Printer Filaments are one of the many different types of resources in The Division 2 that are essential during the End-Game. They are used to upgrade the Crafting Bench, which in turn allows you to craft weapons and gear at a higher World Tier.
You need quite a bit of them as well, because you need to upgrade the
Crafting Bench repeatedly at each and every World Tier. As of now, that’s five times.
And unlike other resources like Polycarbonate, Printer Filaments cannot be found through enemy drops and Control Points. To get them, you need to deconstruct Gear Mods that you collect while playing the game.
For each of these you deconstruct, you get Printer Filaments. And the higher grade the Gear Mod is, the more you get. You should also consider unlocking the Deconstruction Perk at the Quartermaster to maximize the amount of Printer Filaments you get from each Mod.
Just make sure you don’t accidentally scrap all of your most useful Mods. They’re not exactly rare, but the best ones are tough to come by.