Author Affiliations
1School of Mechanical Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China2Nanjing Institute of Advanced Laser Technology, Nanjing, Jiangsu 210038, Chinashow less
Fig. 1. Diagram of laser paint removal
Fig. 2. Effect of interaction of all factors on surface composition
Fig. 3. Cleaning surface micromorphology and elemental composition under different overlap rates. (a) 50%; (b) 75%
Fig. 4. Effects of spot overlap rate and power on surface composition. (a) Contour graph; (b) response graph
Fig. 5. Effects of spot overlap rate and number of scans on surface composition. (a) Contour graph; (b) response graph
Fig. 6. Effect of interaction of all factors on surface roughness
Fig. 7. Cleaning surface micromorphology and line roughness at different powers. (a) 20 W; (b) 25 W
Fig. 8. Effects of power and number of scans on surface roughness. (a) Contour graph; (b) response graph
Fig. 9. Effects of power and spot overlap rate on surface roughness. (a) Contour graph; (b) response graph
Element | C | Si | Mn | Cr | Ni | S | P | N | Fe |
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Mass fraction /% | ≤0.08 | ≤1.0 | ≤2.0 | 18.0-20.0 | 8.0-10.5 | ≤0.03 | ≤0.035 | ≤0.1 | Bal. |
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Table 1. Main chemical composition of 304 stainless steel
Parameter | Value |
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Wavelength /nm | 1064 | Power /W | ≤ 100 | Pulse width /ns | 100 | Frequency /kHz | 10-100 | Scan speed /(mm·s-1) | ≤8000 | Focal length /mm | 160 | Waist diameter /mm | 0.05 |
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Table 2. Main technical parameters of laser paint removal system
Factor | Extreme value |
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Low(-1) | Medium(0) | High(+1) |
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Power P /W | 15 | 20 | 25 | Spot overlap rate γ /% | 25 | 50 | 75 | Number of scans N | 2 | 3 | 4 |
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Table 3. Experimental factors and level design
No. | Parameter | Result |
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P /W | γ /% | N | S | Sa /μm |
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1 | 25 | 25 | 3 | 50 | 0.6966 | 2 | 25 | 50 | 2 | 60 | 0.8036 | 3 | 25 | 75 | 3 | 20 | 1.1528 | 4 | 25 | 50 | 4 | 30 | 1.5258 | 5 | 15 | 50 | 2 | 40 | 1.5620 | 6 | 20 | 50 | 3 | 85 | 0.5980 | 7 | 20 | 50 | 3 | 85 | 0.6330 | 8 | 15 | 50 | 4 | 85 | 1.0620 | 9 | 20 | 50 | 3 | 80 | 0.7070 | 10 | 20 | 75 | 4 | 10 | 1.0588 | 11 | 20 | 50 | 3 | 80 | 0.7860 | 12 | 20 | 75 | 2 | 20 | 1.0844 | 13 | 20 | 50 | 3 | 75 | 0.5900 | 14 | 20 | 25 | 2 | 30 | 0.8038 | 15 | 20 | 25 | 4 | 65 | 0.8788 | 16 | 15 | 25 | 3 | 40 | 0.9316 | 17 | 15 | 75 | 3 | 60 | 0.9498 |
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Table 4. Design matrix and experimental results
Source | Sum of squares | Degree of freedom | Mean square | F | Probability |
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Model | 10321.99 | 9 | 1146.89 | 16.62 | 0.0006 | P | 528.13 | 1 | 528.13 | 7.65 | 0.0278 | γ | 703.13 | 1 | 703.13 | 10.19 | 0.0152 | Pγ | 625.00 | 1 | 625.00 | 9.06 | 0.0197 | PN | 1406.25 | 1 | 1406.25 | 20.38 | 0.0027 | γN | 506.25 | 1 | 506.25 | 7.34 | 0.0303 | γ2 | 3968.38 | 1 | 3968.38 | 57.52 | 0.0001 | N2 | 1592.85 | 1 | 1592.85 | 23.09 | 0.0020 | Lack of fit | 393.75 | 3 | 131.25 | 5.89 | 0.0599 | Note: residual-square R2=0.9553; adjusted residual-square =0.8978; predicted residual-square =0.4040; adeq precision AP=11.479. | |
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Table 5. ANOVA for surface composition model
Source | Sum of squares | Degree of freedom | Mean square | F | Probability |
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Model | 1.30 | 9 | 0.14 | 25.26 | 0.0002 | γ | 0.11 | 1 | 0.11 | 19.17 | 0.0032 | Pγ | 0.048 | 1 | 0.048 | 8.42 | 0.0230 | PN | 0.37 | 1 | 0.37 | 65.52 | <0.0001 | P2 | 0.32 | 1 | 0.32 | 56.24 | 0.0001 | N2 | 0.38 | 1 | 0.38 | 66.34 | <0.0001 | Lack of fit | 0.012 | 3 | 0.004 | 0.60 | 0.6484 | Note: R2=0.9701, =0.9317, =0.8196, AP=15.336. | |
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Table 6. ANOVA for surface roughness model
Name | Criteria | Weight |
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| Goal | Lower | Upper |
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P | In range | 15 | 25 | 1 | γ | In range | 25 | 75 | 1 | N | Equal to 3 | 2 | 4 | 1 | S | Maximize | 75 | 100 | 1 | Sa | Minimize | 0 | 1 | 1 |
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Table 7. Optimization criteria and weight
Number | P /W | γ /% | N | S | Sa /μm |
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1 | 19.18 | 46.06 | 3 | 82.9 | 0.661 |
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Table 8. Optimization results