the tool shape boundary surface passes and the tool boundary nearest point that is the point on the tool shape boundary surface that is closest to the tool boundary grid point. Means for identifying and creating tool-shaped grid point data that describes a pair of data sets of coordinates of a tool boundary neighboring grid point and a tool boundary nearest point;
If at least one of the lattice points near the product boundary described in the product shape lattice point data is positioned at the tool reference point from among the lattice points located in the z direction above the lattice point near the product boundary, the boundary of the tool shape A temporary reference that describes the coordinates of the specified temporary reference plane neighboring grid point by specifying the grid point having the largest z coordinate as the temporary reference plane neighboring grid point while the surface passes through the spherical region of at least one product boundary neighboring grid point Means for creating surface grid point data;
For each temporary reference plane neighborhood grid point described in the temporary reference plane grid point data, the tool reference point is placed at the temporary reference plane neighborhood grid point, which is the center grid point of the spherical area through which the tool-shaped boundary surface passes Identify each coordinate of the grid point group near the tool boundary, for the grid point group near the product boundary where the arranged tool boundary grid point group is described in the product shape grid point data,
(1) In all xy coordinates, the minimum z coordinate of the grid point near the placement tool boundary is not less than the minimum z coordinate of the grid point near the product boundary, and
(2) There is at least one lattice point near the product boundary that matches the lattice point near the placement tool boundary.
First determination means for determining whether or not the first condition is satisfied,
For the grid point near the temporary reference surface that satisfies the first condition, the product boundary nearest point for the grid point near the product boundary that matches the grid point near the placement tool boundary is read from the product shape grid point data, Calculate the reversal tool boundary nearest point that is the point on the boundary surface of the tool shape that is reversed by placing the tool reference point and that is located closest to the temporary reference surface vicinity lattice point, and the temporary reference surface vicinity lattice The point and the calculated reversing tool boundary nearest point are
(3) Temporary reference plane vicinity grid points are located outside the reversed tool shape, or all reverse tool boundary nearest points exist in the spherical area of temporary reference plane vicinity grid points, and
(4) At least one reversing tool boundary nearest point exists in the spherical region of the temporary reference plane vicinity lattice point,
Means for determining whether or not the second condition is satisfied,
For the temporary reference surface vicinity lattice point satisfying the second condition, the product boundary closest point used to calculate the reverse tool boundary closest point is the temporary reference surface vicinity lattice point among the reverse tool boundary closest points. Means for identifying the closest reversing tool boundary closest to and creating tool reference surface data describing the reversing tool boundary closest
Means for adding a grid point adjacent to a temporary reference plane neighboring grid point satisfying the second condition to the temporary reference plane grid point data;
An apparatus for creating tool reference plane data. Based on the product shape data describing the product shape, a method for creating tool reference surface data describing a tool reference surface for processing a material into a product shape.
processing to store product shape data describing the product shape arranged in the xyz space;
A process of storing tool shape data describing a tool shape arranged in an xyz space having a tool reference point as an origin in the electronic computer;
A process of setting a grid point group arranged in the xyz direction at a predetermined interval in the xyz space in which the product shape data describes the product shape, and partitioning a spherical region having a predetermined radius around each set grid point;
The near-product-boundary grid point, which is the center grid point of the sphere area through which the product-shaped boundary surface passes, and the product boundary nearest point, which is the point on the product-shaped boundary surface that is closest to the product-boundary grid point Identifying and creating product shape grid point data describing the data group of the pair of the coordinates of the grid point near the product boundary and the coordinate of the product boundary nearest point,
A process of setting a lattice point group arranged in the xyz direction at the predetermined interval in the xyz space in which the tool shape data describes the tool shape and partitioning the spherical region of the predetermined radius centered on each set lattice point When,
The tool boundary near grid point that is the center grid point of the sphere area through which the tool shape boundary surface passes and the tool boundary nearest point that is the point on the tool shape boundary surface that is closest to the tool boundary grid point. Processing to identify and create tool shape grid point data describing a pair of data sets of the coordinates of the grid points near the tool boundary and the coordinates of the tool boundary nearest point;
If at least one of the lattice points near the product boundary described in the product shape lattice point data is positioned at the tool reference point from among the lattice points located in the z direction above the lattice point near the product boundary, the boundary of the tool shape A temporary reference that describes the coordinates of the specified temporary reference plane neighboring grid point by specifying the grid point having the largest z coordinate as the temporary reference plane neighboring grid point while the surface passes through the spherical region of at least one product boundary neighboring grid point Processing to create surface grid point data;
For each temporary reference plane neighborhood grid point described in the temporary reference plane grid point data, the center grid point of the sphere area through which the tool-shaped boundary surface located by positioning the tool reference point at the temporary reference plane neighborhood grid point passes The coordinates of the grid point group near the placement tool boundary are specified, and the grid point group near the placement tool boundary is the product boundary grid point group described in the product shape grid point data.
(1) In all xy coordinates, the minimum z coordinate of the grid point near the placement tool boundary is not less than the minimum z coordinate of the grid point near the product boundary, and
(2) There is at least one lattice point near the product boundary that matches the lattice point near the placement tool boundary.
A process for determining whether or not the first condition is satisfied,
For the grid point near the temporary reference surface that satisfies the first condition, the product boundary nearest point for the grid point near the product boundary that matches the grid point near the placement tool boundary is read from the product shape grid point data, Calculate the reversal tool boundary nearest point that is the point on the boundary surface of the tool shape that is reversed by placing the tool reference point and that is located closest to the temporary reference surface vicinity lattice point, and the temporary reference surface vicinity lattice The point and the calculated reversing tool boundary nearest point are
(3) Temporary reference plane vicinity grid points are located outside the reversed tool shape, or all reverse tool boundary nearest points exist in the spherical area of temporary reference plane vicinity grid points, and
(4) At least one reversing tool boundary nearest point exists in the spherical region of the temporary reference plane vicinity lattice point,
A process for determining whether or not the second condition is satisfied,
For the temporary reference surface vicinity lattice point satisfying the second condition, the product boundary closest point used to calculate the reverse tool boundary closest point is the temporary reference surface vicinity lattice point among the reverse tool boundary closest points. Processing to create the tool reference plane data that specifies the closest to the reverse tool boundary,
A process of adding a grid point adjacent to a temporary reference plane neighboring grid point that satisfies the second condition to the temporary reference plane grid point data;
Of creating tool reference plane data to execute.

Images