Usually when using a commercial 3D printer it is quite difficult to print a single object that contains multiple materials. However, an experimental new system could make it easier by using a “programmable filament”.
Most consumer 3D printers create objects using a process called fused deposition modeling. To do this, they are loaded with a spool of polymer filament, which they then heat to the melting point and then extrude from their pressure nozzle. In this way they build objects, one horizontal layer at a time.
Typically, when you want to 3D print an object that contains multiple types of polymers (such as those with different colors) you will have to switch the various polymer filament spools in and out of the printer as the different parts of the object will be printed.
This can potentially get very fiddly. For example, if you were to print a vase with different colored vertical stripes on the sides, you would have to switch between filaments on each printed layer. This is where the programmable filament system comes into play.
Various examples of items printed with programmable filament technology
First, the computer model of the object to be printed is analyzed and it is determined which parts of this object are printed from which polymers in which order. The existing 3D printer is then used to create a custom spool of filament, the various sections of which are made from the various polymers.
This coil is printed as a flat horizontal spiral. To begin with, all of the sections that need to be made from the first type of polymer are printed with gaps in between for the other polymers to enter. The one or more other polymers are then deposited in these gaps, the connections between the various filament sections being interconnected.
While the process still requires the user to manually change the various source coils, this only needs to be done once for each type of polymer used.
Once the resulting multipolymer composite coil is loaded into the printer, the object can be printed all at once. At those points in the building process where changes between the polymer types must occur, the extruded “programmed” filament changes accordingly.
The system is being developed in collaboration with scientists from Meiji University (Japan), Osaka University and Texas A&M University. It is demonstrated in the video below.
An article on the research was recently presented via the online ACM-UIST conference.
Source: Haruki Takahashi (YouTube) via IEEE Spectrum
Programmable filament – UIST2020 (long version)