One issue with 3D printing is the problem of printing multi-colour objects. Currently the colour of an object is fixed by the colour of the 3D printer filament loaded prior to the start of the printing job. A new patent filed in the US outline a method to coat the printer filament upstream of the extrusion head and then this coating would remain at the surface of the filament downstream.
The 3D printer would require two additional components:
1. Mixer unit – A set of printer dye nozzles for coating the printer filament. The material used does not have to be limited to colour dyes but could also include materials that have additional properties e.g. conductive or structural properties;
2. Coating Unit – coats the 3D filament with the mixture of coating materials applied at 1;
3. a fixing component that ensures that the material applied by 1. stays adhered to the surface of the printer filament.
This development would require a change in the properties of the 3D filament used but would certainly increase the variation in products that would be able to be designed and built on a single machine.