HTPLA Carbon is some AWESOME stuff. SUPER stiff and strong…who cares if it wears out nozzles, they are replaceable.
I have played with HTPLA carbon and FINALLY got it successfully working on the mini. I did end up going to the aerostruder and a 0.6mm nozzle. (aerostruder may not be 100% needed, but a larger than 0.5mm nozzle should be used)
I had similar results at first. first 5 to 10mm was fine, then it started with crappy layers. I think I finally figured it out though. what you are seeing in the multiple “hollow” layers is some slipping of the filament, much like a clog. This seems to be due to heat creep going up the filament which softens it at the extruder hobbed bolt and clamp bearing and then your clamp pressure goes down and it slips. HTPLA carbon is VERY stiff when cold, but softens up and gets flexible when it warms up. I would always have to adjust my filament clamp pressure after the first several layer to keep a good grip on it…even with the aerostruder. in fact I don’t like how stiff the spring is in the aero…but that is another story.
I think the best solution is to keep the HTPLA carbon heated as you print it, so it stays in a more flexible state as it gets to the extruder. I have a food dehydrator setup to do this the next time I print with it. If you can’t do that, just tighten the extruder clamp pressure after 5 or 10mm of printing. ALSO, use the biggest nozzle you can (hardened of course). I used the HTPLA settings in cura, which seemed to work fine, though I may have customized them some (I will have to check).
… on another note, I had to change my extruder Y position in the ending G-code for CURA because it normally parks it under the spool. this stresses the VERY stiff filament and after a few days it would just snap randomly.