Solutions through laser vision systemsDifferent processes need a different approach.One of the toughest issues during automated welding is to overcome product tolerances and achieve a good accuracy and repeatability. ARC|EYE offers high-performance laser vision systems for welding applications and fix this matter.
Seam findingThe first and simplest method to overcome product tolerances is Seam Finding. Seam finding allows the robot to locate the seam- start and/or end-positions prior the actual weld. This method is low cost and very common in robotic welding applications. The most widely used seam finding variant is called touch sensing. When using touch sensing the robot physically touches the part to be welded, to detect its presence and the amount of deviation. Touch sensing has also its drawbacks. The joint to be found needs to be large enough and be electrically conducting to be able to be touched in a proper way. Standard touch sensing also assumes that the joint only deviates in the direction normal to the surfaces to be touched.
The one-on-one replacement for Touch Sensing is our Distance Spot Sensor. The ARC|EYE Distance Spot Sensor offers the same functionality as Touch Sensing but with more flexibility and a higher accuracy. During the seam finding process the sensor-to-part distance is continuously measured. This makes the ARC|EYE Distance Spot Sensor also suitable for finding thin plate lap joints and small butt joints.
Where Touch-Sensing, and other laser vision sensors require robot movements to detect the start/end position of a seam, the ARC|EYE Circular Scanning Sensor can measure, with its 3D and 6-DOF scanning capabilities, the start/end position of a seam in one single scan. Seam mappingThe second method to overcome product tolerances is also a pre-weld strategy called Seam mapping. With Seam mapping the joint to be welded is measured at multiple locations prior the actual weld. While scanning these locations both position and geometry can be measured to change welding parameters according joint dimensions along the weld.
For seam mapping applications, the ARC|EYE Distance Spot Sensor can be used to sweep across the joint at each scan location. With each sweep the ARC|EYE Distance Spot Sensor can measure all detectable edges. For example in case of a V-groove, both top edges can be used to determine the weaving width and the center-line as being the joint location offset.
With seam mapping applications, the ARC|EYE Circular Scanning Sensor measures at every interval the joint location, orientation and geometry. Every scan point takes about 0.2 to 0.5 seconds, depending on filtering used to eliminate any unwanted distortion. Again the scanning process does not require any secondary movements of the robot. Seam trackingSeam Finding and Seam Mapping are both pre-weld methods to overcome product tolerances. Also both methods do not compensate material distortion during the process caused by one-sided heat input. Seam Tracking offers the ability to adjust the robot movements real-time during the process. The most well known method of doing this is measuring the change in electrical parameters through the arc whilst weaving. This requires a stable arc and a joint shape big enough to detect a stable deviation in the electrical parameters.
While the ARC|EYE Distance Spot Sensor only makes depth measurements, only vertical deviations can be tracked. In case weaving is applied and the ARC|EYE controller can receive its world position in real-time, the section view of the joint can be recreated by plotting all depth measurements in relation to the travel direction and the horizontal weaving movements. Based on these plotted depth points an correction offset can be calculated and applied. In short, this method is basically the same as using the electrical parameters of the arc whilst weaving except. The difference lies in the fact the ARC|EYE Distance Spot Sensor looks ahead of the tool and does not need a stable arc to make meaningfull measurements. Still this method needs quite a large joint and weaving width to be able to track.
The ARC|EYE Circular Scanning Sensor makes a full 3D measurement of the joint with every single scan. Also due to the circular scan pattern the joint is always measured twice. First measurement location is near to the tool and second measurement location lies far from the tool into the traveling direction. This makes the ARC|EYE Circulare Scanning Sensor very suitable for seam tracking applications. Adaptive weldingAdaptive welding |
 The ARC|EYE sensor can detect the start position and welding direction in one single scan.
 Each 3D shaped corner can be located by our ARC|EYE sensor with one single scan.
 The ARC|EYE sensor can detect tiny edges, narrow gaps and measure its distance in one single movement.
 The ARC|EYE sensor can track any detectable shape, even on highly reflective surfaces.
 In case something really special needs to be done, our ARC|EYE sensor software offers high flexibility and intelligent integration tools. |
