When I tested the Markforged Mark Two 3d printer and started using the continuous carbon, glass
and especially the Kevar fiber inlays, there was that one question that kept bugging me:
Could we actually make 3D prints that are bulletproof? 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 to withstand. But that’s easy to test out!
I started with these 50mm or 2” diameter discs. At first, I only made them 3mm or about
⅛ of an inch thick, since just as a rough estimate, 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 scored pretty well in the Filaween testes, that is
regular old PLA and DAS FILAMENT PETG, I’ll bring in a few more standard materials later.
I also printed a test part on the Mark Two that was completely filled with continuous
glass fiber and one that used Kevlar. All of these were 3mm thick, and I was hoping
that would be enough to stop the air rifle’s pellet, which has an energy of less than 7.5
Joules. Relatively speaking, that’s not a lot of energy, but you definitely don’t
want to get hit by these. I thought the PETG would at least stand a bit of a chance, but
neither it nor the PLA seemed to slow the pellet 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. Because neither 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 Nylon surface of the parts. Remember, these are
all 3D-printed fiber on the inside, and only a 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 quick call with Mark 3D, they agreed to sponsor
the costs of this video, which did include renting a Sony RX100, which still does 1000
frames per second, but the image just looks so much better. I also asked them to print
a few more fiber-filled parts since I did have to return the Mark Two in the meantime,
and they printed a bunch more parts in Onyx Nylon 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 particularly the 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 to use the converted CNC mill, I made this part
from aluminum. But as it turns out, a converted 3D 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 translucent green DAS FILAMENT PLA, bright green rigid.ink
PLA Plus+, which is an impact-modified type and if there’s anywhere that property would
shine, It would be with actual impacts. I also used the brown DAS FILAMENT PETG again
and threw in REC ABS in grey, since one of the core properties of ABS is, again, that
impact resistance. It ended up being quite a bit of material with two full sets of all
these pucks, the largest ones are almost 50 grams of material each.
And then it was time to head to the shooting range. They’ve not had a major accident
on this range so far, and I didn’t want to have caused the first one, so we decided
to scrap the aluminum holder and went for wood and duct tape instead. Still worked,
not quite as fancy, but probably a bit safer and 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 definitely no joke. And almost as expected, none of the
smaller 5mm thick parts stood any sort of a 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 did stop the bullet, but it was backed up against
the wood, while the other parts were only supported at their edges. Moving on to the
10mm thick parts, we can start seeing how the different materials perform. The PLA just
gets a fairly clean hole stamped out, and the same for the impact-modified PLA Plus+
and ABS. However, PETG completely shatters into bits, it doesn’t stop the bullet, but
as it breaks, we can see that it doesn’t break along layer or extrusion lines, but
into mostly random bits, so once again we can confirm that the 3D prints with copolyesters
make for parts that don’t differ too much in strength from mass-produced, injection-molded
parts. The Markforged Onyx Nylon part shows almost 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 glass fiber 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 inside and the layers did split, but that’s about
it. The Kevlar part did bulge out on the back and split off half of the print completely,
but also managed to stop to bullet. But it was definitely time to upgrade the wooden
holder, as the cheap OSB part was starting to crack quite a bit.
So let’s move on the fattest parts, the 20mm pucks. Without any fibers inside, will
these be able to stop a bullet? Well, most of them can! Good old PLA actually does quite
a good job here, the part fractured, but the bullet 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 does not 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 the part didn’t get enough material for the
individual 3d printed tracks to completely bond to each other, with perfectly square
cracks, as well as the PLA+ part, which, if you 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 with a 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 and it’s going to be carrying about three times
as much energy as the .22 we just used. I think 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 skipping right to the 20mm thick one, since we already
know the thinner ones aren’t going to be able to do anything, and not surprisingly,
even the thicker ones weren’t able to stop the .45 bullet, either. It smashed right through
the PLA and PLA Plus+ parts and took a sizeable chunk out of the ONXY sample. Again we see
that tunneling effect on the PLA Plus+ and a nice indentation where it hit. The PETG
part got completely obliterated, and while it looks like it actually took quite a bit
of energy out of the bullet and scraped off bits of the metal jacket, it did not stop
it going through. But we did end up finding bits of PETG all around the range afterwards.
And let’s finish this up with the fiber parts, 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 up and 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 the hole. We had to remove that one by force.
Did the Kevlar part do any better? Um, sort of. Since the Kevlar fibers are softer, the
part simply split in half and the bottom half then got dragged through the hole as a single
piece. There’s a pretty obvious mark where the bullet hit and it got thrown almost all
way down the range. I don’t think we can quite call this stopped.
Maybe with a bit more contact area to the holder parts, these fiber prints would actually
be able to stop a .45 bullet, but I think even 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 catch that .22 bullet, too, but required 20mm of
material to do so and only PLA and ABS were able pull it off without shattering into a
million pieces. PETG did stop it, too, but there’s not a whole lot left of it.
So should you be 3D printing your next bulletproof vest? Well, probably not, these parts were
a lot thicker and heavier than something actually made for the job, but these experiments still
showed which 3D printing materials are able to take a beating. Obviously, the Markforged
continuous fiber materials did extremely well here, even with the thinner prints, but it’s
nice to see that sufficiently solid blocks of standard PLA and ABS can still perform
really well. And while I usually recommend 3D printing with PETG instead of ABS for most
things, I think we might have found the weak spot of PETG. Whereas the ABS part now has
a 22 caliber bullet solidly embedded inside it, 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 from one manufacturer might behave completely different
than one from another supplier. There are most certainly ABS materials out there that
are much weaker than this one and possibly PETG and copolyesters that don’t shatter
as easily. But I think this was still good fun and hopefully educational for you, too.
If it was, give the video a thumbs up, and if 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 with keeping the channel going, get subscribed,
check out the affiliate links in the video description or even join in over on Patreon
for monthly hangouts and more. Thanks for watching and I’ll see you in the next one.