3D-printed gears straddle the line between functional and hobbyist components, yet they perform as well as any gears when appropriately designed.
Most 3D printed gear failures are from choosing the wrong materials, incorrect printer settings, and specifying the wrong infill (which leads to weak gears that snap or gears that cost too much in raw materials).
This article covers how to 3D print gears like a pro with seven tips from our 3D printing experts.
Let’s jump in!
Test your printer
Firstly, take your 3D printer for a test drive. Gears are simple, but the teeth can present a challenge with the wrong 3D printer settings.
You must determine the best settings for your 3D printer, which also applies to your materials. Try printing a test gear and putting it into use to see if your printer’s tolerances produce accurate gears.
Nylon > PLA > ABS
When choosing materials for 3D printing gears, the best materials are nylon, PLA, and ABS, in that order.
Nylon is strong and durable with a low friction coefficient, and the high inter-layer adhesion produces solid parts with no flaws.
The downside to nylon is it absorbs moisture, so if your gears will work in humidity, PLA is the best option. PLA is more rigid than ABS, harder-wearing under cycling, and offers greater detail for sharper gears.
If printing with resin with the Formlabs Form 3, use Tough Resin or Durable Resin. These offer excellent performance and relatively fast print speeds.
Print with a solid infill
A solid infill uses more filament, but you get stronger, more durable gears in return. Gears go through lots of mechanical stress, and using a 100% infill ensures that there are no points of failure in the gears from hollow areas.
If you are prototyping gears and can live with a lower durability, opt for an infill of 15% to 30% so that gears are still test-worthy.
Gear design is everything
Although your 3D printer and materials are critical to producing gears, your gear design is critical to how the gear performs.
Gears have two basic parameters – pitch and teeth number. The pitch is the number of teeth within one inch of diameter, determining the correct teeth quantity. You should also consider the teeth size and profile.
Most gears are of the involute design, considering pitch diameters, pressure angles, face widths, centre distances, and modules. If you are not clued up on these and are designing gears from scratch, this guide will help.
Need a gear design fast? There’s a site for that!
You can find free 3D printer files at Thingiverse and Instructables, and there are several more great places to pick up free files here.
If you need 3D-printed gears that use standard profiles, there’s a strong chance that you can get a head start with a pre-designed file.
Most free files are open source, letting you modify them in CAD to slash your design time. If the files are STLs, you can use Tinkercad to modify them.
Strengthening your gears
You can strengthen your gears with a 100% infill or print them thicker (which also strengthens the teeth). Doubling the thickness doubles its strength, but you must consider the gear’s compatibility with other gears.
While plastic 3D printed gears are weaker than metal gears, using the correct 3D printer heat settings offers noticeable improvements in strength, curing the plastic on the print bed so that proper inter-layer adhesion occurs.
Another option is metal 3D printing with the Markforged Metal X. The Metal X can produce metal gears, or you can create hybrid gears like in the image above.
You can’t rush perfection
Gears have lots of facets and take a while to print. You should use the smallest nozzle diameter possible and let the printer work as slowly as needed to produce an accurate gear – rushing the print process will give you lacklustre results.
If you need faster gear print speeds, consider increasing the infill to 15-30% (remember – you don’t want a hollowed-out, weak gear), and print with PLA. PLA is the fastest material to print and offers excellent durability and quality. Another option is upgrading your 3D printer to one with a faster print speed.
Find out more
You can call us on 01765 694 007, send us an email at firstname.lastname@example.org or book a discovery call with our Formlabs specialists Elaine Rutledge or Tammy O’Neill.