10. 3D Printers – Different kinds of filament
One of the key strengths of FDM is the wide range of available materials. These can range from commodity thermoplastics (such as PLA and ABS) to engineering materials (such as PA, TPU, and PETG) and high-performance thermoplastics (such as PEEK and PEI).
Image 10.1. Thermoplastic materials pyramid available in FDM. As a rule of thumb, the higher a material is the better its mechanical properties [source]
The material used will affect the mechanical properties and accuracy of the printed part, but also its price. The most common FDM materials are summarized in the table below.
| Material | Characteristics |
|---|---|
| ABS | Good strength Good temperature resistance More susceptible to warping |
| PLA | Excellent visual quality Easy to print with Low impact strength |
| Nylon (PA) | High strength Excellent wear and chemical resistance Low humidity resistance |
| PETG | Food Safe * Good strength Easy to print with |
| TPU | Very flexible Difficult to print accurately |
| PEI | Excellent strength to weight High cost |
* the notches at the layer interface are critical points for bacterial growth, so thorough cleaning after every use is needed.
Image 10.2. PLA filaments [source]
What follows is a more in-detail exposition of FDM basic materials:
10.1 ABS
ABS is usually picked over PLA when higher temperature resistance and higher toughness is required.
| Pros | Cons |
|---|---|
| Can be post-processed with acetone vapors for a glossy finish | UV sensitive |
| Can be post-processed with sanding paper and painted with acrylics | Odor when printing |
| Acetone can also be used as strong glue | Potentially high fume emissions |
| Good abrasion resistance |
10.2 PLA
PLA is the easiest polymer to print and provides good visual quality. It is very rigid and actually quite strong, but is very brittle.
| Pros | Cons |
|---|---|
| Biosourced, biodegradable | Low humidity resistance |
| Odorless | Can't be glued easily |
| Can be post-processed with sanding paper and painted with acrylics | |
| Good UV resistance |
10.3 Nylon
Nylon possesses great mechanical properties, and in particular, the best impact resistance for a non-flexible filament. Layer adhesion can be an issue, however.
| Pros | Cons |
|---|---|
| Good chemical resistance | Very low humidity resistance |
| Potentially high fume emissions |
10.4 PET
PET is a slightly softer polymer that is well rounded and possesses interesting additional properties with few major drawbacks.
| Pros | Cons |
|---|---|
| Food safe (FDA approved) | |
| High humidity resistance | |
| High chemical resistance | |
| Recyclable | |
| Good abrasion resitance | |
| Can be post-processes with sanding paper and painted with acrylics | |
| Can be glued |
10.5 TPU
TPU is mostly used for flexible applications, but its very high impact resistance can open for other applications.
| Pros | Cons |
|---|---|
| Good abrasion resistance | Difficult to post process |
| Good resistance to oil and grease | Can't be glued easily |
10.6 PC
PC is the strongest material of all, and can be an interesting alternative to ABS as the properties are quite similar.
| Pros | Cons |
|---|---|
| Can be sterilized | UV sensitive |
| Easy to post-process (sanding) |
Choosing the right polymer is critical to get the right properties for a 3D printed part, especially if the part has a functional use.
For a detailed article of “the best 3D printing filaments in 2017”, please follow this link: http://my3dmatter.com/what-are-the-best-3d-printing-filaments-in-2017/#more-1077
Other sources:
[1] https://www.3dhubs.com/knowledge-base/introduction-fdm-3d-printing#materials
[2] https://www.3dhubs.com/knowledge-base/fdm-3d-printing-materials-compared