3D printing filament is the

thermoplastic A thermoplastic, or thermosoftening plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Most thermoplastics have a high molecular weight. The polymer chains as ...

feedstock A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials/Intermediate goods that are feedstock for future finishe ...

for

fused filament fabrication Fused filament fabrication (FFF), also known as fused deposition modeling (with the trademarked acronym FDM), or ''filament freeform fabrication'', is a 3D printing process that uses a continuous filament of a thermoplastic material. Filament is ...

3D printers 3D printing, or additive manufacturing, is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer ...

. There are many types of filament available with different properties. Filament comes in a range of diameters, most commonly 1.75 mm and 2.85 mm, with the latter often being confused with the less common 3 mm. Filament consists of one continuous slender plastic thread spooled into a reel.

Production

Commercially produced filament

3D printing filament is created using a process of heating,

extruding Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex ...

and cooling plastic to transform nurdles into the finished product. However, unlike a 3D printer, the filament is pulled rather than pushed through the nozzle to create the filament. The diameter of the filament is defined by the process that takes place after the plastic has been heated rather than the diameter of the extruder nozzle. A different force and speed is applied to the filament as it is pulled out of the extruder to define the width of the filament, most commonly 1.75 mm or 2.85 mm diameter. The plastic nurdles are always white or clear. Pigments or other additives are added to the material before it is melted to create coloured filament or filament with special properties, e.g. increased strength or magnetic properties. Before the filament is extruded the nurdles are heated to 80 °C to dry it and reduce water content. The nurdles must be dried as many thermoplastics are

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

and extrusion of damp plastic causes dimensional flaws (this is also the case when the finished filament is being

printed Printing is a process for mass reproducing text and Printmaking, images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabon ...

). From there the nurdles are fed into a single screw extruder where it is heated and extruded into a filament. The diameter is often measured by a laser beam(not melting) as part of a quality control mechanism to ensure correct diameter of the filament. The filament is then fed through a warm water tank which cools the filament which gives the filament its round shape. The filament is then fed through a cold water tank to cool it to room temperature. It is then wound onto a spool to create the finished product.

DIY filament production

DIY filament production machines use the same method as FDM 3D printers of pushing the filament through the extruder to create the correct diameter filament. There are several DIY filament machines available as both open source plans and commercially available machines. A

food dehydrator Tomato slices ready to be dried in a convection-type food dehydrator. In this model, multiple trays can be stacked on top of each other and warm air flows around the food. A food dehydrator is a device that removes moisture from food to aid in i ...

can be used to remove water from hygroscopic materials at above 70 °C.

Usage

The process of transforming 3D printing filament into a 3D model # The filament is fed into the FDM 3D printer. # The thermoplastic is heated past its

glass transition The glass–liquid transition, or glass transition, is the gradual and Reversible reaction, reversible transition in amorphous solid, amorphous materials (or in amorphous regions within Crystallinity, semicrystalline materials) from a hard and rel ...

temperature inside the hotend. # The filament is extruded and deposited by an extrusion head onto a build platform where it cools. # The process is continuous, building up layers to create the model.

Materials

References

{{reflist Plastics 3D printing materials