JPH0381081A - Laser beam machining head - Google Patents

Abstract

PURPOSE:To meet variation of the distance between a lens barrel and a workpiece only by moving a lens by arranging the lens at the front stage side in the incident direction from a mirror in the elbow-shaped lens barrel and sliding the lens in the direction of an optical axis according to the distance between the other end face of the lens barrel and the workpiece. CONSTITUTION:A laser beam Le introduced through the inside of an arm 1 from a laser beam oscillator is reflected by the mirror 5 and transmitted through the lens 28 and then, further converged and reflected by a converging mirror 26 and the workpiece W is irradiated from a tip opening 37 of a nozzle 12. At this time, when the height of the workpiece W is changed due to unevenness, etc., of the workpiece W and the distance C between the workpiece W and the tip of the nozzle 12 is changed to C', the laser beam Le can be focused on the surface of the workpiece W and welding can be performed under speci fied welding conditions regardless of variation of the distance by moving the lens 28 up to the virtual line position P.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a laser processing head for the purpose of laser processing, typified by laser welding.

2. Description of the Related Art In this type of laser processing head, for example, as shown in FIG. There is one that focuses upward and moves the lens 54 up and down to change the focal length when the distance C between the lens barrel 51 and the workpiece W changes (
A similar structure is disclosed, for example, in JP-A-61-46389).

Although this structure can be easily applied to processing such as fusing without scattering of spatter, it is generally unsuitable for welding with significant scattering of spatter because the lens 54 is likely to be damaged due to adhesion of spatter. It is said that

Therefore, as a structure with improved so-called spatter resistance for welding and the like, there is a structure in which the lens is removed from the part of the optical system near the workpiece W, as shown in FIG. This is the laser beam Le introduced from one end of the lens barrel 6■.
Mirror 62 and metal condensing mirror (parabolic mirror) 6
3 and then directly irradiates the workpiece W.

Problems to be Solved by the Invention However, since the structure shown in FIG. 4 does not have a variable focus lens mechanism as shown in FIG. This must be handled by the movement of the machining base machine, such as a robot, to which the machining head is attached.

As a result, in a robot with a large number of axes, the above distance @C
The position of the machining head must be corrected using the combined feed of each axis in response to fluctuations in the machining speed, which complicates calculation processing and slows response.In addition, the accuracy of the machining machine such as a robot directly affects the machining accuracy. There is a problem with doing so.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a laser processing head that has spatter resistance and has a variable focus function using a lens adjustment mechanism. It is in.

Means for Solving the Problems The present invention provides an opening at the other end of the lens barrel by reflecting a laser beam introduced from one end of an elbow-shaped lens barrel attached to a processing base machine with a mirror provided at a corner of the lens barrel. In a laser processing head that performs laser processing by irradiating a workpiece from the front side, a lens is disposed on the front side of the elbow-shaped lens barrel in the direction of incidence than the mirror, and the other end surface of the lens barrel The structure includes a lens adjustment mechanism that slides and displaces the lens in the optical axis direction according to the distance between the lens and the workpiece.

According to this structure, the laser light introduced from one end of the lens barrel passes through the lens, is reflected by the mirror, and is irradiated onto the workpiece. Since the focal length is changed by sliding the lens in the optical axis direction by the action of the lens adjustment mechanism, the laser processing head alone can respond to changes in the distance between the lens barrel and the workpiece. Moreover, since the lens is located in front of the mirror and is away from the workpiece, there is no problem of spatter adhesion during welding.

Embodiment FIGS. 1 and 2 are diagrams showing an embodiment of the present invention.

In the figure, 1 is a hollow arm of an industrial robot that serves as a processing base machine, 2 is an elbow-shaped holder that is attached to the tip of arm 1 and functions as a wrist, and 3 is a laser processing device that is attached to the tip of holder 2. head (hereinafter simply referred to as a processing head).

The holder 2 is rotatably supported by the arm 1 via a bearing 4, and includes a driven gear 6 as well as a mirror 5 that reflects the laser beam Le introduced through the inner periphery of the arm 1. The driven gear 6 is in mesh with a drive gear 8 which is rotationally driven by a motor 7, and therefore the holder 2 is rotated by the arm 1 due to the action of the motor 7.
It is configured to rotate in the α direction with the center line of the rotation center as the center of rotation. 9 is a speed reducer, and 10 is a rotating shaft.

The processing head 3 includes a head body 11 and a tapered nozzle 12.
Lens barrel 13 formed into an elbow shape by combining
and a sleeve 14 integrally connected to this lens barrel 13, and the sleeve 14 is rotatably supported by the holder 2 via a bearing 15.

A driven gear 16 is integrally fixed to the sleeve 14, while a motor 18 having a drive gear 17 is fixed to the side of the holder 2 as shown in FIG. 2, and the drive gear 17 meshes with the driven gear 16. ing.

Therefore, the processing head 3 is configured to rotate via both gears 16 and 17 by the action of the motor 18.

In other words, the processing head 3 has a rotational degree of freedom in the α direction as well as a rotational degree of freedom in the β direction about the axis perpendicular to the arm center line. 19 is a speed reducer, and 20 is a cover.

Inside the lens barrel 13, a metal condensing mirror (parabolic mirror) 26 is provided at a corner thereof, and a lens 28 supported by a lens holder 27 is provided in front of the condensing mirror 26. is provided. The lens holder 27 is configured to be movable in the optical axis direction while being guided by a guide rod 29 provided in the lens barrel 13.
is screwed onto a screw shaft 31 which is rotationally driven by a motor 30. Therefore, the lens 28 slides in the axial direction within the lens barrel 13 in accordance with the rotation of the screw shaft 31, and the motor 30 and the screw shaft 31 are connected to the reduction gear R32 and the gear 33.
34 and the like constitute a lens adjustment mechanism 35. 3
6 is a rotation detector.

In the device configured in this way, the laser beam Le introduced from a laser oscillator (not shown) through the inside of the arm l is reflected by the mirror 5, transmitted through the lens 28, and further condensed by the condensing mirror 26. The reflected light irradiates the workpiece W from the tip opening 37 of the nozzle 12 .

Then, laser welding is performed by moving the processing head 3 along the trajectory to be welded based on position data inputted in advance to the control system of the industrial robot.

At this time, even if the distance C between the workpiece W and the tip of the nozzle 12 fluctuates due to unevenness of the workpiece W in addition to the movement of the robot as described above, the laser beam Le is always applied. The position of the lens 28 is adjusted so that it is focused on the surface of the workpiece W. This is the lens 28 according to the above distance C.
This can be handled by inputting position data to the control system of the motor 30 in advance.

For example, when the height of the workpiece W changes and the distance C changes to C1 as shown in FIG. 1, by moving the lens 28 to the imaginary line position P, the height of the workpiece part is changed. Even if the distance C changes, the laser beam Le can be focused on the surface of the workpiece W, and welding can be performed under constant welding conditions regardless of the change in the distance C.

Effects of the Invention As described above, according to the present invention, the lens is disposed on the front side in the direction of incidence of the mirror part of the elbow-shaped lens barrel, and the lens is arranged in accordance with the distance between the lens barrel and the workpiece. By providing a lens adjustment mechanism that slides the lens in the direction of its optical axis, it is possible to respond to the above-mentioned distance fluctuations by simply moving the lens on the laser processing head side, without relying on movement on the processing base machine. Become. As a result, calculation processing is easier and responsiveness is improved compared to the case where the above-mentioned changes in distance are handled by movement on the processing base machine side, and at least the change in distance between the lens barrel and the workpiece is On the other hand, since the positional accuracy of the machining base machine side is not affected, the machining accuracy can be improved.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a main part showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Figs. 3 and 4 show a conventional laser processing head. It is a configuration explanatory diagram. DESCRIPTION OF SYMBOLS 1... Arm of industrial robot, 3... Laser processing head, 11... Head body, 12... Nozzle, 1
3... Lens barrel, 26... Condensing mirror, 27... Lens holder, 28... Lens, 29... Guide rod,
30...Motor, 31...Screw shaft, 3
5... Lens adjustment mechanism, Le... Laser light, W...
・Workpiece.

Claims (1)

[Claims] (1) Laser light introduced from one end of the elbow-shaped lens barrel attached to the processing base machine is reflected by a mirror installed at the corner of the lens barrel, and is directed to the workpiece from the opening at the other end of the lens barrel. In a laser processing head that performs laser processing by irradiating light with A laser processing head characterized by being provided with a lens adjustment mechanism that slides and displaces a lens in its optical axis direction according to the distance between the lenses.