Test focuses on some details: dimensional accuracy, precision and the pressure quality. Winding precision is a visual test in which I check whether the filament works well on the coil, without crossovers that can cause snakes when printing.
The print quality takes place with a CNET calibration test, which I used to test all 3D printers that I check. When checking the filament quality, I am looking for noticeable roughness and missing filament, in which moisture or other contaminants have interrupted the process of melting and cooling.
The dimensional accuracy may be the most important test because it measures the consistency of the filament. As you move, the filament diameter changes and arranges the 3D printer over or under extruded filament. This creates striking scars in your model or worse, a complete mistake. You want the material to have the same diameter all the way.
In order to measure the accuracy, I take a 5-meter piece of filament from the start, center and end of the roll and measure the diameter with four same points. I then add up all of these measurements and divide the total measurement by 12 – the total number of measurements carried out – to give me an average of the role. Most modern printer use a 1.75 mm filament, so that the filament is as close as possible.
Great filament has a deviation of plus or minus 0.02 mm, a good filament plus or minus 0.03 mm and the rough filament is everything plus or minus 0.05 mm. All filaments that we recommended here are at least 0.03 mm on average.
