JPH04100676A - Device and method for profile gas cutting - Google Patents

Abstract

PURPOSE:To perform profile cutting with high accuracy and to improve cutting efficiency by carrying out automatic follow-up by cutting sequence so as to hold the butting torch tip at the specified distance from the work cutting surface while a cutting torch always being turned toward the normal direction of the work cutting surface. CONSTITUTION:X, Y and Z axes actuators 8, 9 and 11 to move the torch 18 along X, Y and Z axes, a theta axis actuator 14 to turn the torch 18 with a vertical thetaaxis as a center and an A axis actuator 15 to move the torch 18 along an A axis in the normal direction of the work cutting surface are provided with a height sensor S3, for detecting the work 1 height and two cutting surface sensors for detecting the distance between the torch 18 and the work cutting surface. A controller CPU controls operations of the X and Y axes actuators 8 and 9 so as to move the torch 18 by profiling an X-Y program locus stored in advance and controls the Z axis actuator 11 according to a detection signal of the height sensor S3 and controls the theta axis and A axis actuators 14 and 15 by the two cutting surface sensors.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a profiling gas cutting apparatus and method.

BACKGROUND OF THE INVENTION For example, a box-shaped cross-sectional member curved in the longitudinal direction used as a side beam of a bogie frame of a railway vehicle has an upper surface and side surfaces, is open at the bottom, and has two mouth-shaped cross-sectional members that are curved in plan view.
It can be constructed by assembling the sides and welding their open ends together, or by welding a flat plate to the open end of a bipedal cross-sectional member.

The above-mentioned mouth-shaped cross-sectional member is generally constructed by cutting a plate into a generally developed shape, hot-pressing it to form a mouth-shaped cross-section, and then cutting the lower end of the side surface to a constant height.

Items molded by hot pressing as described above are
As the mold heats up and expands during continuous processing, there is a difference between press-formed products processed before the mold temperature has risen significantly and press-formed products processed after the mold temperature has risen. Widths, lengths, etc. are slightly different, and some degree of variation in dimensional accuracy cannot be avoided.

The following three methods are currently in use for cutting the lower end of the side of a press-molded product such as a biped to a constant height.

That is, the first method is to cut along the marked line, and the second method is to install a copying jig with the same shape as the surface to be cut, that is, the side surface of the mouth-shaped cross-sectional member, along the workpiece. This is a method of cutting by running a cutting torch unit following a jig.
The third method is an NG cutting method using teaching.

Problems to be Solved by the Invention The first method of the above-mentioned conventional cutting methods requires slicing work, centering work after setting it on the machine, and furthermore, it is difficult to cut curved parts. There are problems in that accurate cutting cannot be performed unless the operator is a skilled worker, such as having to feed it by hand.

The second method has the problem that it is time-consuming because the copying jig must be set every time the workpiece is changed, and that cutting of curved parts is limited by the torch unit.

The method shown in Figure 3 involves inputting a predetermined cutting point into the control device with a teaching point using a contact sensor while the workpiece is set, and detecting a curve by tracing the curved surface of the workpiece using two contact sensors. The height is also input to the control device using a contact sensor, and the torch moves based on the external shape information of the actual workpiece that is input to the control device to perform the prescribed cutting. .

This method is not only troublesome as it requires accurate centering when setting and setting the workpiece, but also, if the dimensional accuracy of the workpiece varies as mentioned above, each time the workpiece is set, the actual centering must be performed accurately. It is inefficient as it is necessary to re-enter information about the workpiece outline.

Furthermore, since a contact sensor is used, the detection accuracy is relatively low, there is a limit to the minimum detectable radius of the curved surface, and the cutting speed is also limited.

The main purpose of the present invention is to address the problems of the conventional cutting methods as described above.

Means for Solving the Problems In the present invention, a workpiece consisting of a mouth-shaped cross-sectional member curved in the elongated direction is placed at a set position located at the coordinates of vertical X, horizontal Y, and height 2, and a cutting torch is used to cut the workpiece into the shape. In a device that cuts the lower end of a workpiece to a set height, a similar figure larger than the planar projection figure of the workpiece is input in advance as an X-Y program locus into the memory of the control device by off-line teaching from drawing information. During cutting, the cutting torch moves according to the X-Y program trajectory, and uses a height sensor such as a non-contact sensor such as a laser sensor, and a cutting surface sensor to check the setting position of the workpiece and the dimensional accuracy of the workpiece. Detects the amount of relative change in the height of the workpiece and the cut surface of the workpiece with respect to the cutting torch due to variations, etc., and operates the control object that controls the height of the cutting torch, the turning angle, and the distance to the cutting surface according to the detected value information. , the cutting torch is oriented at a set height in the normal direction of the workpiece cutting surface, and the cutting torch is automatically tracked according to the cutting sequence while keeping the tip of the cutting torch at a constant distance from the workpiece cutting surface to cut the workpiece.

As a result of the above, there is no need to teach the external shape of the actual workpiece, and even if the set position is slightly different from the workpiece or there are variations in the dimensional accuracy of the workpiece, the cutting torch can be cut while always pointing in the normal direction of the cut surface of the workpiece. The cutting sequence automatically follows the torch tip to keep it at a constant distance from the workpiece cutting surface, allowing highly accurate cutting and improving cutting efficiency.

Example Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 3 show specific details of the cutting device according to the present invention.
FIG. 3 is a diagram showing an example, and ``■'' is a workpiece molded into a mouth-shaped cross-sectional member that has an upper surface and side surfaces, is open at the bottom, and is curved in plan view.

The workpiece 1 is transported by a conveying means 2 such as a roller conveyor to two lift cylinders 3, 3 at the front and rear provided at the bottom of the cutting device.
The workpiece 1 is transported upward, and after three points of the workpiece 1 are applied to the stoppers 4, 4', and 4'', the workpiece 1 is stopped, and the lift cylinders 3, 3 are extended to raise the workpiece 1 to a predetermined height.

The line xx connecting the centers of the top surfaces 3a, 3a of the front and rear lift cylinders 3, 3 is the X coordinate, and the line Y-Y perpendicular to the center of XX is the Y coordinate. Determine the reference coordinates.

- Of the stoppers 4 and 4', the center part of the widthwise dimension of the workpiece 1 almost coincides with the X-X line, and 4'' is the top surface 3a of the lift cylinder at the longitudinal end of the workpiece 1, 3
Adjust in advance so that the protrusion lengths from a to the front and back are approximately equal. In addition, the lift cylinders 3, 3 are
During conveyance of the work, the top surfaces 3a, 3a are located slightly below the upper surface of the conveyance means 2 of the roller conveyor.

5.5' is an X-axis guide rail arranged parallel to the X-X line, and running plates h6 and 6' fixed to the transverse frame 7 parallel to the Y-Y line are the X-axis guide rails. 5 and 5', respectively, and movement in the X-axis direction is controlled by an X-axis actuator 8.

The X-axis actuator 8 includes a rack 8a provided on the side of one X-axis guide rail 5 and one running frame 6.
A pinion (
(not shown) and an X-axis servo motor 8b that rotationally drives the binion.

A Y-axis actuator 9 is attached to the transverse frame 7.

The Y-axis actuator 9 includes a cylindrical member 9a incorporating therein a ball screw (not shown) and a slide part (not shown) that slides in the Y-axis direction by rotation of the ball screw, and an end portion of the cylindrical member 9a. The Y-axis servo motor 9b is attached to the Y-axis servo motor 9b and rotates the ball screw.
The Y-axis direction movement of the Y-axis gear ridge 10 coupled to the slide component is controlled by driving the axis servo motor 9b.

Reference numeral 11 denotes a Z-axis actuator that controls movement in the upward direction, that is, in the Z-axis direction. Like the Y-axis actuator 9, the Z-axis actuator 11 has a ball screw inside and a movement relative to the ball screw by rotation of the ball screw. A cylindrical member 11a incorporating a slide part that slides in the axial direction, and a Z-axis servo motor llb attached to the upper end of the cylindrical member 11a to rotationally drive the ball screw, and connected to the slide part. The Z-axis gear ridge 12 that has been
The cylindrical member 11a is connected to the shaft gear ridge 10 by a coupling fitting, and is configured to move in the Z-axis direction together with the Z-axis servo motor llb when driven by the Z-axis servo motor 11b.

A θ-axis actuator 14 is attached to the lower end of the cylindrical member 11a of the Z-axis actuator 11, which rotates around the θ-axis that coincides with the centerline of the cylindrical member 11a.

The θ-axis actuator 14 includes a swing bed 14a and a θ-axis servo motor 14b that rotationally drives the swing bed 14a via a boot and a timing belt.

On the fixed base 11c fixed to the lower end of the cylindrical member 11a of the two-axis actuator 11, four swing bearings 13 having stepped grooves on the outer peripheral surface are rotatably installed. A swing bed 14a having a V-shaped protrusion formed on its outer circumferential surface that fits into the shaft is fitted and supported by four swing bearings 3 so that it can rotate around the θ-axis, and is attached to a fixed base 11c and rotated by a θ-axis servo motor 14b. By hanging the timing belt 14e between the pulley 14c fixed to the center of the swing bearing 14a, the θ-axis servo motor 14b
The swing angle θ of the swing bearing 14a about the θ axis can be controlled by driving the swing bearing 14a.

A cylindrical member 15a is disposed horizontally on the lower surface of the swing bearing 14a and incorporates a pole screw therein and a slide component that slides by rotation of the pole screw;
An A-axis actuator 15 consisting of an A-axis servo motor 15b that rotationally drives the pole screw is attached, and the A-axis gear ridge 16 connected to the slide component by rotation of the A-axis servo motor 15b is parallel to the center line of the cylindrical member 14a. It is configured to move in the A-axis direction.

A bracket 17 is fixed to the A-axis gear ridge 16, and a cutting torch 18 (hereinafter simply referred to as a torch) and a non-contact sensor s, such as a laser sensor, are attached to the bracket 17.
, s2. and S3 are installed.

It is assumed that the A-axis and the center line of the torch 18 are in the same vertical plane, and S1 and S2 are located on both sides of the torch 18, and as shown in FIG. Detect the distances H, , H2 of the points, and calculate the detected distance H
1, H2 information is input to the control device CPU, S3 faces the top surface of the workpiece 1, detects the height H3, and inputs the information to the control device CPU.
This is what you input.

The torch 18 is a plasma torch (however, any conventionally known torch can be used), its plasma gas power supply 19 and each servo motor 8b, 9b, llb, 1
The servo controller drivers 20 and the like of 4b and 15b are appropriately attached to the transverse frame 7, and the control device CPU is also attached to the transverse frame 7.

Next, control when actually cutting the workpiece I with the cutting device will be explained.

First, a similar figure slightly larger than the planar projection figure of the workpiece 1 is stored in advance in the memory of the control device CPU as an XY program locus.

The figure of this X-Y program locus is a figure that is thicker by 6 dimensions from the side of the workpiece 1 to the center of the Z-θ axis, and is made using a conventionally known CAD (computer-aid
Program points can be easily set using an automatic drawing machine such as ED Design.

Workpiece 1 is actually transported, and the stroke, pass 4゜4',
4'' and set upward by the lift cylinder 3.3, the x-
The width direction dimensions e and e of the workpiece 10 are equal to the X-ray, and Y
-Longitudinal dimension of workpiece 1 relative to Y line/2, l/
2 is in the ideal set position where
-Y program trajectory is located exactly 6 dimensions outside from the side of workpiece l, and detection signal H3 of non-contact sensor S3
The cutting height is set by operating the Z-vehicle actuator 11 based on the above, and the X-axis actuator 8 is operated so that the Z-θ axis center follows the X-Y program trajectory. The Y-axis actuator 9 performs X-Y axis control, and the non-contact sensor 31.
By controlling the turning angle θ with the θ-axis actuator 14 so that Hl - H2 = 0 based on the detection signals H1 and H2 of S7, the torch 18 is always directed in the normal direction to the cutting surface (workpiece side surface). , the purpose can be achieved.

However, as mentioned above, the work l is formed by hot press pressure, and there are variations in the method, and the stopper 4
, 4', 4'' is difficult to completely regulate the position, so the workpiece 1 is not set at the ideal position with respect to the X-Y program trajectory on the memory of the control device CPU, as shown in Fig. 5. The workpiece 1 is often placed offset from the X-Y program trajectory.

Therefore, even if workpiece 1 deviates from the ideal position, at least
-The setting position shall be regulated by the stoppers 4, 4', and 4'' to the extent that there is no chance of the setting position exceeding the -Y program trajectory.

Then, the 2-θ axis center moves along the X-Y program trajectory, and while moving, the non-contact sensors S1 and S2 detect the distances H1 and H2 to the side of the workpiece, and based on the detection signals, the control device CPU The shaft actuator 15 is operated to perform corrections of ±a (the direction approaching the workpiece is +, the direction away from the workpiece is -), and the distance Δd between the tip of the torch 18 and the side surface of the workpiece is always kept at an appropriate value. Cutting is performed in accordance with speed information such as a preset feed rate of 1 curve section constant speed control.

The cutting sequence will be explained below with reference to FIG.

(1) Preparation for operation The torch waits at a point on the fast forward trajectory Ls.

In this case, the height is the midpoint of the Z-axis stroke.

The A-axis is retracted to the stroke limit in one direction, and the θ-axis is the angle at which the torch points toward the workpiece 1 on the Y-Y line. (3) and lowers to the specified height (specified in advance depending on the workpiece) using the search preparation 2-axis actuator.

Rotate the torch in the direction of the X-Y program trajectory using the θ-axis actuator.

Advance until the center of the Z-θ axis matches the X-Y program trajectory.

The torch is moved forward (+ side) by the A-axis actuator, and by calculating the detected value of the sensor S I + 32, the A-axis is aligned with the normal direction of the cutting surface and the interval Δ between the torch tips is adjusted.
d (for example, 5 mm), and correct it to the height H using the Z-axis actuator based on the calculation of the detected value of sensor S3.

(4), advance the search Z-θ axis center along the X-Y program trajectory,
After searching for the start end of the end face using the fail output of one of the sensors S2 (see FIG. 6(o)), the robot moves a specified distance and then stops.

(5), torch alignment Aim the torch at the starting point.

(6), Cutting torch ignition, start cutting (7), Cutting■ While moving and cutting the Z-θ axis center following the X-Y program trajectory, use the A-axis actuator to adjust the distance △d between the torch tip and the cutting surface (for example, 5 mm), and the θ-axis actuator is used to correct the condition such that Hl −H2=O, thereby controlling the torch to always point in the normal direction of the cutting surface.

(8), Termination detection■ After detecting the termination with the fail output of sensor S1, it stops upon receiving the plasma torch's arc breakage signal.

(8), Termination detection■ Move to rapid traverse trajectory LS using the Y-axis actuator.

(10), Preparing for restart, pull the A-axis actuator to the stroke limit in one direction, use the θ-axis actuator to turn the torch to a position parallel to the Y-Y line (11), fast forward on the fast forward trajectory Ls to the (11) position (Move to N slightly past the start end) (12), advance until the search preparation 2-θ axis center matches the X-Y program trajectory and stop.

Rotate the torch in the direction of the cutting surface using the θ-axis actuator,
The A-axis actuator advances the torch in the + direction, and by calculating the detection values of sensors Sl and S2, the torch is directed in the normal direction of the cutting surface and the distance Δd of the torch tip (for example, 5
Corrected to height H by calculating the detected value of sensor S3 using the Z-axis actuator.

(13), Search same as above (4) (14), Torch alignment same as above (5) (15), Cutting same as above (6) and (7) (16), End detection I above (8) Same as (17), end detection ■ Same as (9) above (18), At the end of operation, use the A-axis actuator to arch the torch in one direction, and use the θ-axis actuator to move the torch parallel to the Y-axis and facing the opposite side of the workpiece. Rotate into position.

(19), End of operation■ Return the fast-forward trajectory Ls to the origin (19), ie, (1).

Pull up to the midpoint of the stroke using the Z-axis actuator.

Cutting is performed by the above cutting sequence.

In the above embodiment, the torch 18 is attached to the bracket 17 at an angle α with respect to the horizontal line for cutting the weld groove at the lower end of the workpiece as shown in Fig. 7 (A). It is also possible to perform height cutting as shown in FIG. 7(a) by attaching the cutter to a

Furthermore, in the above embodiment, the side surface of the workpiece 1, which is the cut surface, is vertical, but the cut surface, that is, the side surface of the workpiece 1, is inclined as shown in FIG. Any shape can be cut in the same way.

In FIG. 6, (A) is an output characteristic diagram when laser sensors are used as the sensors sl and s2, and a linear output characteristic range is used for detecting the distances H1 and H2 from the side surface of the workpiece.

In addition, for detecting the cutting start and end ends of the workpiece, the fail output obtained by converting the output in [A] above as shown in (rl) is used.

FIG. 6(C) is an output characteristic diagram when a laser sensor is used as the sensor S3, and it is assumed that a linear output characteristic range is used for detecting the height H3 of the upper surface of the workpiece.

Effects of the Invention As described above, according to the present invention, a workpiece made of a mouth-shaped cross-sectional member curved in the longitudinal direction is placed at a set position positioned on x, y, and z coordinates, and the lower end of the workpiece is set. In the device that cuts to the specified height, the torch is
The X-axis actuator, Y-axis actuator, and Z-axis actuator move the torch along the vertical axis.
A θ-axis actuator that rotates the torch around the axis and an A-axis actuator that moves the torch along the A-axis in the normal direction of the cut surface of the workpiece are installed to create a similar figure that is slightly larger than the planar projection figure of the workpiece in an X-Y program. The torch is input in advance into the memory of the control device as a trajectory, and when the control device operates the X-axis actuator and Y-axis actuator, the torch moves following the X-Y program trajectory. A contact height sensor and two non-contact cutting surface sensors that detect the distance between the torch and the workpiece cutting surface are provided on the torch support member, and the control device controls the Z-axis actuator based on the detection signal from the height sensor. The control device operates the θ-axis actuator to position the torch in the normal direction of the workpiece cutting surface, and the A-axis actuator is activated based on the detection signals from the two cutting surface sensors. By operating the torch to correct the distance between the torch and the cut surface of the workpiece, various effects listed below can be obtained.

(a) The X-Y program trajectory can be taught offline from drawing information, so it can be easily created on a desk using CAD data, etc., and information on many different non-work items can be set. Compared to the conventional method in which teaching is performed by copying the actual workpiece, cutting preparation time can be significantly reduced.

(b) Cutting while automatically following the direction of the torch by operating the θ-axis actuator and correcting the distance of the torch in the normal direction to the cut surface of the workpiece by operating the A-axis actuator, based on the detection signal of the cutting surface sensor. As a result, even if there is a dimensional error in the workpiece or the workpiece setting position is slightly shifted, good cutting and height dimensional accuracy can always be obtained.In particular, the workpiece setting work is simplified and facilitated. obtain.

(C) With (a) and (b) above, it is possible to completely automate the work of bevel cutting and height cutting of a workpiece with a complicated shape curved in the direction of the pitcher's force, and it is possible to significantly improve work efficiency. It can be measured.

(d) In combination with peripheral equipment such as workpiece transport equipment, it becomes possible to introduce a side beam automatic layering system that combines a cutting system and a welding system.

[Brief explanation of drawings]

FIG. 1 is a perspective explanatory view showing an outline of the cutting device according to the present invention, FIG. 2 is a front view showing the main parts of the cutting device shown in FIG. 1, and FIG. 3 is a plan view of the torch attachment part of FIG. 2. It is a diagram. Fourth
5 and 5 are plan views showing the set state of the workpiece relative to the X-Y program locus, respectively. FIG. 4 shows an ideal set state, and FIG. 5 shows an deviated set state. Figure 6 shows the non-contact sensors s, s2 of Figures 1 to 3.
．． It is a diagram showing the output characteristics of s3, (a) is sl, s2
The output characteristics of (b) are Sl. (c) shows the fail output characteristic of S2, and (c) shows the output characteristic of S3. Figure 7 (a), shi), (c). It is a figure which each shows an example. 1... Workpiece, 3... Lift cylinder, 4°4'
, 4"...stopper, 5,5'...X-axis guide rail, 6.6'...travel frame, 7...transverse frame, 8...X-axis actuator, 9...Y Axis actuator, 11... Z-axis actuator, 14
... θ-axis actuator, 15... A-axis actuator, 18... Cutting torch, Sl, S2. S3...
Non-contact sensor, CPU...control device, L...X
-Y program trajectory, Ls... fast forward trajectory. -4′th? Figure (a) (b) (c) (two

Claims (2)

[Claims] (1) A workpiece consisting of a longitudinally curved ■-shaped cross-section member is placed at the set position located at the vertical X, horizontal Y, and height Z coordinates, and the lower end of the workpiece is set with a cutting torch. an X-axis actuator for moving the cutting torch along the X, Y, and Z axes;
A Y-axis actuator, a Z-axis actuator, a θ-axis actuator that rotates the cutting torch around the vertical θ-axis, an A-axis actuator that moves the cutting torch along the A-axis in the normal direction of the cutting surface of the workpiece, and the workpiece. Equipped with a height sensor consisting of a non-contact sensor for height detection and two cutting surface sensors consisting of non-contact sensors for detecting the distance between the cutting torch and the cut surface of the workpiece. The operation of the X-axis actuator and the Y-axis actuator is controlled to move the cutting torch following an X-Y program locus that is a similar figure that is larger than the planar projection figure of the workpiece, and cutting is performed using the detection signal of the height sensor. The Z-axis actuator is controlled to set the torch height to the set height, and the θ-axis actuator is controlled to direct the cutting torch in the normal direction of the cutting surface of the workpiece based on the detection signals of the two cutting surface sensors. 1. A profiling gas cutting device comprising: a control device that controls an A-axis actuator to correct a deviation in distance between the A-axis actuator and the workpiece cutting surface. (2) In the profiling gas cutting device of claim (1),
- Input the Y program trajectory, the operation information of the X-axis and Y-axis that operate following the program trajectory, and the sequence information of the Z-axis, θ-axis, and A-axis into the control device in advance, and cut at the time of cutting. The torch is X
-Y While operating according to the program trajectory, the height sensor and cutting surface sensor detect the workpiece set position and the amount of relative change in the workpiece height and workpiece cutting surface with respect to the cutting torch due to variations in the dimensional accuracy of the workpiece, etc., The Z-axis, θ-axis, and A-axis control targets are operated according to the detected relative change information, and the cutting torch is directed in the normal direction of the workpiece cutting surface at a set height, and the tip of the cutting torch is aligned with the workpiece cutting surface. A tracing gas cutting method characterized by cutting a workpiece by automatically tracking the workpiece according to a cutting sequence while maintaining a constant distance from the workpiece.