JPH03240805A - Production of path data for cornering tool - Google Patents

Abstract

PURPOSE:To improve the producing accuracy for the tool path data by producing a specific path based on a reference line which is supplied approximately along the corner of a working surface turned into a model via a curved surface, detecting the largest angle changing point as a corner, and producing another path in the same way at a point distant away from the specific path by a fixed distance in order to detect the corner. CONSTITUTION:The shape data of an object 2 obtained via a digitizer 1 is sent to an arithmetic unit 4 via a floppy disk 3. Thus the cornering working tool path data is obtained and sent to a machine tool 6 via a data medium 5. Then a reference line 8 is set approximately along a line at a corner of a working surface 7 for acquisition of a segment that is orthogonal to a projected curved line 8a formed on an XY surface of the line 8 at the start point P1 of the line 8a. A path 9 is produced from the points P'1 and P'1 connected to each other on the surface 7 at an end point of the segment. Then the largest angle changing point Q'1 of a component point set on the path 9 is detected as a corner point. Another path is produced in the same way on the line 8a at a point P2 distant away from the point P1 by a fixed distance C.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for creating tool path data for cornering, and is useful when applied to creating tool path data in CAD/CAM systems, automatic programming devices, etc. It is something.

<Prior art> When creating tool path data for angular machining for machining corners of a workpiece surface modeled by a single curved surface or a compound curved surface, in the conventional technology, as shown in FIG. First, all paths 02 in a direction substantially orthogonal to the corner line 01 were determined within a specified range, and then corner points on each path 02 were detected and connected to obtain tool path data for cornering.

〈The problem that the invention tries to solve〉 The conventional technology has the following problems.

(1) Tolerance processing is difficult (accuracy guarantee is difficult).

Each path 02 that is orthogonal to the corner line 01 is calculated with a certain constant pitch amount, and therefore the point sequence connecting the corner points on each of these paths 02 is output at approximately equal intervals, and the interval is controlled according to shape changes. Because it cannot be made pure, the accuracy cannot be kept constant.

(2) Operation is complicated.

It is divided into two steps, and each step requires human intervention. To comment further, it is divided into the first step of calculating path 02 and the second step of detecting corner points on path 02 and connecting each point, and a human instructs the calculation of the first step. After finishing, display this result and
It is necessary to give step instructions.

(3) Calculation time is required.

The calculation range of each path 02 perpendicular to the corner line 01 needs to have a length with a considerable margin before and after the guideline, and therefore there are many unnecessary calculations.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for creating tool path data for angular machining, which solves the problems of the prior art described above and can create high-quality tool path data at high speed.

<Means for Solving the Problems> The configuration of the present invention that achieves the above-mentioned conventional object is that ta (bl Base 1!l! A line segment perpendicular to the curve at the starting point P1 of the curve projected on the XY plane, and the left and right ends of the starting point P1 with respect to the curve. A point p, which is a point of
/, p, #, and the starting point P.

Point P on the machined surface above the line segment P'P'' passing through,y
, P, NIl; tc+ a step of detecting the point Q' with the maximum angle change from the constituent points on the path as a corner point; (e+ (From the constituent points on the path generated by dl,
The corner point Q'2 is detected using the same method as in (c).

(f) Corner points Q'3 to Q' in a similar manner. seek,
Furthermore, a step of calculating the radius of curvature of the shape by finding a circle passing through three consecutive points Q', 41 Q/, Q/, +1 and finding an error by linear interpolation; (g) a tolerance for which the error is specified; When exceeding Q'i
-, 'Q's by a method similar to that described above; and a step of sequentially connecting the corner points of Q's and Q's.

According to the present invention having the above configuration, it is possible to create tool path data subjected to tolerance processing along the corner line, and also to perform pre-calculation to find the corner point, that is, a curve obtained by projecting the reference line onto the XY plane. Since the range of path calculations in the direction orthogonal to can be minimized, tool data for cornering can be obtained quickly.

<Example> Embodiments of the present invention will be described in detail below based on the drawings.

As shown in FIG. 1, shape data of an object 2 obtained by a digitizer 1 is outputted to a F4P disk 3 and then sent to an arithmetic unit 4. In this arithmetic unit 4, a predetermined angular machining tool path is created using an algorithm that will be described in detail later. The tool path data for angular machining thus obtained is sent via the data medium 5 to the machine tool 6 for machining.

The procedure for creating tool path data for cornering in the arithmetic unit 4 is as follows.

(1) As shown in FIG. 2 (at), a reference 1s8 is provided that is approximately along the corner line of the processing surface 7 to be processed.

(2) As shown in FIG. 2 (bl), above the line segment p, / p, # of length a+b perpendicular to the curve 8a at the starting point Pl of the song $8m, which is the projection of the reference line 8 onto the XY plane, That is, the points P on the machined surface 7 corresponding to the points p, / and p,', respectively,
', P1' (see FIG. 3), which is a tool path, is generated.

(3) As shown in FIG. 3, a point Q'1 having the maximum angle change is detected as a corner point from the constituent points on the path 9.

(4) As shown in FIG. 2(b), at a point P2 on the curve 8a that is a certain amount C away from P, above the line segment p, j p2# perpendicular to the curve 8a, (2) Generate other paths in a similar way.

Here, P2' and P-'' are the intersections of straight lines that pass through Q and are inclined by a certain angle α on the left and right with respect to a straight line that is parallel to line segment 2, and line segments p and p, respectively.

+5) The constituent points on the path generated by +41 seconds, (
Corner point Q'2 is detected using the same method as in a).

(6) In this way, points Q', ~Q1. Then, as shown in Figure 4, three consecutive points Q'i-1tQ
′i, Q′i. The radius of curvature of the shape is calculated by finding a circle that passes through 1, and the error e due to linear interpolation is found.

-(7) When the error e exceeds the specified tolerance, a corner point is calculated at the point Q'L-1'Q's in the same manner as described above, as shown in FIG.

(8) Connect the above corner points in order to form a tool path for corner cutting.

<Effects of the Invention> As specifically explained above in conjunction with the embodiments, the present invention provides the following effects.

(1) Smooth corner cutting tool path data within specified tolerances can be created.

(2) Computation time is reduced.

(3) Human intervention is minimized.

[Brief explanation of drawings]

Fig. 1 ζ is a block configuration diagram showing an apparatus for realizing the embodiment method of the present invention, Fig. 2 (a) is an explanatory diagram showing the relationship between the machined surface and the reference line, and Fig. 2 (bl indicates the reference line). An explanatory diagram showing the relationship between a curve projected on the XY plane and the XY plane, Fig. 3 is an explanatory diagram showing a method for finding corners on a path, and Fig. 4 is an explanatory diagram showing a method for forming corner points. Figure 5 is an explanatory diagram showing the method of processing the lines connecting corner points, and Figure 6 is the conventional
It is an explanatory view showing t. In the drawing, 7 is the machined surface, 8 is the reference line, 8a is the curve, Q, #Q,, Q, #Ql. 8j Q, , is a corner point.

Claims (1)

[Claims] (a) A step of providing a reference line approximately along the corner line of the work surface to be machined modeled by a single curved surface or a composite curved surface; (b) Reference line Starting point P_1 of the curve projected onto the XY plane
A point P_1', which is a line segment perpendicular to the curve, and is the end point on the left and right sides of the starting point P_1 with respect to the curve,
A line segment defined by P_1'' and passing through the starting point, P_1 @P_1
Point P_1'' on the machined surface above 'P_1''@, P_1
(c) the point Q' of the maximum angle change from the constituent points on the path;
(d) detecting _1 as a corner point, and (d) detecting a line segment @P_1'P_ perpendicular to the curve at point P_2, which is a certain amount C away from P_1 on the curve;
1″@ by the process of generating another path in the same manner as in (b), and (e) From the constituent points on the path generated in (d), (c)
The corner point Q'_2 is detected using the same method as . (f) Find corner points Q'_3 to Q'_n in the same way,
Furthermore, three consecutive points Q'_i_-_1, Q'_i, Q'
(g) when the error exceeds the specified tolerance, calculate the radius of curvature of the shape by finding a circle passing through _i_+_1 and find the error by linear interpolation; and (g) when the error exceeds the specified tolerance,
A method for cornering processing characterized by comprising the steps of calculating corner points between i_-_ and Q'_i by the same method as described above, and (h) sequentially connecting the above corner points. How to create tool path data.