Using Palette+ for 3-material printing with PVA as support requires a little bit of fiddling with cura.
Mosaic Manufacturing offers a very useful device that allows to print using up to 4 different materials, with just one extruder. That provides a great possibility for 1-extruder printers to create not only multicolor objects, but also to use water-soluble material as support for the overhangs and bridges. After the printing such object is being post processed with water so that the supports are gone and the pure model remains in perfect shape.
However here is a problem that can arise during the print of a 3-color model with the 4th material as support.
After configuration of Cura according to manual (that is very informative, in fact), we can load a multi-color model that consists of 3 different models:
In Cura 15.04.6 we should select each model and choose “Dual extrusion merge”, which makes Cura set a different extruder for each model, keeping them together though
Good, we have 3 models associated to 3 different extruders. But once we decide to have the 4th material as support, Cura 15.04.6 does not allow to do it (starting from Cura 2.x generation there is a setting to choose the proper extruder for the support material). In fact, it is possible to choose only between the first and second extruder, but that means we associate the support and the model to be printed with the same extruder (the same material):
In case we want the support to be water-soluble we experience the following situation where one of the models is going to be eliminated together with the supports:
One way to solve this problem is to create a tiny model, associate it with the support material and then merge it with the other 3 models. I created a simple rectangle 5x5mm large and 0.2mm high, so that it will cause only the first layer of the print:
Cancel all the models loaded to Cura. This new model named tri_support.stl should be loaded the first:
Then load the three models for printing and merge them as before. Check that the Support dual extrusion is set for the first extruder.
After saving the gcode and loading it in Chroma, we obtain thew following result:
The soluble material is now associated only with the tiny rectangular and the supports, that will dissolve during the post processing.
The FABtotum and the Palette+ can both be now initialized with all the corresponding filaments loaded and the print launched as usual.