Non-planar multinozzle additive manufacturing of thermoset composite microscaffold networks

Non‐Planar Multiprocess Additive Manufacturing of Multifunctional Composites

“…The error is only 30 µm larger than the nozzles diameter of the multinozzle, which is not a problem for deposition of the thermosetting filaments. [ 49 ]…”

“…The NURBS surface was then used to generate a non‐planar multinozzle AM toolpath using the Multinozzle Toolpath Generator, a custom software based on non‐planar parameterized surface projection, developed in previous work. [ 49 ] The toolpath was generated to fabricate a non‐planar microscaffold network and imported in a robotic simulation software (RoboDK, version 5.4.1) to solve the inverse kinematic problem for each coordinate of the toolpath. The toolpath was then converted to TPP and imported to the 6‐axis robot controller.…”

“…The error is only 30 μm larger than the nozzles diameter of the multinozzle, which is not a problem for deposition of the thermosetting filaments. [49] In the multinozzle process, the observed shear-thinning behavior of the 0GM12FS formulation (Figure 1d), fitted by a power law (i.e., n = 0.3578, K = 6,673 Pa s n ), facilitates the highly viscous material extrusion by reducing the apparent viscosity of the material 𝜂 app to ≈20-50 Pa s for process-related shear rates of ̇𝛾w ≈ 10 3 -10 4 s −1 . The immediate recovery of shear storage modulus G′ and its dominance over the shear loss modulus G″ after removal of high shear stress (Figure 1e) allow the printed thermosetting filaments to keep their shape upon extrusion for a working time of up to 45 min.…”

“…[ 45–47 ] The addition of a multinozzle printhead to a 6‐axis robot arm has been shown to reduce the time it takes to print high‐resolution large‐scale microscaffold networks made of thermosetting polymer. [ 48,49 ]…”

“…[45][46][47] The addition of a multinozzle printhead to a 6-axis robot arm has been shown to reduce the time it takes to print high-resolution large-scale microscaffold networks made of thermosetting polymer. [48,49] In this work, two different AM technologies, including FFF of HTRP and multinozzle DIW of a thermosetting composite are integrated into a multiprocess AM approach using a 6axis robot arm to demonstrate a manufacturing proof-of-concept of a large-scale non-planar complex multifunctional part. The achievement of this objective is demonstrated by manufacturing a relatively large non-planar aircraft component demonstrator, composed of a curved high-performance thermoplastic sandwich panel and a network of interconnected abradable thermosetting microscaffolds.…”