Filament-based and Powder-based 3d Printing

Filament-based 3D Printing

Standard home printers usually work with plastic filament. The technology behind this is usually known as a Fused Filament Fabrication (FFF). Instead this new form of 3D printing I shall cover is a new technology called Fused Deposition Modelling (FDM).

In an FDM printer, a long plastic filament is fed by a spool to a nozzle where the material is liquefied and sketched on the platform, where it immediately cools and hardens again. The nozzle moves to place the item in the right location to build your model or item up layer by layer by layer. When a layer is drawn, the platform lowers by one layer so the nozzle can start to draw the next layer.

Unlike most standard home printers, the FDM printing machine actually uses another filament that is used for building support material. Because the material used to build the model cannot fully support its own structure at this time, the support material prevents it from falling down. After the printing process has finished, the model is then put into a bath with special chemicals and soap. The support material because of its make-up and reaction to the chemicals inside the bath dissolves automatically. Due to this process, designs can be really intricate, complex and contain interlocking, interlinking, and movable parts.

An example of the kind of item you can make using this technology is the fully functional, continuously adjustable spanner all printed in one piece. The printing material these type of printers use is called ABS. ABS is very useful for functional applications because it has an 80% match of the properties of real injected production material. However, the surface of the models produced by this form of printing is rougher compared with other materials.

Powder-based 3D Printing

The type of printers that I will concentrate on is not based on filament but on powder. Laser Sintering is used to create 3D prints in Polyamide, Titanium, Alumide and Rubber.

The inside of the printer is heated up slightly below the melting point of the powder. The printer then spreads out an incredibly thin fine layer of this powder. A laser then heats up the areas that need to be sintered together just above melting point. This process then reveals the parts that were touched by the laser are now fused together while the rest continues to remain loose powder.

The models are printed layer by layer with the assistance of this laser beam. After a layer is printed, a new layer of powder is spread over the surface. After the printing is finished, the result is a large block of powder that contains the printed/sintered models inside the block. In order to get the prints out of the large powder block, the block has to be mechanically slammed against the box of un-sintered powder and the excess brushed away.

Other materials such as Stainless Steel and High Detail Stainless Steel also use powder, but are not laser sintered. Instead, a binder is used to glue parts together. This technology is referred to as Powder- & Binder-based 3D Printing.