3D filaments are thermoplastic feedstock used in 3D printers for fused deposition modeling. Different types of filaments with different properties are available, each requiring different temperatures for printing 3D objects. They come in standard diameters of 1.75mm and 3mm.

3D filaments are created by a heating, extruding and cooling plastic “nurdles” into a finished product. The filament is heated and pulled through a single screw extruder at a force and speed that defines its width of either 1.75mm or 3mm. The nurdles are clear or white and pigments or additives are added before melting to create filaments with different colors or special properties.

The diameter is measured with laser technology before being passed through a tank with warm water that produces its round shape. It is finally cooled to room temperature and the finished product is wound around a spool.

Choosing the Right Filament

When choosing filaments for 3D Printing you need to take into account the different types, features, and characteristics of filaments and what filament diameter your 3D printer uses. Some 3D printers are designed to use only 1mm diameter filaments while others can use filaments with diameters other than the standard 1.75mm and 3mm. The three most common filament types are ABS, PLA, and PVA.

ABS Filaments

The cheapest and most popular, ABS filaments are very strong and long-lasting, relatively heat resistant, and slightly flexible. They require temperatures of around 225 degrees Celsius to melt. ABS is suitable for a wide variety of applications; however, the ABS material is non-biodegradable petroleum-based plastic which produces toxic fumes when heated and should be used in a well-ventilated area.

PLA Filaments

In contrast to ABS, PLA is biodegradable thermoplastic derived from renewable sources which makes it more environmentally friendly. Another significant benefit of PLA is that it is biocompatible with the human body with no adverse effects when in close contact with the materials. This is why PLA filaments are preferred for use in the medical industry. It is also shatterproof and significantly more flexible than PVA or ABS. A disadvantage of this type of plastic filament is that it softens at temperatures of around 50 degrees Celsius.

PVA

PVA or Polyvinyl Alcohol is relatively expensive and designed for use in 3D printers with multiple extruders that provide a support structure for objects with no layers below it. This type of filament usage requires special storage conditions and the materials are difficult to source.

3D Printing Process Using 3D Printing Filaments

The process of creating a 3D model from 3D printing filament involves the following process:

First, the printing filament is put into the FDM 3D printer. The 3D printer then heats the thermoplastic in the filament past the glass transition temperature in the hot end. Once the filament has melted it is extruded by an extrusion head and deposited onto a build platform. The thermoplastic material cools down on the platform and the next layer is deposited in a continuous process until the finished model has been created.

Filament Grades

There are several different grades of filament that are considered to be standard by the 3D printing community such as PA-747 for ABS and 4043D or 2003D for PLA. Suppliers normally supply the specific name grades of the filaments they sell and is a good indication of quality.