Ross Yeager and David Kalinowski, graduate students at UC Berkeley and founders of 3D Prints Express, have launched the 3D Refiner on Kickstarter.  The project's funding goal of $5,000 has been doubled in two days.

The 3D Refiner is a system designed to address 3D print smoothness, more an issue with Fused Filament Fabrication printers in the personal class than their more expensive cousins.  Even when printing at a 100 micron vertical layer resolution, there are often slight ridges along the sidewalls of a 3D print, a result of the layering.  At lower resolutions, such as 300 or 400 micron layers, printers print faster, but the layer ridges become more pronounced, making the final print visibly rough compared to a higher resolution print.

TIP:  A lower vertical resolution number means higher resolution printing, because "vertical layer resolution" is a measurement of layer height.  An object with shorter vertical layers requires more layers to print than the same object made up of taller vertical layers.  Thus, a vertical layer resolution of 100 microns produces a higher resolution object than a vertical layer resolution of 200 microns.

If the desired goal is to print faster, but present a final appearance of higher resolution smoothness, post-processing must be done in the form of sanding, acetone bathing/steaming, or perhaps machine powered surface polishing with a device like a Dremel.  Such post-processing may be necessary even when printing at slower, higher resolutions, if a genuinely smooth finish is required.

Enter the 3D Refiner, a machine that lowers a printed object into a tank of solvent, then rotates it in front of a fluid pump jet, evenly smoothing the surface.  The exact chemical composition of the non-flammable, water-diluted solvent isn't disclosed on the Kickstarter page, but "Klean-Strip" is included in the package, a variable acetone product commonly used to remove excess layers of latex, oil-based paints, polyurethane, epoxy, varnish and shellac.  A well-ventilated usage area is recommended.  The pump and above-tank electronics are shielded from the solvent to prevent corrosion.  Maximum object size is 165 x 165 x 203 mm.

The $269 early adopter pledges are sold out, as are the $389 limited edition pledges.  At the time of this writing, there are still $299 standard pledges available.