# 3D printing filament

3D printing filament is the thermoplastic feedstock for fused deposition modeling 3D printers. 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 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 and extrusion of damp plastic causes dimensional flaws (this is also the case when the finished filament is being printed). 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 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 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

| Filament | Special Properties | Uses | Strength | Density (kg/m$^3$) | Flexibility | Durability | Difficulty to print | Print Temperature (°C) | Bed Temperature (°C) | Printing notes |
| PLA | Easy to printBiodegradable, though only in very specific conditions | Consumer Products | Medium | 1240 | Low | Medium | Low | 180 - 230 | No heated bed needed or, 60-80C are recommended also | |
| ABS | DurableImpact resistant | Functional Parts | Medium | 1010 | Medium | High | Medium | 210 - 250 | 50 - 100 | |
| PETG (XT, N‑Vent) | More flexible than PLA or ABSDurable | All | Medium | 1270 | High | High | Medium | 220 - 235 | No heated bed needed | |
| Nylon | StrongFlexibleDurable | All | High | 1020 | High | High | Medium | 220 - 260 | 50 - 100 | Hygroscopic, keep sealed when not in use |
| TPE | Extremely flexibleRubber-like | Elastic PartsWearables | Low | | High | Medium | High | 225 - 235 | 40 | Print very slowly |
| TPU | Extremely flexibleRubber-like | Elastic PartsWearables | Low | | High | Medium | High | 225 - 235 | No heated bed needed | Print slowly |
| Wood | Wood-like finish | Home Decor | Medium | 1400 | Medium | Medium | Medium | 195 - 220 | No heated bed needed | |
| HIPS | Dissolvable | Support structures when using ABS on a dual extrusion printer. | Low | 1040 | Medium | High | Medium | 210 - 250 | 50 - 100 | |
| PVA | DissolvableWater SolubleBiodegradableOil Resistant | Support structures when using PLA or ABS on a dual extrusion printer. | High | | Low | Medium | Low | 180 - 230 | No heated bed needed | Hygroscopic, keep sealed when not in use |
| PET (CEP) | StrongFlexibleDurableRecyclable | All | High | | High | High | Medium | 220 - 250 | No heated bed needed | |
| PLA Metal | Metal Finish | Jewelry | Medium | | Low | High | High | 195 - 220 | No heated bed needed | Use hardened nozzle |
| PLA Carbon Fiber | RigidStronger Than Pure PLA | Functional Parts | Medium | | Low | High | Medium | 195 - 220 | No heated bed needed | Use hardened nozzle |
| Lignin (bioFila) | BiodegradableStronger than PLA | | Medium | | Low | Medium | Low | 190 - 225 | 55 | |
| Polycarbonate | Very strongFlexibleDurableTransparentHeat Resistant | Functional Parts | High | 1180 – 1200 | High | High | Medium | 270 - 310 | 90 - 105 | Use enclosed heated chamber at ambient temperature of around 60 °C |
| Conductive (usually a graphite-plastic blend) | Conductive | Electronics | Medium | | Medium | Low | Low | 215 - 230 | No heated bed needed | Use hardened nozzle |
| Wax (MOLDLAY) | Melts Away | Lost wax Casting | Low | | Low | Low | Low | 170 - 180 | No heated bed needed | |
| PETT (T‑Glase) | StrongFlexibleTransparentClear | Functional Parts | High | | High | High | Medium | 235 - 240 | No heated bed needed | |
| ASA | RigidDurableWeather Resistant | Outdoor | Medium | | Low | High | Medium | 240 - 260 | 100 - 120 | |
| PP | FlexibleChemical Resistance | Flexible Components | Medium | 1040 | High | Medium | High | 210 - 230 | 120 - 150 | |
| POM, Acetal | StrongRigidLow FrictionResilient | Functional Parts | High | | Low | Medium | High | 210 - 225 | 130 | |
| PMMA, Acrylic | RigidDurableTransparentClearImpact Resistant | Light diffusers | Medium | | Low | High | Medium | 235 - 250 | 100 -120 | |
| Sandstone (LAYBRICK; styled plastic) | Sandstone Finish | Architecture | Low | | Low | Low | Medium | 165 - 210 | No heated bed needed | |
| Glow-In-The-Dark plastic | Phosphorescence | Fun | Medium | | Medium | Medium | Low | 215 | No heated bed needed | Use hardened nozzle |
| Cleaning | Cleaning | Unclogging of Nozzles | N/A | | N/A | N/A | Low | 150 - 260 | No heated bed needed | |
| PC-ABS | RigidDurableImpact ResistantResilientDeflecting Heat | Functional Parts | Medium | | Low | High | High | 260 - 280 | 120 | |
| Magnetic (PLA blend) | Magnetic | Fun | Medium | | Medium | Medium | High | 195 - 220 | No heated bed needed | |
| Color Changing (plastic blend) | Thermochromism | Fun | Medium | | Medium | Medium | Low | 215 | No heated bed needed | |
| nGen (co-polyester) | Similar to PETGHeat ResistantTransparent | All | Medium | | High | High | Medium | 210 - 240 | 60 | |
| TPC | Extremely FlexibleRubber-LikeChemical resistantHeat resistantUV light resistant | Elastic PartsOutdoor | Low | | High | Medium | High | 210 | 60 - 100 | |
| PORO-LAY | Partially Water Soluble | Experimental | Low | | High | Medium | Low | 220 - 235 | No heated bed needed | |
| FPE | Flexible | Flexible Parts | Low | | High | High | Medium | 205 - 250 | 75 | |
| PEI | Heat ResistantStrongFlame Performance | Functional Parts | High | 1270 | Medium | High | Medium | 340 - 380 | 180 - 200 | Use enclosed heated chamber at 220 °C |