What is 3D printing filament made of ?

Introduction

3D printer filaments can be made from a wide variety of thermoplastics, each with its own unique set of properties.

A thermoplastic is a polymer that can be repeatedly melted and cooled. Polymers are long chains of molecules and can be found everywhere in our lives: like the natural polymers in the carbohydrates that we eat or the synthetic polymers in plastic bottles.

Here you can find a list of all the different thermoplastics that are available as 3D printer filaments as well as some important background information on all thermoplastics and their different properties.

About

Many of the thermoplastic properties important in 3D printing depend largely on whether it is a crystalline or amorphous polymer. The molecules of crystalline polymers are very well ordered and packed together, like a diamond, making them very strong. Amorphous polymers have a very jumbled molecular structure, looking more like spaghetti, making them flexible.

When you heat a crystalline polymer there is an exact point at which it will become liquid. Amorphous polymers do not have an exact melting point, they have a gradual transition from solid to liquid: this is called the glass transition temperature (Tg) where the polymer is very soft and viscous. This is an important consideration in 3D printing as it will effect the functionality of the final product.

Crystalline polymers are usually more opaque, more resistant to heat and more resistant to deformation than amorphous polymers. Polymers with higher crystallinity, like PLA or PP, are more suited to products where hardness and rigidity are needed. On the other hand, products that need flexibility will be more suited to amorphous polymers, like HIPS or ABS.

The filaments used in 3D printing can be Bio-based (like PLA) or completely synthetic (like ABS or PVA). Filaments come in a wide range of colours and can have have "superpowers" like glow in the dark filaments. Some of the most popular filaments used are PLA, ABS, Nylon and PETG however there are many others available to choose from.

When choosing your filament there are lots of factors you can consider. The table below summarises the most common properties and descriptions of 3D printing filaments.

Property Description Unit
CAS Number A unique identifier code given to every chemical substance by the Chemical Abstracts Service. --
Crystallinity The degree of structural order within a polymer. Higher crystallinity means the polymer will be harder, more rigid with a higher melting temperature and smaller glass transition temperature. Polymers with low crystallinity are 'amorphous' %
Melting Temperature The temperature at which the filament becomes a liquid. °C / °F
Glass Transition Temperature The temperature range where amorphous polymers start to go soft or rubbery. °C / °F
Printing Temperature Also known as the Extrusion Temperature. This is the temperature that the 3D printer nozzle needs to be heated to in order to print with the filament. °C / °F
Density The mass of a given volume of filament. This is important for calculating the final weight of your product and the length of filament that this will require. g/cm3
Rigidity The stiffness of the filament. How well does it resist bending? MPa / psi
Strength How well a filament resists breaking or deformation under mechanical stress MPa / psi
Impact Resistance How well a filament can withstand a high force over a short period of time. ft.lb/in2
Tensile Strength The resistance of the filament to breaking under pulling tension. MPa / psi
Tensile Elongation The amount that a filament will stretch as it is pulled in tension. %
Flexural Strength Also known as the Bend Strength. This is the amount of bending force a filament can endure before breaking. MPa / PSI
Layer Adhesion How well each layer of the 3D printing filament bonds and solidifies with each other. --
Water Soluble Will the filament dissolve in water? --
Other Solvents What can the material be dissolved in? --
Diameter The width of the filament mm
Color Measurable in RGB, RAL or Pantone --
Transparency How see-through the filament is --
Bio-Based Is the filament made from substances derived from living things, like sugar cane. --

That may look like a lot of factors to think about to buy your 3D printer filament but with our filter tool you can search for the right filament with just a few clicks. It even uses a 1-5 rating system for properties like strength and layer adhesion.