CHOPPER is a pelletizer
takes 1-3mm strands of polymers, including filament, then chopping them discreetly
the chopper stuff are called pellets or granules
it is unique because CHOPPER is designed to chop every 3-4mm to make short/stubby pellets
it is known from this diagram that stubby pellets are better for screw extruders
The fill ratio is higher, and easier to feed
it is not that these pellets dont exist, but most likely they are expensive because for special use
CHOPPER is open source and modifiable per your needs
for example it can be mounted with stepper or with electric drill
so chopper is an accessibility tool built for the reason explained here : Economics of Pellets vs. Filaments
it is largely 3d printed, but critical parts are off the shelf
heavy duty either for low or high speed, given you have a motor with enough torque
some filaments are harder to chop
whats unique about chopper is that it cuts TPU
not obvious but TPU is really stretchy and is usually pelletized underwater
chopper can do that dry
thanks to its adjustable knife clearance
every pelletizer has two parts to cut the strand : stationary and rotary knife
these two part needs clearance
some filament can be cut even with 0,5mm clearance
TPU will just slide
so if we adjust it to near-touching then TPU can be cut
CHOPPER is driven by any motor, and the shaft drives a feed mechanism by belts so it doesnt make noise
there is noise from cutting, however
and also big vibration which may fatigue your hands and arms if you operate it while carrying it
thats why it can be mounted to a desk to a steper motor so it does its job by itself
note that the steper motor needs a driver
the driver need to run the stepper continuously, and design for enclosure is available here: