DE102008018130A1 - Method for producing vehicle bodies - Google Patents

Abstract

The invention relates to a method for producing vehicle bodies with complex geometric multi-dimensional structures by means of a laser beam (1), the laser beam (1) having a focal point (2) on and / or in at least one of the elements (3, 4) to be welded different materials or the same material, for example metal, is focused in a seam region for producing a weld with a predetermined focus angle (10). The invention has for its object to carry out a method such that the resulting by movements of a robot tolerances in the distance between the laser optics and the surface of the element to be processed (3, 4) are compensated and uninterrupted and as constant as possible energy input into the element (3, 4) is made possible. According to the invention, the focus angle (10) of the laser beam (1) is set in a range between 2 ° and 7 °. This makes it possible that with a tolerance fluctuation, the change of the diameter (14, 15) and thus the cross-sectional area of the laser beam (1) in the welding plane (12, 13) is low. The laser beam (1) is focused during the welding of 12) and there knows a minimum diameter (14). When changing the distance of the laser optics to the element (3), due to tolerant movements of the robot, the laser beam (1) strikes in a different ...

Description

The The invention relates to a method for producing vehicle bodies with complex geometrical multidimensional structures by means of a laser beam, wherein the laser beam with a focal point on and / or in at least one of the elements to be welded made of different materials or the same material, for example metal, in a seam area to produce a weld with Focusing a predetermined focus angle.

A method for increasing the seam quality in the laser welding of automotive components with complex 3D structures is from the DE 196 05 888 A1 known. In this method, a weld seam with a large seam depth is produced by means of the inclination of the processing optics and thus the laser irradiation at a defined angle with respect to the surface.

A device for optimizing the machining of a workpiece by means of a laser beam through a modified focus angle shows the JP 2000-263269 A ,

The JP 2000-263267 A and the JP 2000-254792 A also show a device with variable laser beam focus angle.

To the Welding the laser beam on the surface the elements to be welded focused in such a way that the energy input into the material of the elements as possible is great. Because the transferable energy depends of the diameter of the laser beam in the focal point, this is In automated welding, strive for the distance the laser optics to comply with the element to be processed exactly. The Movement tolerances of the welding robot are determined by the Wear of the robot, especially created game in joints and gears, the welding speed and the dynamic forces from the direction changes of the robot certainly.

In front In this background, the invention is based on the object Method of the type mentioned above to carry out such that the tolerances resulting from movements of the robot in the Distance between the laser optics and the surface of the to be processed element to be balanced and an uninterrupted and as constant as possible energy input into the element is possible.

These The object is achieved by a method according to Features of claim 1. The dependent claims relate particularly expedient developments of the invention.

According to the invention Thus, a method is provided in which the focus angle of the laser beam in a range between 2 ° and 7 ° is set. hereby it becomes possible that with a tolerance fluctuation the change the diameter and thus the cross-sectional area of the laser beam is low in the welding plane. When welding with a large focus angle, are common at least 17 °, results in a tolerance variation of the distance the laser optics to the welding plane of a few millimeters to a multiplication of the cross-sectional area of the laser beam in the welding plane. When welding with a sharp focus angle, for example, 5 °, changed the cross-sectional area of the laser beam in the welding plane barely. Old and inexpensive systems often have large Motion tolerances on. By compensating the movement tolerances will laser accurate welding with older ones and lower cost equipment, in higher welding speed ranges and / or possible with a higher process stability. Of Furthermore, component fluctuations in the parts to be welded are Workpieces easier to compensate.

Farther It is favorable that the elements are welded through become. This makes it possible to welds produce with higher quality. As special it has been found favorably that at least two Elements, in particular sheets, with a respective thickness up to 3.2 millimeters, mainly with a respective strength 1 mm to 2.8 mm, to be welded. Of the acute focus angle of the laser beam allows a deeper welding in the elements to be joined, what the penetration resistance substantially increased, and allows that at unchanged movement tolerances of the robot's fluctuations the energy input are much lower. This will be a uninterrupted and almost constant energy input into the Element possible.

Usually In the seam area, a seam is created in which the focal point of the Laser beam set with a mean diameter of 600 microns is, wherein the diameter of the focal point at least 300 microns and a maximum of 1000 microns. For as possible planar power transmission in the welding area it is advantageous that in the seam area a plurality of welds be generated simultaneously and / or sequentially. This will it possible, with smaller overall seam area to transmit the same or a greater force. It is favorable that the focal point of the laser beam for producing the welds with a middle one Diameter of 200 microns is set, the diameter of the focal point at least 100 microns and a maximum of 500 microns having.

The Invention allows for numerous embodiments. To further clarify its basic principle, one of them is in the drawing and will be described below. These shows in

1 a schematic representation of a laser beam with a large focus angle;

2 a schematic representation of a laser beam with a small focus angle according to the invention;

3 a schematic representation of two different seam areas.

The 1 and 2 show a laser beam 1 when welding two elements 3 . 4 , The laser beam 1 is thus on a focal point 2 focused that the laser beam 1 in the desired welding plane 12 a minimum diameter 14 having.

1 shows this laser beam 1 , as known in the art, with a large focus angle 10 of 20 °. For changes in the distance of the laser optics to the element 3 , due to tolerant movements of the robot, the laser beam hits 1 in a different welding level 13 on the element 3 , where the distance of the focal point 2 to the laser optics is unchanged. In the deviant welding plane 13 is the diameter 15 of the laser beam 1 greater than in the target welding level 12 , The energy input into the elements 3 . 4 is significantly reduced, so that a suspension of the welding process is possible.

The 2 shows the laser beam according to the invention 1 with a small focus angle 10 of 5 °. Meets the laser beam 1 in the deviant welding plane 13 on the element 3 so is the diameter 15 of the laser beam 1 much less enlarged. The energy input into the elements 3 . 4 reduces only insignificantly, an uninterrupted and almost constant energy input into the elements 3 . 4 is possible.

3 shows a seam area 5 with a weld 6 with a mean diameter of 600 microns and a seam area 5 with several welds 7 . 8th . 9 with a mean diameter of 200 microns. Although the total area of the welds 7 . 8th . 9 smaller than the area of the weld 6 , these can transmit the same or a greater force. The welds 6 . 7 . 8th . 9 be from the laser beam in a welding direction 11 generated. The welds can 7 . 8th . 9 be generated simultaneously and / or sequentially.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19605888 A1 [0002]
• JP 2000-263269 A [0003]
• JP 2000-263267 A [0004]
• - JP 2000-254792 A [0004]

Claims (6)

Method for producing vehicle bodies with complex geometric multi-dimensional structures by means of a laser beam ( 1 ), wherein the laser beam ( 1 ) with a focal point ( 2 ) on and / or in at least one of the elements to be welded ( 3 . 4 ) of different materials or the same material, for example metal, in a seam area ( 5 ) for producing a weld ( 6 ) with a predetermined focus angle ( 10 ), characterized in that the focus angle ( 10 ) of the laser beam ( 1 ) is set in a range between 2 ° and 7 °. Method according to claim 1, characterized in that at least two elements ( 3 . 4 ), in particular sheets, with a respective thickness of up to 3.2 millimeters, mainly with a respective thickness of 1 millimeter to 2.8 millimeters, are welded. Method according to claim 1 or 2, characterized in that the elements ( 3 . 4 ) are welded through. Method according to at least one of the preceding claims, characterized in that the focal point ( 2 ) of the laser beam ( 1 ) is set with a mean diameter of 600 microns. Method according to at least one of the preceding claims, characterized in that the focal point ( 2 ) of the laser beam to produce the welds ( 7 . 8th . 9 ) is set with a mean diameter of 200 microns. Method according to at least one of the preceding claims, characterized in that in the seam area ( 5 ) several welds ( 7 . 8th . 9 ) are generated simultaneously and / or sequentially.