JPH0711762B2 - NC data correction device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an NC (Numerical Control) data correction device obtained by measuring a model by a digitizer, and more particularly to the NC described above.
The present invention relates to an NC data correction device that automatically corrects data disturbances and creates smooth NC data.

(Technical background of the invention and its problems) Digitizing data (NC data) obtained by measuring a stylus attached to a tracer head while abutting the surface of the model with a digitizer.
Is not output as a smooth point cloud on the actual model surface due to the roughness of the model surface itself, contact friction between the stylus and the model, tracer head tracking accuracy, etc., so-called "fluctuation" or "hunting". Is output as disordered point cloud data. Then, when using the NC data obtained in this way as it is, when machining a workpiece such as a mold with an NC machine tool, the tool is smooth because the NC data point cloud has the above-mentioned disorder. It cannot move and the feed speed cannot be increased beyond a certain speed. Therefore, NC machining based on NC data as described above not only increases the machining time, but also includes the amount of disturbance of the point group of NC data in the finishing allowance in advance, that is, adding the finishing allowance accordingly. Therefore, there is a problem that the number of man-hours for final finishing cannot be reduced because the NC machining must be performed.

Moreover, these problems can be solved by correcting the disorder of the point data of the NC data as described above, but conventionally there is a correction device that can easily and accurately correct such NC data. There wasn't.

(Object of the Invention) The present invention has been made under the circumstances as described above, and an object of the present invention is to automatically correct the disturbance of NC data measured by a digitizer to create smooth NC data. To provide the NC data correction device.

(Summary of the Invention) The present invention relates to an NC data correction device, which analyzes NC data composed of point cloud data of measurement by an input digitizer, and creates a coordinate value table corresponding to the coordinate value of each measurement point of the NC data. An NC data storage unit that is created and stored, a correction condition storage unit that stores correction conditions set for each correction item such as hunting, retrograde, taper, and shake that have been input, and a correction condition storage unit that stores the correction conditions. According to the correction conditions, the above NC
The number of coordinates in the coordinate value table stored in the data storage unit; a correction point detection unit that detects a correction point in series; a correction point storage unit that stores the correction point data detected by the correction point detection unit; An NC data correction unit that automatically corrects the input NC data based on the stored correction condition data and correction location data, and, in the hunting correction of the correction item, Hunting ON, hunting OFF, and each set value for the hunting measurement length (hunting search length) are used as correction conditions, the point cloud existing in the hunting ON and OFF areas is deleted, and the two points before ON and OFF Latter two
Corrections are made by using the intersections that extend the respective points as update points, and in the retrograde correction of the above correction items, the set value for the increment of the data in the measurement direction (digitizing direction) and the reverse direction is the correction condition, and the set value is set. Correction was made to delete measurement points with the above increments, and in the taper correction of the above-mentioned correction items,
Taper OFF measurement with the set values for taper ON and OFF of the Z-direction change amount to make the taper ON and the taper value to determine the taper ON and the X-direction change amount to taper OFF and the taper value to determine the taper OFF to be the taper ON and OFF Correction is performed with the point in the horizontal direction or tangential direction from the point as the update point.When correcting the fluctuation of the correction item, the setting value for shaking ON and the setting value for tolerance are set as the correction conditions, and Correction is made so that the tolerance amount becomes the tolerance setting value.

(Embodiment of the Invention) FIG. 1 is a block diagram showing the outline of an NC data correction device according to the present invention. This NC data correction device is provided separately from a digitizer and an NC device. In FIG. 1, reference numeral 1 is an external storage medium such as a fixed disk or a floppy disk, and NC data measured by a digitizer is stored in this external storage medium 1. Reference numeral 2 is an NC data input section for reading the NC data stored in the external storage medium 1. Reference numeral 3 is for analyzing the read NC data and creating a coordinate value table for correlating the NC data with the coordinate values. It is an NC data storage unit that stores the data. on the other hand,
Reference numeral 4 denotes an input device such as a keyboard for inputting correction conditions described later, and reference numeral 5 denotes a correction condition storage unit for storing the correction conditions input from the input device 4. 6 is in accordance with the correction condition stored in the correction condition storage unit 5 as described later,
This is a correction point detecting section for detecting a correction point in the coordinate table stored in the NC data storage section 3 and outputting the detected correction point to the correction point storage section 7 for storage. The correction point detecting unit 6 receives the NC data corresponding to the correction point from the NC data input unit 2 and outputs it to the NC data correcting unit 8. And this NC data correction unit 8
Is based on the correction condition stored in the correction condition storage unit 5 and the correction point stored in the correction point storage unit 7,
After the necessary correction processing is automatically added to the NC data output from the correction point detection unit 6 as described later, the corrected NC data is displayed on the CRT display device 9 or drawn by the plotter 10. At the same time, the NC data stored on the fixed disk 1 is modified and written.

With such a configuration, its operation will be described with reference to the flowchart of FIG.

First, the correction condition is set by the input device 4 (step S
1), setting items are input / output NC data file and taper part,
These are correction items such as hunting, and these correction conditions are stored in the correction condition storage unit 5. After this, NC data for one buffer is set (step S2). This is because the NC data for one buffer from the external storage medium 1 is the NC data input section 2
It is carried out by inputting the data through, analyzing and storing in the NC data storage unit 3. Then, the presence / absence of NC data is judged (step S3), and if there is no NC data, the process ends.
If there is, the correction point detection section 6 detects the correction section of the NC data (step S4). FIG. 3 shows an example of NC data displayed on the CRT display device 9, which is a graphic display of a tool path DT in which each measurement point group DD1, DD2, ... DDn obtained by the digitizer is connected by a broken line, and these. Each measurement point group DD1 to D
The character display of the character data DC, which is the X, Y, and Z coordinate values of Dn, is displayed. In this NC data example, areas AR1 and A
The R2 data is the part that needs correction. The display of the character is not always necessary. After detecting such a correction point, the NC data correction section 8 stores the NC data stored in the NC data storage section 3, the correction condition stored in the correction condition storage section 5 and the correction point storage section 7. The NC data for one buffer is automatically corrected on the basis of the corrected position data as described below.
The automatically corrected NC data is displayed on the CRT display device 9 and drawn by the plotter 10, and is stored in the external storage medium 1 (step S5). Such a correction operation for each buffer is repeated for all NC data.

Here, as the above-mentioned correction condition, the above-mentioned correction point detecting method, and the above-mentioned correction processing method, the conditions and respective methods listed below according to the above-mentioned disordered state are used.

(I) Hunting correction When the NC data is the hunting data of points P _{1 to} P ₁₀ as shown in FIG. 4 (A), the hunting ON / OFF points are searched as follows. That is, first, as shown in FIG. 5, 3 measurement points Pi _-1 consecutive among the measurement point group P ₁ to PN in NC data, Pi, for Pi _+1, between two measurement points Pi, Pi ₊₁ Distance | dl
And the angle θi formed by these three measurement points Pi ₋₁ , Pi, Pi ₊₁ simultaneously satisfies the following conditions (1) and (2), the measurement point groups P _{1 to} Pn are measured point group Pi ₋ It is detected that hunting is occurring (hunting ON) at ₁ , Pi, Pi ₊₁ .

| dl |> Set value (Ld) ……… (1) θi <Set value (θh) ……… (2) Measurement point group P ₁ ~ where hunting ON is detected in this way
Regarding Pn, when the following conditions are satisfied as shown in FIG. 6, the hunting is terminated (OFF). That is, the intermediate point within the range of the set length Ls inflection point Pn _-1 in Pn
Except for (angle θc formed by this intermediate point Pc> set value θs), the next inflection point Pn (angle θn formed by this inflection point Pn <set value θ
When t) does not exist, hunting OFF is detected and the hunting ends. However, if the next inflection point Pn exceeds the predetermined hunting search length Li, it is determined that hunting is not performed.

Therefore, in the NC data shown in FIG. 4A, the point P ₅ is searched for hunting ON and the point P ₈ is searched for hunting OFF. Therefore, as shown in FIG. 4B, these hunting points P _{5 to} P Remove ₇ . And two points P3, P4 and O before ON
The two points P ₈ and P ₉ after the FF are respectively expanded to obtain the intersection, and the point P ₄ ′ obtained inside is set as a new update point as shown in FIG. 4 (C). This removes hunting and corrects the NC data to be smooth.

With the above hunting correction, for example, NC data hunting as shown in FIG. 7 (A) and FIG. 8 (A)
The correction is performed smoothly as shown in FIGS. 7 (B) and 8 (B), respectively.

(II) Retrograde correction In retrograde correction, hunting correction is performed and then data in the opposite direction is corrected. That is, as shown in FIG. 9, when the increment dx has a sign opposite to the measurement direction, it is set as retrograde data. It is considered that the above-mentioned increment dx is in the opposite direction when there is an error in the measured value P _{2 of} this time or an error in the measured value P _{1 of the} previous time. Therefore, as shown in FIG. 10 (A), the measured value P _{2 for} which the increment dx is in the opposite direction is deleted, and as shown in FIG. 10 (B), the increment dx is in the opposite direction.
Discard measurement point P ₁ . As a result, the remaining measurement points (P ₀ , P ₃ , P ₄ ) are in the same direction as shown in FIG. 10 (C).

(III) Taper part correction Turning ON / OFF of the taper part of NC data is shown in Figures 13 (A) and (B).
Then, the correction as shown in FIG. 14 is made. Here, when the taper part ON satisfies | dz |> Dz ……… (3) | dx / dz | <T _ON ……… (4) in NC data as shown in Fig. 13 (A). Only detected in. Dz in the above equation (3) is a set value of the Z displacement amount for turning the taper portion ON, and T _ON in the above equation (4) is a taper value for determining the _ON of the taper portion. The taper part is turned on by the above formulas (3) and (4)
There is detected, a point P ₁ of the starting point of FIG. 13 of the tapered portion ON (A)
And Also, the taper section OFF is when NC data as shown in Fig. 13 (B) satisfies | dx |> Dx ……… (5) | dx / dz | ＞ T _OF ……… (6). Only detected. Dx in the above equation (5) is the X displacement amount for turning off the taper portion, and the above (6)
T _{OF in the} equation is a taper value for determining whether the taper portion is OFF. Then, when the above equations (5) and (6) are simultaneously satisfied from the point of turning on the taper portion, the taper portion is turned off.
In the example of FIG. 13 (B), the end point of the tapered portion is P ₂ .

FIG. 14 shows a method of correcting the tapered portion, in which the point Q _{1 in the} horizontal direction or the point Q _{2 in the} tangential direction is obtained and the point P ₂ is corrected to the point P ₂ ′.

(IV) Shake correction When the shake of NC data is corrected, it is not possible to distinguish between the actual unevenness of the model surface and the shake on the data, so it is clear only for the pattern of shake on the data. Perform shake correction. That is, the detection of the shaking and when tolerance Tr shown in FIG. 15 is larger than the set value T _R, modifications tolerance amount per unit length In tolerance Tr is set to be a set value T _R. here,
The fluctuation that can be corrected on the data is shown in FIG. And the angle θ formed by P ₁ P ₂ and P ₄ P ₅ is θ> Yθm ……… (10), And if Ht of <T _R ......... (12). A determining length of about YLa is shaking in the above formulas, Yshitaemu the shaking determined angle, YL is shaking the determining length, T _R is the tolerance determination value per unit length. Then, according to the above equations (8) and (9), there is a good section without shaking before and after the shaking, and it may be defined so that the shaking during the section can be discriminated. Along with this, the straight line before and after that from the above equation (10) The difference between the slopes is small and it is defined as a normal section, and in order to distinguish it from the actual unevenness by the above equations (11) and (12), the fluctuation is defined by setting a smaller value. In addition, shake ON is shown in Fig. 17 and Fig. 18, This is when θ <{180 ° -tan ⁻¹ T _R } θ> Yθa.

Examples of the shake correction are shown in FIGS. 19 to 21, and in all of them, the upper diagram shows the NC data before the correction and the lower diagram shows the NC data after the shake correction.

(Effects of the Invention) As described above, according to the NC data correction device of the present invention, it is possible to automatically correct the disturbance of the NC data and obtain smooth NC data. Therefore, NC machining is performed by the NC machine tool. In doing so, it is possible to use a higher feed rate than before, which can shorten the processing time, minimize the finishing allowance, and significantly reduce the number of final hand finishing processes. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a flowchart showing an example of the operation, FIG. 3 is a view showing an example of NC data display, FIGS. 4 to 6 are diagrams for explaining hunting correction, FIGS. 7 (A) and 8 ( (A) is a diagram showing an example of NC data having hunting, FIGS. 7 (B) and 8 (B) are modified diagrams of FIGS. 7 (A) and 8 (A), and FIG. 9 to FIG. FIG. 12 is a diagram for explaining retrograde correction, FIGS. 13 (A), (B) and FIG. 14 are diagrams for explaining taper portion correction, and FIGS. 15-18 are diagrams for explaining shake correction. FIG. 19 and FIG. 21 are diagrams for illustrating an example of shake correction. 1 ... External storage medium, 2 ... NC data input section, 3 ... NC
Data storage unit, 4 input device, 5 correction condition storage unit, 6 correction portion detection unit, 7 correction portion storage unit, 8
...... NC data correction section.

Claims (5)

[Claims] 1. The input digitizer analyzes NC data consisting of measurement point cloud data, creates and stores a coordinate value table corresponding to the coordinate values of each measurement point of the NC data.
The NC data storage unit, the correction condition storage unit that stores the correction conditions set for each correction item such as the entered hunting, retrograde, taper, and shake, and the correction conditions stored in the correction condition storage unit NC
A correction point detection section for detecting a correction point in a coordinate value sequence of a coordinate value table stored in the data storage section; a correction point storage section for storing the correction point data detected by the correction point detection section; An NC data correction device comprising: an NC data correction unit that automatically corrects the input NC data based on the stored correction condition data and correction location data. 2. In the hunting correction of the correction item, hunting ON and hunting OFF, and each set value for the hunting measurement length (hunting search length) is used as a correction condition, and the hunting ON and OFF areas are set. 2. The NC data correction device according to claim 1, wherein the point data existing in 1 is deleted, and the correction is performed by using the intersections obtained by extending 2 points before ON and 2 points after OFF as update points. 3. In the retrograde correction of the correction item, the set value for the increment of the data in the direction opposite to the measurement direction (digitizing direction) is used as the correction condition, and the measurement point having the increment of the set value or more is deleted. The NC data correction device according to claim 1, which performs correction. 4. In the taper correction of the correction items, the Z direction change amount for turning on the taper, the taper value for determining taper ON, and the X direction for changing the taper OFF and the taper value for determining taper OFF are set. The NC data correction device according to claim 1, wherein the correction value is a set value for ON / OFF of the taper, and correction is performed by setting a point in the horizontal direction or a tangential direction from a measurement point of the taper OFF as an update point. 5. A shake is included in the shake correction of the correction item.
The NC data correcting device according to claim 1, wherein the setting value for ON and the setting value for tolerance are used as a correction condition, and correction is performed so that the tolerance amount per unit length of fluctuation becomes a tolerance setting value.