There exist several technologies and methods to produce 3D printed objects, one of the cheapest methods is FDM (Fusion deposition modeling) and it is often used in entry level 3D printers.
One of the first 3D printing methods developed was SLA (Stereolithography), dating back to early 1980’s, this method consists on production of layer by layer using photo-reactive resin cured by a controlled light source. DLP (digital light processing) is a similar method which uses light as well but instead, a whole layer is projected at once instead of a single spot; LCD based resin 3D printing uses a different type of curing resin, LCD based 3D printers are much affordable than SLA or DLP.
SLA generally uses focused UV light, a guided laser system guides the UV light to cure/harden the resin material, forming layer by layer, each layer is more accurate thanks to the laser but this comes with the disadvantage of low speed.
There are other types of UV resin implementation besides that of SLA and DLP, for example Massivit 3D use a combination of FDM and SLA methods, by using a gel dispensing head, such gel cures/hardens under UV light, this method helps reduce the print times.
The advantage of UV-curing gel is that a larger amount of material can be laid out in a single pass and controlling the speed at which it cures guarantees for a faster print, this makes the Massivit 1800 able to 3D print a full size human model in less than 5 hours.
Another UV related 3D printer is the Mimaki 3DUJ-553, basically is a FDM printer that takes advantage of 2D UV curing printers. This method consists in printing a plastic layer and applying a final UV ink coating of approximately 22 microns using CMYK and white or clear ink, and then proceeding with the next layer.
This 3D printer is able to make full color 3D prints, the company claims it can print a color gamut of around 10 million different colors, becoming the most color accurate 3D printer, some even call it photo-realistic 3D printing.
UV based technology has shown to be versatile in the application of 3D printing, it’s a really good option, but it tends to be expensive. UV curing resins are expensive but thanks to 3D printers becoming more accessible manufacturers are cutting down prices and you can find 1L bottles of UV-Curing resin for about $60. UV-Curing gel on the other hand, is Massivit’s secret 3D printing formula, Dimengel, a proprietary photo polymeric acrylic gel is not cheap but certainly guarantees fast curing 3D prints.