Wednesday, November 14, 2012

Perpetual Filament Printing

Almost all the end user 3D printers use filament plastic as the raw material.
End user printers are mainly based on CNC devices which are quite mature in design.  Therefore, the most critical part of additive manufacturing systems is deposition of just the right amount of material at right location. The location precision can be guaranteed up to an acceptable level.  However material deposition cannot be controlled precisely at the moment. This results in low quality output for end user 3D printers.

For high quality printing the followings need to be improved:
- Filaments must be made of homogeneous raw material
- Filaments must have consistent diameter

The quality of raw materials mainly depends on the manufacturer. The coloring materials used in the filament also affect the quality of print.  For high quality outputs, one needs to fine tune the extrusion settings every time the filament role is changed.

Filament diameter inconsistency can be compensated by using filament compensation electronics.  The extrusion speed can be adjusted based on the filament shape.  The filament shape can be determined using hall-effect sensors.  For further detail you can check Motate128 Stepper Motor Control System. It was discussed in Filabot's forum under filament compensating electronics topic.

Another important topic on 3D printing using plastic filaments is sustainability.

For sustainability it is important to recycle the plastic. In order to obtain a nice looking print, one needs try couple of times.  The end result is a lot of discarded faulty prints.  I propose a new index for 3D printing "Discarded Plastic Ratio (DPR)".  An example of a DPR would be: “With the current technology, 100 gr of plastic used in order to print, 40 gr of usable object.  So the DPR of the printing is 60%“.  After using the printer for some time, it becomes really important to recycle the waste.  There are projects going on to resolve this problem.  Filabot is the first successful filament manufacturing device developed for the end user.  Additionally there is a perpetual plastic project.  The idea sounds good.  However, I find it quite impractical to melt different plastics into one and form a filament.  The filaments produced this way would be unpredictable in behavior.  The print quality would suffer.  Also the chemical fumes coming out of such filaments may be health hazardous.  In my opinion, the recycling of plastic is a complex process and therefore should be handled with a recycle center.  On the other hand, recycling of defective 3D prints is a more feasible solution for perpetual plastic printing.