JPH0747256B2 - NC data creation method for side area processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a method for creating NC data for side surface area machining, and particularly to rough machining and finishing using tool diameter compensation based on a side surface finish shape input in advance. The present invention relates to a method for creating NC data for machining lateral areas of automatic programming for creating machining NC data.

[Conventional technology]

The NC data of the side surface region processing in which an arbitrary side surface shape of the workpiece is processed by a tool such as an end mill is created so that the tool moves on the side surface shape. This NC data is offset to the right or the left in the advancing direction by the tool radius correction function of the numerical control device, and the tool moves relative to the work piece according to the NC data after the offset. In this way, it is common to process an arbitrary side surface shape.

In the finishing of the side surface region processing, a tool having a relatively small diameter is used so that the processing can be performed in consideration of the radius of the inner circular arc of the side surface finishing shape and the size of the inner chamfer. Further, in rough machining, in order to reduce the cutting time and improve the machining efficiency, a tool having a larger tool diameter than the finishing tool, that is, a tool having a tool radius larger than the radius of the inner arc and the size of the inner chamfer is used. It is generally used.

[Problems to be Solved by the Invention]

However, if you try to create NC data for roughing and finishing using the tool radius compensation function by inputting only the side surface finish shape with automatic programming, when creating NC data for roughing with conventional automatic programming, It was created so that the NC data that moves on the finish shape would be offset by the tool radius for rough machining by applying tool diameter correction and move on this tool center path. For this reason,
If a tool with a large tool radius is used for rough machining, there is a problem that the rough machining tool creates NC data that causes overcutting into the side surface finish shape depending on the side surface finish shape.

For example, as shown in FIG. 5, side surface finish shapes EL ₁ , EL ₂ ,
When the tool center paths PT ₁ , PT ₂ , PT ₃ are found by offsetting the tool radius R of the roughing tool TL to the left in the traveling direction based on EL ₃ , for example, the points on the found tool center path PT ₁ When the tool TL moves to the position A, the tool TL is excessively cut into the side surface finish shape EL ₃ . for that reason,
When machining is performed using such NC data, an NC alarm is generated and the NC controller stops the machine.

Also, if a tool that matches the side surface finish shape is used from the rough machining to machine the side surface area of the workpiece so that the NC alarm does not occur, it will take a large amount of machining time and the machining efficiency will decrease. Occurred.

Therefore, a method of separately inputting the side rough machining shape for rough machining and the side finish machining shape for finishing machining can be considered.
If they are input separately, the number of shape elements to be input increases, and it is easy to make an input error, and it takes a lot of time. Further, in the side surface rough machining shape, it is necessary to delete a shape element that causes overcutting by hand, which causes a problem of defective products due to an erroneous deletion.

From the above, the purpose of the present invention is to create an NC data for rough machining used for the tool radius compensation function by inputting only the side surface finish shape, causing overcutting to the side surface finish shape, NC
It is to provide a method for creating NC data for side area processing of automatic programming that can create NC data without alarm occurrence.

[Means for Solving the Problems]

The present invention was devised in order to solve the above-mentioned problems, and end mills any side surface shape of a workpiece by using a side surface finishing shape in which each shape element made of a canonical form having a cutting direction is connected. When processing with tools such as
Creates NC data of a roughing tool that prevents overcutting that occurs when using a roughing tool that is thicker than the finishing tool.In the NC data creation method for side area machining, the tool of the roughing tool is used. A step of offsetting the side surface finish shape by a tool radius by using a radius offset data to obtain a tool center path formed of a canonical form, and a cutting direction of a shape element of the side surface finish shape and the tool radius offset corresponding thereto The step of comparing the cutting direction of the shape element of the tool center path that was cut, and the result of the comparison, the shape element of the tool center path whose cutting direction is reversed is recognized as the shape element of the tool center path that causes excessive cutting. Then, find the intersection between the shape elements of the tool center path before and after the tool center path with this cutting direction reversed,
This intersection is defined as the movement end point and the movement start point of the shape element of the tool center, and the step of deleting the shape element portion of the tool center path in which the cutting direction is opposite, and the advancing direction of the tool center path in the opposite direction. A side surface region characterized by comprising the step of deleting the shape element portion and creating NC data of the rough machining tool using the shape element of the tool center path in which the intersection is defined as the movement end point and the movement start point. This is the method for creating NC data for machining.

[Action]

When the tool diameter of the roughing tool is specified, the processor 1 uses the tool diameter to offset the side surface finish shape element by element by the tool radius of the roughing tool. Next, it is checked whether the advancing direction of the shape element of the side finish shape before offset and the advancing direction of the corresponding shape element of the tool center path are opposite. If there is a reverse element, the reverse element is deleted. The device 4 deletes the reverse element of the tool center path after the offset. Then,
The tool center path after the offset that deletes the reverse element,
The reverse offset processing device 5 offsets the tool radius in the opposite direction by the tool radius to create a side surface rough machining shape for rough machining, and also registers it in the rough machining machining shape memory 6.

〔Example〕

Hereinafter, a method for creating NC data for side surface area processing according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an NC data creating apparatus which is an embodiment of the present invention.

1 is a processor (CPU), 2 is an offset processing device that offsets a shape element by a predetermined tool diameter, 3 is an offset machining shape memory that stores the tool center path processed by the offset processing device 2, and 4 is a shape before offset Compared with the traveling direction of the element, check whether the traveling direction of the shape element of the tool center path after offset is reverse direction, and if there is a reverse element, delete this reverse element Delete reverse element A device 5 is a reverse offset processing device that reversely offsets the tool center path after the offset in which the reverse elements are deleted by the reverse element deletion device 4 to create a side surface rough machining shape for rough machining, and 6 is a reverse offset processing device. It is a machining shape memory for rough machining that stores a side rough machining profile for rough machining created by the offset processing device 5.

FIG. 2 is a flow chart of NC data creation processing for side surface area processing according to the present invention. The NC data creation process will be described below with reference to this flowchart. Note that the NC data creation process is performed based on the side surface finish shapes (NC data) EL ₁ , EL ₂ , EL ₃ shown in FIG. 5, and the side surface finish shapes EL ₁ , E shown in FIG.
It is assumed that L ₂ and EL ₃ are created and registered in a predetermined storage area.

When the operator specifies the tool diameter of the rough machining tool (step 11), the processor 1 offsets the side surface finish shape element by element by the offset processing device 2 using this tool diameter, and the tool center path PT ₁ after the offset, Obtain PT ₂ and PT ₃ (step 12, see FIG. 5). For this offset, an offset processing routine described later in FIG. 3 is used.

Next, based on the reverse element deletion routine described later in FIG. 4, the advancing direction of the shape element of the side surface finish shape before offset and the corresponding advancing direction of the shape element of the tool center path after offset are reversed. Check whether or not,
If there is a backward element portion, this backward element portion is deleted (step 13). Note that P ₁ is the intersection of the tool center paths PT ₁ and PT ₃ after the offset.

A value obtained by adding "-1" to the tool diameter value is set as a tool diameter value for offset processing (step 14). Then, with respect to the tool center paths PT ₁ ′ and PT ₃ ′ after the offset in which the reverse direction element portions are deleted, the value is obtained by adding “−1” to the value of the tool diameter to perform the reverse offset, and the side surface rough machining shape ( Create machining shapes for rough machining) EL ₁ ′, EL ₃ ′ (step
15, see Fig. 6). Next, the side rough machining shapes EL ₁ ′ and EL ₃ ′ for rough machining that have been created are registered in the side rough machining shape memory 6 (step 16), and NC of automatic programming (not shown) is registered.
The data creation processing device creates NC data for rough machining and finish machining based on the side surface rough machining shape, and ends the NC data creation process.

In the automatic programming of the present invention, the side surface finish shape, the tool center path, and the side surface rough machining shape consist of a set of shape elements such as straight lines and arcs, and each shape element is recorded as a canonical form having a cutting direction. To be done. For example, as shown in FIG. 7, the linear element is the linear element ELa
Unit vector Va in the normal direction to the right of the traveling direction of
, The X component Vx and Y component Vy of the normal unit vector Va
And the distance | Ve | from the origin 0 is recorded. This data is called linear canonical form.
Although the distance | Ve | from the origin 0 is a positive real number, the distance Ve from the origin 0 is positive when the origin 0 is on the left side of the traveling direction of the straight line, and is negative when it is on the right side. 8th arc element
As shown in the figure, the coordinate value (x ₀ , y ₀ ) of the center point Q of the arc ELb, the radius r _0, and the traveling direction (clockwise direction CW,
Alternatively, it is recorded as data in the counterclockwise direction CCW). This data is called an arc canonical form.

And when performing offset processing on linear elements and arc elements,
For example, when offsetting to the right by the tool radius, the third
This is performed according to the flow chart of the offset processing in the figure.

That is, when the offset routine is started, the processor 1 sets the offset element pointer i to i = 1 (step 101) and calls the side surface finish shape element corresponding to the offset element pointer i from a predetermined storage area to It is determined whether the attribute of the finish shape element is a straight line, a clockwise circular arc (CW circular arc), or a counterclockwise circular arc (CCW circular arc) (step 102).

If the result of step 102 is a straight line, the offset amount (tool radius) is added to the distance from the origin of the canonical form (step 103). If it is a CCW arc, only the tool radius is added to the arc radius of the canonical form (step 104). If it is a CW arc, subtract the tool radius from the arc radius of the canonical form (step 10
Five).

Next, the intersection of the shape element to be represented by the new canonical form (canonical form after offset processing) and the shape element represented by the canonical form processed by the previous element pointer (i-1) is calculated ( Step 106).

Then, a new canonical form is output and registered in the post-offset machining shape memory 3 by using the calculated intersection as the starting point of the shape element represented by the new canonical form (step 107).

When the offset processing of the shape element corresponding to the offset element pointer i is completed, the processor 1 increments (i + 1) the offset element pointer i (step 108). Then, it is determined whether the incremented offset element pointer i is smaller than the number M of shape elements plus one (i <M + 1). In other words, it is determined whether or not the offset processing has been completed for all the shape elements (step 109). If the result of determination is that the offset element pointer i is greater than the number M of shape elements plus one (i> M + 1), the offset routine processing is terminated. On the other hand, if the offset element pointer i is smaller than the number M of shape elements plus 1, the processing from step 102 is repeated.

By the above offset routine processing, for example, when the linear element ELa in FIG. 7 is offset to the right in the traveling direction by the tool radius L ₁ , the linear element ELa has a distance | Ve | from the origin 0 of the canonical form to the tool diameter L ₁ What is added (| Ve | + L ₁ ) is the canonical form of the linear element PTa after offset. Further, when the CCW circular arc element ELb in FIG. 8 is offset to the right in the traveling direction by the tool radius L ₂ , the radius r _{0 of the} canonical form of the CCW circular arc element ELb is changed to the tool radius L 2.
_The canonical form of arc PTb after offset processing is obtained by adding ₂ (r ₀ + L ₂ ).

FIG. 4 is a flow chart of a reverse element deletion process (reverse element deletion routine) of the tool center path after offset according to the present invention. The reverse element deletion processing according to the present invention will be described below with reference to the flowchart of FIG.

When the backward element deletion routine (step 13) of FIG. 4 is started, the processor 1 sets the backward check element pointer j to j = 1 (step 21).

Next, the processor 1 calls the shape element of the tool center path after offset corresponding to the backward check element pointer j, and determines whether the attribute of the shape element is a straight line element or a circular arc element (step 22). As a result, if it is a circular arc element, it is judged whether the circular arc radius R is a negative number (R≤0) (step 23), and if R≤0, the side surface finish shape is over-machined in the opposite direction. It is determined that the element exists, and the processing from step 25 is performed. On the other hand, if R> 0, the processing from step 27 onward is performed.

If it is a straight line element in the judgment of step 22, then it is judged whether or not the advancing direction of the shape element of the tool center path after the offset is opposite to the advancing direction of the side surface finish shape before the offset (step 24) If the traveling direction is not the opposite direction, the processing from step 27 onward is performed. On the other hand, if the traveling direction is opposite, it is determined that there is a reverse element that causes overcutting in the side surface finish shape, and the reverse element is deleted. Next,
Intersection points before and after the reverse element of the tool center path after offset (for example, the offset machining shapes PT ₁ and PT _{3 in} FIG. 5)
Seeking the intersection P _1), newly create a tool center path by deleting the reverse element intersection P ₁ as the starting point of the tool center path PT ₃ after the end point or offset of the tool center path PT ₁ after the offset (step 25, step 26).

Then, the backward check element pointer j is incremented (j = j + 1) (step 27), and whether the backward check element pointer j is smaller than the number m of the machining shapes plus 1 (j <m + 1). to decide. In other words, it is judged whether the backward check processing is completed,
If the reverse check element pointer j is smaller than the number m of side surface finish elements plus 1, (j <m +
1), the process from step 22 is repeated. On the other hand, if it is not smaller (j ≧ m + 1), all shape elements of the tool center path after the backward element deletion are registered in the offset machining shape memory 3 (step 29), and the backward element deletion processing ends.

〔The invention's effect〕

As described above, according to the present invention, the side surface roughening shape is created by deleting the shape element cut into the side surface finishing shape, and the side surface roughening shape is used to create the NC data for roughing processing. Even if the radius of the tool for rough machining is made larger than the radius of the inner arc of the shape or the size of the inner chamfer, it is possible to create NC data that does not cut into the side surface finish shape and does not generate an NC alarm. Efficiency is significantly improved. Also, since NC data for roughing and finishing can be created by inputting only the side surface finish shape, the number of side surface shape inputs can be reduced, input errors can be reduced, and side surface shape input time can be greatly reduced. You can

[Brief description of drawings]

FIG. 1 is a block diagram of an NC data creating apparatus according to an embodiment of the present invention, FIG. 2 is a flow chart of NC data creating processing for side surface area machining of the present invention, FIG. 3 is a flow chart of an offset processing routine, and FIG. FIG. 7 is a flow chart of reverse element deletion processing after offset processing according to the present invention, FIGS. 5 and 6 are explanatory views of an embodiment of the present invention, FIG. 7 is an explanatory view of a canonical form of a line segment, and FIG. FIG. 8 is an explanatory diagram of an arcuate canonical form. 1 ... Processor (CPU), 2 ... Offset processing device, 3 ... Offset machining shape memory, 4 ... Reverse element deletion device, 5 ... Reverse offset processing device, 6 ... Rough machining shape memory .

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G05B 19/4097

Claims (1)

[Claims] 1. A finishing tool when processing an arbitrary side surface shape of a workpiece with a tool such as an end mill by using a side surface finish shape formed by connecting shape elements each of which is a canonical form having a cutting direction. In the NC data creation method of the side area machining to create NC data of the rough machining tool that prevents overcutting that occurs when using a thicker rough machining tool, the tool diameter offset data of the rough machining tool A step of offsetting the side surface finish shape by a tool radius to obtain a tool center path formed of a canonical form, and a cutting direction of the side surface finish shape element and a tool center path offset by the tool radius corresponding thereto The step of comparing the cutting direction of the shape element of, and the result of the comparison is that the shape element of the tool center path in which the cutting direction is opposite is cut too much. It is recognized as the shape element of the tool center path that causes the cutting, and the intersection point between the shape elements of the tool center path before and after the tool center path whose cutting direction is reversed is obtained, and this intersection point is defined as the shape element of the tool center path. The step of deleting the shape element part of the tool center path in which the cutting direction is the reverse direction by defining the movement end point and the movement start point, and deleting the shape element part of the tool center path in which the advancing direction is the reverse direction, And a step of creating NC data of the tool for rough machining using the shape elements of the tool center path defined as the movement end point and the movement start point.