Resin 3D printer

Resin 3D printers are a significant development in 3D printing technology. By using liquid photopolymer resin, which is cured layer by layer with ultraviolet light, a superior degree of detail and strength is achieved in the finished product, compared to traditional FFF (Fused Filament Fabrication) printers, which are a layer on layer technology. For 3D printing professionals, it may be worth exploring resin 3D printers.

How a Resin 3D Printer works

Resin 3D printers work using a process called stereolithography. This process uses ultraviolet (UV) light to harden liquid resin layer by layer, creating the 3D print.

When a print is started, the file is loaded onto the printer and the print plate is slowly lowered along the Z-axis into the resin container. Once the circuit board is in place, the UV light is turned on and shines through the image created on the LCD screen. The UV light passes through the unmasked areas on the LCD screen and thereby hardens the resin where it is exposed to the light.

The first few layers, or bottom layers, are exposed for a longer time to ensure that the print is properly attached to the plate. After the exposure of a layer, the light is turned off and the printed circuit board is raised about 5 mm and then lowered back down.

This lifting and lowering process serves two purposes: First of all, the printed layer is "peeled" from the FEP sheet at the bottom of the resin container. Although FEP is a non-sticky material, resin still adheres to FEP due to the suction effect and curing process. By slowly lifting the PCB, the PCB is allowed to peel off the FEP film without detaching from the PCB. The second purpose is to allow fresh resin to flow back into the space where the print was peeled off the resin.

This process continues until all the layers have been exposed and the print is complete. After finishing the print, it's time to move on to finishing, including washing and further curing

Types of Resin 3D Printers

SLA printers use UV laser beams to harden resin. The laser beams are very powerful, and they therefore work better with resins that harden slowly​​.

DLP printers use light projectors to harden the resin. DLP printers are not as accurate as SLA printers, and the size of the printed model can affect accuracy. The surface of DLP printed parts is often not as smooth as those printed with SLA technology. However, this can be corrected with more sophisticated optical systems, which are often expensive​​.

LCD printers are the latest type of resin 3D printers, and they use LED light to harden the resin. Instead of mirrors that DLP printers use, LCD printers have LCD panels that selectively block light in areas that don't need to be cured. LCD printers are cheaper and faster than the other technologies, but their LED matrices produce high levels of heat, which can be a problem for long prints. To avoid this, an efficient cooling system is necessary​​.

Some resins work with more than one type of resin printer, but some manufacturers recommend only using their brand with their machines. Therefore, it is important to check both the printer's and the resin manufacturer's data sheets to be sure if a brand is compatible with your printer

 

Advantages and disadvantages of a Resin 3D printer

 

Advantages	Disadvantages
Better resolution: Resin 3D printers can reproduce very fine details in their models. They are only limited by the size of the laser emitted in the liquid resin, resulting in a much higher degree of detail than traditional FFF printers​​.	Higher costs: Resin 3D printing is more expensive, both in terms of the printer and the raw materials needed. The price of a Resin 3D printer is higher, and the same applies to the cost of the liquid resin that must be used​​.
Faster printing process: The printing process with resin is significantly faster than with filament. This is because the emission of laser light to resins is much faster than the extrusion of filament in an FFF printer​​.	Requires full resin container: When printing with resin, you must fill the entire resin container every time you start a new project, which can result in resin waste.
Stronger finished products: Resin 3D printers produce parts with stronger layer-to-layer adhesion, resulting in more consistent mechanical properties across all axes. This makes them a preferred choice for technical components and functional parts​1​.	Requires the use of UV protection: Due to the use of ultraviolet light in the curing process, it is necessary to take appropriate precautions to protect the user's eyes and skin2 ​.

Comparison between Resin 3D printers and FDM 3D printers

Category	Resin 3D Printers	FDM 3D Printers
Resolution	High (limited by the laser)	Lower (limited by nozzle size)
Print process	Faster (can cure entire layers at once)	Slow (layer-by-layer deposition of filament)
Strength of the finished product	High (strong layer-to-layer adhesion)	May be weak along the layer lines
Costs	Higher (both machine and raw materials)	Lower (both machine and raw materials)
Usability	Can be more complex	Generally more user-friendly
Post-processing	Often needed (washing and curing)	Less necessary (depends on filament type)