Fig. 1. (a) In vitro biological tissue test sample; (b) experimental setup
Fig. 2. (a) Measuring peak temperature of incision; (b) measuring tensile strength
Fig. 3. Peak temperature changing curve of sample during welding
Fig. 4. Tensile strength dispersion map
Fig. 5. Peak temperature dispersion map
Fig. 6. (a) Three-dimensional surface map and (b) contour map showing the effects of laser power and spot movement speed on tensile strength
Fig. 7. Three-dimensional surface maps and contour maps showing the effects of factor interactions on peak temperature of in vitro skin tissue incision. (a)-(b) Spot movement speed and laser power; (c)-(d) laser frequency and laser power; (e)-(f) laser frequency and spot movement speed
Fig. 8. Fusion morphology of in vitro skin tissue at optimized parameters. (a) Front view; (b) back view; (c) cross-section
Weldingparameter | Encodingvalue | Coding level |
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-1 | 0 | 1 |
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P /W | X1 | 3 | 3.5 | 4 | v /(mm·s-1) | X2 | 150 | 200 | 250 | F /Hz | X3 | 50 | 100 | 150 |
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Table 1. Horizontal coding and real value table of laser welding parameters
Number | X1 | X2 | X3 | σb /(N·cm-2) | T /℃ |
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1234567891011121314151617 | 0 1 0 1 1 0 0-1-1 0-1 0 1 0 0-1 0 | 1 0-1 1-1 0 1-1 1 0 0-1 0 0 0 0 0 | 1-1-1 0 0 0-1 0 0 0-1 1 1 0 0 1 0 | 38.127.440.229.035.743.637.520.127.744.726.028.844.545.840.422.845.0 | 49.054.050.053.558.053.549.042.039.853.740.753.356.453.153.540.854.0 |
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Table 2. Experimental laser welding parameters and results
Source | Sum of squares | Degree of freedom | Mean square | F value | p-value (P'>F) | Source |
---|
Model | 1081.59 | 9 | 120.18 | 8.170 | 0.0056 | Significant | X1 | 200.00 | 1 | 200.00 | 13.600 | 0.0078 | Significant | X2 | 7.03 | 1 | 7.03 | 0.480 | 0.5115 | - | X3 | 1.20 | 1 | 1.20 | 0.082 | 0.7833 | - | X1X2 | 51.12 | 1 | 51.12 | 3.480 | 0.1045 | Significant | X1X3 | 103.02 | 1 | 103.02 | 7.010 | 0.0331 | - | X2X3 | 36.00 | 1 | 36.00 | 2.450 | 0.1616 | - | | 497.96 | 1 | 497.96 | 33.870 | 0.0007 | Significant | | 101.09 | 1 | 101.09 | 6.880 | 0.0343 | Significant | | 34.20 | 1 | 34.20 | 2.330 | 0.1711 | - | Residual | 102.93 | 7 | 14.70 | - | - | - | Lack of fit | 85.13 | 3 | 28.38 | 6.380 | 0.0527 | Not significant | Pure error | 17.80 | 4 | 4.45 | - | - | - | Total deviation | 1184.52 | 16 | - | - | - | - |
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Table 3. Variance analysis for the tensile strength of in vitro skin tissue incision
Source | Sum of squares | Degree of freedom | Mean square | F value | p-value (P'>F) | Source |
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Model | 547.15 | 9 | 60.79 | 508.43 | <0.0001 | Significant | X1 | 429.25 | 1 | 429.25 | 3589.86 | <0.0001 | Significant | X2 | 18.00 | 1 | 18.00 | 150.54 | <0.0001 | Significant | X3 | 4.21 | 1 | 4.21 | 35.17 | 0.0006 | Significant | X1X2 | 1.32 | 1 | 1.32 | 11.06 | 0.0127 | Significant | X1X3 | 1.32 | 1 | 1.32 | 11.06 | 0.0127 | Significant | X2X3 | 2.72 | 1 | 2.72 | 22.77 | 0.0020 | Significant | | 60.56 | 1 | 60.56 | 506.48 | <0.0001 | Significant | | 8.76 | 1 | 8.76 | 73.27 | <0.0001 | Significant | | 13.53 | 1 | 13.53 | 113.14 | <0.0001 | Significant | Residual | 0.84 | 7 | 0.12 | - | - | - | Lack of fit | 0.41 | 3 | 0.14 | - | 0.4028 | Not significant | Pure error | 0.43 | 4 | 0.11 | - | - | - | Total deviation | 547.98 | 16 | - | - | - | - |
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Table 4. Variance analysis for peak temperature of in vitro skin tissue incision
Factorencoding value | σb /(N·cm-2) | T /℃ |
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P | v | F | P | v | F |
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-1.00 | 24.15 | 31.20 | 32.77 | 40.82 | 50.83 | 48.43 | -0.75 | 30.35 | 33.91 | 34.50 | 44.39 | 51.22 | 49.52 | -0.50 | 35.13 | 35.92 | 35.76 | 47.46 | 51.39 | 50.35 | -0.25 | 38.50 | 37.21 | 36.56 | 50.04 | 51.35 | 50.92 | 0 | 40.46 | 37.80 | 36.89 | 52.12 | 51.08 | 51.23 | 0.25 | 41.00 | 37.68 | 36.75 | 53.70 | 50.60 | 51.28 | 0.50 | 40.13 | 36.86 | 36.15 | 54.79 | 49.89 | 51.07 | 0.75 | 37.85 | 35.32 | 35.08 | 55.38 | 48.97 | 50.60 | 1.00 | 34.15 | 33.08 | 33.55 | 55.48 | 47.83 | 49.87 |
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Table 5. Tensile strength and peak temperature response values for single factor effect
Sample number | σb /(N·cm-2) | T /℃ |
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1 | 43.9 | 55.0 | 2 | 44.7 | 54.5 | 3 | 42.3 | 56.3 | 4 | 42.1 | 55.6 | 5 | 46.5 | 55.4 | 6 | 43.2 | 56.0 | 7 | 44.1 | 54.5 | 8 | 44.0 | 56.7 | 9 | 42.1 | 55.3 | 10 | 43.5 | 55.0 | Average value | 43.6 | 55.4 | Predicted value | 44.8 | 55.3 |
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Table 6. Tensile strength and peak temperature of experimental samples incision