3D printing is a vast topic. There are so many different types of 3D printing that it can easily seem confusing for someone new to this field. FDM, SLA, and SLS are three different 3D printing methods that are often misunderstood by people new to 3D printing. Each offers unique and useful features. So, it is essential to learn the difference between FDM and SLA, and SLS to understand which would be best for you. This post would compare FDM vs SLA vs SLS in detail and provide you with a comprehensive view while making your purchasing decision.
When choosing between FDM, SLA and SLS 3D printing, it all comes down to your preference. Each printer can print different types of objects at variable accuracy. What kind of materials you are aiming to use can also factor into your choice.
Knowing what FDM, SLA and SLS 3D printing are will help you decide which one to use. As all of them have quite a lot of differences in terms of cost, strength, print accuracy, speed, etc. As you can understand, there’s a lot to talk about, so let’s dive right in.
What are FDM, SLA and SLS In 3D Printing?
FDM is the short form of fusion deposition modeling. It is a very common technique of 3D printing where an object is printed layer by layer. After the 3D printing software slices the model into extremely thin layers, the 3D printer prints the object layer by layer on top of each other.
FDM printers extrude the material (ABS, PLA) just beyond its glass transition temperature through the nozzle and draw the first layer. You can picture it like toothpaste coming out of the tube. The layers build on top of each other. Fused deposition modeling isn’t a universal term. Stratasys trademarked this term in 1991 so it’s a trading name. The generic term for FDM is fused filament fabrication or FFF.
SLA or stereolithography is also known as resin 3d printing. This type of 3d printing is well known for its ability to produce highly accurate objects and parts with various materials. SLA 3d printed parts contain a smooth and accurate finish. Although the basic principle is more or less the same, SLA printers cure liquid resins to hard plastics. The arrangement of components differs between SLA and SLS.
SLS or selective laser sintering on the other hand is a completely different 3D printing technique. It belongs to the powder bed fusion family. The materials used in this technique come in the form of powder. The powder is spread across the print bed, then a laser sinters the powder particles in the form of the first layers of the object.
The print bed then lowers, a recoating blade spreads a new layer of powder across the board, a laser draws the second layer, and so on. SLS printing is used for making complex shapes and producing prints with a top-notch finish.
But the end product differs between SLA and SLS parts. SLA parts have the highest accuracy, precise finish, and accurate details. Print quality is way better than SLS and FDM printers, hence it is used for making prototypes and various tools.
What Are The Differences Between FDM, SLA and SLS?
As we have mentioned above, there are some notable differences between FDM, SLA, and SLS 3D printing in terms of strength, speed, and cost. Let’s have a brief look at those:
FDM VS SLA vs SLS in Strength
When it comes to FDM vs SLS strength, many people think that SLS printers yield stronger prints compared to FDM printers. However, tests have proven otherwise. The tensile strength of SLS printed parts was 10 MPa at -60°C whereas FDM parts were shown to have strengths 30 MPa greater than SLS. The strength and durability of FDM-printed parts are superior to SLS.
SLS and SLA are quite similar in terms of strength, with SLA being a bit tougher. However, FDM beats them both when it comes to strength.
FDM VS SLA vs SLS in Speed
There are variables that determine print speed. However, you should not judge a 3D printer based on its print speed alone. It can depend on the print material, the size of the object, filament thickness, nozzle temperature, etc. SLS 3D printers are typically slower than FDM printers.
FDM printers can print between 50 and 150 mm/h, depending on the printer model. Half the speed of FDM printers, SLS printers can reach around 50 mm/h. So, in terms of speed, FDM printers are faster.
SLA 3d printers use lasers to print objects. The lasers have a small surface area so it takes more time to cover each layer. SLA printing also takes more time in post-processing. In terms of speed, FDM is the winner between FDM and SLA. so, among FDM, SLS, and SLA, FDM is the fastest.
FDM VS SLA vs SLS in Costs
The SLS vs FDM cost differs quite heavily. SLS printers produce highly accurate models. It can also make metal parts. SLS printers are extensively used in industrial applications like healthcare, aerospace engineering, electronics, etc. So, as you can understand, SLS printers are costly.
FDM printers use cheap print materials. It is used mostly by individuals who 3D print as a means of hobby or pastime. Or maybe to make small household objects. FDM printers are cheaper than SLS printers and print materials, and overall maintenance cost is also lower.
When you compare SLS and SLA printers, SLS printers are very expensive. SLS printers cost a minimum of $5000 whereas you can get an SLA printer for much less than that, at around $3000. Material cost can vary, but in terms of initial cost, SLA printers beat SLS machines. However, FDM is the cheapest in terms of machine and material cost.
FDM, SLA and SLS 3D Printing – Which Is Better?
In the case of FDM vs SLS printing both have their own use cases in the 3D printing industry. Let’s take an in-depth look at how they are used to help you get a better idea of which you should choose.
Using the FDM technology for 3D printing is a cost-effective approach to getting into the 3D printing world. This option is great for individuals on a budget. They melt the filament layer by layer on top of each other to create the final object.
Sintering is a process that is used to print objects in SLS printers. Sintering means that the object is undergoing solidification due to heat without reaching the melting point. The material is fused together using heat and pressure.
SLS printed objects do not require any support structure. As a result, this technique can be used to create complex and interconnecting shapes. A major advantage of FDM is that it can print an object in a short period of time. Although the finish may not be accurate, it’s good enough to be a prototype.
FDM printers are great for printing experimental objects before printing the final form because it takes very little time. On the other hand, SLS printers can also print an object in a short period of time, but there is no room for post-processing with this method of printing.
The FDM products pale in comparison to this one in terms of both appearance and polish. When it comes to mobility, 3D printing FDM is superior since it allows for more fluid movements of the entire mesh.
Now if you put SLA into the comparison, it is the clear winner because it produces prints with the best finish among the three. Although SLS prints are stronger than SLA, their print quality isn’t as good as SLA printers. FDM has the lowest accuracy among the three but it’s also the cheapest. SLA produces the best finish but at a greater cost.
Finally, FDM 3D printing is the ideal choice if you want to print something with the least amount of complexity. SLS 3D printing technology is geared toward experts and more complex tasks. SLA 3d printing is the next level after SLS 3d printing. If you have the budget and require that level of accuracy, you can use SLA printers; if the budget does not suit to get SLA printers, you can settle for SLS printers.
When it comes to the difference between SLS and FDM and SLA printing, each of them has its own virtues. There is no clear winner as it all ultimately comes down to what you want as an enthusiast. For commercial works where you need to provide the highest accuracy possible to your customers, you should go for an SLA printer if you have the budget; or you can opt for SLS printers. For home usage as an individual, FDM 3D printers should suffice.