Würzburg, Germany — Two presentations at the biannual SKZ Süddeutsches Kunststoffzentrum Silicone Elastomers conference in Würzburg addressed recently introduced liquid silicone rubber 3D printing systems.
Florian Liesener, manager of the new ACEO 3D printing business unit at Wacker Chemie AG in Burghausen, Germany, classified the company's new drop-on-demand (DOD) material dosing of silicone in viscous paste form.
He pointed out that DOD differs from the commonly used fused filament fabrication (FFF) used in fused deposition modeling (FDM) from extruded plastic filaments.
Samples included a branched blood vessel model and an ear implant, as well as net cube cubic lattice grid structures with crosswise superimposed beams, the latter described as an example of "producing the impossible."
For Wacker, opening the ACEO campus with its Open Print Lab in mid-2016 preceded the world premiere of the company's package of 3D printing LSR materials at K 2016.
Liesener called ACEO "a true system solution" with the ACEO campus functioning as a service provider, also via a worldwide web shop.
Bernd Pachaly, Wacker's silicones research head, said the ACEO research team started developing a 3D printing system for LSR in 2014. The company compared the process to squeezing toothpaste out of a tube, with the LSR material shear thinning for easy flow when under pressure, then sitting firmly in position when higher viscosity returns with removal of shear force.
ACEO prints "voxels" (volume elements) in its contactless DOD system, followed by curing activation of each layer by ultraviolet light in less than one second. The printed part is subsequently post-cured at elevated temperature. A water-soluble support material enables overhangs and cavities and is rinsed away by hand from fully cured parts.
Liesener said ACEO offers LSR materials for 3D printing that result in cured parts between Shore A 10 (soft) to Shore A 80 (hard). A variety of colors are available.
Food contact and biocompatibility test data are expected in the third quarter. Work continues on material developments, with completion dates for optical transparency expected in 2017, adhesion in 2018, media resistance in 2019 and electrical conductivity in 2018/2019, Liesener said.