A device for cutting a filament of a 3D printer includes a blade having a first end and a second end opposite the first end. The device also includes a support that is attachable to a heater block of the 3D printer and supports the blade, such that the blade is movable relative to the heater block. The first end of the blade is a cutting end, and the second end of the blade is a drive end. The drive end of the blade has a surface configured to receive a force from outside of the device, such that the blade moves relative to the heater block.