Additive manufacturing of multi-material and hollow structures by Embedded Extrusion-Volumetric Printing.

Tomographic volumetric additive manufacturing support-free 3D printing has significantly faster print speed than traditional vat photopolymerization and material extrusion techniques. At the same time, tomographic volumetric additive manufacturing allows the embedding of external objects in the print volume before the print to produce complex multi part assemblies by so-called overprinting. As tomographic volumetric additive manufacturing increases its popularity, more and more of its limitations with regards to available materials are removed, and printing with acrylates, ceramics and glasses has been shown. However, creating multi material parts without resorting to overprinting is still challenging. Here, multi-material tomographic volumetric additive manufacturing printing is presented by combining tomographic volumetric additive manufacturing and Embedded 3D printing: photopolymerizable support baths are used to deposit inks in defined shapes allowing the consecutive definition and volumetric printing of multi-material structures via tomographic volumetric additive manufacturing. We show the fabrication of several multi-material structures with arbitrarily positioned materials, as well as chips with microchannels having diameters lower than 120 µm.