Carbon fiber filled XT arrived yesterday. It’s not often that I drive into work on Saturday to play 3D printing, but I did today. I’ll do more of a write up later, but basically: IT’S AWESOME.
Prints very easily, easier even than standard XT. The prints are the stiffest I have ever made. The output is not too brittle despite being stiff. The tough, flexible amphora as matrix polymer really shines here giving really nice layer adhesion, overhangs, bridges etc. Support material and raft removal is superior to unfilled XT.
The prints look gorgeous, graphite grey with a twinkle of lustre from the carbon. The filament is incredibly consistent as you would expect from colorfabb. I was able to print through a 0.25mm nozzle with no drama, but did most of my testing on 0.40mm.
I used standard brass nozzles, even though I have some stainless ones, I want to study The wear rate of carbon on our brass nozzles. I’ll report back when I have data on that.
My company has thought about adding the Mark Forge to sales, the difference with the material is that the actual Carbon Fiber and Kevlar is more like pre-preg filament vs an infused filament and much more expensive for material.
@Mark_Rehorst nope, no exposed fiber on the surface. I’ve inspected the printed objects extensively under a microscope and the polymer matrix entirely encapsulates the fibers such that you can’t really transfer by contact fiber from object to human.
@Kevin_Billett colorfabb have some useful data on their page about CFXT20 It’s not quite ASTM but really you can’t actually apply formal properties like that to printed objects reliably, prints just aren’t isotropic enough. Especially fiber filled prints where all sorts of micro structure weirdness is going on.
@Sanjay_Mortimer1 Semi true about 3D parts but if they based on same material, printer and build orientation then that is enough use a ASTM 13x128x3mm sample to do the tests and get reasonably reliable results. trouble is the market is also flooded with not only variable printers, but numerous producers of filament whose standards of quality are going to vary. This is a secondary benefit of commercial machines are the consistent standards. I would imagine as they advertise some of it, Mark Forge most likely has this ASTM data.
Best example of what would be nice… http://www.stratasys.com/materials/fdm/compare-fdm-materials
How does it compare to CFPLA by protopasta? I found it incredibly easy to print, it has an incredible finish also, and incredible stiffness/weight ratio… but… but… the binder is PLA, how sad!! Now, since XT is my second choice when I can’t print in PLA (or Nylon), CFXT will obviously become a must for me given how much I loved CFPLA. I expect it to be a little less stiff though, but much more resilient and heat-resistant of course.
@marc_kerger the very unusual property of this filament is that you need to print it fast! Else it melts by conduction on a higher portion, which impedes the flow (carbon is an excellent heat conductor)! My only troubles were b/c I printed too slowly (including the first layer), but I used 0.4 mm nozzles mainly.
@Jeremie_Francois
So Colorfabb list their XT-CF20 as being 6.2GPa, vs Proto-Pasta CFPLA being listed 6.56GPa.
I still have the test objects printed in CFPLA, exactly the same machine, same GCODE.
However my subjective finger-instron testing seems to show that the XT-CF20 feels stiffer than the CFPLA. Significantly stiffer. There may be some noise in this information however as the CFPLA part has been used and handled a great deal for nearly a year now, whereas the XT-CF20 part is right off the machine and not yet been flexed or fatigued.
The CFPLA is definitely easier to print, but XT-CF20 is pretty damn easy too. The bed adhesion isn’t as good as CFPLA, but it’s still more than adequate. CFPLA has nearly zero warp, even on cold blue tape. XT-CF20 does need the bed at 80C or so, with some glue stick, but I have yet to have a single corner lift. You also need to print XT-CF20 at over 250C, so you need a proper hotend to print this stuff too.
@Sanjay_Mortimer1 excellent info, thanks! I was skeptical at first with CF fibers, but once tested I bought 6Kg to print part for drones… with lots of warning to my client about heat resistance. Now I will have to buy some XT in addition, it’s all your fault And you bet I have proper hotends on my printers…
I was skeptical at first with CF fibers, but once tested I bought 6Kg to print part for drones… with lots of warning to my client about heat resistance. Now I will have to buy some XT in addition, it’s all your fault 
And you bet I have proper hotends on my printers…