JP2936088B2 - Method of creating shape data for mold processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CAD system.
Te, gold to create a mold machining shape data by forming a fillet surface between the curved surface constituting the surface model
The present invention relates to a method for creating shape data for die machining .

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a product having a complicated shape, shape data is created using a CAD system, and NC processing data for processing a mold is obtained from the shape data. A mold is created based on the data, and a product is manufactured from the mold.

In this case, a wire frame model for a product is first created from the shape data, and then a surface model is created by setting a surface to the wire frame model. Then, in order to smoothly connect between the curved surfaces constituting the surface model,
The fillet face is set. As a method of forming the fillet surface, for example, a method described in Japanese Patent Application Laid-Open No. 58-160041 is known.

In this method, two connected curved surfaces are offset by a predetermined amount in a direction for forming a fillet surface,
An arc tangent to each of the curved surfaces with the obtained intersection of the two curved surfaces as the center is defined as a component line of the fillet surface, and a surface composed of a set of the component lines is generated as a fillet surface.

[0005]

In the above-mentioned prior art, no problem occurs when a single fillet surface is formed with respect to a surface model having a simple shape. When two or more fillet planes intersect, as in the case of forming a plurality of fillet planes, a situation occurs in which the crossed portions are not connected smoothly. Conventionally, such a part does not form a new fillet surface by an operator's instruction separately, or performs processing on shape data, but performs on-site work on a mold created in accordance with the shape data. This was dealt with by directly performing the mold finishing work. Therefore, the operation requires a considerable amount of time and labor.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned disadvantages. In a CAD system, a connecting surface for smoothly connecting a plurality of fillet surfaces can be easily formed.
An object of the present invention is to provide a method for creating shape data for mold processing .

[0007]

In order to achieve the above object, the present invention provides a method for forming a fillet surface between curved surfaces constituting a surface model of a mold set on a CAD system. mold pressing to create a mold machining shape data by
In the method for creating working shape data , set between the above-mentioned curved surfaces
Has been selected two of the fillet surface to be connected, the the first step of setting each of the end point on the each surface of the fillet surfaces, a curve connecting between the respective end points, the surface model on a curved surface And a second step of setting the selected fillet plane on each of the selected fillet planes, and a third step of generating a connecting plane surrounded by each of the curves, and connecting the two fillet planes with the connecting plane. Features.

[0008]

According to the present invention, a connection surface is set by connecting the end points of the fillet surfaces to be connected, and a curved surface is set in an area surrounded by the outline so as to smoothly connect the fillet surfaces. Generate

[0009]

FIG. 1 shows a CAD system 1 to which the present invention is applied.
FIG. 3 is a block diagram showing a configuration of a 0. CAD system 10
Has a central processing unit for performing graphic calculation, display control, database management, etc., and a large-capacity storage device 14 capable of storing and updating a large amount of graphic information.
And a graphic-compatible display device 16 which is a central device for the interaction between the CAD system 10 and the operator.
And a keyboard 18 as an input device and a tablet 2
0, a mouse 22, a light pen 24, an external auxiliary storage device (CMT) 26, and an XY plotter 28 as a graphic output device.

The controller 1 of the CAD system 10
2 has many programs as shown in FIG. Each program can be classified into the following modules according to the functions to be shared.

(A) An operating system 30 and a control module 32 for controlling the processing of the controller 12 and the flow of information.

(B) An input module 34 for assisting various input devices, for example, input operations corresponding to the keyboard 18 to be performed smoothly.

(C) An input interpretation module 36 that interprets the input information according to the format of a command instruction.

(D) A display module 38 for managing display information and performing display processing in accordance with a command.

(E) A command module 40 for performing graphic processing according to a command composed of sub-modules corresponding to the instruction.

(F) CAD stored in the database 42
A database operation module 44 for efficiently searching and storing a large amount of information necessary for the system 10;

(G) A macro module 48 for executing a macro program 46 which is an automatic design program.

(H) An external system interface 50 for exchanging information with another CAD system and performing interlocking processing.

Further, in order to maintain expandability and maintainability, the controller 12 has a system control file 52 for storing the configuration and standard values of the CAD system 10, and a command control for storing operability of each command and a program control procedure. Auxiliary files such as a file 54 and a display control file 56 for storing the model and configuration of the display device 16 are prepared. Other auxiliary components include a graphics processing library 58 for performing graphics processing and a display library 6 for displaying on the display device 16.
0, a program such as a drawing utility 62 for outputting the processing result to the XY plotter 28, and a data exchange utility 64 for coupling with another CAD system.

Next, each module will be briefly described. The control module 32 integrates programs into modules and intervenes between the modules to centrally manage the control in the system and standardize the calling procedure.
Its functions are start, end, abnormal processing, execution control of each module, recording of execution history, debugging, special processing with the operating system 30, and the like.

The input module 34 provides an operator with a comfortable input procedure in accordance with the unified specifications of various input devices. The functions are input promotion for instructing an operator on the type of information to be input, an input method and an input device, selection of an input device, conversion of input information to a standard type, and the like.

The input interpretation module 36 unifies the input information interpretation method and the result display, thereby supporting various input instruction methods, improving input operability, and maintaining the expandability of the system. Its function is to interpret the input information and display the result of the interpretation.

The display module 38 processes various display operation requests in a unified manner, and manages a display device, controls display, manages display information, and manages a display state.

The command module 40 centrally manages the format of input arguments, the calling of a processing program according to the command, and the processing method of the result, and maintains the maintainability and expandability of the system.

The database operation module 44 standardizes the request method from other modules and provides recovery means when a failure occurs. Its functions are management and operation of the use state of the database 42, processing when a failure occurs, and the like.

The external system interface 50 standardizes information exchange with other systems, and makes effective use of the CAD system 10. The functions are information exchange with an external system and operation control of an external program.

The macro module 48 controls the execution of the CAD system 10 according to the created macro program 46. Its function is to translate and execute the macro program 46.

Next, a description will be given of a method of forming a fillet surface on a surface model in the CAD system 10 provided with each of the programs as described above and forming shape data for preparing NC machining data.

FIG. 3 shows an overall flowchart for creating the shape data, and FIGS. 4 to 11 are explanatory diagrams of the processing procedure.

First, data constituting the surface model shown in FIG. 4 is read from the mass storage device 14 (FIG. 1). This surface model includes, for example, ridge lines R1 to R4.
And a plurality of curved surfaces S1 to S4 connected by the Then, fillet surfaces F1 to F4 are set for the ridge lines R1 to R4 between the curved surfaces S1 to S4 as shown in FIG. 5 (step S100).

FIG. 12 shows a subroutine for creating the fillet plane F1, and FIG. 13 is an explanatory diagram thereof. First, a plane Hn passing through the point R1n on the ridge line R1 and orthogonal to the ridge line R1 is obtained (step S200). Then, the intersection lines K1n, K1 between the plane Hn and the curved surfaces S1, S2
2n, the intersection lines K1n and K2n are offset by the radius rn on the plane Hn, and the center Cn of the arc An is determined (step S201). Then, an arc An having a radius rn is obtained from the center Cn (step S202). After the above processing is performed on all the planes Hn set at predetermined intervals between the end points R1s and R1e of the ridge line R1 (step S2).
03), outlines g1 and g2 formed by smoothly connecting points where each arc An comes into contact with the curved surfaces S1 and S2, and the end point R1.
The outlines g3 and g4 composed of arcs corresponding to s and R1e are obtained (step S204). Lastly, a fillet plane F1 is created by setting a plane using, for example, the Coons formula in a region surrounded by these outlines g1 to g4 and defined by the circular arcs An (step S1). S205). In addition, other fillet surfaces F2
F4 is similarly created.

Here, each of the fillet surfaces F1 to F4 created as described above has a ridge line R1 as shown in FIG.
R4 are superimposed on each other in the vicinity of the point Q where they meet, and a smooth curved surface cannot be obtained as it is.
Therefore, a connecting surface that smoothly connects these fillet surfaces F1 to F4 is created.

First, as shown in FIG.
An intersection (point P2) between the outer line of No. 1 (corresponding to the outer line g2 in FIG. 13) and the outer line of the fillet surface F2 is obtained (step S101). Since this point P2 is on the curved surface S2, it can be easily obtained as an intersection of the two outlines. Next, the contact point on the curved surface S1 of the arc (corresponding to the arc An in FIG. 13) on the fillet surface F1 passing through the point P2 is determined as the point P1 (step S1).
102). Similarly, after the intersection (point P3) of the outline of the fillet surface F2 and the outline of the fillet surface F3 is determined (step S103), the contact point on the curved surface S4 of the arc on the fillet surface F3 passing through the point P3 is obtained. Is obtained as a point P4 (step S104). And points P1, P2
A new fillet surface F1 ^* is created by cutting the fillet surface F1 by an arc between them, and a new fillet surface F3 ^* is created by cutting the fillet surface F3 by an arc between the points P3 and P4 (FIG. 6, Step S10
5).

Next, the point P obtained as described above
An outline L1 that smoothly connects the points P1 and P4, and points P2 and P
3 is determined (step S).
106).

FIGS. 14 and 15 are subroutines for obtaining the outline L1, and FIGS. 16 to 18 are explanatory diagrams thereof. First, the fillet plane F1 passing through the point P1
^The unit tangent vector V1 for the outline g5 of the fillet plane F3 ^* passing through the point P4 is determined along with the unit tangent vector V1 for the outline g1 of ^* (step S300). Next, using the unit tangent vectors V1, V4 and the coordinate values of the points P1, P4, outlines g1 and g
A temporary contour line C0 that smoothly connects No. 5 is obtained (step S301). In this case, the temporary outline C0 is the outline g1,
Since it is set based only on the condition in contact with g5, FIG.
As shown in FIG. 7, generally, it does not coincide with the target outline L1.

Then, a unit normal vector VV1 passing through the point P1 and orthogonal to the curved surface S1 and a unit normal vector VV4 passing through the point P4 and orthogonal to the curved surface S4 are obtained (step S302). The projection vector VV is obtained by combining the line vectors VV1 and VV4 (step S303). Then, using the projection vector VV, the temporary contour line C0 is projected onto the curved surface S1, the curved surface S4, and the fillet surface F4, so that the projected curve C1,
Find C2 and C3 (FIG. 17, step S30)
4). The projection curve C1 is set between a point P1 which is an end point of the fillet plane F1 ^* and a point P5 which is an end point on the ridge line R4, and the projection curve C2 is an end point of the point P5 and the end point of the fillet plane F3 ^* . The projection curve C3 is set between a certain point P4 and the projection curve C3 is set between points P6 and P7 on the fillet plane F4 (see FIG. 17). An outline L1 is obtained by setting the connection relationship between the projection curves C1 to C3 obtained as described above according to a subroutine shown in FIG. 15 (step S305).

First, the projection curve including the point P1 is defined as a start curve C
s (projection curve C1), and the projection curve including the point P4 is set as the final curve Ce (projection curve C2) (step S).
400). Next, the start curve Cs (projection curve C1)
Is set as a transfer check target that moves from the outline g1 shown in FIG. 17, and a flag is set on the start curve Cs (projection curve C1) as shown in (1) of FIG. 18 (step S401). Next, it is determined whether or not the current transfer check target is the final curve Ce (projected curve C2) (step S402). If it is not the final curve Ce, i = 1 is set (step S403), and the projected curve Ci has already been set. It is determined whether or not a transfer check has been set, that is, whether or not a flag has been set (step S40).
4). Since a flag has already been set for the projection curve C1, i = i + 1 is set (step S405), and the flag of the projection curve Ci is checked (step S404). In this case, no flag is set for the projection curve C2 (see (1) in FIG. 18). Therefore, it is determined whether or not the projection curve C2 is smoothly connected to the projection curve C1 previously set as the transfer check target (step S406). In this case, the projection curve C2 corresponds to the point P5
Since the projection curve C1 is not smoothly connected to the projection curve C1, i = i + 1 is set (step S405), and the process of step S404 is repeated. In this case, no flag is set for the projection curve C3 (see FIG. 1).
8 (1)), the process of step S406 is performed. Since the projection curve C3 is smoothly connected to the projection curve C1 previously set as the transfer check target, the projection curve C3 is set as the transfer check target (step S407), and (2) in FIG. As shown in
The flag of the projection curve C3 is set. Then, the processing from step S402 is repeated. In step S402, since the current transfer check target is the projection curve C3 and not the final curve Ce, the processing from step S403 is performed. In this case, in step S406,
Since the projection curve C2 is smoothly connected to the projection curve C3 previously set as the transfer target (step S406), the projection curve C2 is set as the transfer check target (step S407), and (3) in FIG. The flag of the projection curve C2 is set as shown in FIG. And
The process of step S402 is performed again. At this time, since the transfer check target matches the final curve Ce, FIG.
Based on the flags set in the order shown in FIG.
→ C3 → C2 are linked in this order (step S408), and an outline L1 is set. The outline L2 can be set in the same manner.

Next, the points P1, P2 on the fillet surface F1 ^*
An outline g4 set between them, an outline g6 set between the points P3 and P4 of the fillet plane F3 ^* , and a connection plane C () surrounded by the outlines L1 and L2 set as described above. (See FIG. 8), the outline L1,
Constituent points are generated at predetermined intervals on L2 (FIG. 3, step S107). The method of generating the constituent points will be described with reference to the flowchart shown in FIG. 19 and the explanatory diagrams shown in FIGS.

First, as shown in FIG.
A plurality of constituent points Kn ^* and Kn are set on the contour lines L1 and L2 according to the curvatures of L1 and L2 (step S50).
0). Next, the curve lengths l ₁ , l _{2 of} the respective outlines L1, L2
Is obtained (step S501). And the curve length l
_1, and l _2, points P1, P2 and the component points Kn ^*, Kn
The distance between k _n ^*, the distance ratio between _{^{k n k n * / l 1}} , k n /
l ₂ is obtained (step S502). Next, n = 1 (step S503), and the distance ratio k _n ^* / l ₁ , k
If _n / l ₂ is not within the predetermined range, i.e., when not satisfied _{^{k n * / l 1 ≒ k}} n / l 2 conditions (step S504), for example, the point P1 composing point Kn ^* and the New point Km between
^* Is added (step S505). The above operation is performed for all constituent points (steps S506 and S507), and a set of corresponding constituent points (for example, constituent points Kn ^* and Km in FIG. 21) is set. Thus, each contour line L
1, the same number of component points and substantially the same interval are set on L2.

Next, a curve RR is set between the constituent points of the set determined in step S107 (FIG. 3, step S10).
8). This curve RR is obtained according to the flowchart shown in FIG. In FIG. 23, first, unit tangent vectors Vt1 and Vt2 with respect to contour lines L1 and L2 at constituent points Kn ^* and Km forming a pair are obtained (step S6).
00). Next, a combined vector Va of the unit tangent vectors Vt1 and Vt2 is obtained (step S60).
1) A unit direction vector Vh from the constituent point Kn ^* to the constituent point Km is obtained (step S602). Then, an outer product vector Vb of the unit direction vector Vh and the composite vector Va is obtained (step S603), and an outer product vector Vp of the outer product vector Vb and the unit direction vector Vh is obtained (step S604). Next, the outer product vector Vp and the normal vector V at the constituent point Kn ^* are obtained.
A cross product vector Vv1 with u1 is obtained, and a cross product vector Vv2 between the normal vector Vu2 at the constituent point Km and the cross product vector Vp is obtained (step S605).
Note that these cross product vectors Vv1 and Vv2 are
Represents the tangent vector of the curve RR at the constituent points Kn ^* and Km.

Using the tangent vectors (outer product vectors Vv1, Vv2) obtained as described above, a curve RR consisting of a Bezier curve is obtained. In this case, as shown in FIG. 24, control points Q1 and Q2 are set on an extension of the outer product vectors Vv1 and Vv2, and distances q ₁ and q ₂ to the control points Q1 and Q2 are expressed by the following equation (1). (Step S606). Then, a curve RR is generated using the control points Q1 and Q2 (step S607). In addition,
In the equation (1), r ₁ and r ₂ are unit tangent vectors V
represents the distance between the intersection O of t1 and Vt2 and each of the constituent points Kn ^* and Km, and θ represents the central angle of the sector O-Kn ^* -Km.

Q _i = 4 · (1−cos (θ / 2)) · r _j / 3 · sin (θ / 2) (1) (θ ≠ 0, j = 3-i) (Step S109 in FIG. 3), all the curves RR on the connection plane C are set, and the connection plane C is determined.

When the connection plane C is determined, the data is temporarily output to the mass storage device 14 (step S11).
0), fillet planes F2 and F4 intersecting with connecting plane C
Is cut using the data of the connection plane, and the fillet plane F
2 ^* and F4 ^* are created (FIG. 9, step S11)
1). Then, data composed of the fillet planes F1 ^{* to} F4 ^* and the connecting plane C is output to the mass storage device 14 as fillet plane data (FIG. 10, step S11).
2).

In the above-described embodiment, a case has been described in which the connecting surface C capable of smoothly connecting the mutually overlapping fillet surfaces F1 to F4 is created. For example, a previously set fillet surface is designed. In the case of being cut off by a change or the like, the present invention can be similarly applied when creating a connecting surface connecting these fillet surfaces.

Finally, by synthesizing the surface model data shown in FIG. 4 and the fillet plane data, FIG.
Model data in which the fillet surfaces F1 ^{* to} F4 ^* , the connecting surface C, and the curved surfaces S1 ^{* to} S4 ^{* shown in} FIG ^{. 1} are set are created (step S113).

The model data created as described above is converted into NC processing data, and then transferred to an NC control device (not shown), where a die for forming a product is processed. In this case, since the NC processing data includes a fillet surface that smoothly connects the curved surfaces of the surface model, a mold having a desired shape can be automatically and accurately created.

In the embodiment described above, the intersection (point P2) of the fillet surfaces F1 and F2, the fillet surfaces F2 and F3
Has been described, and the connection plane C is set between the fillet planes F1 and F3 using these points P2 and P3. However, the points P2 and P3 are set at arbitrary positions. Needless to say, the present invention is also applicable to a case where the connecting surface C is set between the two fillet surfaces F1 and F3.

[0048]

As described above, according to the present invention, the CAD system
Raw against the set mold surface model on Temu
In the case where the fillet surface to be formed intersects, it is possible to easily create a connection surface that smoothly connects the fillet surfaces intersecting. This makes it possible to automatically and accurately obtain final mold processing shape data composed of smoothly connected curved surfaces.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a CAD system to which the present invention is applied.

FIG. 2 is a software configuration diagram of a controller shown in FIG. 1;

FIG. 3 is an overall processing flowchart for creating shape data.

FIG. 4 is an explanatory diagram of a surface model.

FIG. 5 is an explanatory diagram of a fillet surface set in the surface model shown in FIG. 4;

FIG. 6 is an explanatory diagram of a fillet surface cut by another fillet surface.

FIG. 7 is an explanatory diagram of an outline of a connection surface set between fillet surfaces.

FIG. 8 is an explanatory diagram of a connecting surface set between fillet surfaces.

FIG. 9 is an explanatory diagram of a fillet surface set on a surface model.

FIG. 10 is an explanatory diagram of fillet model data.

FIG. 11 is an explanatory diagram of a model obtained by synthesizing a surface model and a fillet model.

FIG. 12 is a flowchart of a process for creating a fillet surface.

FIG. 13 is an explanatory diagram of a process of creating a fillet surface.

FIG. 14 is a flowchart for obtaining a projection curve forming an outline of a connection surface.

FIG. 15 is a flowchart for connecting projection curves and obtaining an outline of a connection plane;

FIG. 16 is an explanatory diagram of a process for creating a projection curve.

FIG. 17 is an explanatory diagram of a process of creating a projection curve.

FIG. 18 is an explanatory diagram of a process for creating a projection curve.

FIG. 19 is a flowchart of a process for setting a constituent point on an outline of a connection surface.

FIG. 20 is an explanatory diagram of a process of setting constituent points on an outline of a connection surface.

FIG. 21 is an explanatory diagram of a process of setting constituent points on an outline of a connection surface.

FIG. 22 is a flowchart for generating a curve connecting the constituent points of the connection surface.

FIG. 23 is an explanatory diagram of a process of generating a curve connecting the constituent points of the connection surface.

FIG. 24 is an explanatory diagram of a process of generating a curve connecting the constituent points of the connection surface.

[Explanation of symbols]

Reference Signs List 10 CAD system 12 Controller 14 Large-capacity storage device 16 Display device C Connecting surface F1 to F4 Fillet surface R1 to R4 Edge line S1 to S4 Curved surface

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) G06F 17/50 G06T 17/00 G05B 19/4097 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A for die machining to create a mold machining shape data by forming a fillet surface between the curved surface constituting the server <br/> Fes model of the set mold on CAD system < in br /> shape data creating method, the selected two of the fillet <br/> Tsu up surface to be connected which is set between the respective curved surfaces, the upper to the each surface of the fillet surface
A first step of setting each end point of the surface model; a second step of setting a curve connecting the respective end points on a curved surface of the surface model and on each of the selected fillet surfaces; third step and consists, mold machining shape data creating method, characterized by connecting the two fillets surfaces by said connection surfaces to generate a coupling surface. 2. The method according to claim 1, wherein the end point is located at an intersection with another fillet plane that intersects with each of the selected fillet planes and on each of the fillet planes corresponding to the respective intersection points. A method for creating shape data for die machining, wherein the method is set by an end point. 3. The method according to claim 1, wherein the curve connecting the end points of each of the fillet surfaces is obtained by obtaining a tangent vector at each of the end points of an outline forming each of the fillet surfaces, and then obtaining each of the tangent lines. seeking temporary curve based on the vector, then the projection of the provisional curve relative to the curved surface which is set between the fillet surfaces, mold machining shape data creating method and obtaining a projected curve. 4. The method according to claim 3 , wherein the connecting surface is generated by setting a constituent point on the projection curve and setting a curve connecting the corresponding constituent points. To create shape data for die machining .