Study on the Geometric Design of Supports for Overhanging Structures Fabricated by Selective Laser Melting
Abstract
:1. Introduction
2. Solid Piece as Support Structure for Heat Dissipation
3. Experimental Methods
3.1. Equipment and Material
3.2. Experimental Design
3.2.1. Design of Specimens
3.2.2. The Taguchi Method
3.2.3. Evaluation of Deformation and Surface Roughness
4. Results and Discussion
4.1. Effect of Supports on the Deformation
4.2. Tensile Property, Morphology and Microstructure
4.3. Effect of Supports on the Roughness
5. Example of Support Addition
6. Conclusions
- Solid pieces or cuboids as support structures can reduce the deformation and then increase the forming property of SLMed overhanging structure through improving the heat dissipation condition;
- The teeth connecting supports and part are more effective than the added solid cuboids at resisting the deformation of part. Therefore, when designing the support structure, the parameters related to the tooth geometry should be mainly considered;
- The strength of the support teeth can be weakened approximately from 495 MPa to 396 MPa and then to 127 MPa by narrowing the gap between the cuboids and the overhang from 0.72 mm to 0.48 mm and then to 0.24 mm. Similar to the main body of the tensile specimen, small amount of martensite α’ can also be found in the support teeth. The thickness of support teeth is unstable along the building direction and increases layer-by-layer;
- The distance between every two adjacent walls of support and the gap between the cuboids and the overhang, respectively, most influence the part’s deformation and surface quality. As the gap between the cuboids and the overhang decreases, the bottom surface of part has a better quality.
- Absolutely, the gap between the cuboids and the overhang cannot be too small. A gap of 0.3 mm is preferred to form a non-assembly mechanical structure in this work.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Elements | Al | V | Fe | O | C | N | H | Ti |
---|---|---|---|---|---|---|---|---|
Content (wt. %) | 5.5–6.75 | 3.5–4.5 | <0.3 | <0.2 | <0.08 | <0.05 | <0.015 | Balance |
Process Parameter | Value |
---|---|
Laser power | 170 W |
Scanning speed | 1250 mm/s |
Hatch distance | 100 µm |
Spot diameter | 100 µm |
Layer thickness | 30 µm |
Preheating temperature | 35 °C |
Atmosphere | Ar (Oxygen level <0.1%) |
Level | Gupper (mm) | Hcuboid (mm) | Glower (mm) | Dhatch (mm) | Ltop (mm) | Gteeth (mm) |
---|---|---|---|---|---|---|
1 | 0.30 | 0 | 0 | 0.5 | 0.3 | 0.3 |
2 | 0.45 | 0.6 | 0.6 | 1.0 | 0.6 | 0.6 |
3 | 0.75 | 3.0 | 3.0 | 1.5 | 1.0 | 1.0 |
N | Gupper (mm) | Hcuboid (mm) | Glower (mm) | Dhatch (mm) | Ltop (mm) | Gteeth (mm) | Warp (–) | Roughness (µm) | S/NW (dB) | S/NR (dB) |
---|---|---|---|---|---|---|---|---|---|---|
1 | 0.3 | 0 | 0 | 0.5 | 0.3 | 0.3 | 3 | 16.9 | −9.54 | −24.56 |
2 | 0.3 | 0 | 0 | 1 | 0.6 | 0.6 | 4 | 17.3 | −12.04 | −24.76 |
3 | 0.3 | 0 | 0 | 1.5 | 1 | 1 | 4 | 17.1 | −12.04 | −24.66 |
4 | 0.45 | 0.6 | 0.6 | 0.5 | 0.3 | 0.3 | 1 | 20.9 | 0.00 | −26.40 |
5 | 0.45 | 0.6 | 0.6 | 1 | 0.6 | 0.6 | 3 | 21.2 | −9.54 | −26.53 |
6 | 0.45 | 0.6 | 0.6 | 1.5 | 1 | 1 | 4 | 21.7 | −12.04 | −26.73 |
7 | 0.75 | 3 | 3 | 0.5 | 0.3 | 0.3 | 1 | 23.4 | 0.00 | −27.38 |
8 | 0.75 | 3 | 3 | 1 | 0.6 | 0.6 | 1 | 24.1 | 0.00 | −27.64 |
9 | 0.75 | 3 | 3 | 1.5 | 1 | 1 | 2 | 23.8 | −6.02 | −27.53 |
10 | 0.3 | 0.6 | 3 | 0.5 | 0.6 | 1 | 3 | 16.5 | −9.54 | −24.35 |
11 | 0.3 | 0.6 | 3 | 1 | 1 | 0.3 | 1 | 16.1 | 0.00 | −24.14 |
12 | 0.3 | 0.6 | 3 | 1.5 | 0.3 | 0.6 | 4 | 15.8 | −12.04 | −23.97 |
13 | 0.45 | 3 | 0 | 0.5 | 0.6 | 1 | 1 | 17.6 | 0.00 | −24.91 |
14 | 0.45 | 3 | 0 | 1 | 1 | 0.3 | 1 | 16.8 | 0.00 | −24.51 |
15 | 0.45 | 3 | 0 | 1.5 | 0.3 | 0.6 | 4 | 17.1 | −12.04 | −24.66 |
16 | 0.75 | 0 | 0.6 | 0.5 | 0.6 | 1 | 1 | 22.3 | 0.00 | −26.97 |
17 | 0.75 | 0 | 0.6 | 1 | 1 | 0.3 | 1 | 20.1 | 0.00 | −26.06 |
18 | 0.75 | 0 | 0.6 | 1.5 | 0.3 | 0.6 | 4 | 21.5 | −12.04 | −26.65 |
19 | 0.3 | 3 | 0.6 | 0.5 | 1 | 0.6 | 1 | 13.8 | 0.00 | −22.80 |
20 | 0.3 | 3 | 0.6 | 1 | 0.3 | 1 | 3 | 13.3 | −9.54 | −22.48 |
21 | 0.3 | 3 | 0.6 | 1.5 | 0.6 | 0.3 | 2 | 14.7 | −6.02 | −23.35 |
22 | 0.45 | 0 | 3 | 0.5 | 1 | 0.6 | 1 | 18.2 | 0.00 | −25.20 |
23 | 0.45 | 0 | 3 | 1 | 0.3 | 1 | 4 | 18.5 | −12.04 | −25.34 |
24 | 0.45 | 0 | 3 | 1.5 | 0.6 | 0.3 | 1 | 19 | 0.00 | −25.58 |
25 | 0.75 | 0.6 | 0 | 0.5 | 1 | 0.6 | 1 | 19.8 | 0.00 | −25.93 |
26 | 0.75 | 0.6 | 0 | 1 | 0.3 | 1 | 4 | 18.6 | −12.04 | −25.39 |
27 | 0.75 | 0.6 | 0 | 1.5 | 0.6 | 0.3 | 3 | 19 | −9.54 | −25.58 |
Warp 1 | Warp 2 | Warp 3 | Warp 4 |
Level | Gupper | Hcuboid | Glower | Dhatch | Ltop | Gteeth |
---|---|---|---|---|---|---|
1 | −7.863 | −6.412 | −7.472 | −2.121 | −8.810 | −2.789 |
2 | −5.074 | −7.195 | −5.465 | −6.134 | −5.188 | −6.412 |
3 | −4.405 | −3.736 | −4.405 | −9.088 | −3.345 | −8.141 |
Delta | 3.458 | 3.458 | 3.067 | 6.967 | 5.465 | 5.352 |
Rank | 4.5 | 4.5 | 6 | 1 | 2 | 3 |
Source | DOF | Seq SS | MS | F | p | Contribution (%) |
---|---|---|---|---|---|---|
Gupper | 2 | 60.57 | 30.284 | 3.30 | 0.067 | 7.71 |
Hcuboid | 2 | 59.20 | 29.600 | 3.23 | 0.070 | 7.54 |
Glower | 2 | 43.68 | 21.839 | 2.38 | 0.129 | 5.56 |
Dhatch | 2 | 220.12 | 110.062 | 12.00 | 0.001 | 28.03 |
Ltop | 2 | 139.16 | 69.582 | 7.59 | 0.006 | 17.72 |
Gteeth | 2 | 134.26 | 67.128 | 7.32 | 0.007 | 17.09 |
Error | 14 | 128.43 | 9.173 | – | – | 16.35 |
Total | 26 | 785.42 | – | – | – | 100 |
Level | Gupper | Hcuboid | Glower | Dhatch |
---|---|---|---|---|
1 | −23.90 | −25.53 | −24.99 | −25.39 |
2 | −25.54 | −25.45 | −25.33 | −25.21 |
3 | −26.57 | −25.03 | −25.68 | −25.41 |
Delta | 2.67 | 0.50 | 0.69 | 0.21 |
Rank | 1 | 3 | 2 | 4 |
Source | DOF | Seq SS | MS | F | p | Contribution (%) |
---|---|---|---|---|---|---|
Gupper | 2 | 32.7634 | 16.3817 | 22.06 | 0.000 | 65.80 |
Hcuboid | 2 | 1.3039 | 0.6519 | 0.88 | 0.433 | 2.62 |
Glower | 2 | 2.1236 | 1.0618 | 1.43 | 0.265 | 4.27 |
Dhatch | 2 | 0.2305 | 0.1152 | 0.16 | 0.857 | 0.46 |
Error | 18 | 13.3696 | 0.7428 | – | – | 26.85 |
Total | 26 | 49.7911 | – | – | – | 100 |
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Zhang, K.; Fu, G.; Zhang, P.; Ma, Z.; Mao, Z.; Zhang, D.Z. Study on the Geometric Design of Supports for Overhanging Structures Fabricated by Selective Laser Melting. Materials 2019, 12, 27. https://doi.org/10.3390/ma12010027
Zhang K, Fu G, Zhang P, Ma Z, Mao Z, Zhang DZ. Study on the Geometric Design of Supports for Overhanging Structures Fabricated by Selective Laser Melting. Materials. 2019; 12(1):27. https://doi.org/10.3390/ma12010027
Chicago/Turabian StyleZhang, Kaifei, Guang Fu, Peng Zhang, Zhibo Ma, Zhongfa Mao, and David Z. Zhang. 2019. "Study on the Geometric Design of Supports for Overhanging Structures Fabricated by Selective Laser Melting" Materials 12, no. 1: 27. https://doi.org/10.3390/ma12010027
APA StyleZhang, K., Fu, G., Zhang, P., Ma, Z., Mao, Z., & Zhang, D. Z. (2019). Study on the Geometric Design of Supports for Overhanging Structures Fabricated by Selective Laser Melting. Materials, 12(1), 27. https://doi.org/10.3390/ma12010027