JP2000296452A - Flaw removal method for steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent useless chamfer states from being formed in edges by changing over the grinding depth control from presser force control or grinding power load control to grinding wheel position fixing control in grinding the edges. SOLUTION: A grinding wheel 51 is rotated from this side before a grinding start point (a) and moved along the X axis to the grinding start position (a). When the grinding wheel 51 reaches the grinding start position (a), the grinding wheel 51 is lowered, and when it reaches the grinding depth position (b), it is moved and ground along the X axis to an edge position (c). During moving from the point (b) to the point (c), the grinding wheel is controlled by the presser force control toward the thick board T to the grinding power load control. When the grinding wheel 51 approaches near the edge position (c) and an edge detector 61 detects the output change, the grinding wheel 51 is changed over from the presser force control or the grinding power load control to the grinding position fixing control so as to control the Z-axial position of the grinding wheel 51, thereby holding a prescribed position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing flaws on a steel sheet, for example, by automatically taking care of flaws dispersed on the surface of the steel sheet.

[0002]

2. Description of the Related Art For example, Japanese Unexamined Patent Publication No. 9-155715 discloses an image processing apparatus mounted on a traveling vehicle for searching for a flaw mark described in a flaw portion of a steel plate, and guiding the traveling vehicle to a grinding device mounted thereon. 2. Description of the Related Art A self-propelled flaw removing device that automatically cleans a surface flaw of a steel sheet is disclosed. The control of the grinding amount by the apparatus controls the pressing force of a mechanism for pressing the grindstone of the grinder against the surface of the thick plate.

The mechanism for pressing the grindstone of the grinder against the surface of the thick plate is a highly rigid one such as a linear guide using a ball screw. The height of the grindstone is controlled by a servomotor or the like while the height position in the vertical direction is controlled. Pressed perpendicular to the surface. The vertical position of the grindstone is controlled so that the pressing force is always constant. During the grinding, the pressing force or a grinder load current or the like correlated with the pressing force is measured, and these values are fed back to the grinding wheel height position control servo mechanism.

[0004]

In the above-mentioned conventional thick plate flaw removing apparatus, at the plate edge portion, a feedback of a value obtained by measuring the pressing force or a grinder load current correlated with the pressing force during grinding is provided. The control system of the grinding wheel height position control servo mechanism cannot cope with this sudden change, and an unnecessary chamfering state of the plate edge occurs, so that there is room for improvement.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a method for removing flaws on a steel sheet in which an unnecessary chamfering state does not occur at an edge portion.

[0006]

SUMMARY OF THE INVENTION A method for removing flaws on a steel sheet according to the present invention is a method for removing flaws dispersed and present on the surface of a steel sheet by a grinding device mounted on a self-propelled flaw removal device. In the case of grinding, by switching the grinding amount control from pressing force control or grinding power load control to grinding wheel position fixing control and performing grinding, the apparent pressing force or grinding power load increases, so that over-cutting with edges chamfered can occur. It can be prevented from occurring.

[0007] In addition, when a grinder mounted on a self-propelled flaw removing device cares for flaws dispersed and present on the surface of a steel sheet, in the case of edge-to-edge grinding, the output difference of the displacement meter due to the step of the plate edge is increased. By switching the grinding amount control from the pressing force control or the grinding power load control to the grinding wheel position fixing control based on the above, the accuracy of the switching can be improved and malfunction can be prevented from occurring.

[0008] In addition, when the flaws dispersed and present on the surface of the steel sheet are cared for by a grinding device mounted on a self-propelled flaw removing device, in the case of edge-to-edge grinding, the grindstone moves in a direction from the steel sheet toward the edge. By grinding only when moving
The grindstone can be prevented from impacting against the edge of the thick plate, and the edge can be prevented from being excessively ground in a chamfered state.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a side view showing an embodiment of the present invention. The removal of the scattered flaws dispersed and present on the surface of the thick plate T and the linear flaws that are generated in a long straight line, or the grinding by the grinder for performing the care of a large area is applied to the edge portion, the grindstone 51 is set in advance. It is rotated from the position in the X-axis direction before the point a of the grinding start position determined by the grinding operation plan, and is moved along the X-axis to the point a of the grinding start position. In addition, the movement in the Z-axis direction is performed when the grindstone 51 is just moved to the X-axis grinding start position a.
When reaching the point, the grindstone 51 is lowered so as to contact the thick plate T surface. The grindstone 51 is gradually lowered from that position, and when the point b at the predetermined grinding depth position is reached, the grindstone 51 is moved along the X axis up to a point c at the edge position at a predetermined speed to perform grinding. Do.

While moving from point b to point c, the grindstone 51 is controlled so as to obtain a desired grinding depth by controlling the pressing force against the thick plate T or controlling the grinding power load.

The edge position c at which the grinding wheel 51 finishes grinding
When reaching the point, the edge detector 61 provided so as to detect the edge in a vertical direction at a predetermined distance from the center of the grindstone 51 reaches the point c of the edge position, and the edge detector 61 changes its output. When detected, the grinding depth control of the grindstone 51 is switched from the pressing force control or the grinding power load control to the grindstone position fixing control, and the Z-axis direction position of the grindstone 51 is controlled so as to maintain a constant position.

As the edge detector 61, a laser displacement meter is used. During grinding, the whetstone 51 is at a predetermined distance from the edge c of the thick plate T and reaches one edge detector 6 which has reached the edge c position.
1 and the difference between the output from the other edge detector 61 are taken in as a control amount.

The grinding wheel 51 employs a flat wheel-shaped flap wheel grinding wheel. The flap wheel is a grindstone made by bundling a number of pieces of abrasive cloth with abrasive grains attached radially.
By changing the abrasive grain density and the number of polishing cloths at the edge portion and the central portion of the grinding wheel, it is possible to change the grinding ability in the width direction of the grinding wheel. That is, it is possible to weaken the grinding ability at the corners of the grinding wheel and perform the edge grinding in the width direction of the grinding wheel. The grinding wheel 51 and a high-frequency motor whose grinding wheel rotation speed does not decrease even during grinding within the allowable grinding load range.

FIG. 4 shows a grinding mechanism provided with the grinding wheel 51.
It is mounted on a self-propelled flaw removing device shown in (a) and (b). This self-propelled flaw removing device 1 has two front wheels 1
a, a traveling vehicle 2 having two rear wheels 1b, a front CCD camera 3 for taking an image of the shape of the plate-like material and an image on the plate-like material in the traveling direction of the traveling vehicle 2, and a flaw marked on the steel plate The CCD camera 4 for grasping the width of the mark for grasping the width of the mark, the rear CCD camera 5 for taking an image on the steel plate behind the traveling direction of the traveling vehicle 2, and the CCD cameras 3, 4 and 5 Image processing is performed on the received image, and based on the information, the traveling vehicle 2 is instructed on the next position to be moved, the posture of the traveling vehicle 2 is controlled,
A control device 6 for instructing a grinding device mounted on the traveling carriage 2 with grinding conditions at the flaw mark position, a flaw grinding grinder 7 constituting the grinding device, and a grinder pressing mechanism for pressing the grinder 7 against the surface of the steel plate. 8
And an X-axis linear guide 9 for moving the grinder 7 horizontally on the traveling vehicle 2 in the width direction of the traveling vehicle, and for moving the grinder 7 vertically on the traveling vehicle 2 in a direction orthogonal to the traveling direction. Z-axis linear guide 10
And illumination 11. FIG. 4 (a)
Reference numeral 12 in FIG. 4B denotes a power supply device.

Z for moving the grindstone 51 in the thickness direction of the thick plate T
The shaft linear guide 10 has a high rigidity like a linear guide using a ball screw. The vertical position of the shaft is controlled by a servomotor or the like, and the vertical position of the shaft linear guide 10 is perpendicular to the surface of the thick plate T by the grinder pressing mechanism 8. Pressed. The vertical position of the grindstone 51 is controlled so that the pressing force is always constant. During the grinding, the pressing force or the load current or the like correlated with the pressing force is measured, and the grindstone 5 is measured.
These values are fed back to the 1 height position control servo mechanism. Thus, even if the grindstone diameter decreases during grinding, the grindstone pressing force is always kept constant while correcting the decrease.

In the self-propelled flaw removing device 1 described above, the traveling vehicle 2 is composed of two front wheels 1a or two rear wheels 1b.
180 around the direction orthogonal to the line connecting the centers
The steering angle can be set to be the same over a range of degrees (90 degrees to the right and 90 degrees to the left in the longitudinal direction of the plate), and the steering angle of the front wheel 1a and the steering angle of the rear wheel 1b are mutually different. It can be changed freely without interference.

Therefore, as shown in FIG. 5 (a), when the steering angles of the front wheels 1a and the rear wheels 1b are the same, the direction of the steering angle (all directions) is maintained without changing the attitude of the traveling vehicle 2. The traveling carriage 2 can be moved (omnidirectional movement mode).

As shown in FIG. 5B, the steering angle of the front wheels 1a is inclined with respect to the straight traveling direction of the traveling vehicle 2 (the longitudinal direction of the vehicles 2), and the steering angle of the rear wheels 1b is adjusted. When the vehicle is in the straight traveling direction of the traveling vehicle 2, the traveling vehicle 2 can change its attitude toward the steering angle direction of the front wheels 1a (vehicle mode).

As shown in FIG. 5C, the steering angle of the front wheels 1a is inclined rightward with respect to the straight traveling direction of the traveling vehicle 2 (longitudinal direction of the vehicles 2), and the steering of the rear wheels 1b is performed. When the corner is inclined to the left with respect to the straight traveling direction of the traveling vehicle 2, the traveling vehicle 2 can turn with a constant radius (minimum turning radius mode).

As shown in FIG. 5 (d), the steering angles of the front wheels 1a and the rear wheels 1b are set in a direction orthogonal to the straight traveling direction of the traveling vehicle 2 (the longitudinal direction of the vehicle 2).
When the rotation direction of the front wheels 1a and the rear wheels 1b is the same, the traveling vehicle 2 can be moved right beside without changing the attitude of the traveling vehicle 2 (direct lateral movement mode).

Further, as shown in FIG. 5 (e), the steering angles of the front wheel 1a and the rear wheel 1b are set in the direction of the inscribed circle, and the rotation directions of the front wheel 1a and the rear wheel 1b are set in the same direction. , The front wheel 1a and the rear wheel 1b can be rotated along the inscribed circle, and the traveling trolley 2 can adjust the trolley attitude to a few degrees without changing its position.
It can be arbitrarily changed on the spot, such as 0 degree inversion.
(In-situ rotation mode).

Embodiment 2 FIG. In the first embodiment, when the output change is detected by the edge detector 61, the grinding depth control of the grinding wheel 51 is switched from the pressing force control or the grinding power load control to the grinding wheel position fixing control to maintain a constant position. Thus, the position of the grinding wheel 51 in the Z-axis direction is controlled. By the grindstone 51 controlled in this way, the grinding and maintenance of the range N of the right side edge portion of the thick plate T shown in FIG. 2A is performed when the grindstone 51 moves from the steel plate T toward the edge c. Grinding only.

That is, the grinding depth control is switched from the pressing force control on the steel plate T or the grinding power load control to the grinding wheel position fixing control by the output change of the edge detector 61, and the grinding wheel 51 to be ground moves in the width direction of the plate. When the carriage 2 is disengaged from the edge c, the traveling carriage 2 is moved by a predetermined pitch in the longitudinal direction of the thick plate T, and the grindstone 51 is raised to return to a predetermined position on the right side at a height at which the thick plate T is not ground. . As a result, the grindstone 51 can be prevented from impacting the edge c of the thick plate T by impact, and the edge can be prevented from being excessively ground into a chamfered state.

When the grinding range N of the thick plate T shown in FIG. 2B does not extend to the edge, the grinding is performed by controlling the grinding depth of the grindstone 51 by pressing force control or grinding power load control in the width direction of the thick plate T. Reciprocating grinding.

In the case of grinding the area N of the right side edge portion in the longitudinal direction of the thick plate T shown in FIG.
When the grinding wheel 51 to be ground is moved from the pressing force control or the grinding power load control to the grinding wheel position fixing control by the output change of the edge detector 61 and moves off in the width direction of the plate and is separated from the edge c, the traveling carriage 2 becomes thick. One-way grinding is performed in which the grinding wheel 51 is moved up to a predetermined pitch in the longitudinal direction of the plate T to return to a predetermined position on the left side at a height that does not grind the thick plate T.

When the grinding range N does not cover the edge, the grinding is performed by reciprocating grinding while moving the grindstone 51 by the traveling carriage 2 in the longitudinal direction of the thick plate T by a predetermined length as shown in FIG.
The maintenance may be performed in which the X-axis linear guide 9 feeds the pitch in the width direction of the thick plate T.

[0027]

As described above, according to the present invention, the edge can be prevented from being excessively ground in a chamfered state, and the edge portion can be reliably maintained, and the commercial value can be improved.
Furthermore, the life of the grinding wheel can be extended, and productivity and economy can be improved.

[Brief description of the drawings]

FIG. 1 is a side view showing Embodiment 1 of the present invention.

FIG. 2 is an explanatory view showing Embodiment 2 of the present invention.

FIG. 3 is an explanatory diagram showing another embodiment of the second embodiment of the present invention.

4A and 4B are a front perspective view as viewed from the front and a rear perspective view as viewed from the rear, respectively, showing the self-propelled flaw removing device according to the present invention.

FIG. 5 is a plan view showing an operation mode of the self-propelled flaw removing device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Self-propelled flaw removal device 1a Front wheel 1b Rear wheel 2 Traveling trolley 3 Front CCD camera 4 CCD camera for grasping flaw mark width 5 CCD camera for back confirmation 6 Control device 7 Grinder for flaw grinding 8 Grinder pressing mechanism 9 X axis Linear guide 10 Z-axis linear guide 11 Lighting 12 Power supply device 51 Grinding stone 61 Edge detector T Thick plate

Continuation of the front page (71) Applicant 000004123 Nippon Kokan Co., Ltd. 1-2-1, Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Hiroyuki Hayashi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Yoshinori Anabuki 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Prefecture Kawasaki Steel Corporation Mizushima Steel Works, Ltd. Inventor Satoshi Deguchi 4-33 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture F-term in Sumitomo Metal Industries, Ltd. 3C058 AA03 AA09 AA11 AA12 AA13 AA16 AC01 AC02 BA07 BA09 BB02 BC02 CA01 CB02 CB03 CB05

Claims (3)

[Claims] When a flaw distributed and present on the surface of a steel sheet is cared for by a grinder mounted on a self-propelled flaw removing device, in the case of edge-to-edge grinding, the grinding amount control is controlled by pressing force control or grinding power. A method for removing flaws on a steel sheet, comprising switching from load control to grinding wheel position fixing control for grinding. 2. When the grinding device mounted on a self-propelled flaw removing device cares for flaws dispersed and present on the surface of a steel sheet, in the case of edge-to-edge grinding, the output difference of the displacement meter due to the step of the plate edge. A method for removing scratches on a steel sheet, wherein the grinding amount control is switched from the pressing force control or the grinding power load control to the grinding wheel position fixing control on the basis of the above. 3. When a grinder mounted on a self-propelled flaw remover cares for flaws dispersed and present on the surface of a steel sheet, in the case of edge-to-edge grinding, the whetstone moves in a direction from the steel sheet toward the edge. A method for removing scratches on a steel sheet, characterized in that grinding is performed only when moving.