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Plastics in additive manufacturing
Plastics have become indispensable in today’s world. No matter where we look, you accompany us everywhere. We use them as packaging material, clothing, in cars, in technical devices and much more.
Due to their high flexibility and robustness against environmental influences, the plastics are used in all areas of life.
Plastics in solid or liquid form play a major role as a material, especially in 3D printing.
The range of materials is growing from year to year, which also results in rapid growth in the areas of application for 3D printing.
Despite or precisely because of their good durability, plastics are unfortunately also a major problem for the environment.
However, we must also be aware that people have also achieved the current standard of living with plastics. Fridges, computers, planes, cell phones…….
The list could be continued indefinitely.
3D printing offers us an incredible opportunity to save large amounts of plastic. Be it with the help of the design optimization of the components or the fact that only the quantity that is actually required has to be produced economically.
In order to use these resources consciously and, above all, sensibly, we must first know what plastics actually are and how they are manufactured.
What are plastics?
Plastic is the term used to describe materials that are mostly made up of giant molecules. This means that plastics are polymers and are made up of repeating basic units called monomers.
A polymer can be naturally based, semi-synthetic, and synthetic.
Most of the ones we know and use are semi-synthetic or synthetic.
They are made from natural raw materials such as petroleum, natural gas, cellulose and salt.
There are three different synthesis processes to produce plastics from these natural materials. polymerization, polycondensation and polyaddition.
More information about the production of plastics is summarized in this video.
What types of plastic are there and what distinguishes them?
They are divided into three large groups:
Thermoplastics, duroplastics and elastomers.
thermoplastics can be melted down and reshaped, e.g. PET bottles
thermosets are heat and dimensionally stable. They can no longer be reshaped, eg epoxy resins
elastomerers have high elasticity and cannot be melted, e.g. rubber
Plastics are generally characterized above all by their versatile technical properties such as formability, strength, rigidity, hardness, toughness, temperature and weather resistance and many more.
Depending on the choice of the type of molecule, the manufacturing process and the admixture of additives, special plastics can be produced depending on the area of application.
Where and how are they used?
Plastics can be specially manufactured for different fields of application. As a result, plastics can occur in all areas of life and there in the most diverse variants.
Packaging film, water bottles or housings for electronic components are just a few examples.
Here is a nice overview of where plastics are found in a car.
We will now take a closer look at how and in what form the plastic is used in 3D printing.
Plastics in 3D printing
Plastics also play a large and important role in additive manufacturing.
They currently make up the largest group of materials that can be processed using 3D printing and will probably continue to do so in the years to come.
Especially the variety of plastics in unity with 3D printing often leaves hardly anything to be desired in product manufacture. There is hardly any plastic that cannot be printed.
In additive manufacturing, the material is differentiated according to its original form (e.g. powder form, solid or liquid material). The form of material used then decides which printing process can be used.
It is divided between the following forms:
–liquid plastics
The term “liquid plastic” usually refers to the synthetic resin, which is known in specialist circles as resin is known.
The shape of the printable solid plastics is much more versatile than the liquid ones. A distinction is made here between filament, powder, granulate and foil.
filament and powder are currently the most used.
The way the materials are processed has a significant influence on the component properties and consequently on the area of application.
In order not to go beyond the scope of this article, I have compiled special information on the individual plastic molds in an extra article.
In addition to the general information, the printing processes associated with the material forms are also explained in more detail.