Re: Filament Extruder - Convert pellets to filament
They can't really patent extruding 1.75mm rod any more than I can try to patent extruding 1.55mm rod. As far as I can tell, the only thing really being patented here is using a laser micrometer, a microcontroller and a PID function to adjust the puller speed on the fly to keep filament within tolerances. I don't know how effective it can really be, because the measurement has to be taken right at the die, before the filament has reached it's final diameter. Otherwise it has to be a little further out which means it has to predict if a variance is going to go over the limit and make an adjustment in advance. There will always be a little lag between the speed change and then the measurement of the effect of that change.
Everything else described in that patent is already standard practice.