Best Filament For Functional Parts: A Detailed Guide
Every day, lots of engineers try to improve technology, and 3D printing isn’t an exception. It’s important to know that there are way more filament materials available to the creator than a few years ago. Even though 3D printing hobbyists mostly use PLA as their filament of choice, better options are used to make functional parts.
While manufacturers mostly use traditional processes to produce nuts, bolts, gears, and similars, 3D printing is swiftly developing. Today new high-performance and engineering filaments are introduced to the market and provide superior mechanical properties that were not an option in the past.
This article is an overview of these materials and tries to find the best filament for functional parts production. Note that each filament requires specific 3D printing machines and setups, so everyone should first know the available options and pick the one that suits their case.
Before getting into the details, there is one common question that many beginners ask in their first experiences. And the question is:
What is the best filament for functional parts production that is also easy to print?
More robust materials are harder to 3D print. The typical ones like PLA are super easy to use but not that useful. There is a material that has both advantages in the middle range, and this material is nylon.
It has enough strength and wear resistance and doesn’t require a professional 3D printing setup. Hence, nylon is the best filament for functional parts production, especially in small projects.
The best evidence is that most gears and functional parts of the RC toy cars are made out of nylon. Yet, these gears are produced with plastic injection machines and have better properties.
Three Main Categories Of Filaments
Here we check the filaments in three different categories:
The first group is the high-performance materials. They are the leading edge of technology and have the most outstanding mechanical properties.
On the other hand, 3D printing high-performance materials need a heating chamber and precise temperature control that is only available in professional industrial machines.
Engineering materials are the second group. These filaments are specifically designed to withstand relatively high temperatures and harsh environments. 3D Printing these materials are more accessible than the first group. Most engineering filaments can be printed using a desktop 3D Printer.
Commodity filaments like PLA are the last category. They are so easy to work with, and their properties are limited. However, there are some ways to improve these features. Annealing is one of the famous processes covered in its section.
High-Performance Filaments
Note that these materials need high extrusion temperatures, and domestic 3D Printers can’t use them. Yet, you can contact a 3D Printing service and set your order at a fair price.
PEEK
PEEK is a semi-crystalline thermoplastic known for its outstanding mechanical properties. It has been used in the manufacturing industry for years, and it’s now available as a 3D printing material. Mainly known as wear and heat resistant, PEEK has often considered a high-performance filament material.
Looking closer at its structure reveals that when it melts, the molecules rearrange under the effect of heat. Thus, they’ll settle in their specific positions after the whole part completely solidifies. This feature alone helps PEEK to perfectly keep its characteristics after a temperature rise like an injected piece.
The semi-crystalline structure gives us decent mechanical properties, though it makes the 3D printing process much harder.
Printing with PEEK needs an advanced 3D printer paired with an extruder that can warm up to 400o C, a heating chamber with precise temperature control, and a heated bed that can reach 230o C.
When it comes to performance, PEEK is the best filament for functional parts production to the point that most prothesis nowadays is made out of it.
Below you can see two tables about mechanical properties and the recommended printer setting from 3d4makers. This information is a valuable source for designers and gives us a sense of this material. These values are only shown for comparison, and the exact measures can differ based on several factors.
You also can check the price for this filament here.
| Mechanical properties of PEEK | ||
| Description | Value | Test method |
| Tensile Modulus | 4.1 GPa | ISO 527 |
| Tensile Strength | 105 MPa | ISO 527 |
| Impact strength Notched Izod | 5 KJ/m2 | ISO 180/A |
| Density | 1.26 g/cm3 | ISO 1183 |
| Printer settings | |
| Description | Value |
| Printer nozzle temperature | 370 – 420o C |
| Heated bed temperature | 120o C |
| Print speed | 15 – 30 mm/s |
| Adhesion | PEI sheet |
| Drying recommendation | 110o C, 2 – 4 hours |
PEKK
First of all, PEKK is a thermoplastic with the best chemical resistance and outstanding mechanical properties. However, the crystallization rate of PEKK is lower than PEEK, so it is easier to print. It also has more layer adhesion and tensile strength compared to PEEK. Nevertheless, it is too expensive and harder to print compared to more popular filament materials.
3D printing this material also requires industrial machines. Prerequisites for printing with PEKK are the same as PEEK, except for the extruder temperature. PEKK should be extruded in a range of 340 to 360o C.
Below, you can see the mechanical properties of PEKK. You can also check the price for this filament here.
| Mechanical properties of PEKK | ||
| Description | Value | Test method |
| Ultimate strength | 324 MPa | ISO 527 |
| Tensile Strength | 134 MPa | ISO 527 |
| Izod Impact, Notched | 0.534 J/cm | ISO 180/A |
| Density | 1.36 – 1.60 g/cm3 | ISO 1183 |
PEI (Ultem)
Ultem or Polyetherimide (PEI) is very similar to PEEK and has many of its desired characteristics. Compared to PEEK, this material has lower strength and impact resistance. But, it’s much cheaper and still ideal for printing mechanical parts.
Depending on the specified filament brand and manufacturer, Ultem has properties of around 104 MPa tensile strength and a flexural modulus of 3.3 GPa. Its high glass transition temperature ( around 220o C) makes it hard to print, and many 3D printers can’t handle it. For example, printing Ultem 9085 needs a nozzle temperature of 350o – 380o C and a heated bed temperature of up to 120 – 150o C.
So Ultem is cheaper than PEEK and PEKK. It still has decent mechanical properties; it’s one of the best options, especially for small projects.
You can also check the price for this filament here.
Engineering Filaments
As the name suggests, engineering filaments are created for engineering projects and provide sufficient characteristics for prototype and final product creation.
3D printing these materials can be challenging for beginners though it’s possible. We’ll check the famous cases in the following.
Nylon
Nylon is a branch of synthetic polymers that is mainly based on polyamides. It is strong, durable, and somehow flexible though the worst thing about Nylon filament is its hydrophilic characteristic. So it tends to absorb moisture and has short shelf durability. However, the excellent durability to the flexibility ratio of Nylon filaments makes them ideal for functional parts.
The most typical Nylons in FFF printing and traditional manufacturing consist of PA 66 and PA 6.
Every filament manufacturer makes his filament with a combination of PA 66, PA 6, and additional materials to give them some necessary properties. Hence there are many different Nylon filaments with various properties. PA neat is an excellent example of Nylon filaments.
PA Neat from the famous Colorfabb company is specifically designed to withstand high temperatures (up to 120o C) while preserving its mechanical properties. This filament is stiff, durable, and has slightly more tensile strength compared to others.
Nylon filaments are usually in the mid-range when it comes to suitable filaments you can use to print gears. They are easier to print than high-performance materials like PEEK, but they are much more convenient.
Here you can see specific mechanical properties and printer settings for the PA Neat filament: (data from colorFabb’s technical datasheet). You can also check its price here.
| Mechanical properties of PA Neat | ||
| Description | Value | Test method |
| Tensile elongation at break | 4.4 % | ISO 527 |
| Tensile Strength | 78 MPa | ISO 527 |
| Charpy Impact strength, unnotched | 90 KJ/m2 | ISO 179 1eU |
| Density | 1.14 g/cm3 | ISO 1183 |
| Printer settings of PA Neat | |
| Description | Value |
| Printer nozzle temperature | 265 – 290o C |
| Heated bed temperature | 40 – 50o C for high infill prints |
| Print speed | 30 – 40 mm/s |
| Adhesion | buildTak, Glass plate |
| Active cooling fan | 50% |
PETG
Polyethylene is the most used plastic in different industries and products like pipes or water bottles. PETG is also a modified version that suits best for 3D printer filaments. For example, the ‘G’ in the name PETG stands for glycol-modified. So, this material has somewhat similar properties as the commonly used Polyethylene.
This filament material can absorb a limited amount of moisture if left aside. Still, it’s a good idea to dry it before printing. This feature makes PETG a more suitable filament for functional parts production in humid environments.
PETG is also mostly known as a middle ground between PLA and ABS. We’ll also check these filaments though there is a high chance that you know about them beforehand.
| Mechanical Properties Of PETG | |
| Description | Value |
| Tensile Modulus | 2.95 GPa |
| Tensile Strength | 28.3 – 58.6 MPa |
| Impact strength Notched Izod | 15.25 J/m |
| Density | 1.38 g/cm3 |
| Printer settings | |
| Description | Value |
| Printer nozzle temperature | 230 – 250o C |
| Heated bed temperature | 70o C |
| Print speed | 60 – 100 mm/s |
PC
Polycarbonate or PC is another plastic that is vastly used through different industries. This material is mainly known for its heat resistance and toughness.
However, 3D printing polycarbonate can be a real pain! Using a heated bed and high nozzle temperature and utilizing an enclosure is crucial for using this filament.
Hygroscopic behavior (absorbing moisture) of PC is another thing to consider. It’s necessary to dry the filament before any usage.
The excellent news is printing PC can be done with domestic-level 3D printers. It doesn’t require extra high temperatures, so with some tweaking and calibration, 3D printing PC is still possible.
Here you can find essential properties and recommended setting for printing polycarbonate.
| Mechanical Properties Of PC | |
| Description | Value |
| Tensile Modulus | 2.3 GPa |
| Tensile Strength | 67 MPa |
| Impact strength Notched Izod | 12 – 16 ft-lbs/in of notch |
| Density | 1.22 g/cm3 |
| Printer settings | |
| Description | Value |
| Printer nozzle temperature | 290 – 310o C |
| Heated bed temperature | 140o C |
| Print speed | 50 mm/s |
Commodity Filaments
ABS
ABS is one of the most common materials in the 3D printing industry and traditional manufacturing methods. This filament is primarily used in additive manufacturing, rapid prototyping, and traditional manufacturing with molding machines.
Relative strength, durability, and convenience of post-processing make ABS a suitable filament for functional parts production. However, you can’t use ABS pieces in power or load transmission machines. They can only be used for simple mechanisms or motion transmission.
Printing ABS needs a hot end temperature of 220 to 250o C and a 95 – 110o C bed temperature.
| Mechanical Properties Of PC | |
| Description | Value |
| Tensile Modulus | 1.12 – 2.87 GPa |
| Tensile Strength | 25 – 50 MPa |
| Density | 1.00 – 1.22 g/cm3 |
| Printer settings | |
| Description | Value |
| Printer nozzle temperature | 240 – 270o C |
| Heated bed temperature | 90o C |
| Print speed | 30 – 60 mm/s |
PLA
The last option for printing functional parts is the PLA filament. First of all, PLA is much easier to print and use.
Every FDM 3D printer, like Ender 3, can print parts out of PLA, and with some post-processing, it yields acceptable outcomes. By ‘acceptable,’ I mean the printed gear can rotate smoothly and endure some light loads. However, the flexibility of PLA can become a problem once you want to create small objects.
If you have printed something out of PLA before, you can use the same settings to print gears, Although you can find the recommended settings down below.
| Mechanical Properties Of PC | |
| Description | Value |
| Tensile Modulus | 3.53 GPa |
| Tensile Strength | 36 – 55 MPa |
| Density | 1.24 g/cm3 |
| Printer settings | |
| Description | Value |
| Printer nozzle temperature | 190 – 220o C |
| Heated bed temperature | Not Necessary |
| Print speed | 30 – 90 mm/s |
