Additive manufacturing,
subtractive manufacturing, do
they go together? Do they
compete? We're going to talk
about machining on this episode
of The Cool Parts Show.
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CarpenterAdditive.com Now back
to the show.
I'm Pete Zelinsky.
I'm Stephanie Hendrixson.
We are with Additive
Manufacturing Media.
And this is The Cool Parts Show
our show all about cool, unique
and weird 3d printed parts.
This is season 3 of The Cool
Parts Show. We're starting a
brand new season. Stephanie, it
feels like it took a long time
to get here.
You know, it kind of did, like
it's been a while since we had a
regular season. But we've been
doing a lot of episodes in the
meantime focused on things
related to the coronavirus
pandemic, checking in with past
subjects of the show. But now
we're kind of back to a point
where it sort of feels like
business as usual.
Yeah, back to cool parts.
Okay, Pete. So I just said that
this is our show about 3d
printed parts. But it looks to
me like you've brought us
something from the subtractive
manufacturing world and your
other job, because that looks to
me like some kind of cutting
tool for machining. And so for
our audience who might not know,
in addition to hosting The Cool
Parts Show and being editor in
chief of Additive Manufacturing,
my co host Pete is also the
editor in chief of Modern
Machine Shop, which is a sister
publication that's focused on
metalworking and CNC machining,
Modern Machine Shop, all about
machining. It's actually how I
first met Stephanie who began as
an intern on Modern Machine
Shop. So yeah, we are going to
talk about machining today.
Okay, so before we get too far
into this episode, maybe just
give us a quick rundown, what is
machining?
Yeah. Machining, in a way sort
of the opposite of 3d printing.
In 3d printing you build a part
starting from nothing, build up
the form in layers. In
machining, you start with a
larger form and you make the
part by precisely cutting down
to the shape you want. It has
traditionally offered the most
efficient way to get a small
batch of parts a small quantity
of precise parts. 3d printing
now sometimes offers a faster
way to get a small quantity of
parts.
Okay, so you're describing two
fundamentally different ways at
arriving at a part or arriving
at small quantities of parts,
building material up or taking
material away. Do you think that
3d printing and machining are
competing with each other? Are
they complimentary? What is
their relationship?
So the answer is yes, yes to
both of those questions, and
that's what this part shows.
That's what we're going to talk
about today. This is a tool for
cutting in machining, this is an
end mill. So this cutter would
be spun rapidly inside of a
machining center and used to
take lots of precise cuts really
fast from a metal workpiece. It
was made through 3d printing not
the conventional way to like
this is made but the way this
one was made. Specifically, the
tool body was made through 3d
printing, it's made of H 13 tool
steel. The cutting edges are
something different, they're
polycrystalline diamond, PCD,
they were added later. But the
value of 3d printing this tool,
part of it at least is these
cooling channels. There are
channels for cutting fluid that
run through this tool. And the
freedom to control the inner
geometry through additive
manufacturing allows these
channels to be shaped and
positioned exactly where the
cutting tool maker wants them to
be. So this is a more effective
end mill. This is a better
performing endmill for milling
aluminum, the purpose it was
designed for. So in that sense
here is 3d printing
complementing machining, but in
another sense here is 3d
printing competing with
machining because machining is
the way this tool would have
been made in the past. Now it
was made additively instead.
Okay, so there's a lot to dig
into there. But one thing you
said that was interesting is
that this is an end mill but
it's not just any end mill it
has these cooling channels
through it. Can you talk about
why you would want to put holes
through your cutting tool?
Sure, sure. So in machining
frequently commonly there is
cutting fluid involved, cutting
fluid delivered at a high
pressure and it serves multiple
purposes. It's called coolant
and it does cool the cutting
edge prevent the cutting edge
from heating up for a better
performing cut in most cases,
but in addition, the coolant the
cutting fluid also gets chips
out of the way. The metal chips
that are removed through milling
could get in the way of milling
if they stick to the tool or if
they remain in the cut. So the
coolant delivered at high
pressure can flush them away.
Now, oftentimes that coolant
that cutting fluid is delivered
through a nozzle that is
external to the process that is
pointed at the tool. But if this
tool is buried in the metal,
maybe that fluid isn't reaching
it effectively. So an
alternative is the spindle that
is rotating this rapidly inside
the machine. Maybe that spindle
is designed so that there is a
cutting fluid channel running
straight through it. And then
continuing straight through this
tool that has its own port
through the body of the tool to
deliver that cutting fluid, not
from outside but through the
tool and so it shoots out right
near the cutting edge. Cools it
blows those metal chips out of
the way. The problem though, is
traditionally how do you make
that through the tool coolant
channel? Well you drill. You
drill a straight line this way,
you drill a straight line from
the side you hope that they
meet. There's very little
control over the cutting fluid
channel that you can get. 3D
printing of course you can have
any shape you want any position
you want. Get those those fluid
channels exactly where you want
them to be delivering the fluid
exactly the way you want.
Okay, so enough machining talk
for now let's get to the 3D
printing. Who made this tool?
Guhring, cutting tool maker
headquartered in Germany, but
they have locations around the
world. It's actually Guhring in
the UK that made this tool.
And what was the printing
process.
So sort of a variation on FDM or
fused filament fabrication, FFF.
So this was made on a Markforged
Metal X machine, which is a
metal 3D printer that uses
polymer filament, carrying the
metal powder as a way to build
up the form of the part. The
process produces an oversized
version of the part and then in
a sintering process, the the
polymer material is melted away.
And the form shrinks down to the
precise solid metal form that
the process produces.
Okay, but you said earlier that
this tool has PCD cutting
inserts. So there's more to the
process than just the 3D
printing, right?
So that's right. So, yeah, to
talk about the total process
I'll let Guhring take it. So
here is Alan Pierce, who is the
PCD supervisor.
Once the tool has been printed
on the Metal X, this is known as
a green part. The next step is
to remove the primary binding or
wax from the material. This is
done using a washing and drying
process. Once the part is dried
this is then known as a brown
part. At this stage it's very
very delicate. Next we place the
part into the sinter. At present
the part is 20% bigger. This
process turns the part into a
dense metal and correct size due
to the shrinkage, ready for the
final operations. Once we have a
tool body, we can now braze
segments into the pockets, grind
our shank to h6 tolerance, and
finally wire the PCD segments to
our required cutting diameter.
So Allen described how the parts
shrinks during sintering. And
I've got the pre-sintered green
form right here, you can see how
much bigger it is.
That's pretty cool. That's a
pretty big difference.
It is and it shows how
controllable and predictable the
shrinkage is. So predictable
that they know they're going to
end up with this precise solid
metal part.
Okay, so we've talked about what
this tool does. We've talked
about how it was made, but I
guess my big question now is
why? You know Guhring is a
tooling company, they have other
ways of making tools. Why 3d
printing?
So Guhring has successfully made
cutting tools like this for a
long time without 3D printing.
Why 3D printing? A lot of
reasons. One is lead time. So
with 3D printing, there are
fewer steps. The the form of the
tool body is essentially done,
very close to done after the 3d
printing process. So a way to
deliver tools to the customer
more quickly. A way to do small
quantities. Right? So this tool,
a diamond cutting edge is
cutting aluminum, it's gonna
last a long time, and the user
might not order all that many.
So 3d printing offers a cost
effective way to do small
batches, particularly if they're
small batches of an unusual tool
design they might not get
another order from. In addition,
there's the cooling channels
that we described. The ability
to control internal geometry to
such an extent that these
channels that deliver the
cutting fluid are just so, just
the right shape, just the right
location with respect to the
cutting edges. But, you know, we
talked initially about how
additive is different and the
ability to start with nothing
and you know, build the form
from the inside out. There's
more going on here than just the
cooling channels. As a result of
being able to build the part
this way, this tool is actually
lighter than it would be if it
was made conventionally, thanks
to 3D printing. Here's Alan
Pierce again, who will talk a
little bit more about why that is.
When comparing tooling made by
both 3D printing against
conventional tooling we found
they performed the same when we
ran them back to back on trials.
The main advantage of the 3D
printed tool was the weight. Our
printed tool in a holder was 30%
lighter in weight, due to the
triangular infill structure
achieved by printing. The
lighter weight of the tool is a
big advantage when on a tool
change machine. When it's
printed, we can change the
actual outside layer. You can
have anything from half a mil up
to two mil. So we give the the
outside layer the maximum so two
mil, but then the infill is
triangular, honeycomb,
triangular honeycomb, and that's
where you get the lightness.
Okay, so I gotta hand it to you
this turned out to be a pretty
cool part even if it came out of
the machining world. And I think
I almost have this but just one
more question. Will it mill?
That is a good question. Um,
know what, I know a guy.
We are at Dan's Custom
Machining, machining job shop in
Williamsburg, Ohio. Dan.
Stephanie.
Nice to meet you.
Nice to meet you.
So you've been milling with that
tool?
Yep.
How'd it do?
Doing great.
So can we see some machining
now?
Yeah, let's go.
So Dan, we're milling on a
vertical machining center. What
machine is this?
It's a Hurco VMX42i.
What are the parameters you're
cutting at?
We're cutting this tool at 1640
surface feet per minute, which
comes out to 10,610 rpm and
we're feeding at 6 thousandths
per tooth feet rate, which is
equal to 188 inches per minute.
This is aluminum right?
This is aluminum 6061 and we are
at 590 thousandths depth of cut
with a 59 thousandths width of
cut.
Thank you. So would you have
known this was 3D printed.
Nope, I would have never been
able to tell.
How does cutting with this tool
compare to cutting with a
regular through coolant tool?
The performance and speed we
were able to achieve is almost
identical, if not the same as a
solid carbide tool would be.
Thank you Dan.
No problem. Thank you.
Okay, so confirmed 3D printing
cutting tool will cut aluminum.
So I think I'm ready to recap
this.
This is a 3d printed end mill
with PCD inserts. 3D printed by
Guhring in the UK using the
MetalX process from Markforged.
This particular cutting tool has
coolant channels through it to
help with with cooling and chip
removal in the cut. And it also
has an infill that makes it 30%
lighter than a comparable tool.
And yes, it mills.
Alright, I think that does it.
That is a wrap. Thank you for
watching The Cool Parts Show.
Thank you for joining us at the
start of season three. 3D
printed cutting tools, that's a
thing. If you want to read more
about more examples of tools
like this see a link in our show
notes. See the show notes for
more about the interplay between
additive manufacturing and
machining, and stick around
season three is just getting
started. We've got a lot more
cool parts we want to talk to
you about.
If you're 3D printing a cool
part that you might like to see
featured, email us cool parts a
 AdditiveManufacturing.med
a.
If you're new to the show, you
want to watch season one, season
two, our special episodes, Th
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