In the early days of 3D printing, developers focused on creating the printers and didn’t think much about the materials they’d use to print 3D objects.
The first type of 3D printing filament was three millimeters in diameter and in the form of 3mm sized acrylonitrile butadiene styrene (ABS) welding rods or wire—which was what was readily available at the time. Soon, 3D printer makers and users discovered 3mm materials didn’t work so well with Bowden type printers. The available tubing at the time had an inner diameter of 3mm, which meant the 3mm filament was too snug.
Newer 3D printers have smaller and lighter print heads and use 1.75mm plastic filament to print 3D objects. Note that while 3mm filament is technically 2.85mm, some people in the 3D printing community still refer to it as 3mm.
Both types of filament are available, but what are the pros and cons of 1.75mm and 2.85mm 3D printing filament?
Benefits of 1.75mm Filament
In addition to greater availability from increasing adoption as a standard size, 1.75mm 3D printer filament works better with smaller nozzles and behaves better with retractions. It also has a higher flow rate that’s easy to control, allowing faster printing with smaller nozzles.
Extruding 1.75mm filament requires less force, therefore less power, than squeezing 2.85mm filament though smaller nozzle sizes. The smaller filament heats up faster and oozes less than 2.85mm filament, making melting and printing faster processes. Finally, 1.75mm filament works better with Bowden tube printers: Its smaller diameter creates a smoother flow through the Bowden tube.
Downsides of 1.75mm Filament
The thinner 1.75mm filament tends to absorb moisture faster than 3mm filaments due to the increased surface area to volume ratio. With flexible materials especially, this size filament can also get stuck or form knots because it bends more easily. This usually creates a mess, takes time to clean up, and you'll probably end up with a ruined print you’ll have to restart.
Advantages of 2.85mm Filament
Larger filament prints faster with large nozzles, making printing large objects more efficient. Thicker filaments are stiffer and less likely to jam while printing, so it’s better for printing with flexible plastics.
Disadvantages of 2.85mm Filament
Because of the ascendancy of 1.75mm as a standard, it’s getting harder to find 2.85mm filament. Only a few manufacturers still make it, and their products tend to be highly-priced. Makers who need it discover that there are few low-cost alternatives.
This filament size has higher tension as the printer reaches the spool’s end. The curvature and stiffness of the filament creates more friction in the final layers of filament on the spool. The high tension toward the end often renders the final few meters of the spool unusable. This means 3mm filament often creates more waste than 1.75mm filaments.
Familiarity with the pros and cons of 1.75mm versus 2.85mm 3D printing filament will help you pick the right filament size and create the 3D objects with the level of quality you desire.