All filament is abrasive to some extent. Speciality filaments such as carbon fibre filament even more so. How is abbrasivness defined for filament and is there a metric that defines the abrasiveness of filament?
If available, are there any filament producers that report the 'abrasiveness' of their filament?
Abrasiveness depends on both the hardness and the roughness of a material. The harder material will grind/polish the softer one. But if both surfaces were perfectly smooth not much would happen, so roughness is important.
For example sandpaper is rated and sold based on its grit which refers to the size of the particles (i.e. roughness).
The encyclopedia Britannica has an excellent article on this, Abrasive | Types, Grades, Uses & Applications. The most relevant part being:
One of the most important properties necessary in an abrasive material is hardness. Simply put, the abrasive must be harder than the material it is to grind, polish, or remove. Hardness of the various abrasive materials can be measured on a number of scales, including the Mohs hardness test, the Knoop hardness test, and the Vickers hardness test.
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Toughness or body strength characteristics are also significant to abrasive function. Ideally, a single abrasive particle resharpens itself by the breakdown of its dull cutting or working edge, which exposes another cutting edge within the same particle.
Some filament manufacturer's do publish data sheets PDFs on their websites, but except for flexible filaments like TPU and TPE I've not seen hardness included, presumably because the hardness of, say, PETG filament should be the same as the hardness of PETG copolyester that can be looked up.
Cheaper filaments tend to have some additives/filler mixed in to make them easier to print or give them desirable properties (like "silk" PLA). These additives are usually not disclosed (they're trade secrets I suppose), so the best we can do is make some educated guesses. "High flow" materials are likely softer than their regular counter parts. Glass-filled filaments hardness will be dominated by the glass. Likewise for carbon-filled.
As for brands which provide data sheets, Fillamentum provide technical data sheets for each of their filaments which include the following specifications:
Hope this helps!
