JPS63192583A - Laser engraving method - Google Patents

Abstract

PURPOSE:To improve the quality of an engraved image peripheral part by finding the relative travel of a machining head corresponding to a time lag at a point of time of detecting the pattern edge and then, correcting the position of a detecting head or the machining head according to the travel. CONSTITUTION:A body 22 to be scanned is arranged on one XY table 18 and a material 28 to be machined is mounted on the other XY table 26. Before the engraving stage, an engraving device is operated to measure the travel (d) corresponding to the time lag from a point of time of detecting the pattern edge of a sensor till a point of time of starting and finishing to irradiate a laser beam. Next, when the engraving stage is started, only the XY table 18 is corrected by the travel (d) in the X direction before moving the table 18 and afterward, the XY tables 18 and 26 are driven synchronously. In this way, the time lag from a point of time of detecting the edge till the starting and finishing of the beam irradiation is dissolved and the indentation of the engraved image disappears and the quality of its periphery is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a laser engraving method, and more specifically, a laser engraving method that uses a sensor to read an engraving pattern drawn on a scanned object such as a pattern sheet, The present invention relates to an improvement in a laser engraving method for engraving a corresponding pattern on a workpiece.

Prior Art In the field of laser processing technology for performing various engravings on workpieces such as wood and resin, for example, Japanese Patent Publication No. 58-15232
As described in the above publication, a masking engraving method has conventionally been used.

In this masking engraving method, a light-shielding plate with a desired engraving pattern formed in a hole is brought into close contact with the workpiece, and the workpiece exposed through the hole is irradiated with a laser beam for engraving. Therefore, the engraving pattern cannot be engraved using this method if it has a shape that completely falls off the light-shielding plate, such as a double circle.

In order to avoid such inconvenience, the present applicant first filed a patent application filed in 1973.
No. 9-56852, a new and useful laser engraving method was proposed. In the laser engraving method according to this proposal, the detection head of the sensor is scanned relative to the workpiece on which the engraving pattern is drawn, and the laser processing head is moved relative to the workpiece in synchronization with this. scan and move,
The engraving is performed by irradiating the workpiece with a laser beam only when the sensor detects the engraving pattern.

Problems to be Solved by the Invention When an engraving pattern on a scanned object is scanned by a detection head, it is first scanned linearly in the X direction from the scan start position, and then a position slightly shifted in the Y direction from the scan start position is scanned. Return the detection head to , and scan in the X direction again. By repeating this scanning procedure, scanning of the entire pattern is completed. Similar to the scanning of this detection head, the laser processing head scans over the workpiece.

If such a normal scanning method is applied to the conventional laser engraving method according to the above proposal, no problem will arise. However, in order to speed up the processing speed of laser engraving, after engraving the workpiece by scanning the laser processing head in the X direction, the laser processing head is scanned slightly in the Y direction from the scanning end position, and then minus (- ) If a reciprocating scanning procedure such as scanning in the X direction is used, the following problems will occur.

This problem is caused by a time lag of about several thousandths of a second that inevitably occurs from the time the sensor detects the pattern edge to the time the laser beam irradiation starts (ends).

In other words, this time lag causes a deviation between the laser beam irradiation end (start) position during X direction scanning and the laser beam irradiation start (end) position during −X direction scanning, resulting in an engraving pattern engraved on the workpiece. The edges become jagged, and the linear delicacy of the sculpture is lost.

OBJECTS OF THE INVENTION The present invention has been proposed in view of the problems of the prior art described above and to suitably solve the problems. At the same time, in synchronization with this, the laser processing head is scanned and moved relative to the workpiece, and the laser beam is irradiated to the workpiece only when the sensor detects the engraving pattern. An object of the present invention is to provide a laser engraving method that enables delicate engraving without making the periphery of an engraving pattern on a workpiece jagged when scanning in the X direction is reciprocating scanning. .

Means for Solving the Problems In order to suitably achieve the above-mentioned object, in the present invention, the relative distance of the laser processing head to the workpiece corresponding to the time lag from the time when the pattern edge is detected by the sensor to the time when the laser beam irradiation starts or ends. A movement distance is determined, and the physical relative position of the detection head with respect to the object to be scanned is advanced in the relative scanning direction of the detection head, or the physical relative position of the detection head with respect to the object to be scanned is advanced in accordance with the relative movement distance, or the distance of the laser processing head is moved relative to the object to be processed. The present invention is characterized in that the physical position of the laser processing head is advanced in the opposite direction of the relative scanning direction 4 of the laser processing head.

The physical relative position of the action detection head with respect to the workpiece is advanced by a time lag in the relative scanning direction of the detection head, or the physical position of the laser processing head with respect to the workpiece is
Since the laser processing head advances by a time lag amount to the opposite side in the relative scanning direction, it can be isometrically considered that there is no time lag.

Therefore, there is no deviation between the laser beam irradiation end (start) position during X direction scanning and the laser beam irradiation start (end) position during −X direction scanning, making it possible to obtain delicate engravings.

Embodiments Next, a preferred embodiment of the laser engraving method according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of a laser engraving device according to an embodiment of the present invention. In FIG. 1, a scanned object 22, for example a white mount, on which a desired pattern 20 to be engraved is depicted in black is placed on an XY table 18.
A detection head 24 of the sensor is configured to scan and move relatively over this object 22 to be scanned. Further, a workpiece 28 made of, for example, a wooden board is placed on another XY table 26, and a laser processing head 30 is arranged above this workpiece 28 so that it can move relative to the workpiece 28 for scanning. has been done. Both of the xY tables 18.degree. 26 can be moved synchronously in the X and Y directions under the action of a drive mechanism (not shown). Electric control circuit 32
In this method, the laser processing head 30 irradiates the workpiece 28 with a laser beam only when the detection head 24 detects a black pattern on the object 22 to be scanned, and the detection head 24 detects the white part on the object 22 to be scanned. When it is detected, it operates to stop the irradiation of the laser beam.

Next, the operation of the laser engraving device having the above-described configuration will be explained.

First, before the engraving process, this laser engraving device is operated, and a distance d corresponding to the time lag from the time when the pattern edge is detected by the sensor to the time when the laser beam irradiation starts (ends) is measured. Therefore, for example, a straight line is used as the engraving pattern, the detection head 24 is relatively scanned in the X direction across the straight line, and a hole is made on the test piece using a laser beam.
A hole is again drilled on the test piece by relative scanning in the X direction (not scanning in the Y direction during this test). The distance between the two holes thus obtained is twice the distance d to be determined.

The distance d thus obtained is set in the control device of the XY table drive mechanism (not shown). When the carving process begins,
As shown in FIG. 2(a), this control device, when moving the XY table 18 in the direction of the arrow X, advances only the XY table 18 by a distance d in the X direction before moving the .26 is synchronized and driven. After this movement in the X direction is completed, the XY table 18.26
is slightly synchronized and shifted in the Y direction, and as shown in Fig. 2(b), only the XY table 18 is shifted by a distance of 2d in the -X direction, and then, while the XY table 18°26 is synchronized, it is shifted in the -X direction. drive Next, after this scanning in the -X direction is completed, the XY table 18.2
slightly synchronized and shifted in the Y direction, and then XY table 1
8 only by a distance of 2d in the X direction,
8. Move 26 in the X direction without synchronizing it.

The scanning of all patterns 20 is completed by repeating the above-described reciprocating movements in the X direction and the -X direction while scanning in the Y direction. A laser beam is irradiated from the laser processing head 30 only when the sensor detects the black pattern 20 on the XY table 18, so that the workpiece 28 on the XY table 26 is irradiated with a laser beam according to the pattern 20. Carvings are made. There are no irregularities on the periphery of this carved image due to time lag.

In the above embodiment, the detection head and the laser processing head are fixed and the XY table is moved, but a configuration may be adopted in which the table side is fixed and the detection head and the laser processing head are moved. In this case, the detection head 24 may be shifted back and forth in the X direction by a distance of 2d for each change of movement in the -8=X direction. Further, the laser processing head 30 or the XY table 26 may be shifted by a distance of 2d every time the X-direction movement changes. However, in this case, the irradiation position of the laser beam is shifted to the opposite side in the relative scanning direction of the laser processing head 30.

Effects of the Invention According to the present invention, since it can be considered that there is no time lag from the time of detecting a pattern edge to the time of starting laser beam irradiation, there is an effect that delicate engravings can be processed quickly by reciprocating scanning.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a laser engraving device according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) are operation explanatory diagrams. 18.26...XY table

Claims (1)

[Claims] A detection head of a sensor is scanned relative to a scanned object on which an engraved pattern is drawn, and a laser processing head is scanned and moved relative to the workpiece in synchronization with this. , in a laser engraving method in which the workpiece is irradiated with a laser beam only when the sensor is detecting the engraving pattern, the time lag corresponds to the time lag from when the sensor detects a pattern edge to when the laser beam irradiation starts or ends. Determining a relative movement distance of the laser processing head with respect to the workpiece, and according to the relative movement distance, advancing the physical relative position of the detection head with respect to the scanned object in the relative scanning direction of the detection head, or A laser engraving method characterized in that the physical position of the laser processing head with respect to the workpiece is moved to the opposite side of the relative scanning direction of the laser processing head.