3Y-TZP DLP Additive Manufacturing: Solvent-free Slurry Development and Characterization

Abstract

Vat photopolymerization (VP) stands out among ceramic additive manufacturing processes for its ability to print sub-100 micrometer complex features. One of the main challenges of this process is the preparation of a homogeneous and stable ceramic slurry with a high solid load and low viscosity. In this work, different dispersants and resins were tested, aiming to provide a solvent-free slurry suitable for DLP additive manufacturing. Disperbyk-111 and PEGDA 250 stood out in the tests, providing a 40 vol% ceramic slurry with no noticeable sedimentation and viscosity of 2.3 Pa.s at 30 s -1 despite the relatively high specific surface area (15 m 2 /g) of the 3Y-TZP powder used compared to powders usually used for VP slurries. The adsorption of Disperbyk-111 on ceramic particles surface was investigated by FTIR. Finally, ceramic bodies were 3D printed, debound and sintered at 1500 ºC for 2 h, confirming the ability to manufacture detailed dense ceramic parts.

Fabrication of ceramics using photosensitive slurries: A comparison between UV-casting replication and vat photopolymerization 3D printing

“…Both additive manufactured parts presented visible cracks and delamination. Moreover, the rotor 3D printed with inclined orientation showed distortion which may be due to the difference in shrinkage between the building direction and the projection plane, which is intrinsic anisotropy of this layered process [5,19,20,26]. On the other hand, the UV-casted rotor showed no visible crack or delamination.…”

“…Two photosensitive ceramic suspensions were prepared according to the route proposed by Camargo et al [19]: i) mullite and ii) 3Y-TZP/mullite composite (4 mol% of mullite) slurries. Therefore, ground electrofused mullite powder with the mean particle size of 0.6 µm (MUB, Elfusa, Brazil) and/or partially stabilized zirconia powder with the mean particle size of 0.04 µm (TZ-3Y-E, Tosoh Corporation, Japan) were processed with the monomer (Poly(ethylene glycol) diacrylate, PEGDA M n = 250, Sigma Aldrich, USA), dispersant (DISPERBYK-111, BYK-Chemie, Germany), and photoinitiator (Phenylbis(2,4,6trimethylbenzoyl)phosphine oxide, Sigma Aldrich, USA) for 24 h in a ball-mill to create homogeneous slurries.…”

“…All the prepared suspensions had a ceramic loading of 40 vol.%, and the amount of used photoinitiator was 2 wt.% of the monomer. Also, the amount of the dispersant was defined as 3 wt.% of the ceramic powder, a proportion indicated as optimal for the used powders in related works [19,20]. The rheological behaviour of the prepared ceramic suspensions was characterized using a rotational viscometer (DV2T extra, Brookfield, Canada) between 23 and 25 °C.…”

A review on the ceramic additive manufacturing technologies and availability of equipment and materials

“…Moreover, the photosensitive slurry (feedstock) have several requirements concerning Wuhan Huake 3D Technol. [162] China HK C250 250x250x250 [158] Figure 12: Zirconia part fabricated by vat photopolymerization [174]. ceramic loading (>40 vol% [177,178]), proper rheological behavior (<3 Pa.s [4,177,179]), stability, etc.…”

“…These systems have a dedicated recoating system [4,355,356] which allows the spreading of constant and homogeneous micrometric layers even for high viscosity feedstock as the high ceramic loading photosensitive suspensions [357]. On the other hand, research using home-built prototypes [174,189,357,358] and low-cost 3D printers [198,359,360], commonly used in the manufacturing of polymers, have emerged and may be a suitable solution for the use of the technique in laboratories and small businesses.…”