With the shorter spring I was able to print my tpu discguard:
It turned out to be too soft to offer much protection though.
But at least it got printed
I've been back testing materials and I think you should look into some special Nylons or PCs. I've tested probably over a hundred 3D printing materials at this point and impact performance is a key metric for me. There are 3 materials that stand out while having enough stiffness for a part like this.
Lexan - Got to get the good stuff from Sabic although other high quality PC may work, generic PC just is crap. Warps bad, needs chamber, have to print at like 300-320C to get good layer bonding but once you get that it's impact performance in all axis is just stupid for how stiff it is.
065 trimmer line - Yes string trimmer line, it's just the wackyest, most flexable, run in through a wood chipper and it gives zero frocks nylon you can get. It's also a nightmare to print, beds that work great with other nylons just kinda barely work with it, decently high temps to get good layer bonding and it warps like nothing thing else you can imagine. But flat parts with lots of bed surface those issues aren't so bad. It's pretty flexible but much stiffer than 98A TPU, maybe half way between ABS/PETG and TPU stiffness wise. Also it's cheap as shit but no color options. Layer bonding even at higher temps is also not quite as good as the other two here.
PA-TPU blends - All the magic of Nylon combined with all the magic of TPU. Prints at reasonable temps, doesn't warp too bad, maybe slightly less than pure nylon, bed adhesion is pretty good on garolite, actually better than nylon by a little. Stiffness similar to the trimmer line so it's flexable but much harder than TPU. Layer bonding is amazing, like unmatched besides TPU. Impact perforamnce is like nothing else, beats the above two, like better numbers than most common 3D print materials with test samples that are half as thick. Some horizontal samples just stop the IZOD test hammer dead. Also very limited availability
this is the only current MFG I've found and it's only limited availability since taulman was closed. I honestly don't understand why everybody doesn't make this stuff, I think all these companies are too obsecsessed with absolute strength with exotic nylons filled with carbon fiber that have garbage layer bonding and crap impact performance. If I want a strong 2D part I'll laser cut or CNC mill it, what's the point of strong materials if they don't have the layer bonding to be strong in all directions.
I do have some other exoitc filaments that should perform well but haven't got a chance to test them yet.