Prusament PC Blend Carbon Fiber prints very fragile  

RE: Prusament PC Blend Carbon Fiber prints very fragile

Hi! 
Unfortunately, this is a normal behavior. It is printable without warping and without an enclosure, but the residual stress stays in the part and the individual layers do not fuse together. In order to make a strong part, the settings which worked for me are just the maximum possible temperatures on a stock prusa printer - including the ambient temperature in an enclosure and around 15% part cooling for MK3S, depending on the ambient temp. Be aware this might be risky, given the printer is printed from PETG.
Some people prefer annealing the part in an oven, but you're putting the dimensional stability at risk then.
On a printer able to achieve so, 310 hotend, 135 bed, 20% MK3S cooling, 60C ambient temps worked the best for large parts.

RE: Prusament PC Blend Carbon Fiber prints very fragile

Hi
When my 3d Printer is finnis I want make an Adapter for my Rugged Tablet. So I tought about using that Filament.
So is a "normal" one better when it come to fall damage?
Thanks

RE: Prusament PC Blend Carbon Fiber prints very fragile

Posted by: @prusaprinters-profile

Hi
When my 3d Printer is finnis I want make an Adapter for my Rugged Tablet. So I tought about using that Filament.
So is a "normal" one better when it come to fall damage?
Thanks

Yes, I think you would have to throw normal PC Blend parts out of an airplane or smth to get them to break from fall damage. I certainly would not say the same for the CF variant. Normal PC Blend is also more elastic and as such should protect better from impacts by absorbing the impact energy (if that is important for the adapter you are making).

RE: Prusament PC Blend Carbon Fiber prints very fragile

The normal mark is 1,5m hight where something falling down.

RE: Comparison tests?

Has anyone seen comparison tests between the two?

RE: Prusament PC Blend Carbon Fiber prints very fragile

Posted by: @prookyon

Hi!

I have done several test prints with PC Blend CF and they all seem to be much weaker than same parts printed from normal PC Blend.
All printed on Prusa Mini with 0,6mm tungsten carbide nozzle, sliced with Prusa Slicer using the included material profiles.

Where a print with normal PC Blend requires a lot of effort to break (even when using pliers) - the same print with PC Blend CF can be snapped easily just by fingers with less effort than even PLA or PETG.
I tried various layer heights (0.15mm - 0.4mm) and increased extrusion width but that did not seem to help.

The description of the material seems to imply that it should be stronger than normal PC Blend but so far I just don't see any advantages besides the lack of warping. Is this normal? Faulty batch? Not actually printable with Mini even though profiles exist?

How did it break? parallel to the layer interface or across the layer? I haven't noticed any such weakness

RE: Prusament PC Blend Carbon Fiber prints very fragile

Posted by: @prusaprinters-profile

Hi
When my 3d Printer is finnis I want make an Adapter for my Rugged Tablet. So I tought about using that Filament.
So is a "normal" one better when it come to fall damage?
Thanks

Normal PC is probably fine for this. Where I've seen carbon fiber filament being used to good effect is in higher temperature applications. Here, the part maintains more strength at temps around 80-100°C than other filaments, and in the particular application doesn't experience shock loads.

RE: Prusament PC Blend Carbon Fiber prints very fragile

Any filled filament will be weaker in tbe z axis compared to the same material unfilled, if used with open printers.

The layer below cools too much and adhesion is compromised.

The only option to improve that on an open printer is to print very slow. Also turn off the fan. It will slightly improve interlayer adhesion. 

Increasing extruder multiplier will also improve it.