4 ms·

> Define high performance polymers as Nylon is also counted as such. By high-performance polymers, I mean polymers suitable for structural parts and the replac

> 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? Happy to take this to PM if you prefer.

dogma1138 7y ago
Well without understanding what polymers exactly it’s hard to have a discussion about it. My experience with Ultem PEI was pretty solid I did do post processing mainly annealing: https://www.thomasnet.com/knowledge/annealing-of-ultem-pei-/ https://www.thomasnet.com/knowledge/annealing-of-ultem-pei-/ In a toaster over I hacked for temp control. 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.
mediaman 7y ago
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.

dogma1138 7y ago

Well without understanding what polymers exactly it’s hard to have a discussion about it. My experience with Ultem PEI was pretty solid I did do post processing mainly annealing: https://www.thomasnet.com/knowledge/annealing-of-ultem-pei-/ https://www.thomasnet.com/knowledge/annealing-of-ultem-pei-/ In a toaster over I hacked for temp control. 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.

mediaman 7y ago

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.