when i tested the markforged mark two 3d printerand started using the continuous carbon, glass and especially the kevar fiber inlays, therewas that one question that kept bugging me: could we actually make 3d prints that arebulletproof? and how well do those normal materials like pla, abs and petg compare?so to be honest, i had no idea how much these 3d printed, plastic parts would be able towithstand. but that’s easy to test out!
materials needed for 3d printing, i started with these 50mm or 2†diameterdiscs. at first, i only made them 3mm or about ⅛ of an inch thick, since just as a roughestimate, i wanted to test these with an air rifle first before moving on to the big guns.so i called up a friend and we set up a quick slow motion rig, using this old casio camera,which does do a 1000 frames per second, but,
well. you can sorta see what’s going on,but not much more. i printed these test parts with a few different materials that scoredpretty well in the filaween testes, that is regular old pla and das filament petg, i’llbring in a few more standard materials later. i also printed a test part on the mark twothat was completely filled with continuous glass fiber and one that used kevlar. allof these were 3mm thick, and i was hoping that would be enough to stop the air rifle’spellet, which has an energy of less than 7.5 joules. relatively speaking, that’s nota lot of energy, but you definitely don’t want to get hit by these. i thought the petgwould at least stand a bit of a chance, but neither it nor the pla seemed to slow thepellet down at all. kinda dissappointing,
i really thought these would be a bit tougher.but once we bring in the markforged parts, things start looking quite a bit better. becauseneither the glass fiber nor the kevlar-filled parts cared too much about being shot at.yeah, they ended up with a bit of a dent, but the pellet didn’t even scratch the nylonsurface of the parts. remember, these are all 3d-printed fiber on the inside, and onlya thin layer of the onyx carbon-fiber-filled nylon on the surface. so that was promising!but as a video guy, the image from that casio camera was driving me nuts, so after a quickcall with mark 3d, they agreed to sponsor the costs of this video, which did includerenting a sony rx100, which still does 1000 frames per second, but the image just looksso much better. i also asked them to print
a few more fiber-filled parts since i didhave to return the mark two in the meantime, and they printed a bunch more parts in onyxnylon and a few filled with that sweet kevlar and glass fiber.obviously, i would have to step up the material thickness for all of these parts and particularlythe regular plastics to stand any sort of a chance against a .22 and .45 caliber bullets.i also needed some sort of a holder for these parts, and probably as more of an excuse touse the converted cnc mill, i made this part from aluminum. but as it turns out, a converted3d printer is not the best choice for doing heavier work like this. who would have though.i also printed a bunch more parts, going for 5, 10, and 20mm thick discs, using the translucentgreen das filament pla, bright green rigid.ink
pla plus+, which is an impact-modified typeand if there’s anywhere that property would shine, it would be with actual impacts. ialso used the brown das filament petg again and threw in rec abs in grey, since one ofthe core properties of abs is, again, that impact resistance. it ended up being quitea bit of material with two full sets of all these pucks, the largest ones are almost 50grams of material each. and then it was time to head to the shootingrange. they’ve not had a major accident on this range so far, and i didn’t wantto have caused the first one, so we decided to scrap the aluminum holder and went forwood and duct tape instead. still worked, not quite as fancy, but probably a bit saferand if we actually hit the wood, it’s probably
going to look pretty good on camera, too!first round: the .22 small-bore. while these are the smallest common caliber for a firearm,they already have over 20 times as much energy as the air rifle, so they’re definitelyno joke. and almost as expected, none of the smaller 5mm thick parts stood any sort ofa chance, even the fiber reinforced parts didn’t manage to stop the .22 bullet. however,when i taped the old 3mm part back on, that was already bent from the air rifle, it didstop the bullet, but it was backed up against the wood, while the other parts were onlysupported at their edges. moving on to the 10mm thick parts, we can start seeing howthe different materials perform. the pla just gets a fairly clean hole stamped out, andthe same for the impact-modified pla plus+
and abs. however, petg completely shattersinto bits, it doesn’t stop the bullet, but as it breaks, we can see that it doesn’tbreak along layer or extrusion lines, but into mostly random bits, so once again wecan confirm that the 3d prints with copolyesters make for parts that don’t differ too muchin strength from mass-produced, injection-molded parts. the markforged onyx nylon part showsalmost the opposite, with a perfectly rectangular hole around its back. so what about fiber?well, this is pretty cool! at just 10mm thick, which is around ⅜ of an inch, both the glassfiber and the kevlar managed to stop the .22 bullet. the glass fiber didn’t even bend,and the largest part of bullet just bumped right off, there’s a tiny bit stuck insideand the layers did split, but that’s about
it. the kevlar part did bulge out on the backand split off half of the print completely, but also managed to stop to bullet. but itwas definitely time to upgrade the wooden holder, as the cheap osb part was startingto crack quite a bit. so let’s move on the fattest parts, the20mm pucks. without any fibers inside, will these be able to stop a bullet? well, mostof them can! good old pla actually does quite a good job here, the part fractured, but thebullet didn’t go through. abs manages to literally catch it without even splintering,and while the petg part looks like it just gets blasted to pieces, the .22 bullet doesnot go through, either. you can actually see the flattened piece of lead tumbling back.the parts that didn’t last were the pure
markforged onyx, which almost looks like thepart didn’t get enough material for the individual 3d printed tracks to completelybond to each other, with perfectly square cracks, as well as the pla+ part, which, ifyou look at the entry hole, seemed to flexed around the bullet as it passed through.so overall, i’m impressed! even the humble pla can stop a bullet dead in its tracks witha 20mm thick part, and the fiber pucks only needed 10mm to do the same.but of course, stopping there would have been pretty lame. so with the second set of parts,let’s see what the .45 can do! yet again, this is a much larger and heavier bullet andit’s going to be carrying about three times as much energy as the .22 we just used. ithink even the fiber parts are going to have
a much harder time.but we’re going to start out with the regular 3d printed plastic samples again skippingright to the 20mm thick one, since we already know the thinner ones aren’t going to beable to do anything, and not surprisingly, even the thicker ones weren’t able to stopthe .45 bullet, either. it smashed right through the pla and pla plus+ parts and took a sizeablechunk out of the onxy sample. again we see that tunneling effect on the pla plus+ anda nice indentation where it hit. the petg part got completely obliterated, and whileit looks like it actually took quite a bit of energy out of the bullet and scraped offbits of the metal jacket, it did not stop it going through. but we did end up findingbits of petg all around the range afterwards.
and let’s finish this up with the fiberparts, the glass fiber first. and while it looks like it did put up a good fight, ultimately,it got pulled through the hole in the wooden holder, at which point the fibers opened upand let the bullet through. but it looks like it absorbed quite a bit of the energy again,as it almost tipped over the stand and it got the fibers quite solidly stuck in thehole. we had to remove that one by force. did the kevlar part do any better? um, sortof. since the kevlar fibers are softer, the part simply split in half and the bottom halfthen got dragged through the hole as a single piece. there’s a pretty obvious mark wherethe bullet hit and it got thrown almost all way down the range. i don’t think we canquite call this stopped.
maybe with a bit more contact area to theholder parts, these fiber prints would actually be able to stop a .45 bullet, but i thinkeven stopping the .22 with a 10mm thick, 3d printed part is pretty impressive. again,that’s just about ⅜ of an inch of material. regular, fiberless parts did manage to catchthat .22 bullet, too, but required 20mm of material to do so and only pla and abs wereable pull it off without shattering into a million pieces. petg did stop it, too, butthere’s not a whole lot left of it. so should you be 3d printing your next bulletproofvest? well, probably not, these parts were a lot thicker and heavier than something actuallymade for the job, but these experiments still showed which 3d printing materials are ableto take a beating. obviously, the markforged
continuous fiber materials did extremely wellhere, even with the thinner prints, but it’s nice to see that sufficiently solid blocksof standard pla and abs can still perform really well. and while i usually recommend3d printing with petg instead of abs for most things, i think we might have found the weakspot of petg. whereas the abs part now has a 22 caliber bullet solidly embedded insideit, the petg just completely shattered after stopping the bullet.one thing to keep in mind is that not all materials are made the same, so filament fromone manufacturer might behave completely different than one from another supplier. there aremost certainly abs materials out there that are much weaker than this one and possiblypetg and copolyesters that don’t shatter
as easily. but i think this was still goodfun and hopefully educational for you, too. if it was, give the video a thumbs up, andif you know someone that might enjoy it, too,
feel free to share it with them.again, thanks to mark 3d for making this video possible, and if you want to help out withkeeping the channel going, get subscribed, check out the affiliate links in the videodescription or even join in over on patreon for monthly hangouts and more. thanks forwatching and i’ll see you in the next one.
