Process visualization and monitoring for laser remote welding

With over 400 Lessmüller Lasertechnik systems installed worldwide, WELDEYE offers trend-setting solutions for seam-tracking and quality assurance.

The module based WELDEYE-system visualizes the welding process, enables real-time seam tracking, it ensures the quality of the laser welding / brazing processes, and it is universal for a variety of existing welding optics (e. g. Scansonic ALO3, Highyag PDT, Blackbird IntelliWeld).

Synchronous recording, evaluation and documentation of image based data and process parameters offer new options in process monitoring. Whether welding wire errors or seam faults caused by dust - WELDEYE sees everything.

 

Video example: recognition of seam interruptions

The system consists of the WELDEYE high velocity camera with optical filter and a powerful illumination source. The high information degree of the camera images allows in combination with different data from the superordinate system (optic and robot data) programming automated data processing and evaluation. 

Quality control algorithms, which are approved during the serial process, monitor the weld position, process and seam, they correct tracking faults and report critical components to the superordinate system control. 

WELDEYE camera module CM 3.0        WELDEYE illumination module LM5     WELDEYE fuel rod with spherical head      WELDEYE illumination module LM4  

Camera module CM 3.0       Illumination module LM5          Fuel rod with spherical head       Illumination module LM4

WELDEYE illumination module LM6      WELDEYE camera module AP 3.0

Illumination module LM6       Camera module AP 3.0

Advantages:

  • Online closed loop controlled seam tracking, visualization, monitoring and quality assurance of welding or brazing processes
  • LIVE camera imaging and real-time image analysis to ensure weld quality standards
  • Synchronous recording, evaluation and documentation of image based data and process parameters (feed rate etc.)
  • Automatic detection and auto-correction of weld faults before the weld fails, solving weld irregularities faster thus reducing scrap rates, test costs and rework
  • Compact and lightweight, small interfering contour
  • Robust industrial design (dustproof construction (IP-64) with robot-drag adapted cables and interfaces)
  • Adaption to and integration in many laser processing heads
  • Communication via standard fieldbuses

Functions

An external intensive WELDEYE illumination allows real-time observation, recording and automated analysis during the active welding process, uninfluenced by the process light.

During the active welding process, the process light is optimally suppressed by a narrowband filter and images are alternately recorded with and without external illumination. Every image is evaluated in real time.

Illuminated images are processed to measure the position of the seam joint position as well as the melt pool and the distribution profile of the light reflected off the cooled seam. Additionally, the illuminated images are used to measure the weld joint gap directly before the welding process.

In no-illuminated images the intensity of the reflected process light is examined.

All welds are continuously recorded, automatically analysed, compared with the reference welds and saved. As a result, the total process is controlled online. Deviations from the reference are reported during the actual welding process.

The modular WELDEYE design allows to implement either the whole system or certain features. 

Alignment support

The WELDEYE system serves as optical tool for aligning the processing head for optimal weld operations and premium quality welds.

The WELDEYE Camera is used in ambient light mode with the optical filter swiveled out. This mode enables an exact and parallel to seam programming of robot or other guiding system before welding. The user obtains a live camera image, on which the position of the processing laser is marked with crosshairs.

The OPTIKCHECK broadens the WELDEYE system by automated configuration of system setup (optics, wire and nozzle).

Optikcheck
Position check of the optics with a crosshair (picture 1), measurement of wire position and nozzle (picture 2) and automatic positioning of the laser beam with a laser shot on a sample piece (picture 3)

Seam joint recognition and seam tracking

Joint recognition algorithms allow the automated control and correction of weld positions, laser beam positions and seam joint positions, regardless of component tolerances.

Kantenerkennung

Online seam tracking: detection of the joint position on the camera image (green line in the yellow boarded region) and on the diagram of the WELDEYE Player

Monitoring

A combination of smart camera, illumination and steering techniques enables automatic monitoring of the welding process. The alternate recording of  illuminated and no-illuminated images serves for the evaluation of the process light and for the high resolution reproduction of the regions around the process beam.

The system displays the surface of the cooled seam together with the seam surface profile. The actual seam profile is generated from image to image and compared with the reference.

Intensity analysis of the secondary process light in no-illuminated images provides insight into the weld quality.

Process parameters are recorded and monitored simultaneously with the image data.

The parametrisation is classified either according to absolute limits or according to limits obtained from reference welds.

Image processing signals serve for quality control purposes and automated online detection and auto-correction of weld faults before the weld fails.

Alternierende Beleuchtung

Sequential camera images with and without illumination used for seam fault detection analysis such as one caused by dust 

Documentation

After every weld, the recorded videos are saved in compatible formats (avi, mp4, mpeg). Together with the simultaneously recorded process parameters, the saved data can be used for subsequent quality assessment (including quality assurance).

The system allows a full documentation of process behaviors and the product quality to review the recorded data of past process. WELDEYE logs up to eight hours of video and data.

Data storage for further process control is possible.

WELDEYEPlayer

Online quality assurance: recognition of a weld tracking fault in the WELDEYE Player (red boarded region on the camera image and red line on the
diagram)