If you want your company to thrive and stay competitive, you need the best quality tools to get the job done. That's an immutable fact.
This is true in any job or industry.
If your goal is to leverage new technologies, you must use cutting-edge machines that ensure you stay ahead of the curve.
The above statement also applies to 3D printing. Now imagine if you could complete tasks faster, more efficiently, and avoid many hassles. That would be
great, right? This convenience is achievable simply by choosing the right 3D printing technology.
To choose the right 3D printing technology, you must evaluate the pros and cons of various techniques.
What are FDM, SLA, and SLS?
These are different technologies, different methods of 3D printing. FDM stands for Fused Deposition Modeling – in this process, models are made by extruding molten material in flat layers, which hardens immediately after extrusion.
SLA is short for Stereolithography, which uses photopolymerization, using light to connect molecular chains to form a 3D polymer structure. Both can be called forms of micro-sculpture, but they use different methods to bond the structures together.
Finally, there is SLS - Selective Laser Sintering, a completely different technology. It uses powder (most commonly polyamide - a type of nylon), which is then heated, and subsequently melted by a laser beam in specific areas, sintering continuous layers into a durable model.
How is it formed? You can imagine a miniature sandbox, where layers of polyamide "sand" are melted in several places, and then a new layer of powder coating is applied, allowing the laser light to reach another layer - again melting in carefully selected places. After this, the structure slowly emerges from the powder.
Accuracy and the Importance of Support Structures
Many people tend to think: the more objects you can print, the better. But in reality, the situation is often the exact opposite. If you print a seemingly clumsy, imprecise object, what's the point of printing huge objects?
As they say, the devil is in the details, and to create objects, you need precision.
The higher the accuracy you need - the narrower the layers you can print - the more complex your model can become. This is why SLS technology is starting to gain traction. Due to the use of polyamide powder with an average particle size of 38 microns, layers as thin as 0.075 [mm] or even thinner can be produced. Compared to SLS: FDM printers typically only achieve layer thicknesses of around 0.100 [mm], and while SLA performs well in this regard, it can still only produce layers twice as thick as SLS (thinnest at 0.15mm).
But it's not all about accuracy. There's also the factor of using support structures.
When you print a model, it needs to be supported, otherwise it will collapse. After all, gravity is quite merciless. If printing with FDM or SLA, special supports are needed to make the model stand or hang.
These support structures must be manually or chemically removed after printing to smooth the surface. This all takes time, but most importantly, using support structures limits your choices when printing. Some things are simply impossible to print. SLS is not subject to these limitations, giving you unparalleled freedom in modeling.
It all comes down to a very clever idea: the support structure is composed of spare powder that is not used in the printing process but is located in the printer's build chamber. Remember the sandbox? It sinters at selected locations during each printing layer. When the model is finished, you simply remove the spare powder, and it's ready to use.
Time and Cost Efficiency
Okay, it's great to print models with a lot of detail, but what if you need quantity rather than complexity and quality?
This is another common question, why not put them all together?
With SLS, this becomes entirely possible, thanks to a process called "nesting." It's very simple - because you need to use more powder than actually needed to print a specific structure (the actual amount will be defined by the height of your model), you can put more models into the printer's build chamber, allowing them to be printed at once. The laser will sinter more points, which will extend the printing process, but the working method is exactly the same. Even if it takes more time, it's still faster than printing each structure one by one, not to mention the fact that an entire complex model can be completed at once.
If you also consider the time required to remove support structures and model components – which is absolutely necessary for FDM and SLA printing. A little thought also reveals that SLS is undoubtedly the fastest 3D printing technology currently available.
However, a question might come to mind: if you have to use so much powder every time you print something, how cost-effective is SLS? It depends, but overall it's much better than it sounds. SLS printers are optimized for large volume printing, but that doesn't mean printing a single model is a bad idea. Making it feasible is most important, you can recycle the unused (sintered) powder from the printing process. You must mix it with some fresh material to make it work - for the Sinterit Lisa printer, the ratio is 7/3 - but ultimately, the cost of using the printer won't be as high as you might think.
Durability and Resistance, Without Cutting Corners
The materials used in SLS printing result in high durability of the printed structures. When measured during Charpy impact tests, PA 12 smooth material, one of the two commonly used types, reached a maximum fracture energy of 5.23 [KJ/m2] for U-notch samples and 3.28 [KJ/m2] for V-notch samples. It is also worth noting that this durability is achieved without sacrificing the option of printing movable parts within the model.
On the other hand, if you choose to use TPU Flexa Black material, you get impressive chemical resistance, temperature resistance, and UV resistance, all while offering extreme flexibility. Flexa Black has a melting temperature of 150-160 degrees Celsius and can withstand UV radiation, not to mention chemicals like acetone, glycerol, gasoline, methanol, and more.
Groundbreaking Technology
As you can see, there is currently a 3D printing technology on the market that has distinct advantages over others - Selective Laser Sintering. You might wonder why SLS isn't used everywhere, because even today, it still has its drawbacks - it requires a lot of space and is quite expensive.
Due to these issues, it has only been used in large manufacturing-sized printers. But technology is constantly advancing, and the world is still changing. With 3D printers like the Sinterit Lisa mentioned above, SLS additive manufacturing technology is now suitable for all medium-sized desktops and affordable accessories.
Original article link: https://www.sinterit.com/sls-the-cutting-edge-in-3d-printing/