A DLP – or Digital Light Processing – printer, is a form of resin printing similar to MLSA and SLA. The fundamental principles are identical with an ultraviolet light source curing a photosensitive resin. The main difference is how that light reaches the resin.
In an SLA printer, a galvanometer – a precisely controllable mirror – is used to trace the image of a layer on the resin with a laser beam. This approach gives perfectly smooth curves in each layer and has a resolution limit the diameter of the laser beam. In an MSLA printer, an ultraviolet backlight is masked with an LCD screen. This allows an entire layer to be exposed at once but limits the resolution of the print to the resolution of the LCD screen. At lower resolutions, this approach can even leave noticeable pixelation artefacts on the print that you will need to smooth during post-processing.
A DLP printer uses a Digital Light Processing chipset that contains thousands or even millions of micromirrors to project an image of a layer onto the resin. Just as in MSLA, the curing of an entire layer at once speeds up the print time compared to SLA printing. DLP is incredibly similar to MSLA, with both styles using mature technologies to expose the resin to UV light. The resolution of the print is still limited by the resolution of the projector. In this case, the resolution of the printer is the number of micromirrors it has.
Note: DLP chipsets are the basis of the operation of most digital projectors. While you may not know the name of the technology, it is common.
As with MSLA printing, DLP is fast, as you print an entire layer at one time. Curved edges within a layer, however, will not be perfectly smooth due to the pixel structure of the printer. While reasonably priced options are available, continuing to increase the resolution of a projector is likely harder than increasing the resolution of a screen so ultra-high-resolution options are generally more expensive, when they’re even available.
Unfortunately for DLP, MSLA appears to have grabbed the attention of the public for resin printing. While there are some DLP printers available, there are many more MSLA options. To make matters more confusing, some sites include MSLA printers when talking about DLP.
Have you got a DLP printer? Let us know your thoughts on its performance down below.