Dual extrusion has the potential to offer double the fun of single extrusion in 3D printing -- but anyone who's tried it can also attest that there's also the potential for double the headaches. Often, in order to avoid common problems including color blending and blemishes and to encourage a clean print, users turn to 'wipe towers', where filament can be wiped off from the extruder in order to forestall accidental color blending or other messy issues. This hasn't been a perfect solution -- and it hasn't been universal. Now, though, Amsterdam-based Printr is offering a new technology that can clean up prints using dual extrusion. Printr calls its solution a 'Donut wipe tower'. While many wipe towers in use from other slicers are solid, Printr's solution is, just as it sounds, donut-shaped. That is, a hollow structure, which is faster and more efficient to produce while still wiping excess filament from the extruder. Printr's Formide platform, which integrates its Katana cloud slicing software, is said to be the first to enable this particular structure, which Printr assures us leads to "exceptionally clean dual prints." Read more at 3DPrint.com: https://3dprint.com/148151/printr-donut-wipe-towers/