JPH01205956A - Nc machine tool - Google Patents

Abstract

PURPOSE:To enable the proper drive control of a machining device by operating and controlling the machining device so that interference can be avoided in the region where the device in a basic posture is judged to interfere with a workpiece. CONSTITUTION:A program giving a variable angle between a tool and a workpiece plane or, for example, 3-spindle control machining program entered from an external input machine 11 is read with a read part 12 and the basic posture of the machining device for a workpiece plane is operated with a basic operation part 13a on the basis of the shift instruction block of the machining device (spindle head). Then, an interference judgement part 14 makes judgement as to whether the machining device in a basic posture will interfere with a workpiece or not. In the region where there is a possibility of interference, an interference avoidance operation part 13b operates the direction of the machining device so that interference between the machining device and the workpiece can be avoided. On the basis of the results of the aforesaid operation, a control part 15 controls an angle between the tool and the workpiece via a servomotor 19. According to the aforesaid construction, it is possible to make the proper drive control of the machining device, while the interference is avoided automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a numerically controlled machine tool in which machining operations are controlled based on a machining program input from the outside.

[Conventional technology]

Generally, in conventional numerically controlled machine tools, the machining program input from the outside is read block by block (command information unit), and based on this, the machining equipment such as the spindle head on which the tool is attached is driven. Control is performed so that the processing device moves relative to the contour of the workpiece.

By the way, programs for controlling such machine tools include the above-mentioned fit I, such as a 3-axis control program.
There are programs that include commands for only translational movement of the device, and programs that include commands for rotational movement in addition to translational movement, such as 4@ or 5-axis control programs. If the program controls only translational movement, the tool attached to the processing device will always face in a fixed direction while the processing device is driving, while if the program controls including rotational movement, the tool attached to the device will always face the same direction while the processing device is driving. The inclination of the tool relative to the object will also change.

[Problem to be solved by the invention]

For example, when control is performed based on a three-axis control program, the tool always takes a posture facing in a fixed direction as the basic posture, as described above. Therefore, when processing a workpiece 101 as shown in FIG. 8, the workpiece 101 and the processing device 102 may interfere with each other at some of the corners shown (double-dashed line in the figure), making processing difficult. There was a point.

On the other hand, when using a 4-axis or 5-axis control program, the orientation of the processing device 102 must be set so as not to interfere with the workpiece 101, and the rotation of the processing device 102 must be controlled to match this orientation. If so, the above problems are solved. However, when attempting to control the machining device 102 including its rotation, the program inevitably becomes complicated, requiring an expensive program creation device, and increasing the number of man-hours required to create the program. There are problems that lead to the upper world. In particular, in the case of 5@ control, 10 grams becomes even more complicated, making it difficult to put it into practical use.

In view of these circumstances, the present invention provides a numerically controlled machine tool that can properly control the drive of a processing device while avoiding interference between the processing device and the workpiece based on a simple program. With the goal.

[Means to solve the problem]

The present invention provides a processing device that has a tool for processing a workpiece and is configured such that the angle between the tool and the surface of the workpiece is variable; a reading means for reading a machining program input via an external input device, and movement of the machining device during the read machining program. Based on the command block, the machine tool J3 is installed in a numerically controlled machine tool equipped with a control means for controlling the driving means so that the processing device moves by 1 pH while maintaining the basic attitude with respect to the workpiece. interference determination means for determining whether or not a processing device located in the area will interfere with a workpiece; and a calculation means for calculating an orientation of the processing device such that interference can be avoided in an area where interference is determined by the interference determination means. and the control means is configured to control the drive of the processing device in the interference determination area based on the calculation result.

[For production]

According to the above configuration, based on the read machining program, it is determined whether or not the machining device in the basic posture interferes with the workpiece, and in the interference area, the machining device that can avoid interference is determined. The orientation is calculated, and appropriate drive control of the processing device is performed based on the calculation result.

(Example) An embodiment of the present invention will be described based on the drawings.

FIG. 2 is a diagram schematically showing the numerically controlled machine tool in this embodiment. In the figure, 1 is a spindle head (processing device) for machining a workpiece 6, and this spindle head 1 has a chuck 1a to which a tool 2 such as an end mill is detachably attached. It has a built-in motor that rotates it.

This spindle head 1 and workpiece 6 are connected to a processing feeder (
The drive means is configured to move relatively in three directions by the drive vJ of >3.4.5. That is, each processing feed device 3 to 5 is equipped with one servo motor (see FIG. 1 below), and the processing feed device 3 is configured to move the workpiece 6 relative to the spindle head 1.
is moved in the X-axis direction (direction perpendicular to the plane of the paper), and the processing feed device 4.5 moves the spindle head 1 relative to the workpiece 6 in the Y-axis direction (horizontal direction in the figure) and the Z@ direction (in the left-right direction in the figure). It is configured to move in the vertical direction). As a result, the spindle head 1 moves in translation with respect to the workpiece 6.

Further, the main spindle head 1 has an A shape as shown in FIG.
It is said to be able to rotate freely around @ (axis parallel to the ) to rotate around these axes. As a result, the spindle head 1 pivots relative to the workpiece 6, and the orientation of the tool relative to the workpiece 6 changes.

FIG. 1 is a block diagram showing the functional configuration of this numerically controlled machine tool. The external input device 11 in the figure is made of, for example, a perforated tape or a 70-tube disk.
A machining program containing information necessary for machining is recorded. The reading unit 12 reads the contents of the program recorded in the external input [311] and analyzes and checks the commands.

The basic calculation unit 13a calculates a vector (i.e., a normal vector) perpendicular to the workpiece 6 at the start and end points of these movement command blocks based on the movement command blocks in the read program. , the rotation angle of the spindle head 1 is determined so that the direction of the tool 2 matches this vector. This calculation determines the attitude that the processing device takes during normal processing, that is, the basic attitude.

The interference determination section 14 determines whether the spindle head 1 taking the basic posture calculated in this way interferes with the workpiece 6 due to the movement by the movement command block.

The interference avoidance calculation section 13b calculates a vector (i.e., an interference avoidance vector) corresponding to the orientation of the spindle head 1 such that interference can be avoided in place of the normal vector in the area where interference has been determined by the interference determination section 14. ), and the corresponding rotation angle of the spindle head 1 is calculated.

The control section 15 includes a command section 16 and a positioning pulse distribution circuit 1.
7, and a servo amplifier 18, the basic calculation section 1
3a or the calculation result of the interference avoidance calculation unit 13b, the drive of each servo motor is controlled. The position and speed information of one moving body (spindle head 1 or workpiece 6) driven by each servo motor 19 is provided in section a, I11 section 15 above.
As a result, appropriate movement control is performed based on the movement command block.

Next, the operation of this numerically controlled machine tool will be explained with reference to flowcharts 1 to 4 in FIG. First, the reading section 12
As a result, the machining program recorded in the external input device 11 is sequentially read block by block, and command analysis is performed (step S1). If the read block is a movement command block for moving the spindle head 1 (YES in step 1 S2), from the two movement command blocks read in advance, the movement command block on the designated plane at the start point and end point is A normal vector (vector perpendicular to the surface of the workpiece 6) is calculated (step S3). This specified plane is a plane on which the spindle head 1 moves in translation, and in principle, the spindle head 1 is rotated around an axis perpendicular to this plane.

For example, when the specified plane is the XY plane, the spindle head 1 turns around the C axis, and when the specified plane is the YZ plane, the spindle head 1 turns around the A axis.

Next, it is determined whether or not interference will occur between the spindle head 1 and the workpiece 6 when the spindle head 1 moves in a posture that matches the normal vector, that is, in the basic posture. (Step S4).

This determination can be made based on the relationship between the shape of the workpiece and the direction of the normal vector, which is determined by pre-reading a plurality of blocks. For example, as shown in FIG. 5(a), the normal vector B1 at point B as the end point of the movement command block (A-+B), or the normal vector B1 at point B as the start point of the movement command block (B-+C). If the normal vector B2 points inward from the outline of the workpiece 6, it can be determined that there is interference. Conversely, if both normal vectors B1.182 are directed in a predetermined range outside the outline of the workpiece 6, it can be determined that there is no interference.

If it is determined that there is interference as described above, an interference avoidance vector is calculated as a vector set in place of the normal vector (step 85). In this embodiment, since the basic attitude of the spindle head 1 is set to be almost perpendicular to the workpiece 6, the valley-shaped corner as shown in FIG. 5(a) above is formed. There is a possibility that interference will occur in part B. Therefore,
In such a case, the center point P is set at an appropriate location outside the workpiece 6 as shown in FIG. A vector directed toward the center point P is calculated, and this is used as an interference avoidance vector. In other words, spindle head 1 is attached to this vector.
If the directions match, there will be no interference between the spindle head 1 and the workpiece 6.

Then, the rotation angle of the spindle head 1 is calculated based on the interference avoidance vector or the normal vector (step Se). In other words, when it is determined that there is no interference, the rotation angle of the spindle head 1 is assigned so that the tool 2 is perpendicular to the workpiece 6 at the start and end points of each block, and the interference is eliminated. If it is determined that there is, the rotation angle of the spindle head 1 is assigned so that the orientation of the tool 2 matches the interference avoidance vector.

Along with this, the amount of position correction of the tool 2 due to the rotation of the spindle head 1 is calculated (step 87). For example, if you want to move the cutting edge of the tool 2 from point to point B as shown in Figure 6, if you move the spindle head 1 as it is, the cutting edge of the tool 2 will deviate from point B due to the above rotation and point B' Therefore, a correction amount for correcting such an error is calculated. For example, if point A is the origin and the coordinates of point B are (χ1./!/1), in order for the cutting edge of tool 2 to move from point A to point B, spindle head 1 will move in the X- and Y-axis directions. I have to move ff
1X1. Yl is expressed by the following formula, where θC1 is the turning angle and L is the turning radius.

X1=χ1-Δχ Y1=/y1-Δ9 However, Δχ=LsinθC Δtri=L(1-cosθC) Δχ and Δchi in these equations correspond to the above correction amount.

Next, the commands for the translational movement amount and rotation angle of the spindle head 1 obtained as described above are assigned to each block (step S8), and the program information is edited to include these information ( Step S9). After that, each block is converted into a command in a form that allows execution commands (
Step 510), pulse signals are distributed by the positioning pulse distribution circuit 17 (step 51).
1), this signal is amplified by the servo amplifier 18 to a value corresponding to the feed speed of the spindle head 1 (step 5).
12). This signal is input to each servo motor 19, and the servo motor 19 is driven (step 513), so that the spindle head 1 moves to a predetermined position relative to the workpiece 6 (step S14). YES).

By receiving such drive control, the spindle head 1
moves in translation with respect to the workpiece 6 while maintaining a basic posture almost perpendicular to the workpiece 6 in areas where no interference occurs, and always moves in translation in the interference determination area as shown in Figure 5(b). By performing translational movement while facing the center point P, the workpiece 6 is processed while avoiding interference.

Therefore, according to this machine tool, a relatively simple program for three-axis control is used to automatically control the drive of the spindle head 1 while automatically avoiding interference between the spindle head 1 and the workpiece 6. be able to.

Moreover, if the basic attitude of the spindle head 1 is set to be perpendicular to the workpiece 6 as in this embodiment,
This has the advantage that the deflection of the tool 2 caused by being pressed against the workpiece 6 is reduced, and machining errors caused by such deflection can be reduced.

Note that the present invention does not necessarily require the basic calculation section 13a for calculating the basic posture as shown in this embodiment, and the above effects can be obtained as long as at least the interference avoidance calculation section 13b is provided.

In this way, when the basic calculation unit 13a is not provided, the orientation of the spindle head 1 and the tool 2 is not controlled during normal times,
Since these always face in one direction, for example, the seventh
Interference may occur between the spindle head 1 and the workpiece 6 even in the chevron-shaped portion B' as shown in Figure (a) (see vector A1 at point C' in the figure). ).

In this case, if the center point P' is set inside the workpiece 6 and the angle of the spindle head 1 is controlled so that it always faces this center point P', the angle of the spindle head 1 can be controlled so that it always faces the center point P'. You can go around.

Further, in the same embodiment, a case was shown in which a machine tool in which the spindle head 1 is movable about 5@ is controlled using a three-axis control program, but the present invention provides a method in which the processing device can move in translation in at least two directions on a specified plane. It can be applied to any machining tool that is movable and can rotate around an axis perpendicular to its plane.

〔Effect of the invention〕

As described above, the present invention provides an interference determining means for determining whether or not a processing device in a basic posture will interfere with a workpiece based on a movement command block for the processing device in a read processing program; and calculation means for calculating the orientation of the processing device such that interference can be avoided in the determined area, and based on the calculation result, the angle between the tool and the workpiece in the interference determination area is controlled. Therefore, it is possible to automatically control the drive of the processing device while automatically avoiding interference between the processing device and the workpiece, based on a relatively simple and low-cost program that only concerns the translational movement of the processing device. There is an effect that can be done.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the functional configuration of a numerically controlled machine tool according to an embodiment of the present invention, Fig. 2 is a schematic front view of the machine tool, and Fig. 3 is a vicinity of the spindle head connected to the machine tool. FIG. 4 is a flowchart showing the operation of the machine tool, FIG. ) is an explanatory diagram showing the actual tool inclination in the movement command block, FIG. 6 is an explanatory diagram showing the position correction procedure of the calculation performed by the machine tool, and FIG. 7 (
a) and (b) are explanatory diagrams for explaining the control of the orientation of the tool in Haku's embodiment, and FIG. 8 is an explanatory diagram showing the relationship between the tool and the workpiece in a conventional numerically controlled machine tool. 1... Spindle head (processing device), 3.4.5... Processing feed device (driving means), 6. ...Workpiece, 11.
...External input device, 12...Reading section, 13b...
Interference avoidance calculation unit (calculation means), 14... interference determination unit,
15...Control unit, 19...Nervo motor. Patent applicant Agent: Shin Nippon Koki Co., Ltd.
Patent Attorney Etsushi Kotani Patent Attorney Yasuo 1) Masayuki Patent Attorney Yasuo Itaya”fs2 Figure 4 Figure 5 (b) Figure 6 Figure 7 (a) C' (b) Figure 8

Claims (1)

[Claims] 1. A processing device that has a tool for processing a workpiece and is configured so that the angle between the tool and the surface of the workpiece is variable, and a reading means for reading a machining program input via an external input device, and a movement command block for the machining device in the read machining program. Based on the above, in a numerically controlled machine tool equipped with a control means for controlling the driving means so that the processing device moves while maintaining the basic posture with respect to the workpiece, the processing device in the basic posture is moved. A collision determining means for determining whether or not interference will occur with a workpiece; and a calculating means for calculating the orientation of the processing device such that interference can be avoided in an area where interference is determined to occur by the interference determining means. A numerically controlled machine tool, characterized in that the control means is configured to control the drive of the machining device in the interference determination area based on the results.