Page 14 - Welding Robots Technology, System Issues, and Applications

xvi List of Figures
2.14. Laser welding modes: Heat conduction-mode – a; deep-
penetration mode – b. Laser beam – 1; vapor channel – 2; weld
pool – 3; welding direction – 4; work-piece – 5; solid melt – 6.................... 46
2.15. Schematic representation of a Nd:YAG laser system................................... 48
2.16. Schematic representation of a CO 2 transverse-flow laser system................. 49
2.17. Characteristic parameters of focal system. .................................................. 51
2.18. Schematic representation of a diode laser..................................................... 54
2.19. Schematic representation of the spot welding process. Electrode-
work-piece interface resistances – R 1 and R 5; resistance of the
work-pieces – R 2 and R 4; resistance in the interface between work-
pieces – R 3..................................................................................................... 55
2.20. Arrangements of the secondary circuit for multiple spot welds; a -
direct welding; b - series welding................................................................. 57
2.21. Schematic representation of current-time relationship for RSW.................. 59
2.22. Timing diagrams of current and force for spot welding: Welding
current – I w; welding time – t w; rise time – t r; fall time – t f; welding
force – F w; forge force – F forge; annealing current......................................... 60
2.23. Seam welding principle. ............................................................................... 61
2.24. Schematic representation of friction stir welding process. ........................... 63
2.25. Friction stir welding probes. Cylindrical threaded pin probe – a;
oval shape Whorl probe - b; flared-triflute probe – c.................................... 65
3.1. The working method of the triangulation method [2]................................... 78
3.2. Scanning principle of a seam tracking combined with the
triangulation method [2]................................................................................ 79
3.3. Illustration of a typical laser scanner sensor mounted ahead of the
welding torch [3]........................................................................................... 80
3.4. Typical standard joint types. Left column: fillet and corner joint.
Right column: lap, butt and V-groove joint [3]. ............................................ 81
3.5. Example of the steps of feature extraction of the segmentation
process: (1) outlier elimination from the scan, (2) line segmentation
generation based on the specific joint template, (3) join the line
segments, and (4) validate against templates and tolerances [3]................... 82
3.6. Left: definition of Tool Center Point (TCP) and weaving directions
during through-arc sensing. Right: the optimal position for seam
tracking in arc sensing [5]............................................................................. 85
3.7. Example of the functionality of the through-arc seam tracking over
segmented plates that deviate both sideways and in height [5]..................... 86
3.8. A T-pipe representing a type of work-piece that should benefit from
a seam tracker which can compensate for both position and
orientation changes [5].................................................................................. 86
3.9. Weld voltage and current waveforms for different metal transfer
modes............................................................................................................ 88
3.10. Successive transfer modes of metal transfer in GMA welding with
increasing mean current (left to right) [23]. .................................................. 89
3.11. A schematic illustration of weld current and related parameters in
pulsed GMA welding. T p and T b denote peak pulse time and