Abstract
The flexible extrusion forming process (FEFP) is a sand mold patternless manufacturing technology that enables digital near-net shaping of complex sand molds. But, it is difficult to achieve the gradient sand molds with high surface strength and strong interior permeability by FEFP. To solve this problem, an extra-squeeze forming method based on FEFP for gradient sand mold was developed. To further reveal the extra-squeeze forming mechanism, based on the Johnson-Kendall-Roberts (JKR) theory and “gluing” notions, the single and double-sided squeeze models of gradient sand molds were established using the EDEM software. The squeezing processes of sand molds with different cavity depths of 60, 100, 140, 180, and 220 mm were systemically studied under single and double-sided squeeze conditions. The variation in the void fraction of sand mold as also investigated at a variety of extra-squeeze distances of 2, 3, 4, 5, and 6 mm, respectively. Simulation and test results show that a deeper cavity depth weakens the extrusion force transmission, which leads to a decrease in strength. The sand mold permeability and void fraction are identified to be positively correlated, while the tensile strength and void fraction appear to be negatively correlated. The void fraction of sand molds decreases with a longer extra-squeeze distance. A 6 mm extra-squeeze distance for the sand mold with 220 mm cavity depth results in a 26.8% increase in tensile strength with only a 5.7% reduction in the permeability. Hence, the extra-squeeze forming method can improve the quality of the sand mold by producing a gradient sand mold with high surface strength and strong interior permeability.
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References
Shan Z D. Patternless casting. Beijing: China Machine Press, 2017: 13–17. (In Chinese)
Shan Z D, Yang H Q, Liu F. et al. Performance of digital patternless freeze-casting sand mould. China Foundry, 2020, 17(4): 308–313.
Liu L M, Shan Z D, Lan D, et al. Research of cutting properties of mold sand based on the precision forming technology without pattern. Foundry, 2016, 65(12): 1167–1171. (In Chinese)
Shan Z D, Zhang S, Gu Z X. Optimization algorithm research of near-net forming sand mold with digital flexible extrusion technology. Journal of Mechanical Engineering, 2016, 52(13): 149–155.
Xie B. A study on the green sand stress field in squeeze mounding and air impact moulding. Doctoral Dissertation. Beijing: Tsinghua University, 1993: 42–47.
Tsuji Y, Kawaguchi T, Tanaka T. Discrete particle simulation of two-dimensional fluidized bed. Powder Technology, 1993, 77(1): 79–87.
Parteli E J, Schmidt J, Blümel C, et al. Attractive particle interaction forces and packing density of fine glass powders. Scientific Reports, 2014, 4: 6227.
Cheng K, Wang Y, Yang Q, et al. Determination of microscopic parameters of quartz sand through tri-axial test using the discrete element method. Computers and Geotechnics, 2017, 92: 22–40.
Maeda Y, Ito Y, Yoshida S, et al. Effects of green sand particle distribution on squeeze compacting behavior analyzed by discrete element method. International Journal of Metalcasting, 2019, 13(3): 546–552.
Chen X P, Nomura H, Maeda Y. Analysis of green sand composition process applying Cooper-Eaton model. Journal of the Korea Foundry Society, 2004, 24(3): 35–41.
He Y, Evans T J, Yu A B, et al. A GPU-based DEM for modelling large scale powder compaction with wide size distributions. Powder Technology, 2018, 333: 219–228.
He Y, Hassanpour A, Behjani M A, et al. A novel stiffness scaling methodology for discrete element modelling of cohesive fine powders. Applied Mathematical Modelling, 2021, 90: 817–844.
Hovad E, Spangenberg J, Larsen P, et al. Simulating the DISAMATIC process using the discrete element method — A dynamical study of granular flow. Powder Technology, 2016, 303: 228–240.
Hovad E. Numerical simulation of flow and compression of green sand. Doctoral Dissertation. Lyngby: Technical University of Denmark, 2017: 8–18.
Li R D, Mi G F. Casting technology. Beijing: China Machine Press, 2013: 17–20. (In Chinese)
Sun Q C. Wang G Q. Introduction to particle mechanics (hardcover). Beijing: Science Press, 2009: 15–43. (In Chinese)
Guo Z. 3D printing forming methodology of multi-material sand mold. Doctoral Dissertation. Beijing: Tsinghua University, 2019: 52–55.
Johnson K L, Kendall K, Roberts A D. Surface energy and the contact of elastic solids. Procrsoclonda, 1971, 324(1558): 301–313.
Potyondy D O, Cundall P A. A bonded-particle model for rock. International Journal of Rock Mechanics and Mining Sciences, 2004, 41(8): 1329–1364.
Maeda Y, Maruoka Y, Makino H, et al. Squeeze molding simulation using the distinct element method considering green sand properties. Journal of Materials Processing Technology, 2003, 135(2–3): 172–178.
Feng Y T, Han K, Owen Y, et al. On upscaling of discrete element models: Similarity principles. Engineering Computations: International Journal for Computer-Aided Engineering, 2009, 26(6): 599–609.
Feng Y T, Owen D R J. Discrete element modelling of large scale particle systems — I: Exact scaling laws. Computational Particle Mechanics, 2014, 1(2): 159–168.
Acknowledgements
This work was financially supported by the National Innovation Center Fund of Lightweight Material Forming Technology and Equipment (No. 111902Q-D), the State Key Laboratory Fund of Advanced Forming Technology and Equipment (No. SKL2020008), and the National Key Research and Development Program (No. 2020YFF0217703).
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Zhong-de Shan Male, born in 1970, Academician of Chinese Academy of Engineering, doctoral supervisor. His research interests mainly focus on digital mechanical equipment and advanced forming manufacturing technology. To date, he has published more than 80 papers and 4 books. E-mail: shanzd@cam.com.cn
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Jiang, Eb., Shan, Zd., Cheng, G. et al. Simulation and experimental research on extra-squeeze forming method during gradient sand molding. China Foundry 19, 288–298 (2022). https://doi.org/10.1007/s41230-022-1130-2
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DOI: https://doi.org/10.1007/s41230-022-1130-2