System and method for aligning laser beam with filler wire for laser joining
Systems and methods determine alignment between a wire and a laser beam in laser joining. A system for checking alignment of a wire relative to a beam of a laser includes a controller configured to align, by tooling, the beam with a sensor system. A laser generates the beam across the wire, with the beam directed to the sensor system. The sensor system measures light intensity of the beam. A processor computes a feature parameter representative of an alignment between the wire and the beam. The processor determines whether the feature parameter is within the process specifications.
1 . A system for checking alignment of a wire relative to a beam of a laser, the system comprising:
an alignment cell including a sensor system that detects light; and
a controller configured to:
move, by tooling, the laser accompanied by the wire to the alignment cell;
align, by the tooling, the beam with the sensor system;
generate, by a laser, the beam across the wire and directed to the sensor system so that the beam casts a shadow of the wire on the sensor system;
measure, by the sensor system, light intensities, including a light intensity of the shadow cast by the wire, a light intensity of the beam on a first side of the shadow, and a light intensity of the beam on a second side of the shadow;
determine, from the light intensities, a first area of the beam on a first side of the shadow and a second area of the beam on a second side of the shadow;
compute, by a processor, a feature parameter representative of an alignment between the wire and the beam as a function of the first area and the second area; and
determine, by the processor, whether the feature parameter is within process specifications.
2 . The system of claim 1 , wherein the laser is configured to generate the beam via a beam delivery system to a welding location for welding a workpiece, wherein the beam delivery system effects the generating the beam across the wire and directed to the sensor system, so that the beam shows the welding location consistent with the delivery for the welding the workpiece.
3 . The system of claim 1 , wherein, prior to computing the feature parameter, the controller is configured to compute, by the processor, the first area of the beam and the second area of the beam.
4 . The system of claim 3 , comprising an actuator responsive to the controller, wherein the controller is further configured to position, via the actuator, the wire in an offset from center in the beam location for processing a workpiece according to an offset specification.
5 . The system of claim 1 , wherein the feature parameter is computed using
λ
=
10
0
×
S
r
-
S
l
S
r
+
S
l
,
where λ is the feature parameter, S l is the first area, and S r is the second area.
6 . The system of claim 1 , wherein a filter is disposed between the laser and the sensor system, wherein the filter is configured to filter background light while allowing the beam to pass to the sensor system.
7 . The system of claim 1 , wherein the sensor system includes an optical lens and wherein the beam is aligned with the lens by the tooling to calibrate the image.
8 . The system of claim 1 , wherein the sensor system includes a camera that is configured to generate pixel data representing light intensities of the beam and of a shadow cast by the wire.
9 . The system of claim 1 , wherein the controller is configured to generate the beam in a low-energy mode when the beam is directed to the sensor system.
10 . The system of claim 1 , wherein the determining, by the processor, whether the feature parameter is within process specifications includes determining, when the process specifications include centering the wire in the beam, whether the feature parameter is approximately zero.
11 . A method for checking alignment of a wire relative to a beam of a laser, the method comprising:
providing an alignment cell including a sensor system that detects light;
moving, by tooling, the laser accompanied by the wire to the alignment cell;
aligning, by tooling operated by a controller, the beam with the sensor system;
generating, by a laser operated by the controller, the beam across the wire and directed to the sensor system so that the beam casts a shadow of the wire on the sensor system;
measuring, by the sensor system, light intensities, including a light intensity of the shadow cast by the wire, a light intensity of the beam on a first side of the shadow, and a light intensity of the beam on a second side of the shadow;
determining, from the light intensities, a first area of the beam on a first side of the shadow and a second area of the beam on a second side of the shadow;
computing, by a processor, a feature parameter representative of an alignment between the wire and the beam as a function of the first area and the second area; and
determining, by the processor, whether the feature parameter is within process specifications.
12 . The method of claim 11 , comprising:
generating, by the laser, the beam via a beam delivery system to a welding location for welding a workpiece;
generating by the beam delivery system, the beam across the wire and directed to the sensor system, so that the beam shows the welding location consistent with the delivery for the welding the workpiece.
13 . The method of claim 11 , comprising, prior to computing the feature parameter, computing, by the processor, the first area and the second area.
14 . The method of claim 13 , comprising positioning, via an actuator responsive to the controller, the wire in an offset from center in the beam location for processing a workpiece according to an offset specification.
15 . The method of claim 11 , comprising computing the feature parameter using
λ
=
100
×
S
r
-
S
l
S
r
+
S
l
,
where λ is the feature parameter, S l is the first area, and S r is the second area.
16 . The method of claim 11 , comprising:
positioning a filter disposed between the laser and the sensor system; and
filtering, by the filter background light while allowing the beam to pass to the sensor system.
17 . The method of claim 11 , comprising:
including an optical lens in the sensor system; and
aligning, by the tooling, the beam with the lens to calibrate the image.
18 . The method of claim 11 , comprising generating, by a camera of the sensor system, pixel data representing light intensities of the beam and of a shadow cast by the wire.
19 . The method of claim 11 , comprising determining, when the process specifications include centering the wire in the beam, whether the feature parameter is approximately zero.
20 . A system for checking alignment of a wire relative to a beam of a laser, the system comprising:
an alignment cell including a sensor system that detects light; and
a controller configured to:
move, by tooling, the laser accompanied by the wire to the alignment cell;
align, by the tooling, the beam with the sensor system;
generate, by a laser, the beam across the wire and directed to the sensor system so that the beam casts a shadow of the wire on the sensor system;
measure, by the sensor system, light intensities, including a light intensity of the shadow cast by the wire, a light intensity of the beam on a first side of the shadow, and a light intensity of the beam on a second side of the shadow;
determine, from the light intensities, a first area of the beam on a first side of the shadow and a second area of the beam on a second side of the shadow;
compute, by a processor, a first area of the beam on a first side of the beam;
compute, by the processor, a second area of the beam on a second side of the beam;
compute, by the processor, a feature parameter representative of an alignment between the wire and the beam as a function of the first area and the second area;
determine, by the processor, whether the feature parameter is within process specifications; and
align, by an actuator and when the feature parameter is not within the process specifications, the beam with the wire.