Fig. 1. Dimension diagram of laser welding joint

Fig. 2. Laser weld joint workpieces

Fig. 3. Principle of single point triangular laser ranging

Fig. 4. Diagram of laser weld surface detection method

Fig. 5. Metallographic morphologies of laser welding joint sections. (a)-(d) Base metal thickness combination is 1 mm+0.6 mm, and gasket thicknesses are 0.04 mm, 0.08 mm, 0.12 mm, and 0.2 mm, respectively; (e)-(h) base metal thickness combination is 0.6 mm+2 mm, and gasket thicknesses are 0.04 mm, 0.08 mm, 0.1 mm, and 0.12 mm, respectively

Fig. 6. Relationship between residual height of laser lap joint and penetration on lower plate

Fig. 7. Surface profile scanning result corresponding to laser weld joint metallographic section in Fig. 5(a)

Fig. 8. Moving mean filtering results of surface profile curves with different numbers of filtering windows. (a) 3; (b) 5; (c) 7

Fig. 9. Surface profile tilting correction method

Fig. 10. Surface profile tilting correction results

Fig. 11. Comparison of four typical profile detection results. (a) Profile detection curve 1; (b) metallographic morphology corresponding to profile detection curve shown in Fig. 11(a); (c) profile detection curve 2; (d) metallographic morphology corresponding to profile detection curve shown in Fig. 11(c); (e) profile detection curve 3; (f) metallographic morphology corresponding to profile detection curve shown in Fig. 11(e); (g) profile detection curve 4; (h) metallographic morphology corresponding to

Fig. 12. Auto-recognition method for feature points on profile curve

Fig. 13. Comparison of residual height and metallographic measurement result obtained by laser noncontact measurement. (a) Detection result comparison; (b) error distribution of detection result obtained from original image; (c) error distribution of detection result after image processing