I mentioned before that an important learning during my recent Canada/US trip was that RepRap filament suppliers don’t all produce filament with the same characteristics.
Filament quality can vary considerably, and even basic dimensions, like the filament diameter, can be all over the map. Like other users reported, I’ve found that 3 mm filament often measures as low as 2.8 mm. That can make a major difference in print quality. As a result, I’ve started to habitually measure and record the characteristics, dimensions, and performance of all filament as I use it.
When I was in Canada, Derek Anderson showed me the test print above that clearly demonstrates the problem. The entire part shares the same geometry and was sliced using the same parameters. The difference is that in mid-print Derek changed from one supplier’s filament to another supplier’s filament.
This wasn’t an accident. Derek devised the test print to clearly show how bad the filament from one of the suppliers actually was, and he clearly succeeded.
There have been other cases reported on the internet, users have discovered foreign contaminants in darker colored filaments where they wouldn’t be visually obvious. One user even found tiny ball bearings that blocked the orifice in their hotend print head.
Using cheap filament may save you a little money upfront, but can lead to losing countless hours, useless prints, and potential damage to your machine.