JPH04143806A - Cut-out method for fillet curved surface - Google Patents

Abstract

PURPOSE:To singularly cut out a fillet curved surface by obtaining a start point, an end point, a center, and a radius forming a circular arc curved surface as the fillet curved surface data and defining the curved surface cutting information to the fillet curved surface data. CONSTITUTION:The points corresponding to those points obtained by dividing equally each reference curve by a dividing number N. At the same time, the i-th circular arc information, i.e., a start point SPi, and point EPi, a center CPi, and a set radius R of a circular arc are obtained by the arithmetic operations on the reference curve where a fillet curved surface is provided. These obtained information are stored in a curved surface memory 4 and an index (i) is increased by '1'. This processing is carried on until the index (i) exceeds the number N. Thus the circular arc information SPi, EPi and CPi (i= O - N) and the radius R are obtained in response to the number N and stored in the memory 4. Thus only the fillet curved surface can be cut out just with the curved surface cutting information defined to the fillet curved surface data.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a surface creation method in an automatic programming device for creating NC data for free-form surface cutting of molds.

Conventional technology When generating a curved surface by dividing multiple reference curves at equal intervals and connecting corresponding points, when inserting a smooth circular arc shape on the intermediate reference curve to create a fillet surface, it is necessary to divide the reference curve into a fillet surface. The start point, end point, and center of a circular arc with a set radius are found on the line connecting the equally divided points, and the fillet surface is found.

Figures 8 and 9 are explanatory diagrams of the procedure for finding the start point, end point, and center of the arc that generates the fillet curved surface.The reference curves P, Q, and S are divided into equal parts, and the position vectors of the corresponding division points are calculated. Let Pi, Qi, and Si be, and when generating a fillet surface that is an arc of radius R on the reference curve Q, the unit vector from point Qi to point Pi is El, and the unit vector from point Qi to point Si is E2. Then, E1= (Pi-Qj)/l Pi-Qj l...(
1) E2= (Si-Qi)/1si-Qi l...
(2) Also, the unit vector E3 of the composite vector of unit vectors El and E2 is E3= (E1+E2)/l E1+E21...(3
), and the unit vector E3 has the angle PiQiSi as θ
Then, the angle θ is divided into two equal parts.

Also, the θ is the (4th
) can be found using the formula.

CO8θ=E1-E2-(4) Also, the ninth
As shown in the figure, an arc of radius R and line PiQi or line Qi
The contact position of Si (the starting point or end point of the arc) and the point Qi
If the distance between the two points is Xl, and the distance between the point Qi and the center CPi of the arc is X2, then X1=R/jan(θ/2)
(5)X2=R/5in(θ/2) ・(6
). E determined by the above (1) to (6)
l, E2. E3. Using Xi and X2, find the starting point SP of the arc
The position vector of i, end point EPi, and center CPi is the following (
7) to (9).

5Pi=Qi+XIXE1...(7) EP
1=Qi+XIXE2...(8)CPi
=Qi+X2XE3...(9) As described above, the starting point SPi and ending point EP of the arc corresponding to each dividing point
i, the coordinate position of the center CPi is determined to obtain fillet curved surface data.

Conventionally, the fillet curved surface obtained between the curved surfaces was cut together with other curved surfaces.

Problems to be Solved by the Invention As mentioned above, there has been a problem in the past in that fillet curved surfaces generated between curved surfaces cannot be cut alone, but only together with other curved surfaces. Further, it is also not possible to cut only the portion excluding the fillet curved surfaces generated between the curved surfaces.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fillet curved surface extraction method that allows the fillet curved surface to be cut alone, and that allows only the portion excluding the fillet curved surface to be cut.

Means for Solving the Problems The present invention divides a plurality of reference curves at equal intervals and connects corresponding points to generate a curved surface, by creating an arcuate curved surface with a radius set on an intermediate reference curve. In the method of inserting,
The start point, end point, and center of the arc corresponding to each of the dividing points constituting the arc surface are determined using the set radius, and the start point, end point, center, and radius are extracted as fillet surface data, and the fillet surface data is extracted. By defining curved surface cutting information for the fillet curved surface, it is possible to cut the fillet curved surface independently. In addition, a point series connection curve of the points projected on the XY plane from each starting point of the fillet curved surface and a point series connection curve of the points of each end point projected on the XY plane are obtained, and the point series connection curve is used as the boundary for area specified cutting. By using it as a line, it is possible to cut only the part other than the fillet curved surface.

The fillet curved surface data consisting of the starting point, end point, center, and radius of the working arc is taken out independently, and only the fillet curved surface is cut by defining curved surface cutting information for the fillet curved surface data.

In addition, the fillet curved surface can be curved by using the dot series connection curve of the points projected on the XY plane from each start point of the fillet curved surface and the dot series connection curve of the points of each end point projected on the XY plane as the boundary line for area specified cutting. Cut only the other parts.

Embodiment FIG. 4 is a block diagram of main parts of an NC automatic programming device that implements the present invention, and reference numeral 1 indicates a processor (CPU).
The CPU includes a ROM 2 that stores a control program;
RAM 3 used for temporary storage of system programs and data for various calculations inputted from a floppy disk (not shown) via the disk controller 7;
, a curved surface storage memory 4 in which various curved surface data and NC data for curved surface machining are stored. Keyboard 5. Graphic display device (hereinafter referred to as CRT display device)6. A disk controller 7 and an XY plotter 8 for plotting a curved surface are connected by a path 9. Note that this automatic programming device is well known and is approximately the same as a conventional one, so detailed configuration will be omitted.

Next, using the automatic programming device, the flowchart shown in FIGS. 1 to 3 shows how to save the fillet curved surface data, cut only the fillet curved surface, and cut only the portion excluding the fillet curved surface according to an embodiment of the present invention. I will explain it together.

FIG. 1 is a flowchart of the process of saving a fillet curved surface performed by the CPU 1 of the automatic programming device. First, the definition of the reference curve (for example, P, Q, S, etc. shown in FIG. 8) that defines the curved surface is inputted from the keyboard 5. Further, the definition of the curved surface is input using the input reference curve, and the reference curve for inserting the fillet curved surface, the radius R of the fillet curved surface, etc. are inputted, and the curved surface generation information is inputted (step 5100). Next, curved surface cutting information such as tool shape, approach from the machining origin, cutting direction, cutting pitch, and feed rate is input (step 8101).

In this way, when the curved surface generation information and curved surface cutting information are input, the CPU divides the longest reference curve among the inputted reference curves by the inputted cutting pitch, rounds off the decimal places, and then adds 1 to the value. The number of divisions N is determined (step 5102).

Next, set the index i to "0" (step 5103),
As explained in Figures 8 and 9, each standard curve is divided into N
(7) to (9) on the reference curve that connects the corresponding points of each dividing point equally divided by , and provides the fillet curved surface.
By calculating the formula, the i-th arc information, that is, the starting point SPi, ending point EPi, center CPi, and radius R of the set arc are obtained and stored in the curved surface storage memory 4 (steps 5104, 5105), The index i is set to “1”
” increment step 5106), determine whether the index i exceeds the number of divisions N (step 5107),
If it does not exceed the limit, return to step 5104 and proceed to step 8.
104 and subsequent steps are repeated until the index i exceeds the number of divisions N, and the arc information SP corresponding to the number of divisions is
i, EPi.

CPi (i=0 to N) and radius R are obtained and stored in the curved surface storage memory 4. When the arc information corresponding to each dividing point is thus obtained and the index i exceeds the number of divisions N, the fillet surface storage process ends. Further, each arc information obtained in this way is transferred from the curved surface memory memory 4 to the disk controller 7.
It may also be stored on a floppy disk or the like via a floppy disk.

FIGS. 2(a) and 2(b) are processing flowcharts for individual cutting of a fillet curved surface, in which the automatic programming device is set to the fillet curved surface individual cutting mode, and data of the fillet curved surface is stored in the curved surface storage memory 4 as described above. When fillet curved surface information is stored in the curved surface storage memory 4 from a floppy disk or the like via a disk controller, and fillet curved surface cutting information is input in the same manner as in step 5101 (step S200
), the CPU 1 determines the cutting direction from the input cutting information (step 5201). The cutting direction is as shown in Figs.
(Fig. 6), there are cases where cutting is performed in a direction that crosses an arc (Fig. 6), and this cutting direction is also input as cutting information.
As shown in the figure, when cutting in the arc direction is commanded,
Set the index i to "0" (step 5202), read out the i-th arc information SPi, EPi, CPi, R (step 5203), if the inter-pass movement input as cutting information is cutting in one direction. Single S that specifies
It is determined whether the cutting direction is zigzag Z (FIG. 5 shows this zigzag cutting) in which the cutting direction is reversed (step 5204);
If Zigzag Z is specified, the end point of the previous path is
If it is the end point of an arc, the end point EPi of the arc of the current pass is set as the starting point of cutting of the current pass, and if the end point of the previous pass is the start point of the arc, the start point of the current path is set as the start point SPi of the arc, and the arc information is NC. Output data and perform cutting. Also,
If the machine tool is not connected to the automatic programming, store this NC data in RAM2, and then
The data is loaded onto a floppy disk or the like, and the floppy disk is input to the NC device of the machine tool. In addition,
Although the arc information of the first pass does not have the end point of the previous pass, in this case, the set approach point is moved to the start point SPi (-8PO) (step S205). This zigzag cutting method is the same as the conventional zigzag cutting method, and the detailed method is omitted.

Next, in step 5, increment the index i by "1".
207), the index i is the number of divisions N (step 510 in FIG.
Step 8203 to Step 5 until the
The process at step 208 is repeated to obtain cutting NC data for each arc of the fillet curved surface, and the process ends. Also, step 5
When it is determined in step 204 that the single cutting S has been set, the process moves from step 5204 to step 8206, where single cutting is performed as in the past, that is, cutting is performed from the starting point SPi to the ending point EPi of each arc, and the set cutting process is performed. Retract in the Z-axis direction by the clearance amount, fast forward to the position of the set clearance amount relative to the start point of the next arc, create and output NC data for cutting from the start point to the end point with cutting feed from this position, and set the index i to "1". ” until the index i exceeds the number of divisions N. Steps 5203 and 5204
, 5206, 5207, 5208 are repeated,
Cutting NC data of only the fillet curved surface is obtained to enable cutting of only the fillet curved surface.

Further, if it is determined in step 5201 that a cutting path in a direction that crosses the arc is set, step 5201 is performed.
1 to step 5209, divide the longest arc by the cutting pitch set in the same way as step 5102, add "1" to the value rounded down to the decimal point to obtain the number of divisions K, and set the index k to "0". ” (step 5210),
Step 5211) to determine whether the movement between paths is zigzag Z or single S. If it is zigzag Z, set 1 to register P.
1" is stored, and the index i is set to "0" (step 5212).

Next, read out the i-th arc information SPi, EPi, CPi, and radius R, and read out the i-th arc information SPi, EPi, CPi, and radius R, and
and outputs the NC data up to this division point Pik (
Steps 8213-5215). Then, the value stored in the register P is added to the index i, and it is determined whether the index i is smaller than 0 or larger than the number N of circular arcs.
217° 5218), since "+1" is initially stored in the register P, the index is larger than "0" and smaller than the number N of circular arcs, so the process returns to step 5213 and processes of steps 8213 to 218 are performed. repeat. Through this process, the NC data of the path passing through the "0"th (k = O) dividing point of each dividing point from the "0"th arc with i=0 to the Nth circular arc with i=N is output. It turns out.

In this way, when the cutting path reaches the Nth circular arc and the index i exceeds N, "-1" is stored in the register P and the value of the register P is added to the index i (steps 5219 and 522
0). Although the index i was a value of N+1 exceeding N in step 5218, "+1" is added in step 5220, so that i=N. Then, "1" is added to the index k (step 5221), and it is determined whether the value of the index exceeds the number of divisions K (step 5222); if it does not,
The process returns to step 5213 and processes from step 8213 onwards are performed. In this case, since "1" is stored in the register P, the value of the index i decreases by "1" each time the process of step 8216 is performed.

As a result, i changes sequentially from N to 0, and the NC of the cutting path passing through the 2nd division point of the Nth arc to the 0th arc
The data will be output. Then, when the value of index i becomes smaller than 0, steps 5217 to 5
The process moves to step 223, stores "1" in register P, and performs the processing from step 8220 onwards. In this way, as shown in FIG. 9, it is possible to obtain NC data for zigzag cutting in which the cutting bus alternately reverses in the direction across the circular arc.

Further, if it is determined in step 5211 that the inter-bus movement is a single S, steps 5211 to 5
The process moves to 224, sets the index i to "0", performs the same processing as steps 8213 to 216, and outputs NC data (steps 8225 to 5228). Then, steps 5225 to 52 until the index i exceeds the number N of circular arcs.
29 is executed, and when the index i exceeds the number N of circular arcs, (
In step 5229), the index k is incremented by "1" (step 5230), and if the index k does not exceed the number of divisions K (step 5213), the process returns to step 5224 and performs the processing from step 8224 onwards. Then, when the index k exceeds the number of divisions K, the process of cutting the fillet curved surface alone ends.

In other words, in the case of this single cutting, the cutting NC data of the path passing through the 0th division point (starting point) of the 0th arc to the Nth arc is output, and then the cutting NC data of the path passing through the 0th dividing point (starting point) of the 0th arc to the Nth arc is output. The cutting NC data of the path passing through the first dividing point will be output, and the cutting NC data of the passes passing through the second, third, etc. Nth dividing point in the same cutting direction will be output in this order. .

FIG. 3 is a flowchart of the cutting process excluding the fillet curved surface.

First, the automatic programming device is set to cutting mode for the portion excluding the fillet curved surface, and step 5100 in FIG.
Curved surface generation information similar to 5IOI.

Steps 5300 and 5301) to input curved surface cutting information.
, fillet surface information is also input (step S30
2). Based on the input fillet surface information, the CPU calculates the starting points SPI to SPN of each arc as shown in FIG.
Step 5303: Create a point sequence connection curve T1 formed by a point sequence projected onto the Y plane, and create a point sequence connection curve T2 formed from a point sequence formed by projecting the end points EPI to EPN of each arc onto the XY plane. , 5304), obtain NC data for performing machining area cutting (AREA cutting) in the same way as conventional methods using the dot series connection curves TI and T2 as boundaries for specifying the machining area (step 5305), and obtain NC data for the part excluding the fillet curved surface. Only cutting is possible.

Effects of the Invention According to the present invention, only the fillet curved surface generated between the curved surfaces can be extracted and cut alone, and the fillet curved surface can also be cut by a different cutting method from other curved surface portions.

Further, it is also possible to cut only the portion excluding the fillet surface generated between the curved surfaces.

[Brief explanation of drawings]

FIG. 1 is a flowchart of a fillet curved surface preservation process according to an embodiment of the present invention, and FIG. (b) is a processing flowchart for cutting a fillet curved surface alone in the same embodiment, FIG. 3 is a processing flowchart for cutting a portion excluding the fillet curved surface in the same embodiment, and FIG. 4 is an automatic programming for implementing the same embodiment. FIG. 5 is a block diagram of the main parts of the device, and FIG. 5 is a diagram illustrating the pass route when cutting the fillet curved surface in the same embodiment in an arcuate direction and the inter-pass movement is zigzag. FIG. In the example, the fillet surface is moved in the direction across the arc,
FIG. 7 is a diagram illustrating the pass route when cutting with zigzag movement between passes, and FIG. 8 and 9 are explanatory diagrams for determining the starting point, end point, and center of an arc when a curved surface is defined by a plurality of reference curves and a fillet curved surface is determined on an intermediate reference curve. P, Q, S...Reference curve, "rQirsi...
・Division point, SPi...start point, EPi...end point, CP
i... Center of circular arc, Tl, T2... Point series connection curve. Cause first country (a)

Claims (2)

[Claims] (1) When dividing multiple reference curves at equal intervals and connecting corresponding points to generate a curved surface, a method of inserting a circular arc surface with a set radius on the intermediate reference curve, Find the start point, end point, and center of the arc corresponding to each of the division points constituting the arc surface using the radii, extract the start point, end point, center, and the radius as fillet surface data, and apply to the fillet surface data. A method for extracting a fillet curved surface in which the fillet curved surface can be cut independently by defining curved surface cutting information. (2) When dividing multiple reference curves at equal intervals and connecting corresponding points to generate a curved surface, in a method of inserting a circular arc surface with a set radius on the intermediate reference curve, the above setting is performed. Find the start point, end point, and center of the arc corresponding to each of the division points constituting the arcuate surface using the radii, extract the start point, end point, center, and radius as fillet surface data, and calculate each start point of the fillet surface. A fillet curved surface is created by finding a point series connection curve of the points projected on the XY plane and a point series connection curve of the points of each end point projected on the XY plane, and using the point series connection curve as the boundary line for area specified cutting. A fillet curved surface extraction method that makes it possible to cut only the other parts.