After swearing off Kickstarter last year due to Lemming Syndrome, I feel like Michael Corleone in the third Godfather movie. "Just when I thought I was out, they pull me back in."

Sometimes a clever innovation comes along and it needs to be covered, whether it is presented as a crowdfunding project or not. Mosaic Manufacturing's Palette is one of those clever innovations. It is essentially a pre-printer filament splicing machine that allows common FDM printers with only one extruder to perform tasks normally reserved for multi-extrusion printers.

Up to four different filaments can be fed into the Palette where they are cut and placed in series to form one filament stream, which then goes to the printer. The filaments can be different colors or entirely different kinds of material, so long as the materials have a similar extrusion temperature. For example, electrically conductive PLA or ABS could be used with regular PLA or ABS to manufacture an entire electronic device.

The concept immediately raises a number of questions. What keeps the Palette from outputting filament at a different speed than the printer needs? How does a printer without multi-extruder firmware know when to start the part requiring a different color or material? How can a clean break between two colors be achieved during the print job when the printer doesn't even know the filament color has changed?

The answer is software. The palette comes with an application that enables a printer to work in concert with the Palette and avoid what would otherwise be a hot mess on a build plate.

First, the 3D model is sliced using any slicing software that has multi-extrusion output options and can produce G-code or .x3g files. The sliced file is then run though Mosaic's application where the printer control code is modified to contain elements related to working with the Palette. A matching .SEEM file is also produced to govern the Palette itself. The new G-code file is sent to the printer, the .SEEM file is sent to the Palette and presto, the two separate devices are on the same page.

A scroll wheel between the Palette and printer monitors the filament being used to avoid slack in the line and a live feedback loop reports actual usage from the printer back to the Palette, allowing it to make adjustments to upcoming lengths of filament if necessary.

Color smear from filament transitions in the hot end can be dodged by settings in the Mosaic software. Not all printers extrude at the same speed. It takes some longer than others to transition between two colors without the output being a secondary color somewhere between one filament and the next. Mosaic's software allows the amount of discarded transition output to be adjusted for this variance.

The Palette is analogous to a razor blade film editing robot with the printer being the projector. It is not a melting extrusion machine designed to merge colors together.

"There is some incidental blending of colours during the transition, which is discarded on the side of the part (we are working on integrating internal/infill dumping as well), however colour blending is not something we're supporting at this time," notes Chris Labelle, Mosaic COO.

Cura users don't even have to open Mosaic's software, because there is a plugin version that allows everything to be done inside Cura.

The current incarnation of the Palette works only with 1.75 mm filament.