We recently purchased a Modix Big 60 printer which uses the Titan Aero hotend. We've had issues from day 1 trying to print ABS with a .4mm nozzle and using Cura for our slicing program. Once we get the brim dialed in and printing nice the job will run for a couple hours and then it will loose extrusion. If we take the filament out of the hotend, you will see where the knurled gear has eaten away the filament. We are using Coex LLC filament and running the temp between 230-250 C with a heated bed between 80-100C The fans run 100% after the initial layer and we are printing our parts with 90% infill as we want them to be similiar to the parts we get off our industrial 3D printers from Stratasys. One thing i plan to try shortly is switching the retraction distance from 2mm to .5mm and see if that makes a difference. Any other ideas?