Changing the Bowden tube to one that is not as sturdy could also be causing the mouse bites. The filament from MatterHackers is good and is within specs but if you some calipers you can measure at various places, there could be some fluctuation in the diameter.
Hot end temperature too low: If the nozzle temperature is too far below the required extrusion temperature for the filament loaded, then the filament will not melt. The solid filament will not be able to extrude through the nozzle, which will cause the hobbed bolt to grind a mouse bite into it. Make sure the nozzle is at the proper temperature for the material you are trying to extrude.
Bed too close to the nozzle: If the bed is too close to the nozzle, then the material will not be able to exit the nozzle. This blockage can cause a mouse bite. Make sure the bed is far enough away from the nozzle by using the z-adjust screw.
Filament catching on the spool: If the filament spool is cross-threaded or becomes stuck, then a mouse bite will likely occur. Make sure not to let filament unspool, as respooling it can easily cause a cross-thread. Make sure there is nothing touching the spool so it can spin freely on the spool minder.
Improper settings selected: Improper temperature, speed, fan, or retraction settings can easily cause a mouse bite. Make sure the proper settings have been used for the material you are printing with.
Incorrect filament diameter: Ensure your filament is the proper diameter (2.85 ±0.1mm). If the filament is too thick, it will cause feeding issues resulting in a mouse bite.
Hot end not fully purged: If the hot end has not fully purged from the previous material, it can cause feeding issues and mouse bites. Though this will only happen if the previous material was a higher temp, it is still good practice to fully purge.
Dirty extruder assembly: Make sure the extruder assembly is clean and free of dust and debris. If there is excess filament shavings, the bolt can skip when feeding material.
I have been battling our AirwolfHDx for a year now. I get about 70% sucess rate with both PLA and ABS and all the prints that fail are because of “mouse-bite”. I am not an engineer but I am convinced the issue resides in the filament drive system mounted on the back of the machine. I run the following printers without issues-- easily 95% print success rates–Lulzbot TAZ4 & TAZ5 and Lulzbot Mini, 3-- Makerbot Rep. 2’s and 2–Makerbot Rep 2x’s-- and these ALL place the filament drive near the extrusion nozzle. My theory-- only a theory-- is that as the filament is being pushed through the Bowden tube there are “spots” in the long filament tube distance where the energy of the filamnet drive is being offset by a movement in the tube as the print head moves and they subtley cancel each other out. Additionally-- as retractions build up in the process of this loss of physical movement through the tube (to the intended destination) the filament is being stripped down by the filamnet drive roll. The physics dictate that the filament drive is pushing UP and OUT-- never down. Only the plastic tube wrapped with the electric cable are directing the forces downward over a pretty substantial span (length). I am convinced this is a design flaw and the tube and the plastic wrap is not sufficient to make sure the force of the filament drive is consistent. If there is an engineer out there-- I would love to get an analysis of this theory. In my mind-- I think this system would work fine IF the printhead was static and the shape of the tube did not change. It’s the constant changing of the tube trajectory that I feel compromises the amount of force of the filament to the nozzle.
What temp are you running your filament at? What speed are you printing at? What size nozzle are you running… I have noticed on my AirWolf HDx I sometimes need to run 10-15 degs. higher on the temp to prevent mousebite… You can counter act the higher temp by running your fan… Also try taking apart the extruder feed assembly and clean out the groves of the bolt, there are also two little springs that help sandwich the filament in between the bolt and a bearing. I took mine out and stretched them to add a little bit more pressure to feed the filament continuously.
