3D printers provide excellent opportunities for engineers and product designers to create real models from their CAD files. Hobbyists also use 3D printers to produce many things, from action figures to car accessories.
Architects make life-like house models using 3D printers. Yet, printing high-performance “mechanical parts” is one of the 3D printer’s boundaries.
Many manufacturers still use traditional methods to make gears, nuts, etc. However, 3D printing technology is developing swiftly, and today new filaments are introduced that weren’t available in the past. They provide high strength and impact resistance and a long life cycle.
In this article, we will discuss the best filaments for gears. Keep in mind, though, that strength comes with a price. Materials with more durability and strength are usually harder to print and, obviously, more expensive.
PEEK is a semi-crystalline thermoplastic known for its outstanding mechanical properties. It has been used in the manufacturing industry for years, and it is now available as a 3D printing filament material. Mainly known as wear and heat resistant, PEEK is often considered a high-performance material.
If you look closely at its structure, you will notice that when it melts, the molecules rearrange under the effect of heat. So they’ll settle in their specific positions after the whole part solidifies. This feature helps PEEK to keep its characteristics after a temperature rise.
While the semi-crystalline structure creates decent mechanical properties necessary for the finished product, it makes the printing process much harder. Printing with PEEK needs an advanced 3D printer paired with an extruder that can warm up to 400o C and a heated bed that can reach 230o C.
So PEEK is one of the best filaments around to print gears, especially for small and medium power transition systems. However, it is expensive and hard to print.
Below you can see two tables about mechanical properties and the recommended printer setting from 3d4makers. These values are excellent sources for designers and mechanical engineers or students.
You can check the price for this filament here.
|Mechanical properties of PEEK|
|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 nozzle temperature||370 – 420o C|
|Heated bed temperature||120o C|
|Print speed||15 – 30 mm/s|
|Drying recommendation||110o C, 2 – 4 hours|
PEKK has excellent chemical resistance and mechanical properties, the highest among all thermoplastic materials. 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.
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|
|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|
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, and 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.
Nylon is a branch of synthetic polymers that is based on polyamides. It is strong, durable, resilient, and somehow flexible. The worst limit of Nylon filaments, in case of durability, is their 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.
Nylon filaments come in some variants that are represented mostly by some letters and numbers. The most common Nylons in FFF printing, as well as general manufacturing, are 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 specific characteristics. So there are many different Nylon filaments with various properties. Below, we review the most suitable ones to print gears with.
The first Nylon filament is PA Neat from ColorFabb. PA Neat is 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.
|Mechanical properties of PA Neat|
|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|
|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%|
NylonX from MatterHackers is another alternative for printing durable gears. It’s reinforced by adding micro-carbon fibers to nylon. So NylonX has the stiffness of carbon and durability of nylons. According to the manufacturer, this filament is designed for its optimum impact resistance, stiffness, and high tensile strength.
The combination of carbon and nylon adds rigidity and stability to the filament. So it is easier to print with NylonX compared to printing with the traditional nylons. Keep in mind, though, that carbon fiber’s abrasive nature can wear out brass nozzles, so you should consider using steel or hardened nozzles for it.
You can find its mechanical properties and advised printer settings down in the tables below. You can also check the price for this filament here.
|Mechanical properties of NylonX|
|Tensile Modulus||4.38 GPa|
|Tensile Strength||63.3 MPa|
|Tensile elongation at break||4%|
|Printer settings of NylonX|
|Extruder temperature||250 – 265o C|
|Heated bed temperature||60 – 70o C|
|Print speed||10 – 80 mm/s|
|Adhesion||PVA with a glue stick|
|Nozzle||Stainless steel or hardened nozzles|
Polymax is a popular filament from Polymaker. It is produced with Polymaker’s Nano reinforcement technology and has decent mechanical properties. It’s easier to print and slightly cheaper.
You can find the mechanical properties and the printer settings for Polymax in the tables below.
|Mechanical properties of Polymax|
|Young’s Modulus||4.38 GPa|
|Tensile Strength||28.1 MPa|
|Charpy Impact strength||12.2 kJ/m2|
|Bending strength||48 MPa|
|Glass Transition Temperature||61o C|
|Printer settings of Polymax|
|Extruder temperature||190 – 230o C|
|Heated bed temperature||25 – 60o C|
|Print speed||40 – 60 mm/s|
|Adhesion||Glass with glue, BluilTak, Blue Tape|
ABS is one of the most common filament materials. This filament is mostly 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 printing gears. However, you can’t use ABS gears in power or load transmission machines, Although they can be used for simple mechanisms or motion transmission.
Printing ABS needs a hot end temperature of 220 to 250o C and a bed temperature of 95 – 110o C.
The last option for printing gears (or similar 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 gear teeth.
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.
|Printer settings of PETG|
|Extruder temperature||180 – 210o C|
|Heated bed temperature||Not necessary|
|Print speed||25 – 90 mm/s|
|Adhesion||Magnetic bed, Glass, PEI|
How to print perfect gears:
Gears need smooth teeth surfaces to rotate. They should be fixed on a shaft and endure constant loads. Here are some helpful tips to produce results that work properly:
- Make the gears as thick as you can. This way, they can withstand higher loads and torques.
- The more teeth you have on your gears, the smoother they will rotate. However, don’t try to increase teeth by making them too small.
- Use standard gear designs. By using Involute spur gears, you will avoid any upcoming problems and will also have better rotations.
- 3D printed gears are not as rigid as metal gears and can quickly wear out each other. So try to adjust the distance between them.
In this article, we discussed different filament materials you can use to print your gears. PEEK has the best mechanical and thermal properties between them, and when it comes to durability, it’s the best filament for gears. Printing PEEK and PEKK can be expensive, though, and they need professional setups. So our third candidate is Ultem. It is not as strong as PEEK, but it’s cheaper and easier to print.
In the mid-range, we have different options like Polymax and nylon-based filaments. They are easier to print, though less rigid and durable. You can print Polymax and nylon filaments with a simple setup like Ender 5.
The last options are the most popular filaments, PLA, and ABS. You can also make gears out of them, but you shouldn’t expect the output to be perfect. However, printing gears out of PLA is an excellent choice for some specific areas like rapid prototyping and test models.