There's one 3d printing technology
that's used in Formula one cars,
Boeing Skyliners and even people walking around today.
This technology is known as the holy grail of the 3d printing industry.
It can produce strong functional parts from exotic materials like titanium or stainless steel.
And hundreds of millions of dollars of investment are pouring into this industry...
...to make the technology more accessible and more cost-effective.
Hello people of the, internet my name's Ben redwood and welcome to this episode of what is 3d printing.
And of course today we're talking about metal 3d printing. So, let's do it!
Metal 3d printers use a laser to
scan and selectively fuse or melt metal
powder particles, bonding them together
and slowly building up a part, one layer at a time.
They're most commonly used in industrial applications...
...like high-end complex engineering products.
The two most common methods of metal 3d printing are SLM, selective laser melting, and DMLS,
direct laser metal sintering.
And both of these technologies belong to the powder bed fusion category...
...like SLS in one of our previous videos.
As SLM and DMLS both produce parts in a similar fashion and the end parts are compatible...
...to save us both some trouble I'm just going to refer to everything as metal 3d printing for the rest of this video.
There are several other 3d printing technologies that can also produce metal parts.
Two that are rapidly rising at the moment are binder jetting and metal FDM printing.
Hence why we have our friend the
Ultimaker back for this video.
We'll talk about these cool new technologies later on so stay tuned!
So what are the key steps that a metal printer follows to produce parts?
Firstly the build chamber is filled up with an inert gas, after this the build chamber and the powder...
...are preheated to an optimal printing
temperature.
A thin layer of metal powder is then spread over the build platform...
...and a high-power laser scans the cross-section of the component, melting
or fusing the metal particles together...
...and creating the first layer of the 3d
printed part.
Finally when the scanning of the first layer is complete, the build platform moves down one layer height...
...and the recoating blade spreads a fresh
layer of powder over the previously printed layer.
This process is repeated over and over again, building the part up one layer at a time
The printing process for metal 3d printing is very similar to SLS.
And like SLS, at the end of printing
the parts are fully encased in powder.
But there's one key difference: metal 3d
printing always requires support structures.
Something SLS doesn't need. And we're going to talk about why later on.
Let's discuss why you would choose to
use metal 3d printing for your design.
One of the biggest strengths of metal 3d
printing is design freedom.
You can now print parts that were previously impossible to produce using traditional manufacturing techniques.
Two particular areas where metal 3d printing is having a large impact on design freedom is part consolidation.
Taking a 100 parts and metal printing them to be just a single piece,
and the production of parts with integrated lattice or porous structures,
particularly useful in the medical industry or areas where strength to
weight ratio is very important.
Obviously one of the big advantages of metal 3d printing is metal.
Metal has a number of superior properties compared to plastics.
And another advantage is that metal 3d printing can produce parts out
of titanium and other advanced alloys.
Okay, we know metal is great but what are
some of the limitations of this technology?
Compared to traditional
manufacturing technologies like CNC machining...
machining the cost of metal 3d printing
is high.
On average a metal printed part, around the size of your fist, will cost about a thousand dollars to print and finish.
With prices rapidly increasing
depending on the geometry.
In simple terms metal 3d printing is really only justified if you're going to see a big improvement in performance.
Another limitation of metal 3d printing is the build size.
The maximum build size for most metal 3d printers is only 200 millimeters cubed...
...so you should keep this in mind when you're designing your parts.
Metal printed parts are never ready to use straight off the build platform.
Every metal 3d printed part requires some form of post-processing,
be it powder removal heat treatment or post machining.
And all of this adds to the cost and lead time of production.
When it comes time to start actually designing your parts there are a few things you should keep in mind.
Metal 3d printing is the most
difficult 3d printing technology to design parts for.
Just like CNC has under
cuts and injection molding has draft angles,
there are a set of rules that
must be followed to ensure your parts print accurately and successfully.
Support structures in metal 3d printing serve 3 different functions.
1, it offers a platform for new layers of the print to be built upon, similar to FDM and SLA.
2, because of the temperatures involved metal 3d printing is particularly prone
to distortion and warping.
To anchor the parts to the bill plate and to help combat warping we use support structures.
And 3, they act as a heat sink
drawing heat away from the part...
...and allowing it to cool more uniformly.
Because of the high dependence on support material part orientation is
critical.
When designing for metal 3d printing the main goal should always be...
...to reduce the dependence on support materials as this adds cost and time.
As a rule of thumb any overhanging angles should not surpass 45 degrees.
Metal printing allows you as a designer to produce parts that include lattice
structures.
These structures are fantastic for maximizing the surface area in a heat exchanger,
or improving the strength to weight ratio of a part.
Other new CAD techniques like topology optimization and generative design are
also perfect to utilize with metal 3d printing.
One important thing to keep in mind is whether all parts of your design actually need to be metal 3d printed.
Often it's better to choose a traditional manufacturing technology like CNC...
...for some of the more basic sections and then use 3d printing for the complex parts...
...assembling these all together at the end. This can save a lot on the overall costs of your design.
For specific design rules that you should follow for metal printing we've got a link in the description below that covers everything.
As I mentioned earlier there are several other printing technologies that are becoming popular alternatives for producing metal parts...
...that are not DMLs or SLM. Metal binder
jetting is one such example.
It's unique way of producing parts makes
it perfect for low to mid volume production runs.
Binder jetting builds parts by depositing a binding agent onto a thin layer of powder a thin layer of powder through ink jet nozzles...
...and slowly builds the part up one layer at a time.
The result of the printing process is a weak path that's held together only by the binding agent.
To achieve a strong metal part we need to take the print and put it into an oven to burn out the binding agent
The parts are then removed from the oven and then centered to fuse the metal powder together...
...resulting in a strong cohesive
component.
Metal extrusion, like the metal X printer from mark forged, is a great low cost 3d printing metal alternative
Like FDM, metal extrusion builds a part
up layer by layer by extruding material through a nozzle.
through a nozzle unlike traditional if
the aim though the filament is
impregnated with metal powder after
printing the part is placed in an oven
and the polymer and the filament is
burnt out and we're left with a metal
powder part this is then scented to
achieve a strong robust component binder
jetting and material extrusion are often
cheaper than traditional metal printing
technologies and they offer more design
freedom but it's important to keep in
mind they require a significant amount
of post-processing and this can add lead
time and cost so let's do a quick recap
metal 3d printing is an industrial
process best suited for complex
high-performance parts it offers a lot
of design freedom over traditional
manufacturing techniques and you get all
the benefit of your parts being made of
metal
however costs are high billed volumes
are small and parts require a lot of
post-processing it's also important to
keep in mind design is difficult and
there's a large dependence on support
structures to ensure you get a good
print we've only just scratched the
surface of this awesome but highly
complex 3d printing technology I would
highly recommend checking out the guides
below in the description for a much more
detailed dive into the world of metal 3d
printing this video is based on the 3d
printing handbook every week we're
giving away 10 copies to new subscribers
to this channel so make sure you
subscribe now
