Robocasting ( Robocasting , in English sources also uses the term Eng. Direct Ink Writing , DIW) is an additive technology that implements layer-by-layer 3D printing of an object by extrusion of “ink” through the forming hole of the head of a 3D printer. The technology was first applied in the USA in 1996 for the manufacture of geometrically complex ceramic objects [1] . 3D objects made using CAD are divided into layers in robocasting in the same way as in other 3D printing technologies. Liquid (usually ceramic slurry), similar to conventional printing technologies called “ink”, comes through a small-diameter nozzle that moves in accordance with the digital CAD model. "Ink" comes out of the nozzle in a liquid state, but immediately assumes the desired shape due to dilatancy . This distinguishes robocasting from fusion modeling , since it does not require hardening or drying of the "ink", they immediately take the desired shape.
Technology
The use of robocasting technology begins with creating an STL file with a calculation of the diameter of the forming hole. The first part of the product made by robocasting is obtained by extrusion of “ink” filaments into the first layer. Further, the working area is shifted down or the forming hole rises up and the next layer is applied at the desired location. This is repeated until the product is completed. When using numerically controlled mechanisms, as a rule, the movements of the forming hole are controlled by application software developed by CAM . Stepper motors and servomotors are usually used to move the forming hole with an accuracy of nanometers [2] .
After manufacturing the product by robocasting, drying and other methods are usually used to give the product the required mechanical properties.
Depending on the composition of the “ink”, printing speed and environmental conditions, robocasting, as a rule, makes it possible to produce structures of considerable length (many times the diameter of the forming hole) and not supported from the bottom [3] . This makes it easy enough to produce 3D designs of a rather complex shape, which is impossible when using other additive technologies, which is extremely promising for the production of photonic crystals , bone grafts , filters, etc. Robocasting allows printing of products of any shape and in any position.
Application
Robocasting allows the manufacture of loose ceramic products that need to be fired before further use (by analogy with a ceramic clay pot), products of a wide variety of geometric shapes and sizes, up to micro-scale “scaffolding” [4] . Today, robocasting is most in demand in the production of biocompatible materials for artificial organs : by 3D scanning, you can determine the exact shape of the desired tissue or organ, develop its digital 3D model and print, for example, calcium phosphate or hydroxyapatite [5] . Other potential applications of robocasting include the production of objects with a complex surface structure such as multilayer catalysts or electrolytic fuel cells [6] .
Robocasting can also be used for applying polymer and gel inks with forming hole diameters <2 μm, which is impossible in the case of ceramic inks [2] .
Notes
- ↑ Stuecker, J. Advanced Support Structures for Enhanced Catalytic Activity (Eng.) // Industrial & Engineering Chemistry Research : journal. - 2004. - Vol. 43 , no. 1 . - DOI : 10.1021 / ie030291v .
- ↑ 1 2 Xu, Mingjie; Gratson, Gregory M .; Duoss, Eric B. .; Shepherd, Robert F .; Lewis, Jennifer A. Biomimetic silicification of 3D polyamine-rich scaffolds assembled by direct ink writing // Soft Matter: journal. - 2006. - Vol. 2 , no. 3 . - P. 205 . - ISSN 1744-683X . - DOI : 10.1039 / b517278k .
- ↑ Smay, James E .; Cesarano, Joseph; Lewis, Jennifer A. Colloidal Inks for Directed Assembly of 3-D Periodic Structures // Langmuir: journal. - 2002. - Vol. 18 , no. 14 . - P. 5429-5437 . - ISSN 0743-7463 . - DOI : 10.1021 / la0257135 .
- ↑ Lewis, Jennifer. Direct Ink Writing of 3D Functional Materials (Eng.) // Advanced Functional Materials : journal. - 2006. - Vol. 16 , no. 17 . - P. 2193-2204 . - DOI : 10.1002 / adfm.200600434 .
- ↑ Miranda, P. Mechanical properties of calcium phosphate scaffolds fabricated by Robocasting. (English) // Journal of Biomedical Materials: journal. - 2008 .-- Vol. 85 , no. 1 . - P. 218—227 . - DOI : 10.1002 / jbm.a.31587 .
- ↑ Kuhn Melanie , Napporn Teko , Meunier Michel , Vengallatore Srikar , Therriault Daniel. Direct-write microfabrication of single-chamber micro solid oxide fuel cells // Journal of Micromechanics and Microengineering. - 2007. - November 28 ( t. 18 , No. 1 ). - S. 015005 . - ISSN 0960-1317 . - DOI : 10.1088 / 0960-1317 / 18/1/015005 .