JPS6229150B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a device for automatically following the focus of a condenser lens or a concave mirror of a laser processing machine onto the surface of a workpiece.

Conventionally, there has been a device of this type as shown in FIG. In the figure, 1 is a laser beam sent from a laser oscillator (not shown), 1a is the focus of laser beam 1, 2 is a support frame, and 3
4 is a servo motor (driver) attached to the support frame 2; 4 is a lens barrel fitted to the support frame 2 so as to smoothly slide up and down; 5
6 is a feed screw connected to the servo motor 3, 6 is a holder that holds the lens barrel 4, and 6a is a feed screw 5.
6b is the slide part, 7 is the nozzle attached to the lens barrel 4, and 8 is the lens barrel 4.
9 is a lens attached to lens holder 8, 10 is holder 6
10a is a plunger of the differential transformer 10, and 11 is a slide portion 6b.
The plunger 10 fits so that it slides up and down.
12 is a probe attached to the slide rod 11; 13 is a workpiece to be processed by the laser beam 1; 14 is a workpiece 13; It is an XY table on which the This XY table 14 is controlled by a numerical controller (not shown).
It moves in a two-dimensional plane by motors (not shown). The optical axis of the laser beam 1 is perpendicular to the surface of the XY table 14. Further, the laser beam 1 is focused 1a on the surface of the workpiece 13 by a lens 9. The differential transformer 10 sends a signal proportional to the displacement of the plunger 10a to a servo amplifier (not shown), and the servo amplifier (not shown) controls the servo motor 3 based on the received signal.

Next, the operation will be explained. laser beam 1
is condensed onto the workpiece 13 by the lens 9 to a focal point 1a. Next, when the XY table 14 is moved to a predetermined shape, the workpiece 13 is cut into that shape. In order to perform this cutting, the focal point 1a of the laser beam 1 must be focused on the surface of the workpiece 13. If the workpiece 13 is not completely flat, the probe 12 will move up and down in contact with the workpiece 13 as the XY table 14 moves.
This displacement of the probe 12 is transmitted to the differential transformer 10 via the slide rod 11 and the plunger 10a, and the differential transformer sends a signal proportional to this amount of displacement to a servo amplifier (not shown). 1) drives the servo motor 3 based on the signal. The feed screw 5 is rotated by the drive of the servo motor 3, and the lens barrel 4 along with the holder 6 moves up and down following the displacement of the probe 12.
Control is performed so that the focal point 1a is always focused on the surface of the workpiece 13.

Since the conventional focus tracking device is configured as described above, even if the focal point 1a is on the workpiece 13 as shown in FIG.
It had some drawbacks, such as sometimes coming off the top of the 3. Further, as shown in FIG.
There were drawbacks such as 2 being mixed together.

This invention was made in order to eliminate the drawbacks of the conventional probes as described above.
By providing a contact formed to surround the focal point 1a instead of 2, as long as the focal point 1a is above the workpiece 13, the height position of the workpiece 13 can be detected without the contact falling down. The purpose is to provide a focus tracking device that can

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 2, 15 is an arm attached to the slide rod 11, and 16 is a ring-shaped contactor attached to the arm 15. This contact 16
As shown in Fig. 3, the laser beam 1 is installed so that the focal point 1a is at its center, and its shape resembles a bottomless dish, and the focal point 1a of the laser beam 1 is located at the bottom with a hole. It's summery. Further, the outer periphery of the contactor 16 is raised like a plate, and is shaped so that when sliding in contact with the workpiece 13, it can easily run onto the workpiece 13 even if there is a step. The other parts are the same as the conventional example, so their explanation will be omitted.

Next, the operation will be explained. laser beam 1
is focused on the workpiece 13 by the lens 9, and the workpiece 1
The cutting process is performed by moving the XY table 14 on which the workpiece 13 is placed, but even if the focal point 1a reaches the edge of the workpiece 13, the
Since the contact 16 is located at 360 degrees, the nozzle 7 does not fall off the workpiece 13 as shown in FIGS. 6 to 8, so that cutting can be performed. Further, even when a hole is cut out in the workpiece 13, as shown in FIG. 9, the contactor 16 stays on the edge of the hole and does not fall into it. This contactor 16 is the workpiece 1
3 is detected by the differential transformer 10, and the lens barrel 4 is moved up and down by the operation of the servo motor 3 as a driving body under feedback control, and the focal point 1a is aligned to follow the surface of the workpiece 13. This is the same as the conventional example except that the probe 12 is replaced by an arm 15 and a contact 16.

In the above embodiment, the contact was formed into a ring shape that surrounded the focal point, but it does not need to be ring-shaped, and it may also be a polygonal shape that surrounds the focal point. Well, again,
It may also be formed in a similar manner but in a circular shape. Although the workpiece is being moved, the lens barrel may also be moved. Also, a concave mirror may be used instead of a lens.

Note that although the case of cutting has been described, the same effect as in the above embodiment can be obtained even in the case of welding.

As described above, according to the present invention, the contact formed to surround the focus is provided as the contact of the detector of the servo mechanism for making the focus of the laser follow the surface of the workpiece. As long as the focus is on the surface of the workpiece, it is effective in preventing abnormalities such as the contact coming off the workpiece.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view showing a conventional focus tracking device for a laser processing machine, FIG. 2 is a cross-sectional front view showing a focus tracking device for a laser processing machine according to an embodiment of the present invention, and FIG. 3 is a cross-sectional front view showing a focus tracking device for a laser processing machine according to an embodiment of the present invention. 4 and 5 are plan views showing the positional relationship between the workpiece 13, the focal point 1a, and the probe 12 in the conventional apparatus, and FIGS. FIG. 9 is a plan view showing the positional relationship between the workpiece 13, the focal point 1a, and the contact 16 according to the apparatus of the present invention. In the figure, 1 is a laser beam, 3 is a servo motor (driver), 9 is a lens, and 16 is a contact. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In the vicinity of the focal point of a lens or concave mirror that focuses the laser beam, a contact element formed so as to surround the periphery of the focal point is arranged so as to be in sliding contact with the workpiece,
The position of the lens or concave mirror is adjusted by a driver that receives the amount of displacement of the contact as an input signal, so that the focal point of the laser beam is adjusted to a position surrounded by the contact. Focus tracking device for laser processing machines.