Michael Graham, 27, an engineer from Portland, Oregon, has designed an ultrasonic 3D print polisher, sharing the building process on Instructables. The Automated Ultrasonic Misting 3D Print Polisher PRO uses acetone vapor to apply a professional polish to ABS 3D printed parts.
Everybody wants their 3D printed parts to look great, but “looking great” can mean many different things. For a lot of makers, the perfect finish will include a polished surface, minimizing that distinctively matte, layered appearance typically associated with 3D printed material. Sounds great in principal, but a silky smooth finish can be difficult to pull off—especially on a budget. Last year, Michael Graham published his first 3D print polisher on Instructables, a repurposed ultrasonic water humidifier, which the engineer hoped would produce a predictable finish while also being “as convenient as a microwave.” Graham has now returned with a more advanced “PRO” version of his machine, complete with an improved form factor, simplified process, and higher level of efficiency.
Although his first 3D print polisher was capable of achieving the desired effects, Graham wanted to create a more portable and efficient version of his machine; one with a single transparent assembly, which could safely be used indoors. With a few technical alterations, he has managed to achieve this goal: “The user interface is now simply an ON/OFF switch and a single momentary button for ‘go’,” Graham explains. “The new design now uses a closed pumping system and has been optimized for maximum fog production; So it is completely sealed allowing for indoor use, it takes less time, consumes less acetone to do the job, and no water ever needs changing!”
At its core, the 3D print polisher uses an animal-shaped ultrasonic cool mist humidifier, (Graham opted for the frog) whose entire system of internal electronics can be repurposed for the polisher. Liquid solvent acetone is pumped from one clear box into another—which contains the 3D printed part—to create an evenly distributed fog within the second box, covering the entire surface of the 3D printed part. Isopropyl alcohol can be used instead of acetone for polishing 'PolySmooth' material.
While acetone could, theoretically, reduce the strength of ABS 3D printed parts, Graham conducted a number of experiments with his machine, eventually coming to an interesting conclusion: “The overall effect of Acetone vapor polishing on ABS effectively makes parts somewhat more isotropic,” Graham explains. “That is, they react more uniformly to applied loads from various directions. In this case, polishing sacrifices strength in their strong axis to increase strength in their weak axis.”
The full list of components and materials needed for the Automated Ultrasonic Misting 3D Print Polisher PRO can be found on its Instructables page. Graham plans to showcase the machine at Portland’s Mini Maker Faire, which takes place September 10-11.



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