JPH1115510A - Numerically controlled machine tool for shape work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a process and to reduce die production cost by position- controlling a feed shaft motor based on obtained command position output and a present feed shaft position which is fed back. SOLUTION: A shape calculation quantity correction part 11 operates shape correction quantity in respective edge position command positions and vector- distributes shape correction quantity to respective feed shaft direction components from respective shape correction directions calculated in a correction direction calculation part 10. A shape correction range judgment part 13 blocks a gate by using an AND gate 14 so that shape correction quantity is taken out to an addition part 3 from the shape correction quantity calculation part 11 only when the respective edge position command positions are contained in a shape correction range which is set and stored in a shape correction range setting/storage part 12. The addition part 3 vector-adds respective shape correction quantities to the respective edge position command positions, obtains the edge position command positions after shape correction, sends the obtained edge position command position after shape correction as command position output and sends it to a feed shaft motor driving part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a shape correcting means useful for making a partial change to the shape of a free-form surface, and a position of a feed shaft motor based on a command position obtained by analyzing a machining program. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerically controlled machine tool for processing a workpiece by controlling the workpiece into a free-form surface shape.

[0002]

2. Description of the Related Art Conventionally, when processing a workpiece into a free-form surface shape, first, a workpiece shape is created using a CAD device, and output data from the CAD is converted into data for a numerically controlled machine tool using a CAM device. (Machining program)
According to the procedure, the operation of the numerically controlled machine tool is controlled based on the created machining program.

FIG. 5 is a block diagram showing an example of a control device in a conventional numerical control machine tool for shape processing. The program analysis unit 1 analyzes the data (machining program) for the numerically controlled machine tool, and the command position calculation unit 2 sequentially calculates the processing trajectory for controlling the tool edge position based on the analysis result of the program analysis unit 1. Then, the obtained cutting edge command position is sent to the feed shaft motor driving unit 4 as a command position output. The feed shaft motor drive unit 4 controls the position of the feed shaft motor 5 based on the transmitted cutting edge command position output, and the position of the feed shaft detected by the position detector 6 is fed back to the feed shaft motor drive unit 4 by position feedback. Is done.

[0004]

In the case of processing a press-forming die, which is a representative of a workpiece having a free-form surface shape, it is necessary to secure the thickness of a sheet metal sandwiched between an upper die and a lower die. Shape processing is performed based on processing program data created so as to generate a certain clearance between the dies.
When a press is actually performed using a mold processed in this manner, distortion or the like may occur in the shape of a molded product due to conditions such as shape drawing and pressing of a sheet metal during press molding. To solve such a problem, the clearance between the upper mold and the lower mold may be partially changed in order to improve the moldability.
Part of the shape data is changed using the
The equipment had to be converted into data for numerically controlled machine tools again, and the procedure of reworking based on the newly created machining program had to be repeated, requiring a lot of time until the final product processing . Therefore, saving the time spent for repeating these series of steps has been a major problem in shortening the lead time in mold production.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to use a machining program data created with a certain clearance between dies as it is, to reduce the clearance. An object of the present invention is to provide a numerically controlled machine tool for shape processing that can perform processing while correcting the shape of a specified processing portion by specifying a portion to be changed.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a numerical value for shape machining for machining a workpiece into a free-form surface by controlling the position of a feed shaft motor based on a command position obtained by analyzing a machining program. Related to controlled machine tools,
The object of the present invention is to provide a processing part reference point designating unit for specifying a processing part reference point for specifying a processing part for partially changing the free-form surface shape, and the free-form surface shape at the processing part reference point. A shape correction reference amount setting means for setting a shape correction reference amount which is a correction amount; a correction reference point designating means for specifying a correction reference point for specifying a shape correction direction at the machining site reference point; Correction direction calculating means for obtaining a shape correction direction at each cutting edge command position from the tool edge command position and the correction reference point, a distance from each cutting edge command position to the correction reference point, and the correction reference point from the machining region reference point. And a shape correction amount calculating means for calculating a shape correction amount at each cutting edge command position from the shape correction reference amount based on the distance to the blade. The shape correction coordinate value for each feed axis at each cutting edge command position calculated by vector distribution from the shape correction direction at the command position to each feed axis direction is added to the command coordinate value for each feed axis at each cutting edge command position for command. This is achieved by obtaining a position output and performing position control of the feed shaft motor based on the obtained command position output and the current feed shaft position fed back. Further, the above object of the present invention is to output the cutting edge command position of the currently used tool as the command position output as it is, and obtain the command position output and the coordinate value of the current feed axis position to be fed back. For controlling the position of the feed axis motor based on the feed axis correction position obtained by subtracting the shape correction coordinate value for each feed axis at each cutting edge command position, or for limiting the processing part for performing the shape correction A shape correction range setting means for setting a shape correction range is provided, and it is determined whether a cutting edge command position of a currently used tool is included in the shape correction range, and the shape correction amount is determined only when it is included. By controlling the position of the feed shaft motor using the above-described method, the control can be more effectively achieved.

That is, in the numerically controlled machine tool for shape machining of the present invention, a fixed clearance between the dies is set by setting a machining portion reference point, a shape correction reference amount, and a correction reference point of a portion whose clearance is to be changed. Using the machining program data created by securing
Processing can be performed while correcting the shape of the specified processing part.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. FIG. 1 is a block diagram showing a first embodiment of the present invention. The same parts as those in the block diagram of the control device in the conventional numerically controlled machine tool shown in FIG. Is omitted.

The operator performs a shape correction to change the clearance, and determines a machining site reference point P serving as a reference.
a is a shape correction reference amount Da which is a shape correction amount at the processing portion reference point Pa by the processing portion reference point designating / storing unit 8.
And a correction reference point Pb for specifying the shape correction direction at the processing portion reference point are determined and stored in advance by the correction reference point designation / storage section 7, respectively. Furthermore, a shape correction range for limiting a processing portion to be subjected to shape correction is set to a shape correction range.
It is set and stored by the storage unit 12.

When the command position calculating section 2 calculates a cutting edge command position (Pn, Pn + 1, Pn + 2...) As a machining locus based on the machining program analyzed by the program analyzing section 1, the correction direction calculating section 10 This cutting edge command position (P
n, Pn + 1, Pn + 2,...) and the correction reference point Pb designated and stored by the correction reference point designation / storage unit 7 are calculated as the shape correction directions at the respective cutting edge command positions. In addition, the shape correction amount calculation unit 11 calculates the distance (| Pb−P) from the processing portion reference point Pa to the correction reference point Pb.
a |) and each cutting edge command position (Pn, Pn + 1, Pn + 2 ·
..) to the correction reference point Pb (| Pb-Pn
|, | Pb-Pn + 1 |, | Pb-Pn + 2 |,.
.) Is multiplied by the shape correction reference amount Da to obtain the shape correction amount (Dn, Dn + 1, D) at each cutting edge command position.
n + 2...), and the obtained shape correction amount at each cutting edge command position is vector-distributed from each shape correction direction calculated by the correction direction calculation unit 10 to each feed axis direction component.

On the other hand, the shape correction range judging section 13 determines the respective cutting edge command positions (Pn, Pn + 1, Pn + 2...).
Is determined to be included in the shape correction range set and stored in the shape correction range setting / storage unit 12, and the shape correction amount is determined only when the cutting edge command position is included in the shape correction range. A gate block is performed using the AND gate 14 so as to be extracted from the shape correction amount calculation unit 11 to the addition unit 3.
The adder 3 is configured to control the respective cutting edge command positions (Pn, Pn +
1, Pn + 2...) And the respective shape correction amounts (Dn, Dn +
1, Dn + 2,...) Are vector-added, and the blade command position (Pn ′, Pn + 1 ′, Pn + 2 ′,...) After shape correction.
・) Is obtained, and the obtained edge-corrected cutting edge command position (P
.. n), Pn + 1 ', Pn + 2'...) are sent to the feed shaft motor drive unit 4 as command position outputs.

An example of the operation of the above-described first embodiment will be supplementarily described with reference to the flowchart of FIG. 2 and the following equations. The machining site reference point Pa and the correction reference point Pb are stored as coordinates on the X, Y, and Z axes, such as Equations 1 and 2, and the coordinates of both reference points are read from the respective setting / storage units. By substituting into Equation 3, the distance (| Pb−Pa) from the machining portion reference point Pa to the correction reference point Pb
|) Is calculated (steps S1 and S2).

(Equation 1)

(Equation 2)

(Equation 3)

Next, the machining program is analyzed (step S3) and the end of the program is determined (step S3).
4) If the program ends, all processing ends,
If not, the process proceeds to step S5. Further, the path to the target value commanded by the machining program is sequentially interpolated and calculated, and the cutting edge command position (P
n, Pn + 1, Pn + 2...) (Step S)
5).

Here, each of the cutting edge command positions (Pn, Pn +
It is determined whether or not (1, Pn + 2...) Is included in the preset shape correction range (step S6). If it is included in the shape correction range, each cutting edge command position (Pn, Pn + 1) is calculated according to Equation 4. , Pn + 2...) To the correction reference point P
The distance to b is calculated (step S7).

(Equation 4)

Further, the inverse ratio Kn of each distance obtained according to | Pb−Pa | of Equation 3 and Equation 4 is calculated by Equation 5 and is multiplied by the shape correction reference amount Da as in Equation 6 to obtain the shape. The correction amounts (Dn, Dn + 1, Dn + 2...) Are calculated (step S8), and the obtained shape correction amounts (Dn, Dn) are calculated.
n + 1, Dn + 2...) are vector-distributed to components in the respective feed axis directions according to Equations 7, 8, and 9 (Step S).
9).

(Equation 5)

(Equation 6)

(Equation 7)

(Equation 8)

(Equation 9)

Next, each of the cutting edge command positions (Pn, Pn + 1, P
The shape-corrected coordinate values (dXn, dYn,
dZn) are added as shown in Expressions 10 and 11, respectively, so that the shape-corrected cutting edge command positions (Pn ′, Pn +
1 ′, Pn + 2 ′...) (Step S1)
0).

(Equation 10)

[Equation 11]

If it is determined in step S6 that each of the commanded edge positions is not included in the shape correction range, each of the commanded edge positions (Pn, Pn + 1, Pn + 2) is determined.
..) Are corrected for each blade edge command position (Pn ′, Pn).
+1 ', Pn + 2'...) (Step S11)
Send it out as is. After these, the calculated blade-edge command positions after shape correction (Pn ′, Pn + 1 ′, Pn + 2 ′...)
) Is used as the command position output to control the position of the feed axis (step S12), and it is determined whether or not the block is completed (step S13). If the block is not completed, the process returns to step S5 to return to step S5 described above. Steps S12 to S12 are repeated, and if one block has been completed, the process returns to step S3.

FIG. 3 is a view showing the relationship between the command position of each point in the numerical control machine tool for shape processing according to the present invention. First, the machining site reference point P of the part where the clearance is to be changed
a, the shape correction reference amount Da at the processing portion reference point Pa,
In addition, a correction reference point Pb for specifying the shape correction direction of the processing portion reference point is preset by the operator.
Next, machining trajectories created based on the machining program data are sequentially calculated, and Pn, Pn + 1, Pn + 2,.
・ The cutting edge command position that changes is determined. Subsequently, the current shape correction direction and the correction amount (Dn, Dn + 1, Dn + 2,...) Are sequentially calculated from the distance and direction from these cutting edge command positions (Pn, Pn + 1, Pn + 2,...) To the correction reference point Pb. Further, the feed axis shape correction coordinate values vector-distributed in each axis direction are calculated and added to the coordinate values for each feed axis of these cutting edge command positions (Pn, Pn + 1, Pn + 2...). , The cutting edge command positions after the shape correction (Pn ′, Pn + 1 ′, Pn + 2 ′...) Are obtained. By controlling the position of the thus-corrected cutting edge command position (Pn ′, Pn + 1 ′, Pn + 2 ′...) As a command position output, the processing is performed simultaneously with the correction of the shape of the specified processing portion.

FIG. 4 is a block diagram showing a second embodiment of the present invention. Hereinafter, portions different from the block diagram showing the first embodiment of FIG. 1 will be described.

The cutting edge command positions (Pn, Pn + 1, Pn + 2,...) Output from the command position calculating unit 2 are sent directly to the feed shaft motor driving unit 4 as command position outputs. Subtraction unit 1 is added to the position feedback part from position detector 6 for detecting the current position of the feed axis.
5 are provided. The subtraction unit 15 performs vector subtraction of the shape correction amounts (Dn, Dn + 1, Dn + 2,...) Calculated by the shape correction amount calculation unit 11 from the current position of the feed axis, and obtains the obtained feed axis correction position. The position is fed back to the motor drive unit 4. With the configuration described above, an effect equivalent to that of the first embodiment can be obtained.

[0021]

As described above, in the numerical control machine tool for shape processing according to the present invention, by directly using the machining program data in which a certain clearance is secured, the portion for which the clearance is to be changed is designated, so that the designated machining site It is possible to process while correcting the shape of. This allows a CAD device or C
There is no need to re-create the machining program data using the AM device, and the process is significantly shortened. In addition to shortening the lead time when creating the mold, the process of re-creating the machining program data can be omitted. The effect of contributing to a significant reduction in the production cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a numerically controlled machine tool for shape processing according to the present invention.

FIG. 2 is a flowchart showing an operation example of the first embodiment of the numerical control machine tool for shape machining of the present invention.

FIG. 3 is a schematic diagram showing a relationship between each point and a command position in the numerical control machine tool for shape processing of the present invention.

FIG. 4 is a block diagram showing a second embodiment of a numerically controlled machine tool for shape processing according to the present invention.

FIG. 5 is a block diagram showing an example of a control device in a conventional numerical control machine tool for shape processing.

[Explanation of symbols]

 1 Program analysis unit 2 Command position calculation unit 3 Addition unit 4 Feed axis motor drive unit 5 Feed axis motor 6 Position detector 7 Correction reference point designation / storage unit 8 Processing part reference point designation / storage unit 9 Shape correction reference amount setting / Storage unit 10 Correction direction calculation unit 11 Shape correction amount calculation unit 12 Shape correction range setting / storage unit 13 Shape correction range determination unit 14 AND gate 15 Subtraction unit

Claims (3)

[Claims] 1. A shape control numerically controlled machine tool for processing an object to be processed into a free-form surface by controlling a position of a feed shaft motor based on a command position obtained by analyzing a processing program. A processing part reference point designating unit for specifying a processing part reference point for specifying a processing part for partially changing a shape, and a shape correction reference amount that is a correction amount of the free-form surface shape at the processing part reference point is set. Shape correction reference amount setting means, a correction reference point specifying means for specifying a correction reference point for specifying a shape correction direction at the processing portion reference point, a cutting edge command position of a tool currently used, and the correction reference point. Correction direction calculating means for obtaining a shape correction direction at each cutting edge command position from the distance from each cutting edge command position to the correction reference point, and the correction base Shape correction amount calculating means for calculating a shape correction amount at each cutting edge command position from the shape correction reference amount based on a distance to a reference point, and obtaining the obtained shape correction amount at the shape at each cutting edge command position. The command position output is obtained by adding the shape correction coordinate value for each feed axis at each cutting edge command position calculated by vector distribution from the correction direction to each feed axis direction to the command coordinate value for each feed axis at each cutting edge command position. A numerical control machine tool for shape machining, wherein position control of a feed shaft motor is performed based on an obtained command position output and a current feed shaft position fed back. 2. The cutting edge command position of the currently used tool is directly output as the command position output, and each of the cutting edge command positions is obtained from the obtained command position output and the coordinate value of the current feed axis position fed back. The numerical control machine tool for shape machining according to claim 1, wherein the position control of the feed shaft motor is performed based on the feed axis correction position obtained by subtracting the shape correction coordinate value for each feed axis in (1). 3. A shape correction range setting means for setting a shape correction range for limiting a portion to be processed for shape correction, wherein a command point of a cutting edge of a currently used tool is included in the shape correction range. 3. The numerical control machine tool for shape machining according to claim 1, wherein it is determined whether or not the position control is performed, and the position control of the feed shaft motor using the shape correction amount is performed only when it is included.