JPH0761590B2 - Tool interference check method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a tool interference checking method, and particularly to moving a tool relative to a workpiece based on digitized position data (tool tip path data). The present invention relates to a tool interference check method for checking in advance whether a tool interferes with a work when cutting the work.

<Prior Art> A numerical control device (referred to as NC device) moves a tool relative to a workpiece based on NC data created in advance,
Performs numerical control machining on the work as instructed. In such numerical control, the trajectory of the tool center does not match the desired machining shape, in other words, the path specified by the NC data (tool tip path data), and the tool diameter equivalent amount to the right or left of the machining direction in the traveling direction. It becomes an offset passage. The trajectory of the tool center is automatically calculated by the NC unit if the machining shape and the tool diameter are given and the G function command for executing the tool diameter offset is given, and the tool is moved along the obtained tool center. , Finish the work into a desired shape. The above NC
In some cases, NC data of the tool center passage (referred to as offset NC data) is created from the data and the tool diameter, and the tool is moved according to the offset NC data to perform desired machining on the work.

By the way, depending on the machining shape (part shape) and tool diameter,
If the tool is moved along the tool center path obtained by offsetting, the tool may interfere with the work and cause tool deposition loss, or overcutting may not be possible to obtain a part with the commanded shape. Occurs.

Therefore, it is necessary to check in advance whether or not the NC data is created and the tool interferes with the work when cutting while offsetting the tool diameter according to the created NC data.

5 to 7 are explanatory views of the tool interference checking method, FIG. 5 is a desired component shape drawing, FIG. 6 is an explanatory view of an offset passage when the tool does not interfere, and FIG. 7 is a case where the tool interferes. FIG. 7 is an explanatory view of the offset passage of FIG.

If the tool center passage (offset passage) for machining according to the part shape (B1 → B2 → ・ ・ B5 → ・ ・) shown in Fig. 5 has a small tool TL diameter and is less than the groove width L As shown in FIG. 6, tool interference does not occur. In the case of FIG. 6, in other words, when the tool interference does not occur, the tool center passage TCP does not form a loop (does not intersect). However, when the diameter of the tool TL becomes large and the diameter becomes larger than the groove width L, the tool center passage with the tool diameter offset
TCP becomes as shown in FIG. 7, and the tool TL interferes with the work WK, and cuts and cuts too much, resulting in tool loss. Then, when such tool interference occurs, the tool center passage (offset passage) forms a loop Lp and intersects at a point Pc.

From the above, conventionally, the tool interference check is performed by checking whether the tool diameter offset passage forms a loop (crosses).

<Problems to be Solved by the Invention> However, in the conventional tool interference checking method, the tool movement along the first axis direction (for example, the X axis direction) and the pick feed operation along the second axis direction (Y axis direction). There is a problem that the tool interference check of NC data for machining the work by repeating and cannot be performed correctly. Incidentally, such NC data is reciprocally moved in the X-axis direction along the model MD by the contact control ST (following surface reciprocation) as shown in FIG. 8, and the contact is made while pick-feeding in the Y-axis direction. It is created by capturing the current position data of the child at predetermined time intervals.

FIG. 9 is an explanatory diagram of the reason why the tool interference check of NC data including the pick feed cannot be correctly performed by the conventional method.

The path of the i-th tool tip is P _i-1 → ・ ・ → A → B → C → P _i , and the pick feed direction is perpendicular to the paper surface (Y-axis direction). If the pick feed point from the passage to the i-th passage is P _i-1 and the pick feed point from the i-th passage to the next (i + 1) -th passage is P _i , the i-th tool The offset path offset by the tool radius R from the tip path becomes P _i-1 ′ → ... → A ′ → B ′ → C ′ → P _i ′, and at the point P _i ′, the path is pick-feeded perpendicularly to the paper surface. As is clear from FIG. 9, when the tool center is moved along the tool offset path, the tool TL interferes with the work WK, but the tool offset path does not form a loop anywhere and does not intersect.

That is, in the conventional tool interference checking method, when a part of the offset passage exists outside the pick feed point P _{i with} respect to the work WK in the X-axis direction (points A ′ and B ′ in the example of FIG. 9). , I could not check the tool interference.

From the above, it is an object of the present invention to perform tool control along the first axis direction and pick feed along the second axis direction to perform numerical control machining on a workpiece, and to reliably perform tool interference check of NC data. It is to provide a check method.

<Means for Solving Problems> FIG. 1 is a schematic explanatory view of a tool interference checking method according to the present invention.

P _i-1 → ・ ・ → A → B → C → P _i is the digitized i-th tool tip passage, P _i-1 is the pick feed direction perpendicular to the paper (Y axis direction) (i-1) th pit microphone feed point from the passage to the i-th path, P _i
Is a pick feed point from the i-th passage to the next (i + 1) -th passage, Q ₁ is a virtual pick feed point separated by a tool radius R in the X-axis direction from the pick feed point P _i to the outside of the work, P _{i -1} '→ ・ → A' → B '→ C' → Q _i ′ is the i-th tool offset path when the virtual pick feed point Q _i is regarded as the pick feed point, LP is a loop, and TL is a tool , WK is a work.

<Operation> A virtual pick feed point Q _i is set at a position distant from the pick feed point P _i on the outside of the work in the tool radius R in the X-axis direction, and the i-th pick feed point is set at the virtual pick feed point Q _i . The tool offset path P _i-1 ′ → ・ ・ ・ → A ′ → B ′ → C ′ → Q _i ′ for the tool tip path P _i-1 → ・ →→ A → B → C → Q _i i Check whether the tool offset path forms a loop LP (intersects), and if they intersect, it is determined that the tools interfere with each other.

<Embodiment> FIG. 2 is a block diagram of an apparatus (digitizer) that executes digitizing processing and tool interference checking processing. 1
Is a digitizer, which has a function to capture the current position of the tracer head while performing follow-up control and digitize, as well as a tool interference check function, a processor 1a, a ROM 1b for storing a control program, a RAM 1c for storing digitized position data, It has a working memory 1d.

Reference numeral 2 denotes an operation panel, which has a function of inputting various operation signals and setting a tracing condition, a tracing area, a tracing method, a tool radius R, and the like.

10X, 10Y, 10Z are the speed data (digital values) in each axis direction commanded from the digitizer 1 and are analog speed signals V _X , V _Y ,
DA converter to convert to V _Z , 11X, 11Y, 11Z are X axis, Y axis,
Z-axis servo circuits, 12 x to 12 z is X-axis, Y-axis, Z-axis motor, 13X～13Z has corresponding motor generates one pulse X _f, X _f, Z _f each time the predetermined angle The pulse generator 14 is a current position register that stores the current position of each axis by reversibly counting the pulses X _f , Y _f , and Z _f according to the moving direction. In addition, TH is a tracer head, SR is a stylus,
MDL is a model.

FIG. 3 is a flow chart of a tool interference check process according to the present invention. Hereinafter, the tool interference check according to the present invention will be described with reference to FIGS.

By a well-known digitizing process, a pick tip path along the Y axis and a movement along the X axis are repeated to create a tool tip passage for machining according to the model shape and stored in the RAM 1c (step 101).

Next, 1 → i is set (step 102), and the i-th pick feed point P _i (see FIG. 1) is set to the outside X of the work.
Determined point Q ₁ that extends in the axial direction by a tool radius R, and virtual pick feed point (step 103).

After that, the i-th tool tip passage P _i-1 from the (i-1) -th pick feed point P _i-1 to the virtual pick feed point Q _i →→→→ A → B → C → Q tool offset for _i path _{P i-1 '→ ··· →} a' → B Request _{'→ C' → Q i '} ( step 104). The tool offset passage can be obtained as follows, for example. That is, assuming that the tool tip passage of the current block and the next block as shown in FIG. 4 are both made of two straight lines L _1, L _2, each tool tip path L _1, L ₂ of the tool diameters respectively r ₁ offset by straight L1 ', L _2' seek, each straight line L ₁ ',
Obtain the intersection T ₁ of the L ₂ ', before the line T ₀ T ₁ is the offset passage if Musube offset end point T ₀ and the intersection T ₁ of the block, an offset passage is produced subsequently by repeating the same process.

When the i-th tool offset path is obtained, it is checked whether the i-th tool offset path forms a loop LP (intersects) (step 105). If the i-th tool offset path intersects, it is determined that the tools interfere and the intersection point S _i ′ (Step 106),
Tool offset passage to loop passage S ₁ ′ → B ′ → C ′ →
S _i 'offset path P _i-1 to remove the' → ··· → A a '→ S _i' with the tool is stored in RAM1c as a tool offset path which does not interfere with the workpiece (step 107), point S _i ′ Is regarded as an offset point of the i-th pick feed point (S _i ′ → P _i ′) ... Step 109.

On the other hand, if the offset paths do not intersect in step 105, the tool radius from the tool tip path from the (i-1) th pick feed point P _i-1 to the i th pick feed point P _i
The offset path offset only by that is stored in the RAM 1c (step 110).

If the i-th tool offset path is obtained in step 109 or step 110, it is checked whether the above processing has been completed for all pick feed points (step 111). If completed, the tool interference check is terminated and completed. If not, i is incremented by 1 by i + 1 → i (step 11
2) Then, the processing from step 103 onward is repeated.

Although the case where the tool tip passage is obtained by digitizing has been described above, the present invention is not limited to such a case and is applicable to a case where the tool tip passage including the pick feed is obtained by another method.

Incidentally, if the virtual pick feed point Q _i is determined by separating the tool radius R from the pick feed point P _{i in the} X-axis direction, a loop is always formed in case of tool interference.

<Effects of the Invention> As described above, according to the present invention, a virtual pick feed point is set at a position distant from the pick feed point in the horizontal direction outside the work (for example, the X-axis direction) by a predetermined amount, and the pick is performed at the virtual pick feed point. The tool offset path is obtained as a feed, and it is checked whether or not the tool offset paths intersect. If they intersect, it is determined that the tools interfere with each other. Therefore, the pick feed is repeated to perform numerical control machining on the work. The tool interference check of NC data can now be reliably performed.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a tool interference checking method according to the present invention, FIG. 2 is a block diagram of a system for realizing the present invention, FIG. 3 is a flow chart of processing of the present invention, and FIG. 4 is an offset path calculation method. FIG. 5, FIG. 5 to FIG. 7 are explanatory views of a conventional tool interference check method, and FIG. 8 and FIG. 9 are explanatory drawings when the tool interference check cannot be reliably performed by the conventional method. P _i-1 → ・ ・ → A → B → C → P _i …… The i-th tool tip passage, P _i-1 …… Pick from the (i-1) -th passage to the i-th passage Feed point, P _i ...... Pick feed point from the i-th passage to the next (i + 1) -th passage, Q _i・ ・ ・ Virtual pick feed point, P _i-1 ′ → ・ ・ ・ → A ′ → _{B '→ C' → Q i} '...... i-th tool offset passage, LP ...... loop, TL ...... tool

Claims (2)

[Claims] 1. A tool interference check method for NC data, wherein a tool is moved along a first axis direction and a pick feed is carried out along a second axis direction to perform a numerical control machining of a workpiece. When a virtual pick feed point is set at a position separated by a predetermined amount in the direction, a tool offset path is determined as if pick feed is performed at the virtual pick feed point, and it is checked whether the tool offset path intersects. Is a tool interference check method characterized by determining that a tool interferes. 2. The tool interference checking method according to claim 1, wherein the predetermined amount is a tool radius.