3D printing vertically: Direct ink writing free-standing pillar arrays. (May 2020)

• Record Type: Journal Article
• Authors: Nan, Bo; Galindo-Rosales, Francisco J.; Ferreira, José M.F.
• Is Part Of: Materials today. Volume 35(2020)
• Page Start: 16
• Page End: 24
• Publication Date: 2020-05
• Subjects: DIW direct ink writing -- DOD drop-on-demand -- FOD filament-on-demand -- LVR linear viscoelastic region -- 3ITT three interval thixotropy test -- SAOS/LAOS small and large amplitude oscillatory shear; Materials science -- Periodicals; Metallurgy -- Periodicals; Metal-work -- Periodicals; Biomedical and Dental Materials -- Periodicals; Manufactured Materials -- Periodicals; Metals -- Periodicals; 620.11
• DOI: 10.1016/j.mattod.2020.01.003
• Languages: English
• ISSNs: 1369-7021

Abstract

Graphical abstract: Highlights: Free-standing pillar arrays are firstly 3D printed in the vertical direction. Precise control is applied to start, cease and restart the flow. The thixotropic flow behavior of the printable inks is analyzed by 3ITT. Pillar arrays made of various materials are applicable in many advanced areas. Versatile degrees of freedom can inspire tissues and organs printing. Abstract: Over the last three decades, a variety of additive manufacturing techniques have gradually gained maturity and will potentially play an important role in future manufacturing industries. Among them, direct ink writing has attracted significant attention from both material and tissue engineering areas, where the colloidal ink is extruded and dispensed according to a pre-designed path, usually in the X - Y plane with suitable increments in the Z direction. Undoubtedly, this way of disassembling geometries, simple or complex, can facilitate most of the printing process. However, for one extreme case, i.e. pillar arrays, the size resolution can deviate from both nozzle and design if the common way of slicing and additive manufacturing is used. Therefore, a different printing path is required – directly depositing pillars in a converse gravitational direction. This paper gives multiple examples of printing viscoelastic colloidal ceramic and metal inks uniaxially and periodically into free-standing and height-adjustable pillar arrays. It is expected to inspire the additive manufacturing community that more versatile degrees of freedom and complex printing paths, not confined within only complex shapes, can be achieved by ink-based 3D printing.