The real problem with printing these materials is that the part isotropy is poor, so you get the expected strength on the x- and y- axes but the z- axis (where all of the layers are stacking up) is quite poor. Turns out that printing things in a layer-by-layer fashion has its own cost.
I'm quite involved in this area, happy to share more if anyone is interested.
Layer separation can be addressed trough proper material selection and print settings.
Nylon and resin based filaments have excellent layer adhesion, also keeping your print area sterile and at a correct temperature is very important dust is your worst enemy.
Also too many people think that printing thin layers improves strength it doesn’t it just compounds the problem.
I’m printing large functional and structural parts in nylon with a 1.2mm nozzle and 0.6-0.8mm layer height and with a glass fiber reinforced filament I’ll have a material failure before layer separation.
Define high performance polymers as Nylon is also counted as such.
If you are talking about exotic stuff like PEEK then from what I know it has even better layer adhesion.
The most exotic thing I got to print with was PEI which also didn’t had issues with layers.
Reading more about this drone I’m not even sure if they used high end polymers for it.
The majority of their focus was around the continuous iteration from design to production workflow not material science.
If the blades they printed for the video are the ones used in flight then they printed them with ABS not some alien stuff.
Drones like this don’t actually experience that much force.
No friction, very little torque, little to no shock.
People print multi rotor drones all the time they work perfectly fine, this one is a bit bigger but nothing that would require a ground breaking advancement in the actual printing technology.
> Define high performance polymers as Nylon is also counted as such.
By high-performance polymers, I mean polymers suitable for structural parts and the replacement of metals like aluminum.
> The most exotic thing I got to print with was PEI which also didn’t had issues with layers.
I'd be really interested to hear about your experience with PEI. From the manufacturers and users I've spoken with, printed Ultem (PEI) has diminished strength along the z-axis because of its amorphous morphology. Do you know what brand of filament you used? Did you post-cure or perform any pre-print steps? How did you test isotropy?
Commodity resins are used to replace metals, and in structural parts all the time. Much of it comes down to part design, filler selection, etc.
For example, glass-filled polypropylenes are used all the time as metal replacements in vehicles (injection molded), even in some structural applications, depending on the exact demands.
Nylon is a pretty good structural material, especially glass-filled or talc-filled depending on abrasion resistance and rigidity required.
I don't have experience with the very expensive stuff (PEEK, etc) though, as usually that's much more expensive than the metal and doesn't confer many benefits except in pretty high end applications.
I also sand my parts and cover them with a protective epoxy (UV blocker).
For failure I’ve tested sheer and compression failures including in parts that where physically compromised e.g. by drilling screw holes or pressing in threaded inserts.
Unlike say ABS the failure was never across the layer lines and there was no layer separation or tearing if and when the parts broke they broke fairly cleanly.
Now this is for my specific application and use cases there could be stresses that could result in layer separation.
However I didn’t observed a significantly diminished z strength even when holes were drilled across the layer plain rather than just through it.
If you want to replace metal in general sintering or a lithographic process is likely going to be your best bet but FDM can work for many applications and you can always solve your material weaknesses in your design by for example altering the layer alignment across your design to ensure that the maximum strength is always where it’s need the most.
I beams are also much stronger in a specific direction but it’s not seen as a weakness but rather strength.
Technically they printed it for a mold but that's because fiberglass is better and while you can can print with glass reinforced materials the fibers have to be quite short which reduces their tensile strength compared to composite sheets.
That said if you really wanted too you could print a functional hull, but it's not a good application for it.
Not every manufacturing method is appropriate we can CNC mill a car from a single block of aluminum too but it's not exactly a good manufacturing process for this task.
EDIT: HanseYachts AG apparently prints a 10m (~33ft) hull for one of their Yachts using a cellulose composite filament.
You could do that, but it wouldn't be a good idea. Fiberglass works very well for that application and is much cheaper, faster, and higher performance.
It seems very large portion of yacht cost is interior installation. Printing might lead to all sort of safety, maintenance, performance and comfort advantages that you can’t achieve with normal manual labour.
I’m guessing some sort of hybrid approach could win.
I'm quite involved in this area, happy to share more if anyone is interested.