There’s one 3d printing technology used in Formula one cars, Boeing’s 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. Hundreds of millions of dollars of investment are pouring into this industry to make the technology more accessible and cost-effective.
What is 3d printing?
Today we’re talking about metal 3d printing. Metal 3d printers use a laser to scan and selectively fuse or melt metal powder particles bonding them together and slowly building up apart 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
1-SLM Selective laser melting
2-DMLs Direct laser metal sintering
Both of these technologies belong to the powder bed fusion category.
SLM and DMLs similarly produce parts, and the end parts are comparable to save us both some trouble.
I’m just going to refer to everything as metal 3d printing for the rest of this article.
Several other 3d printing technologies can also produce metal parts too that are rapidly rising at the moment.
Binder jetting and metal FDM printing.
What are the key steps that our medal 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 high-power laser scans. The cross-section of the component melting or fuses the metal particles 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. Like SLS, the parts are fully encased in powder at the end of printing, 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 100 parts and metal printing them to be just a single piece. 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.
One of the big advantages of metal 3d printing is metal. Metal has several superior properties compared to plastics.
Another advantage is that metal 3d printing can produce parts out of titanium and other advanced alloys.
Limitation of Metal 3D printing Technology:
we know metal is great, but what are some of the limitations of this technology.
- Compared to traditional manufacturing technologies like CNC 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 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 mm3 (cubed). So it would be best if you kept this in mind when you’re designing your metal parts.
- 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
And all of this adds to the cost and lead time of production.
Designing for metal 3d printing parts:
when it comes time to start 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. Just like CNC has undercuts and injection molding has draft angles.
There are a set of rules that must follow to ensure your parts print accurately and successfully.
Support structures in metal 3d printing
support structures in metal 3d printing servant functions.
- It offers a platform for new print layers to be built upon similar to FDM and SLA.
- Because of the temperatures involved, metal 3d printing is particularly prone to distortion and warping to anchor the parts to the bill plate and help combat warping. We use support structures.
- They act as a heat sink, drawing heat away from the part and cooling more uniformly. Because of the high dependence on a support material, part orientation is critical. We’re designing for metal 3d printing. The main goal should always be to reduce the dependence on a support material, which 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 and a heat exchanger or improving a part’s strength to weight ratio.
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 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. In the end, this can save a lot on the overall cost of your design.
As I mentioned earlier, several other printing technologies are becoming popular alternatives for producing metal parts. Those are not DMLs, or SLM metal binder jetting is one such example. Its unique way of producing parts makes it perfect for low to mid-volume production.
Runs binder jetting (binder jetting picture) builds parts by depositing a binding agent onto a thin layer of powder through inkjet 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 on fusing the metal powder 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. 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 are 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. 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 benefits 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.