A Quick Start Guide to Common 3D Printing Methods

A Quick Start Guide to Common 3D Printing Methods

Having the power of a factory on a table in your home: being able to 3D print something in the comfort of your own home instead in a giant factory hall is quite special, especially considering how much effort companies put into making it more accessible for the masses.

So for today's article, three common 3D printing methods will getting the spotlight: Fused Deposition Modeling (FDM), Stereolithography (SLA), Selective Laser Sintering (SLS). 

Each of them will have a brief summary of how the particular method works, the pros and cons and applications where you can encounter the method. By the end of this article, you will also know why I use FDM here at Hand of Stardust!

Fused Deposition Modeling (FDM)

How It Works

The official description for Fused Deposition Modeling or FDM for short,  is 'an additive manufacturing technique that builds three-dimensional objects by depositing successive layers of material'.

In other words: the layers that make up the 3D print are created by layering a material on top of each other, fusing them together. The material itself is pushed or 'extruded' through a small opening to make this happen, the most common nozzle size being 0.4mm in diameter.

If you are a more visual thinker, think of a very thin line of toothpaste and then stacking them each time until you get the desired height. 

Common Uses of FDM

  • You will come across FDM technology in all kinds of industries because of how versatile and cost effective it is, like engineering, manufacturing for prototyping or making final production parts.
  • And in recent years, it has even been used for making prosthetics more accessible for people, even being used with big promise for replacement organs, by using stem cells instead of plastic!
  • The one use-case  you already know of course, is hobbyists and makers using them to make cosplay props, tools and all kinds of other objects.

Pros and Cons of FDM

  • Like mentioned above, FDM is very affordable and accessible, making it an attractive option for both professionals and hobbyists. 
  • FDM printers are relatively easy to use and maintain, and the filament materials are generally inexpensive. Because of this, you can use various materials, including ABS, PLA, and PETG.
  • The resolution (level of detail) and surface finish of FDM-printed objects may not be as high as those produced by other 3D printing methods, such as SLA or SLS. 
  • The layer-by-layer process can also result in visible layer lines and a less smooth finish. While there are ways to post-process FDM printed parts to make them smoother, it is still difficult (but not impossible) to create very fine or intricate details compared to the next 3d printing method....

SLA / DLP 

How It Works

Instead of layering a solid material om top of each other like with FDM, Stereolithography (SLA) or Digital Light Processing (DLP) are an additive manufacturing process that uses a laser to cure liquid resin into solid parts, layer by layer. Both processes begin with a vat of photopolymer resin and a build platform that starts slightly above the vat and raises itself slightly as each layer gets completed. 

This is where SLA and DLP differ in technique: with SLA, highly focused ultraviolet lasers traces a pre-programmed pattern on the resin surface. As for DLP, a projector and mirror are manipulated to get the same type of effect, just in a more cost effective way. The result stays the same: the liquid traced out by the light hardens and form a single layer of the object.

The build platform then descends slightly, allowing a new layer of liquid resin to cover the previous one, and the laser cures the next layer. This process continues until the entire object is constructed.

Common Uses of FDM

  • SLA is renowned for producing parts with high precision and a smooth surface finish, making it ideal for applications that require fine details and accuracy like jewelry, dental molds snd hearing aids.
  • It's also used in areas where engineers and designers for producing small, detailed prototypes and master patterns for molding processes.

Pros and Cons of FDM

  • You can produce parts with high accuracy, fine details, and smooth surfaces.
  • It is capable of creating intricate designs and complex geometries that may be challenging for other 3D printing methods.
  • SLA and DLP produced parts also have good mechanical properties and can be post-processed to achieve a variety of finishes.
  • Hoever, SLA and DLP is less user friendly and more toxic in general, due to using liquid resin:
    • It requires way more post processing steps for the resin to 'cure' properly so it is safe to handle, as improperly cured resin is hazardous to your skin and body.
    • The presence of harsher toxic fumes during the process and handling the resin in general requires careful handling of the photopolymer resin and specialized safety equipment.
  • The process can also be slower compared to other 3D printing methods, and the finished parts may require additional post-curing to achieve optimal strength and stability.

Selective Laser Sintering (SLS)

How It Works

And the final one on our list is Selective Laser Sintering, or SLS for short. With this method, powdered material (usually a powered version of nylon, but also different kinds of metal) is fused together into solid parts using a high-powered laser. It's like welding powder together, but at a more precise, smaller scale. 

You start with a layer of powdered material spread evenly across a build platform. The laser selectively sinters (melts and fuses) the powder according to the shape of the layer, repeating this for each layer of the design.

After each layer is fused, the build platform lowers, and a new layer of powder is spread on top. This cycle repeats until the entire object is formed. Excess powder remains in the build chamber, supporting the part during the printing process and reducing the need for additional support structures.

Common Uses of SLS

  • SLS is widely used in industries that require functional and durable parts. It is popular in aerospace, automotive, and manufacturing sectors for producing complex components with good mechanical properties.
  • SLS is also commonly used for creating prototypes, production parts, and low-volume manufacturing runs. The technology is capable of producing intricate designs and interlocking parts without the need for assembly.

Pros and Cons of SLS

  • The main advantages of SLS include its ability to produce strong and durable parts with good mechanical properties. It can handle a wide range of materials, including various types of nylon, polymers, and composites.
  • SLS parts do not require additional support structures, allowing for complex designs and efficient use of materials.
  • However, just like with SLA and DLP, the powder used with this method also requires specialized safety equipment and careful handling when interacting with the powder. You will also have to remove any excess, unused powder
  • SLS parts could also have a rougher surface finish and lower resolution compared to SLA.

Final Word

So with all of of that said, using FDM as my go-to method for producing my products makes the most sense. I hope this has given you all you need to know the basics about some common 3d printing methods! You can read more about the above, using the two sources I used for this article: 

FormLabs on SLA and DLP: https://formlabs.com/eu/blog/resin-3d-printer-comparison-sla-vs-dlp/

3DS on SLS: https://www.3ds.com/make/service/3d-printing-service/sls-selective-laser-sintering

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