JP2845661B2 - Shape data creation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming shape data, and more particularly, to a model (finished shape) formed by a mold required for NC data of a machine tool having a numerical control (NC) device.
The present invention relates to a method of obtaining a dividing line (parting line) and a dividing surface (parting surface) of a mold from the surface shape of the mold, or a method of creating shape data for obtaining a dividing line and a dividing surface necessary for drawing a mold by CAD.

FIG. 18 is a diagram for explaining an outline of a system in which the present invention is used. The shape data creating means 1 is a device for creating shape data by an operator operating an input device 6 such as a keyboard and a mouse in an interactive manner while watching a screen of a display device 5 such as a CRT. The device can also import drawing data created by standard CAD. When the shape data created by the shape data creation means 1 is input, the tool path generation means 2 creates tool path data based on the input, and sends it to the NC machine tool 4 via the DNC device 3 or to the floppy disk. Disk (F
D), data is output to the NC machine tool 4 via the FD, or an NC tape is created, and tool path data is input to the NC machine tool 4 via the NC tape.
The DNC device 3 is a device that transmits a large amount of NC data to a plurality of NC devices. The NC machine tool 4 performs machining according to the tool path data. The present invention relates to a method of creating shape data by the shape data creating means 1 in such a system.

[0003]

2. Description of the Related Art Conventionally, a parting line (parting line) and a parting surface (parting surface) of a mold have been formed by an operator using a parting line that will be separated from the surface shape of a model formed by the mold. It is empirically guessed (usually plotted where the surface shape of the model protrudes as a representative point) to obtain a drawing, or it is guessed by relying on the operator's intuition using CAM and appropriately calculated. A division plane is created by adding an appropriate width to the obtained division line.

[0004]

The dividing line and the dividing plane created in this way vary in shape accuracy due to the operator's experience and individual differences, and do not become the optimal dividing line and the dividing plane. There are problems that the mold does not open well and that many defects occur in the product shape formed by the mold.

Accordingly, an object of the present invention is to find a dividing line and a dividing surface of a mold that do not have the above-mentioned problems, that is, that the mold opens well and that the shape of a product formed by the mold is extremely low. An object of the present invention is to provide a shape data creating method.

[0006]

To achieve the above object, a method of forming shape data according to the present invention is characterized in that an SM (surface model) is used.
Is stored in a computer, the most protruding portion is automatically detected from the data of the SM shape, and a mold release surface when the mold is released is obtained. FIG. 1 is a flowchart of the basic processing routine of the method according to the present invention.
A shape data generating method according to the present invention for achieving the above object stores a shape of a surface (SM) of a mold model as data in a three-dimensional orthogonal coordinate system X, Y, Z which is orthogonal to each other.
A first step of determining any one point P (x, y, z) near the center of the interior surrounded by the surface of the model;
The shape cutting plane PLn of the model passing through a point P (x0, y0) perpendicular to a reference plane (XY plane) composed of predetermined two axes of a three-dimensional orthogonal coordinate system X, Y, Z is determined, and the point P (x0, y0
), The shape cutting plane PLn is rotated once around a vertical axis VL perpendicular to the X and Y planes, and the shape is cut on the shape cutting plane PLn for each division obtained by dividing one rotation by m at a rotation angle α °. A second step of determining an intersection SC between the plane PLn and the surface of the model;

A third step of obtaining a point Qi farthest from the vertical axis VL at a contact point of a tangent line parallel to the vertical axis VL with respect to each corresponding intersection line SC on each of the m-divided cutting planes PLn. , M divided cutting planes PLn
The predetermined interpolation curves SCi1 to SC forming the respective intersections SC
The starting point, the ending point, and the contact point (tangent to a straight line parallel to the VL axis) for each in
The value of Ln is compared with the local maximum value in the horizontal axis HL direction, and the maximum value is sequentially updated. When the value is equal to the local maximum value in the horizontal axis HL direction, the local maximum value is compared with the local maximum value and the local minimum value in the vertical axis VL direction. The value and the minimum value are sequentially updated, and a point Qi farthest from the vertical axis VL at a contact point of a tangent parallel to the vertical axis VL is defined as:
The finally obtained maximum value Qh, or the finally obtained minimum value Ql, or the finally obtained maximum value and the intermediate value Qm of the minimum value, or the finally obtained maximum value and minimum value A third step of selecting a predetermined point from the proportional distribution value Qp to determine a point Qi, and interpolating a predetermined interpolation curve as a sequence of contact points connecting the obtained points Qi to divide the mold. A fourth step of obtaining a line (parting line) SCQ;

The parting line (parting line) SCQ is offset, that is, in the normal direction of a predetermined (for example, on the XY plane) at each Qi point of the mold parting line (parting line) SCQ, and A point Ri separated by a predetermined width w on the inside or outside surrounded by the surface of
A fifth step of obtaining the SCR by continuously connecting the point sequence Ri, obtaining a SCR (parting surface) by linearly (ruled) interpolating each point Ri corresponding to each point Qi; , Consisting of

[0009]

According to the shape data creating method of the present invention, the shape of the surface (SM) of the mold model is registered as data, an arbitrary point P inside the model surface is determined, and the shape is perpendicular to the reference plane. Is determined by determining a shape cutting plane PLn of the model passing through the point P, and making one rotation about the vertical axis VL passing through the point P and perpendicular to the reference plane. An intersection line SCi between the shape cutting plane PLn and the surface of the model is obtained above, and each of the m-divided cutting planes PLi is obtained.
predetermined interpolation curves SCi1 to
The start point, the end point, and the contact point for each of the SCin are compared with the local maximum value in the horizontal axis HL direction of the cutting plane PLn set in advance, and the local maximum value is sequentially updated to be equal to the local maximum value in the horizontal axis HL direction. Then, the local maximum value and the local minimum value are compared with the local maximum value and the local minimum value in the vertical axis VL direction, and the local maximum value and the local minimum value are sequentially updated.
The finally obtained maximum value Qh, or the finally obtained minimum value Ql, or the finally obtained maximum value and the intermediate value Qm of the minimum value, or the finally obtained maximum value and minimum value The point Qi selected from the proportional distribution value Qp of
A parting line SCQ of the mold is obtained as a contact point sequence connecting the obtained points Qi, and the parting line SCQ is obtained.
Q is offset, that is, a point Ri separated by a predetermined width w in a predetermined (for example, XY plane) normal direction at each Qi point of the mold parting line SCQ is determined, and each point Ri is continuously determined. The connection is made to obtain an SCR, and each point Qi and each corresponding point Ri are linearly (ruled) interpolated to obtain a mold parting surface SF. This parting surface is a division plane at the edge width of the mold.

[0010]

FIG. 2 is a partially broken perspective view of a model having a plurality of surface patches. The shape of each of these surface patches is represented by a predetermined interpolation curve, for example, a three-dimensional Bezier curve or a spline curve. Hereinafter, the surface of the model is simply expressed as SM (surface model).

FIG. 3 is a diagram showing the shape cutting plane PLn and the cross-section rotation center P. In the embodiment of the present invention, each name is defined as follows. Considering three-dimensional coordinate systems X, Y, and Z that are orthogonal to each other, a plane that cuts the SM perpendicular to a predetermined two-dimensional reference plane (XY plane) in the three-dimensional coordinate systems X, Y, and Z is a shape cutting plane PLn. A point P (x0, y0) which is substantially the center of the inside of the SM surface is set on a reference plane (XY plane), and this is set as a cross-section rotation center P (x0, y0), and P (x0, y0) Axis perpendicular to the XY plane passing through
And an axis parallel to the X axis passing through P (x0, y0) is defined as a horizontal axis HL. However, a shape cutting plane PLn is created for each division obtained by rotating PLn one rotation around the VL axis and dividing one rotation by m at a rotation angle α °, and generating PL0, PL1,.
, PLn, ..., PLm (= PL0). here
Where n is an integer of 0 ≦ n ≦ m. Therefore, α ° is (3
60 / m) °.

FIG. 4 is a cutaway view of an SM composed of a plurality of curved surface patches formed by a shape cutting plane PLn, and FIG.
FIG. 6 is a diagram showing an intersection line SCi between the one curved surface patch and the shape cutting plane PLn, and FIG. 6 shows the intersection line SCi of the curved surface patch on the shape cutting plane PLn as a predetermined interpolation curve (in the present invention, a cubic Bezier curve SCi1). FIG. FIG. 4 and
In FIG. 5 , the solid line indicated by the thick line is the intersection of PLn and SM.
SCi , and the solid line part of SM is the front side of the PLn plane, SM
The broken line portion indicates the back side of the PLn plane.

FIG. 7 shows an intersection line SC on the shape cutting plane PLn.
FIG. 8 is a diagram showing a case where there is one contact Qi at a tangent line parallel to the vertical axis VL of i. FIG. 8 shows that the contact point Qi at a tangent line parallel to the vertical line VL of the intersection line SCi on the shape cutting plane PLn is two.
FIG. 9 shows the intersection lines SCi sequentially counted .
In order to calculate, the shape cutting plane PLn is set to α around the vertical axis VL.
° a rotated figure, FIG. 10 was obtained by rotating
The contact point Qi found on the shape cutting plane PLn is used as a contact point sequence.
Conceptually shows where to create the mold parting line SCQ
FIG . 11 shows a mold dividing surface S obtained by making one round around a dividing line SCQ around a line connecting the contact point Qi and the point Ri.
FIG. 12 is a partial view of an offset line SCR obtained by making one round of F and the point Ri, and FIG. 12 is a view showing an example of a finally formed mold division surface SF.

FIG. 13 is a flowchart of a processing routine of a method for obtaining a mold dividing line and a dividing surface from the SM shape model. Hereinafter, the flow chart of FIG . 13 , FIG. 2 to FIG.
19 to 21, a method for obtaining a mold dividing line and a dividing surface according to the present invention will be described in detail. The number following S indicates a step number. In the first stage, S
The M shape data is stored (step S1). Specifically, (1) The SM shape composed of a plurality of curved surface patches as shown in FIG. 2 is converted into a Bezier curve of a three-dimensional orthogonal coordinate system X, Y, Z. (Shape memory is called modeling). (2) Shape cutting plane P for cutting SM as shown in FIG.
The data of the cross-section rotation center point P (x0, y0) of Ln is stored. (3) The start angle of the shape cutting plane PLn passing through the point P is set to 0 ° parallel to the x-axis. Therefore, the HL axis shown in FIG.
The plane formed by the VL axis is the start shape cutting plane PL0. (4) The number m of times that the shape cutting plane PLn is rotated around the rotation center axis VL and one rotation (360 °) is divided every α ° is stored. Therefore, α = (360 / m) °.

[0015] In the second step, determining the shape cutting plane PLn (step S2). Specifically, as shown in FIG.
Sea urchin, (1) designated by the perpendicular X-axis as an XY plane the point P angle α
The shape cutting plane PLn cut at ° is defined as one point P and the point P
It is defined as a plane passing through P and including two straight lines HLn and VL . (2) It is assumed that an axis passing through the point P and parallel to the Z axis of the shape cutting plane PLn is VL, and an axis forming a specified angle α ° with the X axis in the horizontal direction on the XY plane is an HL n axis. (3) Initialize the contact Qh and Ql tables (see FIG. 7 ) .
Step S31 to be described below with irradiation). Further, an intersection line SC between the shape cutting plane and the curved surface patch (SM shape data) is obtained (step S3).

A method for obtaining the intersection SC will be described in detail below. FIG. 14 is a flowchart of a processing routine of a method for obtaining an intersection line between a shape model and a cutting plane. Schematically, (4) a curved surface patch intersecting with the shape cutting plane shown in FIG. 4 is obtained (steps S21 to S24). (5) As shown in FIG. 5, an intersection line SCi between the shape cutting plane and the curved surface patch. (Steps S25 to S28), (6) As shown in FIG. 6, the intersection line obtained for each curved surface is interpolated by each cubic Bezier curve SCi1 to SCin (Step S2).
9). More specifically, the flags of the unprocessed surface patches among all the surface patches of the SM shape data, that is, the individual surface patch flags of all the surface patches constituting the SM shape data are set (step S21). One unprocessed surface patch is searched (step S22), and the processed flag is turned on, that is, the flag set in step S21 is reset (step S23).

FIG . 19 is a diagram showing the relationship between the surface patch constituting the SM and the control.
It is a figure which shows the relationship with a point. Next, as shown in FIG.
To a control point characterizing the Bezier curve for each surface patch,
To determine whether a shape cutting plane intersect, if crossed, the process proceeds to step S25, if not crossed, the process returns to the step S22 (step S24). This method is generally very time-consuming to calculate the interference point of the free curve itself when checking the interference of two solids in CG (computer graphics) and CAD (computer aided design). Therefore, if the interference check is performed using the convex hull property (the convex hull is the smallest convex area including all the control points) in which the Bezier curve is surrounded by the control points instead of the Bezier curve, This is performed by applying the fact that a curve that does not interfere can be quickly found and unnecessary interference calculation can be omitted. Here, the method is executed by a method of finding whether or not adjacent control points intersect the shape cutting plane.

Then, the u and v parameters of the surface patch are divided into n (step S25). Here, the u and v parameters are used to convert a curved surface into three-dimensional coordinates. For example, in FIG.
For 0.0 to 1.0 and v = 0.0 to 1.0, each u,
At each division point obtained by dividing v by n, a curved surface is represented by data in a three-dimensional orthogonal coordinate system X, Y, Z. Next, since v is divided into n from 0.0 to 1.0 based on u, it is moved n + 1 times to find an intersection with the shape cutting plane. For example, if n = 10, u = 0.0
, And v = 0.0, 0.1, 0.2,..., 1.0,
Next, u = 0.1 is fixed, and v = 0.0, 0.1, 0.
2,..., 1.0, and v = 1 until u = 1.0.
For each point divided into 0, find the intersection with the shape cutting plane,
If an intersection is found, it is stored in a table (step S26). Next, this time, u is set to 0.0 with respect to v.
Is divided into n from n to 1.0, that is, n + 1 times, that is, 11 times in this case, similarly, the intersection point with the shape cutting plane is obtained, and if the intersection point is found, it is stored in the table (step S27). .

Next, sorting is performed so that the distance between the data stored in the tables in steps S26 and S27 is minimized by the u and v parameters (step S28), and the three-dimensional Bezier interpolation curves SCi1 to SCi1 to In is obtained, and the process proceeds to step S22 (step S29). And (7) As shown in FIG. 6, the intersection line SC is
The coordinates are converted to n (step S4 in FIG. 13 ).

FIG. 15 is a flow chart of a processing routine of a method for obtaining the contact point Qi, and FIG. 16 is a flow chart of a processing routine for updating the data table in the method of obtaining the contact point Qi. In the third step, a contact point Qi between each line segment SCij forming a continuous curve of the Bezier curve of the SC obtained in the second step and the parallel line of the VL axis is obtained (step S in FIG. 13 ) .
5). Specifically, SCij is extracted (step S3
2) Perform the following steps. Here, shown in FIG.
As described above, Qh and Ql are contact tables, which are initialized in step S31. The values of x and y of Qh (x, y) and Ql (x, y) are the starting points of the intersection SC. Initialize with the value of (x0, y0).

Next, as shown in FIG.
The tangent at the tangent parallel to the vertical axis VL of the intersection SCi on Ln
When there are two points Qi, how to find the contact point Qi
Therefore, the following description is based on the flowcharts of FIGS.
You. The start point and the end point of each SCij are compared with the values of the tables Qh and Ql initialized in step S31, and the table is updated based on the following steps (1) and (2) (steps S33 and S34). . (1) Compare with the HL value (table data of x of Qh (x, y)) of the Qh and Ql tables (steps S40 and S41),
When the HL value of SCij is large, both the values of Qh and Ql are updated (step S42), and when it is small, the process ends. (2) When the HL value of SCij is the same as the HL value of the Qh and Ql tables (the table data of x of Qh (x, y)) (YES in step S40), the VL value of SCij and the VL value of the Qh table are used. Value (table data of y of Qh (x, y)) (that is, the maximum value is compared) (step S4).
3), VL value of Qh (table data of y of Qh (x, y))
If larger, the Qh value is updated (step S44),
If not large, the SCij VL value and the Ql table V
The L value (the table data of y of Ql (x, y)) is compared (that is, the minimum value is compared) (step S45), and the VL value of Ql (the table data of y of Ql (x, y)) is obtained. If it is smaller, the Ql value is updated (step S46). (3) A contact is found between the start point and the end point of each SCij, and if there is a contact, the above (1) and (2) are performed for the HL and VL values of the contact (steps S35, S36, S3)
7). (4) Processes 1 to 3 are performed on all SCij (steps S36, S37, S38), and the median of Qh and Ql is set as the contact point Qm on this plane (step S39). (5) The obtained Qm is converted into a three-dimensional coordinate in a real space and stored as a contact point on the plane PLn (step S6 in FIG. 13 ).

More specifically, the contact table data is initialized (step S31), and a predetermined Bezier interpolation curve SCij is set.
Is stored in the buffer (step S32), and SC
The data of the start point of ij is compared with the data of the contact table set in advance, and steps S40 to S46 are executed (step S33). Similarly, the data of the end point of SCij are compared with steps S40 to S46. Step S
Step 46 is performed (step S34), and the contact point is determined, that is, a contact point having a tangent vector parallel to the VL axis is obtained by differentiating the Bezier interpolation curve SCij. If there is any part that is protruding in between, it is found and the coordinate value of the contact point is stored (step S35).

Next, it is searched whether or not the contact data obtained in step S35 is present (step S36). If there is, the contact table is confirmed according to steps S40 to S46 as in the case of the above-mentioned start point and end point. Then, the process is updated (step S37). After step S37 or when it is determined in step S36 that there is no contact, it is determined whether or not there is an unconfirmed SCij in the predetermined Bezier interpolation curve SCij (step S38). , If it is determined that there is
Returning to step S32, if it is determined that there is no middle point, a midpoint Qm = (Qh + Q1) / 2 is calculated from the values Qh and Ql of the table obtained up to step S37 (step S3).
9). In step S39, the intermediate point is used here, but a maximum point, a minimum point, or a proportional distribution point may be used as a contact point. In addition, since an object such as a cylinder is a straight line from the start point to the end point, there are infinite contact points at which the maximum value HL is obtained. In this case, it is optimal to use an intermediate point. Whether the intermediate point, the maximum point, the minimum point, or the proportional distribution point is used as a contact point is determined in advance, and is uniformly used when obtaining all contact points Qi.

FIG . 20 shows each connection on the created dividing line SCQ.
Project tangents VQi and VQi at point Qi onto XY plane
Vector Vxy and a vector on the XY plane perpendicular to it
FIG. 21 is a diagram showing the relationship with Vhxy.
Vhxy corresponding to each contact Qi on Q is extended by a predetermined length w
Method for determining the (offset) point Ri and the determined R
FIG. 9 is a diagram showing an offset curve SCR created by connecting i.
You. Hereinafter, the parting line will be described with reference to FIGS.
The fourth step of obtaining the in-SCQ will be described below.
In the fourth stage, a parting line SCQ is determined. More specifically, the shape cutting plane is rotated (steps S7 and S8 in FIG. 13 ), that is, (1) As shown in FIG. Is rotated by α ° about an axis perpendicular to (step S <b> 8 in FIG. 13 ). (2) Returning to step S2 in FIG. 13 , the contact Qm is similarly obtained on the new shape cutting plane. Further, (3) as shown in FIG. 21, a parting line SCQ is obtained from the point sequence of the contact point Qm (step S in FIG. 13 ) .
9). That is, the processes of 1 and 2 are repeated until the entire circumference is reached, and interpolation is performed with n cubic Bezier curves sequentially passing through the obtained point sequence.

In the fifth stage, the parting line S
The CQ is offset along the xy plane, and the mold dividing surface SF
Will be described with reference to FIGS . 9, 10, and 11. FIG . Specifically, at the offset stage, (1) As shown in FIG. 9, an XY tangent vector Vxy obtained by projecting a tangent vector at the Qi point of the SCQ onto the XY plane is obtained, and a vector Vhxy orthogonal to the vector Vxy is obtained. (2) As shown in FIG. 10, a point Ri is obtained at a distance w from Qi in the Vhxy direction (step S10 in FIG. 13 ). (3) Point sequence Ri is interpolated by n cubic Bezier and offset
A curve SCR is obtained (step S11 in FIG. 13 ). Furthermore, parting line SCQ and offset curve SCR
To obtain a parting surface SF. Specifically, (4) as shown in FIG. 11, the SCQ and the SCR are linearly interpolated to obtain a ruled (linear) interpolation plane SF (step S12 in FIG. 13 ). (5) The obtained surface SF is used as a parting surface for mold division. (6) Store the surface data as shape data (Step S13 in FIG. 13 ).

FIG. 17 is a flowchart of a processing routine for obtaining the offset line SCR when obtaining the mold division surface SF. First, the data of the three-dimensional curve SCQ and the offset amount w are stored (step S51), and the number of passing points (the number of times the shape cutting plane is rotated around the rotation center axis and divided by α °)
n is set (step S52). Next, i = 1 (step S53), and the passing points Qi (x, y, z) and Qi
A tangent vector Vi (x, y, z) at the point is obtained (step S54). Further, a unit vector Ni orthogonal to Vizo with the Z component of Vi set to 0 is obtained (step S).
55), Ri = Qi + Ni × w is calculated, and Ri is stored (step S56). Here, N of Ni means a normal vector. Then, i = i + 1 is calculated (step S57), i is compared with n, and steps S54 to S57 are executed until i becomes larger than n (step S58). Finally, the point sequence Ri is interpolated with a predetermined interpolation curve, for example, a Bezier curve, to obtain a three-dimensional curve SCR (step S59).

[0027]

As described above, according to the shape data creating method of the present invention, the shape data of the mold dividing line and the dividing surface can be automatically generated without depending on the experience of the operator and individual differences. The mold can be opened well, and the occurrence of defects in the product shape formed by the mold can be extremely reduced. Furthermore, according to the shape data creation method of the present invention,
Regardless of the shape of the model, including the vertical plane, the mold dividing line and the dividing plane can be automatically generated uniquely.

[Brief description of the drawings]

FIG. 1 is a flowchart of a basic processing routine of a method according to the present invention.

FIG. 2 is a perspective view in which a model whose surface is composed of a plurality of surface patches is partially broken.

FIG. 3 is a diagram showing a shape cutting plane PLn and a cross-section rotation center P.

FIG. 4 is a cutaway view of an SM including a plurality of curved surface patches formed by a shape cutting plane PLn.

FIG. 5 is a diagram showing an intersection line SCi between one curved surface patch of SM and a shape cutting plane PLn.

6 is a diagram in which an intersection line SCi of a curved surface patch on the shape cutting plane PLn in FIG. 5 is interpolated by a predetermined interpolation curve.

FIG. 7 is a vertical axis VL of an intersection line SCi on a shape cutting plane PLn.
FIG. 9 is a diagram showing a case where there is one contact Qi in a tangent line parallel to FIG.

FIG. 8 is a vertical axis VL of an intersection line SCi on the shape cutting plane PLn.
FIG. 9 is a diagram showing a case where there are two contact points Qi in tangent lines parallel to FIG.

FIG. 9 shows the state at each contact point Qi on the created dividing line SCQ.
Vector V obtained by projecting tangents VQi and VQi on the XY plane
Relation between xy and vector Vhxy on XY plane perpendicular to it
FIG.

FIG. 10 shows Vhx corresponding to each contact Qi on the dividing line SCQ .
A point Ri obtained by extending (offset) y by a predetermined length w is obtained.
Song created by connecting the calculated Ri
It is a figure showing line SCR.

FIG. 11 shows a line connecting the contact point Qi and the point Ri divided by a dividing line SCQ.
7 is a partial view of a mold dividing surface SF obtained by making one round around and an offset line SCR obtained by making one round of a point Ri. FIG.

FIG. 12 is a diagram showing an example of a finally created mold division surface SF.

FIG. 13 is a flowchart of a processing routine of a method of obtaining a mold dividing line and a dividing surface from an SM shape model.

FIG. 14 is a flowchart of a processing routine of a method for obtaining an intersection line between a shape model and a cutting plane.

FIG. 15 is a flowchart of a processing routine of a method for obtaining a contact point Qi.

FIG. 16 is a flowchart of a processing routine for updating a data table in a method for obtaining a contact point Qi.

FIG. 17 is an offset line S for obtaining a mold division surface SF.
It is a flowchart of the processing routine which calculates | requires CR.

FIG. 18 is a diagram illustrating an outline of a system in which the present invention is used.

FIG. Relationship between surface patches constituting SM and control points
FIG.

FIG. To calculate the intersection line SCi sequentially,
FIG. 7 is a diagram in which a plane PLn is rotated by α ° about a vertical axis VL.

FIG. 21 On the shape cutting plane PLn obtained by rotating
Using the determined contact point Qi as a contact point sequence, the mold dividing line SC
It is the figure which showed the place where Q is created notionally.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shape data creation means 2 ... Tool path generation means 3 ... NC machine tool 4 ... NC machine tool 5 ... Display device 6 ... Input device P ... Reference point PLn ... Shape cutting plane VL ... Vertical axis HL ... Horizontal axis SC ... Shape cutting Intersection line between plane and model surface SCQ ... Parting line (Parting line) SCR ... Offset line SF ... Parting surface (Parting surface) SM ... Model surface shape (Surface model)

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-175504 (JP, A) JP-A-61-125754 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G05B 19/4097 G06F 17/50

Claims (3)

(57) [Claims] 1. A shape data creation method for creating mold division line shape data for manufacturing a model from a given model shape, comprising: a three-dimensional orthogonal coordinate system in which the shapes of the surfaces of the model are orthogonal to each other; A first step of determining an arbitrary one reference point P inside the surface surrounded by the surface of the model, and the reference point perpendicular to a reference plane including two predetermined axes of the three-dimensional orthogonal coordinate system. Shape cutting plane PLn of model passing through P
Is determined, and the shape cutting plane PLn is rotated once around a vertical axis VL passing through the reference point P and perpendicular to the reference plane,
A second step of obtaining an intersection line SC with the surface of the model on the shape cutting plane PLn for each division obtained by dividing one rotation by m at a rotation angle α °; A third step of finding a point Qi farthest from the vertical axis VL at a contact point of a tangent line parallel to the vertical axis VL with respect to each corresponding intersection line SC, and a predetermined interpolation curve as a sequence of contact points connecting the contact points Qi. A fourth step of interpolating to obtain the mold parting line SCQ. 2. A shape data creating method for creating split surface shape data of a mold for manufacturing a model from a given model shape, comprising: a three-dimensional orthogonal coordinate system in which the shapes of the surfaces of the model are orthogonal to each other; A first step of determining an arbitrary one reference point P inside the surface surrounded by the surface of the model, and the reference point perpendicular to a reference plane including two predetermined axes of the three-dimensional orthogonal coordinate system. Shape cutting plane PLn of model passing through P
Is determined, and the shape cutting plane PLn is rotated once around a vertical axis VL passing through the reference point P and perpendicular to the reference plane,
A second step of obtaining an intersection line SC with the surface of the model on the shape cutting plane PLn for each division obtained by dividing one rotation by m at a rotation angle α °; A third step of finding a point Qi farthest from the vertical axis VL at a contact point of a tangent line parallel to the vertical axis VL with respect to each corresponding intersection line SC, and a predetermined interpolation curve as a sequence of contact points connecting the contact points Qi. A fourth step of interpolating to obtain the dividing line SCQ of the mold; and finding each point Ri separated by a predetermined width w in a predetermined normal direction corresponding to each contact point Qi of the dividing line SCQ. Are sequentially connected as a series of contact points to obtain a predetermined interpolation curve SCR, and the respective points Ri corresponding to the respective points Qi are interpolated by a predetermined interpolation curve to obtain the mold dividing surface SF. 5. A shape data creating method, comprising: 3. The third step includes setting a start point, an end point, and a contact point for each of the predetermined interpolation curves SCi1 to SCin that form the corresponding intersections SC on each of the m divided cutting planes PLn. , The previously set cutting plane P
Ln is compared with the local maximum value in the horizontal axis HL direction, and the local maximum value is sequentially updated. When the local maximum value is equal to the local maximum value in the horizontal axis HL direction, the vertical axis V
The maximum value and the minimum value in the L direction are compared, the maximum value and the minimum value are sequentially updated, and a point Qi farthest from the vertical axis VL at a contact point of a tangent line parallel to the vertical axis VL is finally determined. Of the ultimately obtained maximum value Qh, the ultimately obtained minimum value Ql, the finally obtained maximum value and the intermediate value Qm of the minimum value, or the finally obtained maximum value and the minimum value 3. The shape data creating method according to claim 1, wherein a point Qi determined by selecting one predetermined point from the proportional distribution value Qp is determined.