Polymer 3D Printing Processes

There are several types of 3D printing, which include:

• Stereolithography (SLA)

• Selective Laser Sintering (SLS)

• PolyJet

• Digital Light Process (DLP)

• Multi Jet Fusion (MJF)

• Fused Deposition Modeling (FDM)

Selecting the right 3D printing process for your application requires an understanding of each process’ strengths and weaknesses and mapping those attributes to your product development needs.

Let’s outline some common 3D printing processes and discuss when each provides the most value to product developers, engineers, and designers.

Stereolithography (SLA)

Stereolithography (SLA) is the original industrial 3D printing process. SLA printers excels at producing parts with high levels of detail, smooth surface finishes, and tight tolerances. The quality surface finishes on SLA parts, not only look nice, but can aid in the part’s function—testing the fit of an assembly, for example. It’s widely used in the medical industry and common applications include anatomical models and microfluidics.

Selective Laser Sintering (SLS)

Selective laser sintering (SLS) melts together nylon-based powders into solid plastic. Since SLS parts are made from real thermoplastic material, they are durable, suitable for functional testing, and can support living hinges and snap-fits. In comparison to SLA, parts are stronger, but have rougher surface finishes. SLS doesn’t require support structures so the whole build platform can be utilized to nest multiple parts into a single build—making it suitable for part quantities higher than other 3D printing processes. Many SLS parts are used to prototype designs that will one day be injection-molded.

PolyJet

PolyJet is another plastic 3D printing process, but there’s a twist. It can fabricate parts with multiple properties such as colors and materials. Designers can leverage the technology for prototyping elastomeric or overmolded parts. If your design is a single, rigid plastic, we recommend sticking with SLA or SLS—it’s more economical. But if you’re prototyping an overmolding or silicone rubber design, PolyJet can save you from the need to invest in tooling early in the development cycle. This can help you iterate and validate your design faster and save you money.

Digital Light Processing (DLP)

Digital light processing is similar to SLA in that it cures liquid resin using light. The primary difference between the two technologies is that DLP uses a digital light projector screen whereas SLA uses a UV laser. This means DLP 3D printers can image an entire layer of the build all at once, resulting in faster build speeds. While frequently used for rapid prototyping, the higher throughput of DLP printing makes it suitable for low-volume production runs of plastic parts.

Multi Jet Fusion (MJF)

Similar to SLS, Multi Jet Fusion also builds functional parts from nylon powder. Rather than using a laser to sinter the powder, MJF uses an inkjet array to apply fusing agents to the bed of nylon powder. Then a heating element passes over the bed to fuse each layer. This results in more consistent mechanical properties compared to SLS as well as improved surface finish. Another benefit of the MJF process is the accelerated build time, which leads to lower production costs.

Fused Deposition Modeling (FDM)

Fused deposition modeling (FDM) is a common desktop 3D printing technology for plastic parts. An FDM printer functions by extruding a plastic filament layer-by-layer onto the build platform. It’s a cost-effective and quick method for producing physical models. There are some instances when FDM can be used for functional testing but the technology is limited due to parts having relatively rough surface finishes and lacking strength. This is the technology that we use on Ender 3 by Creality.

Source: https://www.protolabs.com/