US 11,786,989 B2
Method for splash-free welding, in particular using a solid-state laser
Patrick Haug, Gerlingen (DE); Nicolai Speker, Pleidelsheim (DE); Marco Opitz, Leonberg (DE); and Tim Hesse, Ditzingen (DE)
Assigned to TRUMPF LASER- UND SYSTEMTECHNIK GMBH, Ditzingen (DE)
Filed by TRUMPF Laser- und Systemtechnik GmbH, Ditzingen (DE)
Filed on May 12, 2021, as Appl. No. 17/317,925.
Application 17/317,925 is a continuation of application No. PCT/EP2019/080878, filed on Nov. 11, 2019.
Claims priority of application No. 10 2018 219 280.4 (DE), filed on Nov. 12, 2018.
Prior Publication US 2021/0260690 A1, Aug. 26, 2021
Int. Cl. B23K 26/035 (2014.01); B23K 26/244 (2014.01); B23K 26/06 (2014.01); B23K 26/32 (2014.01)
CPC B23K 26/035 (2015.10) [B23K 26/0613 (2013.01); B23K 26/244 (2015.10); B23K 26/32 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method for laser beam welding a workpiece, the method comprising:
generating at least a first beam area on the workpiece by a first laser beam; and
generating a second beam area on the workpiece by a second laser beam,
wherein the first beam area and the second beam area are guided in a feed direction relative to the workpiece,
wherein a centroid of the first beam area and a centroid of the second beam area are not coinciding,
wherein the first beam area runs ahead of the second beam area,
wherein a length (LE1) of the first beam area, measured transversely to the feed direction, is greater than or equal to a length (LE2) of the second beam area,
a surface area of the first beam area is greater than a surface area of the second beam area,
wherein a width (BE1) of the first beam area, measured in the feed direction, is greater than or equal to a width (BE2) of the second beam area,
wherein a laser power of the first laser beam is greater than a laser power of the second laser beam,
wherein the second laser beam is irradiated into a weld pool generated by the first laser beam, and
wherein a focus diameter (FD2) of the second laser beam satisfies, at least in one direction transverse to the feed direction:

OG Complex Work Unit Math
with kd,Min: a material-specific constant, with s: a workpiece thickness to be welded, and with v: a feed speed for the laser beam welding,
wherein the workpiece comprises stainless steel or structural steel, and wherein the material-specific constant kd,Min is between 5 and 20 mm2/s for stainless steel, and is between 8 and 20 mm2/s for structural steel.