JPH01177945A - Device for preparing nc data for rough work - Google Patents

Abstract

PURPOSE:To shorten time in process by obtaining the Z value of a mesh through which the whole path and the whole auxiliary path pass in surface copying, and thereby constituting a rough working tool to be checked whether or not it intersects an approximated surface in form a tool off-set position. CONSTITUTION:A digitizing range DR is divided into plural numbers of meshes Mi, j, the Z value of the meshes through which a path shall pass with no position data Qij obtained is computed by means of interpolation for respective two paths Pi and Pi+1 which are adjacent each other. Then, the lengths of the respective paths Pi and Pi+1 are computed, and concurrently respective paths are equally divided by division numbers corresponding to the dimension of of a rough working tool so that the Z value of meshes through which an auxiliary path APij connecting corresponding dividing point Dij and Di+1, j with each other is computed by means of interpolation. Then, the work form in each mesh is approximated by a plane having the Z value of the desired mesh, and the rough working tool TLR are checked whether or not it intersects the aforesaid approximated surface at a tool off-set position. And if intersection is detected, correction is made in height.

Description

[Detailed Description of the Invention] <Industrial Field of Application> The present invention relates to a method for creating NC data for rough machining, particularly a method for creating NC data for rough machining using position data digitized by surface scanning. Regarding.

<Prior art> Position data digitized by surface scanning
There is a method of creating NC data for processing according to the model shape using (position data of the center of the stylus). In this method, the stylus is moved in the X-axis direction at a predetermined tracing speed and moved up and down along the model in the Y-axis direction, and the center position data and displacement amount data of the stylus are recorded every time the position error exceeds a tolerance value. εX # Cy t C2
(Please use the displacement data as the axis component of the normal vector). Then, when it reaches the boundary of the scanning range, it pick-feeds a predetermined amount in the Y-axis direction, and thereafter, while scanning the surface in the same way, the position data of the stylus and the amount of displacement of each axis are captured and digitized, and then the center of the stylus is N using position data and displacement data
Create C data.

By the way, when creating NC data using digitized stylus center position data, if the tool diameter is equal to or smaller than the stylus diameter, the tool is moved while offsetting the tool diameter based on the NC data. will not interfere with the workpiece.

However, in the case of rough machining, a tool TL with a larger diameter than the stylus STL is used as shown in Fig. 4, and in such a case, if the tool is machined while offsetting the tool diameter using digitized position data, the tool will move to the workpiece WK. This may cause tool breakage, excessive cutting, etc.

For this reason, the present applicant proposed a method for creating NC data for rough machining to avoid interference in Japanese Patent Application No. 62-10858.
I am proposing it as number 2. In this proposed method, the digitizing range [IHDR
is a plurality of meshes M of a predetermined size, (r p
3 21.2. .
For each of P141, meshes through which the path passes and for which position data could not be obtained (7th
Interpolate the Z value of the mesh of the point cloud pattern in the figure: Calculate from this, (1ψ) After that, calculate the Z value of all the remaining meshes for which the Z value has not been obtained (white mesh in Figure 7) by interpolation calculation. , (v) The machining shape in each mesh M1... is approximated by the plane S, ... (see Fig. 8) having the Z value of the mesh, (vl) The rough machining tool TL (see Fig. 8) is At the offset position, check whether it intersects with the shape approximation plane of the mesh, and (viil) If it intersects, move it in the height direction so as not to intersect the tool center position (x, y, z), as shown in Figure 9. The rough machining NC data is created by applying d correction to (X, Y, z+d).

<Problem to be solved by the invention> However, in the proposed method for creating NC data for rough machining, Z in all remaining meshes for which position data could not be obtained.
Values have to be calculated by interpolation, and the number of shape approximation surfaces to be checked to see if the rough machining tool will interfere with the workpiece at the offset position increases, which takes a considerable amount of time. There was a problem.

From the above, it is an object of the present invention to provide a rough machining NC data creation method that can shorten processing time.

〈Means for solving problems〉 FIG. 1 is a schematic explanatory diagram of the present invention.

DR is the digitizing range, M, is the mesh, Pl,
P,+, is the adjacent path by surface scanning, Q,, is the digitized position D ” J ’ D Ill,
j is the corresponding division point and A P is the auxiliary path.

<Effect> The digitizing range DR is divided into multiple meshes M1. .

(l p J = ``p 2p ...), and for each of two adjacent paths P,, P, +, of surface scanning, the mesh through which the path passes, and the position data Q, are obtained. (Figure 1 (u
The Z value of the mesh of the point cloud pattern of t is calculated by interpolation.

Next, the length of each pass P,, P,+, is calculated, and each pass is divided equally into the number of divisions according to the tool diameter of the rough machining tool, and the corresponding division points are calculated, D, and 1. 4Figure 1 (1
)) Auxiliary path AP connecting )), 1. Calculate the Z value of the mesh (Figure 1 (hatched area in C1) through which it passes by interpolation,
Approximate the machining shape in each mesh with a plane having the Z value of the mesh, check whether the rough machining tool TLR intersects the shape approximation surface of the mesh at the tool offset position, and if it intersects, change the tool position to the intersection. Create NC data for rough machining by making corrections in the height direction to avoid this.

<Embodiment> FIG. 2 is a block diagram of a device (digitizer) that embodies the method of the present invention.

1 is a digitizer, which has a function of capturing and digitizing the current position and displacement of the tracer head while performing tracing control, as well as an NC data creation function and a tool interference check function, and a ROM 1b that stores a processor/source la and a control program. , a RAMIC for storing digitized position data, and a working memory 1d.

Reference numeral 2 designates an operation panel through which various operation signals are input, as well as tracing conditions, digitizing range DR (see Figure 1), tracing method, vertical and horizontal dimensions of mesh M1.4, and tool radius R1.
It has a function to set other data.

10X, IOY, 102 are DA converters that convert speed data (digital values) in each axis direction commanded from the digitizer 1 into analog speed signals Vx, VY, v2; 1)X;
1) Y1) 1ZLtX-axis, Y-axis, Z-axis servo circuit, 12
X~12Z (respectively X axis, Y axis, Z axis motor, 13
X to 13Z are pulse generators that generate one pulse X, Y, Zf each time the corresponding motor rotates by a predetermined angle, and 14 is a pulse generator that generates pulses X, Y, Zf depending on the direction of movement. Perform reversible counting and calculate the current position of each axis X, Y
This is a current position register that stores A and ZA. In addition, T
H is a tracer head, STL is a squirrel, and MDL is a model.

FIG. 3 is a flowchart of the process of creating NC data for rough machining according to the present invention, and the method of the present invention will be explained below according to this flowchart. In addition, the digitizing range [)R (Fig. 1 (al
) and the vertical and horizontal dimensions of each mesh have already been manipulated! 2 (
(see Figure 2), and the digitizing range DR consists of m x n meshes M, 0, (i =
1 to m, j == l to n).

First, 1 → 1 is set (step 101), and the surface is traced along the first pass P with the feed 9 axis as the X axis, the copying axis as the Z axis, and the big feed axis as the Y axis. In parallel with this, the coordinate values and displacement amounts of the stylus center position Q, . The Z-axis coordinate value Z1. ” is stored in the allocated SRAM 1c (step 102). Note that if two or more digitizing points exist on the same mesh, the larger Z-axis coordinate value is stored as the binary value of the mesh.

Next, the binary value of the mesh through which the path P1 passes and for which the position data Q1 is not obtained (the mesh of the point cloud pattern in FIG. 1) is calculated by interpolation (step 103). For example, the mesh position data on both sides (
Set the Z value to 2. ．． 22) is obtained, then the intermediate mesh Z(1)\(by interpolation, (Z +Z)/
It becomes 2.

Once the binary values of all the meshes through which the path P passes are determined, the length of the path P is calculated (step 104).

After that, check whether the next adjacent path P1+ exists (step 105), and if it exists, the next path P1+,
At the same time, the Z value of the mesh through which path P1.1 passes and for which position data cannot be obtained is determined by interpolation, and then the length of path P1+ is calculated (+1) (step 106 ~108).

Once the Z values and lengths of all the meshes passed by two adjacent paths P,, j, and are found, the number of divisions n1 of each path and each path can be calculated using the following formula. division pitch q
, q,+, are calculated (step 109). In addition, q
is a pitch determined according to the diameter R of the rough machining tool, and is determined so that there are several auxiliary passes within the circle of radius R;

Then, 1→j (step 1) 0) the first dividing point D1) in each path P,, P,+, and 81. (See Figure 1 tb)) Connect the auxiliary paths AP, . . . (Step 1) 1).

If the auxiliary path AP, , is found, the auxiliary path AP.

Z of the mesh through which 1 passes (hatched area in Figure 1(c))
Calculate the value by interpolation, step 1) 2), and then
= n, (step 1) 3).

If j = n, J is incremented by j+1→j, and the processes from step 1) 1 are repeated.

On the other hand, in the judgment of step 1)3, if j = n, l is incremented by i + 1 → l and step 10
Repeat the process from step 5 onwards.

If the above processing is repeated and the binary values of all the meshes through which all the passes and all the auxiliary passes in surface scanning are respectively passed are determined, rNol is obtained in step 105.

After that, the stylus center position data and offset direction data (displacement amount data) are stored in the RAM in the order of digitizing.
Read from 1c (Step 9P1) 6), and when the tool center is located at a point offset by the tool diameter in the offset direction from the point indicated by the data, check whether the tool intersects the shape approximation surface in the predetermined mesh. (
Step 1)7). Note that the shape approximation surface that is used as a counterweight for the intersection check is a mesh (
(including those that intersect).

If it does not intersect with any of the shape approximation surfaces, the tool center position is stored in the RAM 1c as a point on the off-set/soto path that does not interfere with the tool (step, knob 1) 8).

On the other hand, if they intersect in Step 1) 7 (see Figure 8), calculate the amount of Z-direction movement d (see Figure 9) until the tool does not interfere with any of the shape approximation surfaces (Step 1) 9)
.

After that, if the coordinate values of the tool center are (X,, yl, Z,), then (x, , y, , z, + d
) is stored in the RAM 1c as a point on the offset path that does not interfere with the tool (step 120).

Step 1) When the processing in step 8 or step 120 is completed, check whether the above processing has been completed for all digitized tool center data (step 121).
), if not completed, RA the next tool center position data.
Read from M1c, and repeat the processing from step 1) to step 7.

On the other hand, if the processing has been completed for all digitized stylus center positions, the processing for creating the NCC deck for tool and rough machining is completed.

<Effects of the Invention> According to the present invention, find the Z value of the mesh through which all the passes and all the auxiliary passes in surface scanning pass! Kadeyo <,
Check whether the rough machining tool will interfere at the offset position.Since the number of target shape approximation surfaces has been reduced,
The time required to create NC data for rough machining can be reduced compared to the conventional method.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of the present invention, Fig. 2 is a block diagram of the system according to the present invention, Fig. 3 is a flowchart of the processing of the present invention, and Fig. 4 is an explanatory diagram when rough machining tools interfere. , FIG. 5 to FIG. 9 are explanatory diagrams of the conventional method. Drt...Digitizing range, M,...Mesh, j, P,...Adjacent path in surface scanning, Ql,...
・Digitized position, D:, , p D+
+1.4...Corresponding dividing point, AP,...Auxiliary path Patent applicant Fananku Co., Ltd. Agent Patent attorney Chiki Saito Figure 1 Figure 3 (B) Figure 4 STL Figure 5 Figure 6 Figure 7

Claims (2)

[Claims] (1) In the method of creating NC data for rough machining of a workpiece using position data digitized by surface scanning, the process of dividing the digitizing range into multiple meshes and each of two adjacent passes in surface scanning , a step of calculating by interpolation the Z value of a mesh through which the path passes and for which no position data can be obtained, a step of calculating the length of each path and dividing each path into equal parts, and a corresponding division. Z of the mesh through which the auxiliary path connecting points passes
a step of calculating the value by interpolation, a step of approximating the machining shape in each mesh with a plane shape having the Z value of the mesh, and checking whether the rough machining tool intersects the shape approximation surface at the tool offset position; A method for creating NC data for rough machining, comprising the step of creating NC data for rough machining by correcting tool positions in the height direction so that they do not intersect. (2) The method for creating NC data for rough machining according to claim 1, wherein the number of divisions is determined according to the tool diameter of the rough machining tool.