Background: Smoothing of 3D printed parts to hide layer lines and other defects is an essential part of post-processing. Frequently used techniques include applying filler paints followed by multiple rounds of sanding with increasingly fine grit. An alternative method of post-processing involves the use of solvent vapors. Acetone vapor is known to swell ABS (acrylonitrile-butadiene-styrene) and allow the surface layer polymer to reflow. Simple acetone vapor chambers have long been used for post-processing for the hobbyist 3D printing as a surface treatment method. Other polymers such as PETG and PLA may require more dangerous solvents to vapor smooth. Given that ABS is the main polymer allowed on the Polyprinters, a better method of smoothing would allow 3D printing to produce smoothed parts suitable for further processing such as metal plating.
Challenges: Acetone vapor is heavier than air and tends to settle to the bottom of smoothing chambers. Efforts to redistribute the vapors using napkins along the sides of the chamber or using a fan are frequently seen online. The design of those chambers, however, leaves much to be desired about the consistency of the process. A second challenge is the loss of fine details and sharp edges and corners. This is due to overpenetration of solvent into the 3D printed body resulting in smoothing of features when the surface is swelled due to
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