Desktop direct sound 3D printing

3D printing has revolutionized the manufacturing process over the last decade, and the development continues. Recently it was shown that silicone rubber can be rapidly and locally cured using ultrasound. While these findings open the stage for 3D printing with ultrasound, they were produced using general lab equipment and a commercial HIFU transducer, which comes with a high price tag. We first present a simplified setup capable of printing silicone rubber, which uses a piezo bowl element and a class D power amplifier. The silicone rubber cures itself at room temperature, limiting the printing time to one hour. In addition, the uncured material is sticky, which makes separation of the printed object from the printing medium laborious. We were also able to print a mixture of egg white and potato flour, which addressed several of the limitations encountered with silicone. This material only cures if it is exposed to ultrasound and it is stable for several days if refrigerated. Uncured material can be washed away from the object with water, simplifying the cleaning process. The printed object and all residues are biodegradable.