China
Africa
Explore chapters and articles related to this topic
Additive Manufacturing of Ceramics
Published in Amit Bandyopadhyay, Susmita Bose, Additive Manufacturing, 2019
Susmita Bose, Naboneeta Sarkar, Sahar Vahabzadeh, Dongxu Ke, Amit Bandyopadhyay
With the development of this new technology, robocasting has also been applied to construct medical devices and scaffolds for tissue engineering. Calcium phosphate is one of the most common ceramics used for robocasting because of its excellent biocompatibility. TCP has been exploited to produce scaffolds using robocasting for orthopedic applications [208]. The particle size and morphology of TCP were optimized in order to prepare suspension suitable for robocasting. It turned out that TCP powders with reduced particle size and low specific surface area were more appropriate for slurry preparation. Moreover, optimal heat treatment and microstructure analysis resulted in the fabrication of TCP scaffolds with tailored performance which can be utilized for bone tissue engineering applications [209]. In another study, polylactide or polycaprolactone scaffolds with 70 wt% hydroxyapatite (HA) content and bioglass were fabricated using robocasting process. The mechanical properties of these scaffolds did not reduce significantly after submerging in simulated body fluid for 20 days. It was strongly dependent on the ratio of the organic and inorganic phase and could be controlled based on different applications [210]. HA scaffolds with multi-scale porosity to mimic the natural porous architecture of human bone has also been demonstrated. The scaffolds presented in Figure 6.24a and b resulted in excellent bone growth [211]. Information about ceramic suspension utilized for robocasting is given in Table 6.5.
Future Trends in Towpreg-Based Thermoplastic Composites
Published in R. Alagirusamy, Flexible Towpregs and Their Thermoplastic Composites, 2022
The robocasting process is also known as direct ink writing or 3D-plotting process. This process involves the extrusion of viscous polymer liquid from a pressurized orifice. In this technique, the printing platform is stationary while the orifice head moves in all three directions to create a layer-by-layer print product. The quality of the final robocasted product depends on the material viscosity and deposition speed. This technique has a vast range of material flexibility. Ceramics, solutions, suspensions and pastes of materials can be processed in this method.
Additive Manufacturing of Ceramics
Published in Mohamed N. Rahaman, Ceramic Processing, 2017
Robocasting is a method based on computer-controlled, layer-by-layer deposition of a concentrated slurry or paste by extrusion through a nozzle of diameter ranging from ~100 to ~2000 µm (Figure 11.12) [14]. The slurry typically contains ceramic particles and organic additives to achieve as high a particle concentration as possible, coupled with the requisite rheology for extrusion through the nozzle. Following the robocasting step, the as-formed article is dried, heated to burn out the binder, and sintered to produce the final article.
Use of additive manufacturing for the fabrication of cellular and lattice materials: a review
Published in Materials and Manufacturing Processes, 2021
Esmeralda Uribe-Lam, Cecilia D. Treviño-Quintanilla, Enrique Cuan-Urquizo, Oscar Olvera-Silva
Robocasting (RC) has been used for more than a decade as a 3D printing alternative for ceramic materials. Due to the nature of the process to produce open, controlled, and interconnected porosity, this technique is applied to ceramic grids and tissue engineering scaffolds with controlled architectures. The main challenge in the use of this technique is to find the appropriate characteristics and properties for the slurry to achieve the viscoelastic behavior required. As robocasting is an extrusion-based process, the ink or slurry needs to have a dominant elastic behavior and shear thinning to allow the flow through the nozzle.[92] In a recent study, [93] simple and complex (ABAB) circular lattices were fabricated using robocasting with interconnected pores of 200–800 µm between them. Results for compressive strength of these structures were in the range of 32–178 MPa. Additionally, they found that under an applied stress this type of structure fractures gradually instead of catastrophically. This is attributed to the nature of the materials and the lattice topology. In robocasting, the equilibrium between the scaffold porosity required for bone tissue growth and the strength is one of the challenges which research has focused on.
Multi-material additive manufacturing of low sintering temperature Bi2Mo2O9 ceramics with Ag floating electrodes by selective laser burnout
Published in Virtual and Physical Prototyping, 2020
Reza Gheisari, Henry Chamberlain, George Chi-Tangyie, Shiyu Zhang, Athanasios Goulas, Chih-Kuo Lee, Tom Whittaker, Dawei Wang, Annapoorani Ketharam, Avishek Ghosh, Bala Vaidhyanathan, Will Whittow, Darren Cadman, Yiannis C. Vardaxoglou, Ian M. Reaney, Daniel S. Engstrøm
The attention of many researchers has now turned to AM of multi-material structures and a variety of AM processes capable of fabricating such structures have recently emerged with improved printing resolution. These techniques are developing rapidly owing to the capability of making composite structures that obtain their unique properties (e.g. mechanical, electrical, etc.) through a single component made of different materials (metal, ceramic, and polymer). Among the leading AM techniques, robocasting is highly utilised technique which takes advantage of computer-controlled robotic system capable of depositing colloidal suspensions to create 3D structures with a wide range of materials and reduced fabrication cost (Tuttle et al. 2001; Lewis et al. 2006; Lu et al. 2009; Cai et al. 2012; Maazouz et al. 2014; Jakus et al. 2015; Zhao et al. 2017; Peng et al. 2018). Since the process is in a layered manner, it is feasible to tailor the properties of such components by controlling the dimensions of its features.
Development of hybrid multi-head, multi-material paste and ink extrusion type 3D printer for biomedical applications
Published in Journal of Asian Ceramic Societies, 2023
Jishita Ravoor, S.Renold Elsen, Mahendran Thangavel, Dhanabal Arumugam, Deepan Karuppan
The ceramic additive manufacturing sector is a booming industry with $402 million in revenue generated worldwide in 2021, even though the pandemic struck the economy badly and it is expected to reach $3.678 billion by 2028 [1,2]. High-performance ceramics are used in diverse applications for their desirable properties like high hardness, resistance to heat and abrasion, corrosion, and oxidation, in addition to electrical and thermal insulation effects [3,4]. The ceramic additive manufacturing process can be broadly categorized into Vat polymerization, Material Extrusion, Powder Bed Fusion, Binder Jetting, and Material Jetting [5]. Techniques such as Vat polymerization, Binder jetting, and powder bed fusion have certain disadvantages associated with the high equipment cost, limitations associated with particle size and particle size distribution, and high material waste. Whereas, material extrusion-based systems are economical and combat material waste. In the material extrusion-based additive manufacturing technique the material is extruded through a nozzle under the applied mechanical force coupled with temperature and pneumatic pressure. Some of the material extrusion-based techniques include fused filament deposition (FDM) and robocasting/direct ink writing [6]. Robocasting is established as a more suitable method for 3D printing with the leverage to use a wide range of materials, and the ability to print smaller to largest-sized parts with good precision. It can facilitate multi-material printing with the incorporation of multiple print heads, multiple materials can be printed at different layers at the same time. Powder particles with a heterogeneous size distribution can be printed by optimizing the viscosity of the employed slurries. Most robocasting-based printers available in the market consist of single extruder heads and a limited pressure range. Few multi-material print head designs are available in the literature, and the merits and demerits of the reported designs are discussed as follows. A single print head with multiple inlets for material administration multi-material printing is enabled by making multiple material holders that are connected to a single extruder through which different materials flow at different times or all the materials can be extruded together. Some multi-material printers have two material inlets through which two different materials are mixed using a mixer blade to form functionally graded materials. This model comes with a bulky head design and cannot print multiple materials on multiple layers. Another printer design with three different material inlets M1, M2, and M3 pushed out of the nozzle using a screw extruder. It offers to print highly viscous materials but is difficult to control the flow control while printing subsequent materials. In a simple screw-based extruder system, multiple material inlets were placed adjacent to the extruder pipe. This printer has few parts compared to other designs, but controlling the inlet flow pressure is difficult. In another printer design with three material inlets M1, M2, and M3, the flow is controlled by the pneumatic piston arrangement. It creates different dynamics inside the extruder causing inconsistent material flow [7].