SLA Definition and Comparison to FDM

Stereolithography is a photopolymer-based 3D printing technology. It was first invented by Hideo Kodama in 1980 but commercialized and patented in 1986 by Charles Hull. The process works by shining a UV laser against a scanning mirror. The mirror directs the laser light in a pattern that traces out the cross-section of a single layer of the part. This laser then polymerizes the photosensitive material wherever the laser hits a solid surface – either the build platform or the previous layer. After each layer is polymerized, the build platform typically moves upwards with the part appearing to grow out of the liquid. alternatively, a bottom-up type process is also possible, but uncommon. SLA parts need to be post-processed in a solvent bath to remove excess resin and must be post-cured.

This is in contrast to FDM printers which extrude a plastic filament through a heated nozzle and deposit them onto the build plate. SLA can print parts with significantly better resolution than FDM. However, FDM printers are cheaper in general. 

What Are the Advantages of SLA Compared to FDM?

Listed below are some key advantages of SLA vs. FDM:

• SLA has significantly improved resolution and print quality when compared to FDM.
• SLA can print significantly faster than FDM printers without compromising quality.

What Are the Disadvantages of SLA Compared to FDM?

Listed below are some key disadvantages of SLA vs. FDM:

• SLA printing is significantly more expensive than FDM. This is both in terms of the materials and the machine.
• SLA parts tend to be weaker than FDM parts. This is due to the mechanical properties of photopolymers which are weaker than the thermoplastic materials used in FDM.

FDM Definition and Comparison to SLA

Fused deposition modeling is the most well-known 3D printing technology. It was first developed by Scott Crump in 1988 who later commercialized the first FDM printer. The process is relatively simple as it involves guiding a thin filament of thermoplastic through a heated nozzle/hot end. The plastic exits the nozzle and is placed on the build plate in the pattern of the part cross-section. Once a layer is complete, the print nozzle moves up one layer and deposits the plastic on the previous layer until the part is complete. 

FDM is a simpler technology when compared to SLA. It is significantly cheaper for hobbyists, hence its popularity. There are many different thermoplastics and even flexible thermoplastic polyurethanes available.

What Are the Advantages of FDM Compared to SLA?

Listed below are some key advantages of FDM vs. SLA:

• FDM parts are stronger in general when compared to SLA parts. This is due to FDM making use of well-established and widely used thermoplastics that are significantly stronger than photopolymers.
• FDM has a large online community that offers pre-designed parts optimized for FDM. These communities can provide advice and instruction on any possible issue encountered during printing.

What Are the Disadvantages of FDM Compared to SLA?

Listed below are some key disadvantages of FDM vs. SLA:

• FDM layer lines are very visible. Parts often need to be post-processed to get the smooth surface finishes commonly found with SLA parts.
• Despite the strength of the material used in FDM printing, the parts tend to be highly anisotropic in the direction of the print. This is due to the relatively weak interlayer bonding.