I have just seen this YouTube vid and found it interesting, So I thought I would share it…
How would this be considered a scam?
It becomes stiffer, shrinks less compared to the same material without carbon fiber, and is certainly tougher. However, carbon fiber isn’t always the most suitable material for every application.
It is a scam sort of…
Unlike plastic for industrial use out filaments basically only contain grains of fibres, be it glass or carbon.
Even for spray on fibreglass the user can set the length of the fibres according to need.
So far I have not found a filament that came with proper specs for the additives.
Whatever is in the filament has to come out of the nozzle.
Does not require a rocket scientist to work out that those fibres HAVE TO BE tiny so we won’t get constant blocks.
They also can’t be too random in shape and length as this would cause clogging up as well.
What we have as filament is a compromise, giving us some of the goodies but also some drawbacks.
A printed part still won’t come close to the same part moulded with the same plastic and matching fibre lengths.
It still is heaps better than without the additions and THAT is what matters for us …
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I used to work with teflon that was filled with glass beads, brass or graphite and this altered the characteristics of the pure teflon by usually making it less flexible or giving them greater wear resistence. I agree that it’s use in 3d filament is probably less noticable but might still be of use.
He only measured stretching strength of CF, but that is not the strength of it. This is a very misleading video, bordering on “click bait”.
CF gets its strength in pressure, not pulling. That is why he found his curves interesting, he didn’t understand them…
Carbon fibre excels in tension, but the CF in FDM filaments is chopped so small it acts like a binder, giving some change in properties but you wont see much change.
The layering and material makes much more difference than the addition of a binder to it’s strengths.
So far as I can see from the information available to me, it appears cosmetic or improves the handling of the melted plastic. Even from Bambu’s own site, which doesn’t say how it’s tested, there’s little difference between the virgin and CF versions and even reductions in performance.
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I am afraid that I have to agree with @bill.m.davis here in the video being difficult to take seriously. Yes there are standards for tensile testing. And there’s good reason to stick to them. Otherwise, failures can easily exceed the measurement area or prioritize different failure modes. And that is pretty much all that that ca be “scientifically” determined from the video…
Regarding CF in filament, there are two factors that make it interesting. The frequently advertised mechanical reinforcement is only really seen in available test data in a rule of mixtures on stiffness. So max stress is increased but typically comes at the cost of reduced max strain => they do tend to be more brittle.
Much more interesting is the significantly higher thermal conductivity. This helps tremendously with cooling behavior and hence allows a reduction in curling and warping.
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It also gives prints a more matte finish, with better hidden layer lines.
I have printed many things with CF filaments and I agree it doesn’t add much in the way of tensile strength, nor does it help with layer separation.
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The TDS of the filaments downlowdable through the shop pages give details on test standards and print specifications.
The differences between PLA Basic and PLA CF are negligible comparing Stiffness and Strength, having looked at the TDS.
It may even be that the PLA used in the CF range is not the same as used in the Basic range lending a comparison moot as to the improvement gained by adding fibre filler.
It certainly looks pretty tho.
I can’t comment on the scientific properties on Carbon Fiber in filaments but to someone like me, I just look at it as “It’s got carbon fiber in it, so it must make a stronger print”. This looks like it’s not the case.
Not sure if I’d agree with that. The bending stiffness of PLA-CF is 144% of PLA Basic. For the important layer adhesion in impact testing, PLA-CF only achieves 57% of PLA Basic. Those are quite significant differences imo.
The question still remains as to what is actually needed for the part (location and direction).
What I found quite useful when comparing properties was that of the hard materials, only PA6-CF seems to be able to beat PLA Basic in layer adhesion impact testing… by 12%.
But in any case, those properties will not be achieved in a print with varying settings (adaptive layer height, slow down for overhangs, different wall thicknesses,…).
No one prints parts that need to withstand serious mechanical stress using 2 layers and 15% infill. The printed parts were not printed like they would have to be in a real world scenario.
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I don’t see how this is trying to “trick” you. Fiber with added Carbon offers some slightly different properties. Those properties may or may not be important to you.
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