3D-printed shell-truss sand mold for aluminum castings

Shangguan, Haolong; Kang, Jinwu; Deng, Chenglong; Hu, Yongyi; Huang, Tao

doi:10.1016/j.jmatprotec.2017.05.010

Cited by 58 publications

(31 citation statements)

References 8 publications

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“…The cooling efficiency of the lattice-reinforced shell sand mold was much higher than that of the traditional dense sand mold. This could increase the cooling efficiency by at least 30% for the lattice-reinforced shell sand mold casting compared to the traditional dense sand mold casting [16]. This was attributed to the fact that the lattice-reinforced shell sand mold had thin walls and a high surface temperature, resulting in high heat transfer efficiency with the surrounding air.…”

Section: Wheel Hub Casting Experiments Results and Discussionmentioning

confidence: 99%

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The Design of 3D-Printed Lattice-Reinforced Thickness-Varying Shell Molds for Castings

Shangguan

Kang

et al. 2018

Materials

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3D printing technologies have been used gradually for the fabrication of sand molds and cores for castings, even though these molds and cores are dense structures. In this paper, a generation method for lattice-reinforced thickness-varying shell molds is proposed and presented. The first step is the discretization of the STL (Stereo Lithography) model of a casting into finite difference meshes. After this, a shell is formed by surrounding the casting with varying thickness, which is roughly proportional to the surface temperature distribution of the casting that is acquired by virtually cooling it in the environment. A regular lattice is subsequently constructed to support the shell. The outside surface of the shell and lattice in the cubic mesh format is then converted to STL format to serve as the external surface of the new shell mold. The internal surface of the new mold is the casting’s surface with the normals of all of the triangles in STL format reversed. Experimental verification was performed on an Al alloy wheel hub casting. Its lattice-reinforced thickness-varying shell mold was generated by the proposed method and fabricated by the binder jetting 3D printing. The poured wheel hub casting was sound and of good surface smoothness. The cooling rate of the wheel hub casting was greatly increased due to the shell mold structure. This lattice-reinforced thickness-varying shell mold generation method is of great significance for mold design for castings to achieve cooling control.

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Section: Wheel Hub Casting Experiments Results and Discussionmentioning

confidence: 99%

“…Kang et al presented new mold structures, which contain a mold shell, with functional structures and an enforced skeleton [14,15,16]. Due to its unique structural features, the model construction of this type of molds is hard and time-consuming.…”

Section: Introductionmentioning

confidence: 99%

The Design of 3D-Printed Lattice-Reinforced Thickness-Varying Shell Molds for Castings

Shangguan

Kang

et al. 2018

Materials

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“…The different contraction of the thick and thin bars would introduce stress into the casting during the casting process, and this was used to investigate its residual stress Materials 2020, 13, 1596 8 of 28 and deformation. A skeletal sand mold with a bounding size of 400 mm × 300 mm × 180 mm and a shell of 10 mm thickness as well as a lattice support structure with 10 mm × 10 mm bars and 50 mm × 50 mm × 50 mm spacing was designed using a software developed by Shuangguan et al [14], as shown in Figure 4c. The casting and skeletal sand mold were meshed into tetrahedron elements, as shown in Figure 4b,d, and then the heat transfer during casting process was analyzed by ProCast, a commercial software from ESI Company for the casting analysis.…”

Section: Thermo-mechanical Simulation Of the Casting Process Of A Strmentioning

confidence: 99%

“…Materials 2020, 13, x FOR PEER REVIEW 8 of 28 of 10 mm thickness as well as a lattice support structure with 10 mm × 10 mm bars and 50 mm × 50 mm × 50 mm spacing was designed using a software developed by Shuangguan et al [14], as shown in Figure 4c. The casting and skeletal sand mold were meshed into tetrahedron elements, as shown in Figure 4b,d, and then the heat transfer during casting process was analyzed by ProCast, a commercial software from ESI Company for the casting analysis.…”

Section: Thermo-mechanical Simulation Of the Casting Process Of A Strmentioning

confidence: 99%

Modeling and Simulation of the Casting Process with Skeletal Sand Mold

et al. 2020

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The author-proposed skeletal sand mold, which mainly includes a shell, air cavities and a truss support structure, has been experimentally proven to be very useful in controlling the cooling of casting at local areas and at different periods of the casting process. The modeling and simulation of the casting process using a skeletal sand mold were systemically analyzed. Complicated casting/mold and mold/air boundaries, and the thermal and mechanical behavior of the skeletal sand mold during the casting process were highlighted. A numerical simulation of the casting process of a stress frame specimen using a skeletal sand mold was performed. The temperature, stress and displacement fields of the casting and skeletal sand mold were obtained and compared with those using a traditional sand mold. The simulated results were validated with experiments. Using the skeletal sand mold, the cooling rate of the casting can be greatly improved due to the significant heat release from mold surface to environment. The residual stress and deformation of the casting can be reduced because of the decreased stiffness of this kind of mold. Although the skeletal sand mold is susceptible to cracking, it can be avoided by filleting in the conjunctions and increasing the shell thickness.

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“…The present study shows a combination of additive manufacturing, in which fused filament fabrication (PLA) is used to produce the intermediate investment model to be cast in ceramic block by investment casting. Although there are already studies that use similar techniques (e.g., 3D printing of sand molds [52][53][54][55][56], wax, and PLA/ABS [52][53][54][55][56]), the proposed study recurs to vacuum as an auxiliary technique for the filling of thin-rib and high aspect ratio complex three-dimensional metallic scaffolds. Additionally, vacuum is also used to promote the sanity of the resultant samples, as it is known to reduce oxide inclusion [57,58] and porosity [59,60].…”

Section: Introductionmentioning

confidence: 99%

Thin-Rib and High Aspect Ratio Non-Stochastic Scaffolds by Vacuum Assisted Investment Casting

Carneiro¹,

Puga

Peixinho³

et al. 2019

JMMP

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Cellular structures are a classic route to obtain high values of specific mechanical properties. This characteristic is advantageous in many fields, from diverse areas such as packaging, transportation industry, and/or medical implants. Recent studies have employed additive manufacturing and casting techniques to obtain non-stochastic cellular materials, thus, generating an in situ control on the overall mechanical properties. Both techniques display issues, such as lack of control at a microstructural level in the additive manufacturing of metallic alloys and the difficulty in casting thin-rib cellular materials (e.g., metallic scaffolds). To mitigate these problems, this study shows a combination of additive manufacturing and investment casting, in which vacuum is used to assist the filling of thin-rib and high aspect-ratio scaffolds. The process uses 3D printing to produce the investment model. Even though, vacuum is fundamental to allow a complete filling of the models, the temperatures of both mold and casting are important to the success of this route. Minimum temperatures of 250 °C for the mold and 700 °C for the casting must be used to guarantee a successful casting. Cast samples shown small deviations relatively to the initial CAD model, mainly small expansions in rib length and contraction in rib thickness may be observed. However, these changes may be advantageous to obtain higher values of aspect ratio in the final samples.

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3D-printed shell-truss sand mold for aluminum castings

Cited by 58 publications

References 8 publications

The Design of 3D-Printed Lattice-Reinforced Thickness-Varying Shell Molds for Castings

The Design of 3D-Printed Lattice-Reinforced Thickness-Varying Shell Molds for Castings

Modeling and Simulation of the Casting Process with Skeletal Sand Mold

Thin-Rib and High Aspect Ratio Non-Stochastic Scaffolds by Vacuum Assisted Investment Casting

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